Analyzers Documentation

Adding Zero

[Since 0.8.4] - [ -P Structures/AddZero ] - [ Online docs ]

Adding 0 is useless, as 0 is the neutral element for addition. Besides, when one of the argument is an integer, PHP triggers a cast to integer.

It is recommended to make the cast explicit with (int) .

<?php 
// Explicit cast
$a = (int) foo();

// Useless addition
$a foo() + 0;
$a foo();

// Also works with minus
$b $c// drop the 0, but keep the minus
$b $c 0// drop the 0 and the minus

$a += 0;
$a -= 0;
?>


Adding zero is also reported when the zero is a defined constants.

If it is used to type cast a value to integer, then casting with (int) is clearer.

Ambiguous Array Index

[Since 0.8.4] - [ -P Arrays/AmbiguousKeys ] - [ Online docs ]

Indexes should not be defined with different types than int or string.

Array indices only accept integers and strings, so any other type of literal is reported. In fact, null is turned into an empty string, booleans are turned into an integer, and real numbers are truncated (not rounded).

<?php 
$x = [ 1  => 1,
      
'1' => 2,
      
1.0 => 3,
      
true => 4];
// $x only contains one element : 1 => 4

// Still wrong, immediate typecast to 1
$x[1.0]  = 5
$x[true] = 6;
?>


They are indeed distinct, but may lead to confusion.


See also array

Array Index

[Since 0.8.4] - [ -P Arrays/Arrayindex ] - [ Online docs ]

List of all indexes used in arrays.

<?php 
// Index
$x['index'] = 1;

// in array creation
$a = array('index2' => 1);
$a2 = ['index3' => 2];
?>

Multidimensional Arrays

[Since 0.8.4] - [ -P Arrays/Multidimensional ] - [ Online docs ]

Arrays of arrays.

<?php 
$x[1][2] = $x[2][3][4];
?>



See also Type array, Using Multidimensional Arrays in PHP

Multiple Index Definition

[Since 0.8.4] - [ -P Arrays/MultipleIdenticalKeys ] - [ Online docs ]

Indexes that are defined multiple times in the same array.

<?php 
// Multiple identical keys
    
$x = array(=> 2
               
=> 3,  
               
=> 3);

    
// Multiple identical keys (sneaky version)
    
$x = array(=> 2
               
1.1 => 3,  
               
true => 4);

    
// Multiple identical keys (automated version)
    
$x = array(=> 2
               
3,        // This will be index 2
               
=> 4);  // this index is overwritten
?>


They are indeed overwriting each other. This is most probably a typo.

PHP Arrays Index

[Since 0.8.4] - [ -P Arrays/Phparrayindex ] - [ Online docs ]

List of indexes used when manipulating PHP arrays in the code.

<?php 
// HTTP_HOST is a PHP array index. 
$ip 'http'.$_SERVER['HTTP_HOST'].'/'.$row['path'];

//'path' is not a PHP index
?>


Classes Names

[Since 0.8.4] - [ -P Classes/Classnames ] - [ Online docs ]

List of all classes, as defined in the application.

<?php 
// foo is in the list
class foo {}

// Anonymous classes are not in the list
$o = class { function foo(){} }
?>


See also class

Constant Definition

[Since 0.8.4] - [ -P Classes/ConstantDefinition ] - [ Online docs ]

List of class constants being defined.

<?php 
// traditional way of making constants
define('aConstant'1);

// modern way of making constants
const anotherConstant 2;

class 
foo {
    
// Not a constant, a class constant.
    
const aClassConstant 3;
}
?>



See also PHP Constants, PHP OOP Constants

Empty Classes

[Since 0.8.4] - [ -P Classes/EmptyClass ] - [ Online docs ]

Classes that do no define anything at all : no property, method nor constant. This is possibly dead code.

Empty classes are sometimes used to group classes; an interface may be used here for the same purpose, without inserting an extra level in the class hierarchy.

<?php 
//Empty class
class foo extends bar {}

//Not an empty class
class foo2 extends bar {
    const 
FOO 2;
}

//Not an empty class, as derived from Exception
class barException extends \Exception {}
?>


Classes that are directly derived from an exception are omitted.


See also class

Magic Methods

[Since 0.8.4] - [ -P Classes/MagicMethod ] - [ Online docs ]

List of PHP magic methods being used. The magic methods are

__call(), __callStatic(), __get(), __set(), __isset(), __unset(), __sleep(), __wakeup(), __toString(), __invoke(), __set_state(), __clone() and __debugInfo().

__construct and __destruct are omitted here, as they are routinely used to create and destroy objects.

<?php 
class foo{
    
// PHP Magic method, called when cloning an object.
    
function __clone() {}
}
?>


Forgotten Visibility

[Since 0.8.4] - [ -P Classes/NonPpp ] - [ Online docs ]

Some classes elements (property, method, constant) are missing their explicit visibility.

By default, it is public. It should at least be mentioned as public, or may be reviewed as protected or private.

Class constants support also visibility since PHP 7.1.

final, static and abstract are not counted as visibility. Only public, private and protected. The PHP 4 var keyword is counted as undefined.

Traits, classes and interfaces are checked.

<?php 
// Explicit visibility
class {
    protected 
sconst NO_VISIBILITY_CONST 1// For PHP 7.2 and later

    
private $noVisibilityProperty 2
    
    public function 
Method() {}
}

// Missing visibility
class {
    const 
NO_VISIBILITY_CONST 1// For PHP 7.2 and later

    
var $noVisibilityProperty 2// Only with var
    
    
function NoVisibilityForMethod() {}
}
?>



See also Visibility, Understanding The Concept Of Visibility In Object Oriented PHP

Non Static Methods Called In A Static

[Since 0.8.4] - [ -P Classes/NonStaticMethodsCalledStatic ] - [ Online docs ]

Static methods have to be declared as such (using the static keyword). Then, one may call them without instantiating the object.

PHP 7.0, and more recent versions, yield a deprecated error : Non-static method A::B() should not be called statically .

PHP 5 and older doesn't check that a method is static or not : at any point, the code may call one method statically.

<?php 
class {
        static public function 
sm( ) { echo __METHOD__.\n; }
        public public 
sm( ) { echo __METHOD__.\n; }
    } 
    
    
x::sm( ); // echo x::sm 
    
    // Dynamic call
    
['x''sm']();
    [
\x::class, 'sm']();

    
$s 'x::sm';
    
$s();
?>


It is a bad idea to call non-static method statically. Such method may make use of special
variable $this, which will be undefined. PHP will not check those calls at compile time,
nor at running time.

It is recommended to update this situation : make the method actually static, or use it only
in object context.

Note that this analysis reports all static method call made on a non-static method,
even within the same class or class hierarchy. PHP silently accepts static call to any
in-family method.

<?php 
class {
        public function 
foo( ) { self::bar() }
        public function 
bar( ) { echo __METHOD__.\n; }
    }
?>



See also Static Keyword

Old Style Constructor

[Since 0.8.4] - [ -P Classes/OldStyleConstructor ] - [ Online docs ]

PHP classes used to have the method bearing the same name as the class acts as the constructor. That was PHP 4, and early PHP 5.

The manual issues a warning about this syntax : Old style constructors are DEPRECATED in PHP 7.0, and will be removed in a future version. You should always use __construct() in new code.

<?php 
namespace {
    
// Global namespace is important
    
class foo {
        function 
foo() {
            
// This acts as the old-style constructor, and is reported by PHP
        
}
    }

    class 
bar {
        function 
__construct() { }
        function 
bar() {
            
// This doesn't act as constructor, as bar has a __construct() method
        
}
    }
}

namespace 
Foo\Bar{
    class 
foo {
        function 
foo() {
            
// This doesn't act as constructor, as bar is not in the global namespace
        
}
    }
}
?>


This is no more the case in PHP 5, which relies on __construct() to do so. Having this old style constructor may bring in confusion, unless you are also supporting old time PHP 4.

Note that classes with methods bearing the class name, but inside a namespace are not following this convention, as this is not breaking backward compatibility. Those are excluded from the analyze.


See also Constructors and Destructors

Static Methods

[Since 0.8.4] - [ -P Classes/StaticMethods ] - [ Online docs ]

List of all static methods.

<?php 
class foo {
    static public function 
staticMethod() {
        
    }
    
    public function 
notStaticMethod() {
    
    }
           
    private function 
method() {
        
// This is not a property
        
new static();
    }
}
?>


Static Methods Called From Object

[Since 0.8.4] - [ -P Classes/StaticMethodsCalledFromObject ] - [ Online docs ]

Static methods may be called without instantiating an object. As such, they never interact with the special variable '$this', as they do not depend on object existence.

Besides this, static methods are normal methods that may be called directly from object context, to perform some utility task.

To maintain code readability, it is recommended to call static method in a static way, rather than within object context.

<?php 
class {
        static function 
y( ) {}
    }
    
    
$z = new x( );
    
    
$z->y( ); // Readability : no one knows it is a static call
    
x::y( );  // Readability : here we know
?>


Static Properties

[Since 0.8.4] - [ -P Classes/StaticProperties ] - [ Online docs ]

List of all static properties.

<?php 
class foo {
    static public 
$staticProperty 1;
           public 
$notStaticProperty 2;
           
    private function 
method() {
        
// This is not a property
        
new static();
    }
}

function 
bar() {
    
// This is not a static property
    
static $staticVariable;
    
    
//....
}
?>


Constants Usage

[Since 0.8.4] - [ -P Constants/ConstantUsage ] - [ Online docs ]

List of constants being used.

<?php 
const MY_CONST 'Hello';

// PHP_EOL (native PHP Constant)
// MY_CONST (custom constant)
echo PHP_EOL MY_CONST;
?>

Magic Constant Usage

[Since 0.8.4] - [ -P Constants/MagicConstantUsage ] - [ Online docs ]

There are eight magical constants that change depending on where they are used. For example, the value of __LINE__ depends on the line that it's used on in your script. These special constants are case-insensitive.

+ __LINE__
+ __FILE__
+ __DIR__
+ __FUNCTION__
+ __CLASS__
+ __TRAIT__
+ __METHOD__
+ __NAMESPACE__


<?php 
echo 'This code is in file '__FILE__.', line '.__LINE__;
?>



See also Magic Constants,

PHP Constant Usage

[Since 0.8.4] - [ -P Constants/PhpConstantUsage ] - [ Online docs ]

List of PHP constants being used.

<?php 
const MY_CONST 'Hello';

// PHP_EOL (native PHP Constant)
// MY_CONST (custom constant, not reported)
echo PHP_EOL MY_CONST;
?>



See also Predefined Constants

Defined Exceptions

[Since 0.8.4] - [ -P Exceptions/DefinedExceptions ] - [ Online docs ]

This is the list of defined exceptions.

<?php 
class myException extends \Exception {}

// A defined exception
throw new myException();

// not a defined exception : it is already defined. 
throw new \RuntimeException();
?>



See also Predefined Exceptions, Exceptions

Thrown Exceptions

[Since 0.8.4] - [ -P Exceptions/ThrownExceptions ] - [ Online docs ]

Usage of throw keyword.

<?php 
throw new MyException('Error happened');
?>



See also Exceptions

ext/apc

[Since 0.8.4] - [ -P Extensions/Extapc ] - [ Online docs ]

Extension Alternative PHP Cache.

The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.

This extension is considered unmaintained and dead.

<?php 
$bar 'BAR';
   
apc_add('foo'$bar);
   
var_dump(apc_fetch('foo'));
   echo 
PHP_EOL;

   
$bar 'NEVER GETS SET';
   
apc_add('foo'$bar);
   
var_dump(apc_fetch('foo'));
   echo 
PHP_EOL;
?>



See also Alternative PHP Cache

ext/bcmath

[Since 0.8.4] - [ -P Extensions/Extbcmath ] - [ Online docs ]

Extension BC Math.

For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision up to 2147483647-1 (or 0x7FFFFFFF-1 ) decimals, represented as strings.

<?php 
echo bcpow('2''123'); 
//10633823966279326983230456482242756608

echo 2**123;
//1.0633823966279E+37
?>



See also BC Math Functions

ext/bzip2

[Since 0.8.4] - [ -P Extensions/Extbzip2 ] - [ Online docs ]

Extension ext/bzip2.

Bzip2 Functions for PHP.

<?php 
$file '/tmp/foo.bz2';
$bz bzopen($file'r') or die('Couldn\'t open $file for reading');

bzclose($bz);
?>


See also Bzip2 Functions, bzip2

ext/calendar

[Since 0.8.4] - [ -P Extensions/Extcalendar ] - [ Online docs ]

Extension ext/calendar.

The calendar extension presents a series of functions to simplify converting between different calendar formats.

<?php 
$number cal_days_in_month(CAL_GREGORIAN82003); // 31
echo "There were {$number} days in August 2003";
?>



See also Calendar Functions

ext/crypto

[Since 0.8.4] - [ -P Extensions/Extcrypto ] - [ Online docs ]

Extension ext/crypto (PECL).

Objective PHP binding of OpenSSL Crypto library.

<?php 
use Crypto\Cipher;
use 
Crypto\AlgorihtmException;
$algorithm 'aes-256-cbc';
if (!
Cipher::hasAlgorithm($algorithm)) {
    die(
'Algorithm $algorithm not found' PHP_EOL);
}
try {
    
$cipher = new Cipher($algorithm);
    
// Algorithm method for retrieving algorithm
    
echo 'Algorithm: ' $cipher->getAlgorithmName() . PHP_EOL;
    
// Params
    
$key_len $cipher->getKeyLength();
    
$iv_len $cipher->getIVLength();
    
    echo 
'Key length: ' $key_len PHP_EOL;
    echo 
'IV length: '  $iv_len PHP_EOL;
    echo 
'Block size: ' $cipher->getBlockSize() . PHP_EOL;
    
// This is just for this example. You should never use such key and IV!
    
$key str_repeat('x'$key_len);
    
$iv str_repeat('i'$iv_len);
    
// Test data
    
$data1 'Test';
    
$data2 'Data';
    
$data $data1 $data2;
    
// Simple encryption
    
$sim_ct $cipher->encrypt($data$key$iv);
    
    
// init/update/finish encryption
    
$cipher->encryptInit($key$iv);
    
$iuf_ct  $cipher->encryptUpdate($data1);
    
$iuf_ct .= $cipher->encryptUpdate($data2);
    
$iuf_ct .= $cipher->encryptFinish();
    
// Raw data output (used base64 format for printing)
    
echo 'Ciphertext (sim): ' base64_encode($sim_ct) . PHP_EOL;
    echo 
'Ciphertext (iuf): ' base64_encode($iuf_ct) . PHP_EOL;
    
// $iuf_out == $sim_out
    
$ct $sim_ct;
    
// Another way how to create a new cipher object (using the same algorithm and mode)
    
$cipher Cipher::aes(Cipher::MODE_CBC256);
    
// Simple decryption
    
$sim_text $cipher->decrypt($ct$key$iv);
    
    
// init/update/finish decryption
    
$cipher->decryptInit($key$iv);
    
$iuf_text $cipher->decryptUpdate($ct);
    
$iuf_text .= $cipher->decryptFinish();
    
// Raw data output ($iuf_out == $sim_out)
    
echo 'Text (sim): ' $sim_text PHP_EOL;
    echo 
'Text (iuf): ' $iuf_text PHP_EOL;
}
catch (
AlgorithmException $e) {
    echo 
$e->getMessage() . PHP_EOL;
}
?>


See also pecl crypto and php-crypto.

ext/ctype

[Since 0.8.4] - [ -P Extensions/Extctype ] - [ Online docs ]

Extension ext/ctype.

Ext/ctype checks whether a character or string falls into a certain character class according to the current locale.

<?php 
$strings = array('AbCd1zyZ9''foo!#$bar');
foreach (
$strings as $testcase) {
    if (
ctype_alnum($testcase)) {
        echo 
"The string $testcase consists of all letters or digits.\n";
    } else {
        echo 
"The string $testcase does not consist of all letters or digits.\n";
    }
}
?>



See also Ctype functions

ext/curl

[Since 0.8.4] - [ -P Extensions/Extcurl ] - [ Online docs ]

Extension curl.

PHP supports libcurl, a library created by Daniel Stenberg. It allows the connection and communication to many different types of servers with many different types of protocols.

<?php 
$ch curl_init("http://www.example.com/");
$fp fopen("example_homepage.txt""w");

curl_setopt($chCURLOPT_FILE$fp);
curl_setopt($chCURLOPT_HEADER0);

curl_exec($ch);
curl_close($ch);
fclose($fp);
?>



See also Curl for PHP, curl

ext/date

[Since 0.8.4] - [ -P Extensions/Extdate ] - [ Online docs ]

Extension ext/date.

These functions allows the manipulation of date and time from the server where the PHP scripts are running.

<?php 
$dt = new DateTime('2015-11-01 00:00:00', new DateTimeZone('America/New_York'));
echo 
'Start: '$dt->format('Y-m-d H:i:s P'), PHP_EOL;
$dt->add(new DateInterval('PT3H'));
echo 
'End:   '$dt->format('Y-m-d H:i:s P'), PHP_EOL;
?>



See also Date and Time

ext/dba

[Since 0.8.4] - [ -P Extensions/Extdba ] - [ Online docs ]

Extension ext/dba.

These functions build the foundation for accessing Berkeley DB style databases.

<?php 
$id dba_open('/tmp/test.db''n''db2');

if (!
$id) {
    echo 
'dba_open failed'.PHP_EOL;
    exit;
}

dba_replace('key''This is an example!'$id);

if (
dba_exists('key'$id)) {
    echo 
dba_fetch('key'$id);
    
dba_delete('key'$id);
}

dba_close($id);
?>



See also Database (dbm-style) Abstraction Layer

ext/dom

[Since 0.8.4] - [ -P Extensions/Extdom ] - [ Online docs ]

Extension Document Object Model.

The DOM extension allows the manipulation of XML documents through the DOM API with PHP.

<?php 
$dom = new DOMDocument('1.0''utf-8');

$element $dom->createElement('test''This is the root element!');

// We insert the new element as root (child of the document)
$dom->appendChild($element);

echo 
$dom->saveXML();
?>



See also Document Object Model

ext/enchant

[Since 0.8.4] - [ -P Extensions/Extenchant ] - [ Online docs ]

Extension Enchant.

Enchant is the PHP binding for the Enchant spelling library. Enchant steps in to provide uniformity and conformity on top of all spelling libraries, and implement certain features that may be lacking in any individual provider library.

<?php 
$tag 'en_US';
$r enchant_broker_init();
$bprovides enchant_broker_describe($r);
echo 
'Current broker provides the following backend(s):'.PHP_EOL;
print_r($bprovides);

$dicts enchant_broker_list_dicts($r);
print_r($dicts);
if (
enchant_broker_dict_exists($r,$tag)) {
    
$d enchant_broker_request_dict($r$tag);
    
$dprovides enchant_dict_describe($d);
    echo 
'dictionary $tag provides:'.PHP_EOL;
    
$wordcorrect enchant_dict_check($d'soong');
    
print_r($dprovides);
    if (!
$wordcorrect) {
        
$suggs enchant_dict_suggest($d'soong');
        echo 
'Suggestions for "soong":';
        
print_r($suggs);
    }
    
enchant_broker_free_dict($d);
} else {
}
enchant_broker_free($r);
?>


See also Enchant spelling library and
Enchant.

ext/ereg

[Since 0.8.4] - [ -P Extensions/Extereg ] - [ Online docs ]

Extension ext/ereg.

<?php 
if (ereg ('([0-9]{4})-([0-9]{1,2})-([0-9]{1,2})'$date$regs)) {
    echo 
$regs[3].'.'.$regs[2].'.'.$regs[1];
} else {
    echo 
'Invalid date format: '.$date;
}
?>


See also Ereg.

ext/exif

[Since 0.8.4] - [ -P Extensions/Extexif ] - [ Online docs ]

Extension EXIF : Exchangeable image file format.

The EXIF extension manipulates image meta data.

<?php 
echo 'test1.jpg:<br />';
$exif exif_read_data('tests/test1.jpg''IFD0');
echo 
$exif===false 'No header data found.<br />' 'Image contains headers<br />';

$exif exif_read_data('tests/test2.jpg'0true);
echo 
'test2.jpg:<br />';
foreach (
$exif as $key => $section) {
    foreach (
$section as $name => $val) {
        echo 
$key.$name.': '.$val.'<br />';
    }
}
?>



See also Exchangeable image information

ext/fileinfo

[Since 0.8.4] - [ -P Extensions/Extfileinfo ] - [ Online docs ]

Extension ext/fileinfo.

This module guesses the content type and encoding of a file by looking for certain magic byte sequences at specific positions within the file.

<?php 
$finfo finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
foreach (glob('*') as $filename) {
    echo 
finfo_file($finfo$filename) . PHP_EOL;
}
finfo_close($finfo);
?>


See also Filinfo

ext/filter

[Since 0.8.4] - [ -P Extensions/Extfilter ] - [ Online docs ]

Extension filter.

This extension filters data by either validating or sanitizing it.

<?php 
$email_a 'joe@example.com';
$email_b 'bogus';

if (
filter_var($email_aFILTER_VALIDATE_EMAIL)) {
    echo 
'This ($email_a) email address is considered valid.'.PHP_EOL;
}
if (
filter_var($email_bFILTER_VALIDATE_EMAIL)) {
    echo 
'This ($email_b) email address is considered valid.'.PHP_EOL;
} else {
    echo 
'This ($email_b) email address is considered invalid.'.PHP_EOL;
}
?>



See also Data filtering

ext/ftp

[Since 0.8.4] - [ -P Extensions/Extftp ] - [ Online docs ]

Extension FTP.

The functions in this extension implement client access to files servers speaking the File Transfer Protocol (FTP) as defined in RFC 959.

<?php 
// set up basic connection
$conn_id ftp_connect($ftp_server); 

// login with username and password
$login_result ftp_login($conn_id$ftp_user_name$ftp_user_pass); 

// check connection
if ((!$conn_id) || (!$login_result)) { 
    echo 
'FTP connection has failed!';
    echo 
'Attempted to connect to $ftp_server for user $ftp_user_name'
    exit; 
} else {
    echo 
'Connected to $ftp_server, for user $ftp_user_name';
}

// upload the file
$upload ftp_put($conn_id$destination_file$source_fileFTP_BINARY); 

// check upload status
if (!$upload) { 
    echo 
'FTP upload has failed!';
} else {
    echo 
'Uploaded $source_file to $ftp_server as $destination_file';
}

// close the FTP stream 
ftp_close($conn_id);
?>


See also FTP

ext/gd

[Since 0.8.4] - [ -P Extensions/Extgd ] - [ Online docs ]

Extension GD for PHP.

This extension allows PHP to create and manipulate image files in a variety of different image formats, including GIF, PNG, JPEG, WBMP, and XPM.

<?php 
header("Content-type: image/png");
$string $_GET['text'];
$im     imagecreatefrompng("images/button1.png");
$orange imagecolorallocate($im22021060);
$px     = (imagesx($im) - 7.5 strlen($string)) / 2;
imagestring($im3$px9$string$orange);
imagepng($im);
imagedestroy($im);
?>



See also Image Processing and GD

ext/gmp

[Since 0.8.4] - [ -P Extensions/Extgmp ] - [ Online docs ]

Extension ext/gmp.

These functions allow for arbitrary-length integers to be worked with using the GNU MP library.

<?php 
$pow1 gmp_pow('2'131);
echo 
gmp_strval($pow1) . PHP_EOL;
$pow2 gmp_pow('0'0);
echo 
gmp_strval($pow2) . PHP_EOL;
$pow3 gmp_pow('2', -1); // Negative exp, generates warning
echo gmp_strval($pow3) . PHP_EOL;
?>



See also GMP, GNU MP library

ext/gnupgp

[Since 0.8.4] - [ -P Extensions/Extgnupg ] - [ Online docs ]

Extension GnuPG.

This module allows you to interact with gnupg.

<?php 
// init gnupg
$res gnupg_init();
// not really needed. Clearsign is default
gnupg_setsignmode($res,GNUPG_SIG_MODE_CLEAR);
// add key with passphrase 'test' for signing
gnupg_addsignkey($res,"8660281B6051D071D94B5B230549F9DC851566DC","test");
// sign
$signed gnupg_sign($res,"just a test");
echo 
$signed;
?>



See also Gnupg Function for PHP, GnuPG

ext/hash

[Since 0.8.4] - [ -P Extensions/Exthash ] - [ Online docs ]

Extension for HASH Message Digest Framework.

Message Digest (hash) engine. Allows direct or incremental processing of arbitrary length messages using a variety of hashing algorithms.

<?php 
/* Create a file to calculate hash of */
file_put_contents('example.txt''The quick brown fox jumped over the lazy dog.');

echo 
hash_file('md5''example.txt');
?>



See also HASH Message Digest Framework

ext/iconv

[Since 0.8.4] - [ -P Extensions/Exticonv ] - [ Online docs ]

Extension ext/iconv.

With this module, you can turn a string represented by a local character set into the one represented by another character set, which may be the Unicode character set.

<?php 
$text "This is the Euro symbol '€'.";

echo 
'Original : '$textPHP_EOL;
echo 
'TRANSLIT : 'iconv("UTF-8""ISO-8859-1//TRANSLIT"$text), PHP_EOL;
echo 
'IGNORE   : 'iconv("UTF-8""ISO-8859-1//IGNORE"$text), PHP_EOL;
echo 
'Plain    : 'iconv("UTF-8""ISO-8859-1"$text), PHP_EOL;
?>


See also Iconv, libiconv

ext/json

[Since 0.8.4] - [ -P Extensions/Extjson ] - [ Online docs ]

Extension JSON.

This extension implements the JavaScript Object Notation (JSON) data-interchange format. PHP implements a superset of JSON as specified in the original RFC 7159.

<?php 
$arr = array('a' => 1'b' => 2'c' => 3'd' => 4'e' => 5);

echo 
json_encode($arr);
?>


See also JavaScript Object Notation, JSON

ext/kdm5

[Since 0.8.4] - [ -P Extensions/Extkdm5 ] - [ Online docs ]

Extension kdm5 : Kerberos V .

These package allows you to access Kerberos V administration servers. You can create, modify, and delete Kerberos V principals and policies.

<?php 
// Extracted from the PHP Manual
  
$handle kadm5_init_with_password(afs-1GONICUS.LOCALadmin/adminpassword);

  print <
h1>get_principals</h1>\n;
  
$principals kadm5_get_principals($handle);
  for( 
$i=0$i<count($principals); $i++)
      print 
$principals[$i]<br>\n;

  print <
h1>get_policies</h1>\n;
  
$policies kadm5_get_policies($handle);
  for( 
$i=0$i<count($policies); $i++)
      print 
$policies[$i]<br>\n;

  print <
h1>get_principal burbach@GONICUS.LOCAL</h1>\n;

  
$options kadm5_get_principal($handleburbach@GONICUS.LOCAL );
  
$keys array_keys($options);
  for( 
$i=0$i<count($keys); $i++) {
    
$value $options[$keys[$i]];
    print 
$keys[$i]: $value<br>\n;
  }

  
$options = array(KADM5_PRINC_EXPIRE_TIME => 0);
  
kadm5_modify_principal($handleburbach@GONICUS.LOCAL$options);

  
kadm5_destroy($handle);
?>



See also Kerberos V, Kerberos: The Network Authentication Protocol

ext/ldap

[Since 0.8.4] - [ -P Extensions/Extldap ] - [ Online docs ]

Extension ext/ldap.

LDAP is the Lightweight Directory Access Protocol, and is a protocol used to access 'Directory Servers'. The Directory is a special kind of database that holds information in a tree structure.

<?php 
// basic sequence with LDAP is connect, bind, search, interpret search
// result, close connection

echo '<h3>LDAP query test</h3>';
echo 
'Connecting ...';
$ds=ldap_connect('localhost');  // must be a valid LDAP server!
echo 'connect result is ' $ds '<br />';

if (
$ds) { 
    echo 
'Binding ...'
    
$r=ldap_bind($ds);     // this is an 'anonymous' bind, typically
                           // read-only access
    
echo 'Bind result is ' $r '<br />';

    echo 
'Searching for (sn=S*) ...';
    
// Search surname entry
    
$sr=ldap_search($ds'o=My Company, c=US''sn=S*');  
    echo 
'Search result is ' $sr '<br />';

    echo 
'Number of entries returned is ' ldap_count_entries($ds$sr) . '<br />';

    echo 
'Getting entries ...<p>';
    
$info ldap_get_entries($ds$sr);
    echo 
'Data for ' $info['count'] . ' items returned:<p>';

    for (
$i=0$i<$info['count']; $i++) {
        echo 
'dn is: ' $info[$i]['dn'] . '<br />';
        echo 
'first cn entry is: ' $info[$i]['cn'][0] . '<br />';
        echo 
'first email entry is: ' $info[$i]['mail'][0] . '<br /><hr />';
    }

    echo 
'Closing connection';
    
ldap_close($ds);

} else {
    echo 
'<h4>Unable to connect to LDAP server</h4>';
}
?>



See also Lightweight Directory Access Protocol

ext/libxml

[Since 0.8.4] - [ -P Extensions/Extlibxml ] - [ Online docs ]

Extension libxml.

These functions/constants are available as of PHP 5.1.0, and the following core extensions rely on this libxml extension: DOM, libxml, SimpleXML, SOAP, WDDX, XSL, XML, XMLReader, XMLRPC and XMLWriter.

<?php 
// $xmlstr is a string, containing a XML document. 

$doc simplexml_load_string($xmlstr);
$xml explode(PHP_EOL$xmlstr);

if (
$doc === false) {
    
$errors libxml_get_errors();

    foreach (
$errors as $error) {
        echo 
display_xml_error($error$xml);
    }

    
libxml_clear_errors();
}


function 
display_xml_error($error$xml)
{
    
$return  $xml[$error->line 1] . PHP_EOL;
    
$return .= str_repeat('-'$error->column) . '^'.PHP_EOL;

    switch (
$error->level) {
        case 
LIBXML_ERR_WARNING:
            
$return .= 'Warning ',$error->code.': ';
            break;
         case 
LIBXML_ERR_ERROR:
            
$return .= 'Error '.$error->code.': ';
            break;
        case 
LIBXML_ERR_FATAL:
            
$return .= 'Fatal Error '.$error->code.': ';
            break;
    }

    
$return .= trim($error->message) .
               
PHP_EOL.'  Line: '.$error->line .
               
PHP_EOL.'  Column: '.$error->column;

    if (
$error->file) {
        
$return .= "\n  File: $error->file";
    }

    return 
$return.PHP_EOL.PHP_EOL.'--------------------------------------------'.PHP_EOL.PHP_EOL;
}
?>



See also libxml

ext/mbstring

[Since 0.8.4] - [ -P Extensions/Extmbstring ] - [ Online docs ]

Extension ext/mbstring .

mbstring provides multibyte specific string functions that help you deal with multibyte encodings in PHP.

<?php 
/* Convert internal character encoding to SJIS */
$str mb_convert_encoding($str"SJIS");

/* Convert EUC-JP to UTF-7 */
$str mb_convert_encoding($str"UTF-7""EUC-JP");

/* Auto detect encoding from JIS, eucjp-win, sjis-win, then convert str to UCS-2LE */
$str mb_convert_encoding($str"UCS-2LE""JIS, eucjp-win, sjis-win");

/* "auto" is expanded to "ASCII,JIS,UTF-8,EUC-JP,SJIS" */
$str mb_convert_encoding($str"EUC-JP""auto");
?>



See also Mbstring

ext/mcrypt

[Since 0.8.4] - [ -P Extensions/Extmcrypt ] - [ Online docs ]

Extension for mcrypt.

This extension has been deprecated as of PHP 7.1.0 and moved to PECL as of PHP 7.2.0.

This is an interface to the mcrypt library, which supports a wide variety of block algorithms such as DES, TripleDES, Blowfish (default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and GOST in CBC, OFB, CFB and ECB cipher modes. Additionally, it supports RC6 and IDEA which are considered 'non-free'. CFB/OFB are 8bit by default.

<?php 
# --- ENCRYPTION ---

    # the key should be random binary, use scrypt, bcrypt or PBKDF2 to
    # convert a string into a key
    # key is specified using hexadecimal
    
$key pack('H*''bcb04b7e103a0cd8b54763051cef08bc55abe029fdebae5e1d417e2ffb2a00a3');
    
    
# show key size use either 16, 24 or 32 byte keys for AES-128, 192
    # and 256 respectively
    
$key_size =  strlen($key);
    echo 
'Key size: ' $key_size PHP_EOL;
    
    
$plaintext 'This string was AES-256 / CBC / ZeroBytePadding encrypted.';

    
# create a random IV to use with CBC encoding
    
$iv_size mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128MCRYPT_MODE_CBC);
    
$iv mcrypt_create_iv($iv_sizeMCRYPT_RAND);
    
    
# creates a cipher text compatible with AES (Rijndael block size = 128)
    # to keep the text confidential 
    # only suitable for encoded input that never ends with value 00h
    # (because of default zero padding)
    
$ciphertext mcrypt_encrypt(MCRYPT_RIJNDAEL_128$key,
                                 
$plaintextMCRYPT_MODE_CBC$iv);

    
# prepend the IV for it to be available for decryption
    
$ciphertext $iv $ciphertext;
    
    
# encode the resulting cipher text so it can be represented by a string
    
$ciphertext_base64 base64_encode($ciphertext);

    echo  
$ciphertext_base64 PHP_EOL;

    
# === WARNING ===

    # Resulting cipher text has no integrity or authenticity added
    # and is not protected against padding oracle attacks.
    
    # --- DECRYPTION ---
    
    
$ciphertext_dec base64_decode($ciphertext_base64);
    
    
# retrieves the IV, iv_size should be created using mcrypt_get_iv_size()
    
$iv_dec substr($ciphertext_dec0$iv_size);
    
    
# retrieves the cipher text (everything except the $iv_size in the front)
    
$ciphertext_dec substr($ciphertext_dec$iv_size);

    
# may remove 00h valued characters from end of plain text
    
$plaintext_dec mcrypt_decrypt(MCRYPT_RIJNDAEL_128$key,
                                    
$ciphertext_decMCRYPT_MODE_CBC$iv_dec);
    
    echo  
$plaintext_dec PHP_EOL;
?>



See also extension mcrypt, mcrypt

ext/mongo

[Since 0.8.4] - [ -P Extensions/Extmongo ] - [ Online docs ]

Extension MongoDB driver (legacy).

<?php 
// connect
$m = new MongoClient();

// select a database
$db $m->comedy;

// select a collection (analogous to a relational database\'s table)
$collection $db->cartoons;

// add a record
$document = array( 'title' => 'Calvin and Hobbes''author' => 'Bill Watterson' );
$collection->insert($document);

// add another record, with a different 'shape'
$document = array( 'title' => 'XKCD''online' => true );
$collection->insert($document);

// find everything in the collection
$cursor $collection->find();

// iterate through the results
foreach ($cursor as $document) {
    echo 
$document['title'] . PHP_EOL;
}
?>


Note : this is not the MongoDB driver. This is the legacy extension.

See also ext/mongo manual and
MongdDb.

ext/mssql

[Since 0.8.4] - [ -P Extensions/Extmssql ] - [ Online docs ]

Extension MSSQL, Microsoft SQL Server.

These functions allow you to access MS SQL Server database.

<?php 
// Connect to MSSQL
$link mssql_connect('KALLESPC\SQLEXPRESS''sa''phpfi');

if (!
$link || !mssql_select_db('php'$link)) {
    die(
'Unable to connect or select database!');
}

// Do a simple query, select the version of 
// MSSQL and print it.
$version mssql_query('SELECT @@VERSION');
$row mssql_fetch_array($version);

echo 
$row[0];

// Clean up
mssql_free_result($version);
?>


See also Microsoft SQL Server and Microsoft PHP Driver for SQL Server.

ext/mysql

[Since 0.8.4] - [ -P Extensions/Extmysql ] - [ Online docs ]

Extension for MySQL (Original MySQL API).

This extension is deprecated as of PHP 5.5.0, and has been removed as of PHP 7.0.0. Instead, either the mysqli or PDO_MySQL extension should be used. See also the MySQL API Overview for further help while choosing a MySQL API.

<?php 
$result mysql_query('SELECT * WHERE 1=1');
if (!
$result) {
    die(
'Invalid query: ' mysql_error());
}
?>


See also Original MySQL API and MySQL.

ext/mysqli

[Since 0.8.4] - [ -P Extensions/Extmysqli ] - [ Online docs ]

Extension mysqli for MySQL.

The mysqli extension allows you to access the functionality provided by MySQL 4.1 and above.

<?php 
$mysqli = new mysqli('localhost''my_user''my_password''world');

/* check connection */
if (mysqli_connect_errno()) {
    
printf('Connect failed: %s\n'mysqli_connect_error());
    exit();
}

$city 'Amersfoort';

/* create a prepared statement */
if ($stmt $mysqli->prepare('SELECT District FROM City WHERE Name=?')) {

    
/* bind parameters for markers */
    
$stmt->bind_param('s'$city);

    
/* execute query */
    
$stmt->execute();

    
/* bind result variables */
    
$stmt->bind_result($district);

    
/* fetch value */
    
$stmt->fetch();

    
printf('%s is in district %s\n'$city$district);

    
/* close statement */
    
$stmt->close();
}

/* close connection */
$mysqli->close();
?>



See also MySQL Improved Extension, MySQL, Mariadb

ext/odbc

[Since 0.8.4] - [ -P Extensions/Extodbc ] - [ Online docs ]

Extension ODBC.

In addition to normal ODBC support, the Unified ODBC functions in PHP allow you to access several databases that have borrowed the semantics of the ODBC API to implement their own API. Instead of maintaining multiple database drivers that were all nearly identical, these drivers have been unified into a single set of ODBC functions.

<?php 
$a 1;
$b 2;
$c 3;
$stmt    odbc_prepare($conn'CALL myproc(?,?,?)');
$success odbc_execute($stmt, array($a$b$c));
?>


See also ODBC (Unified), Unixodbc, IODBC

ext/openssl

[Since 0.8.4] - [ -P Extensions/Extopenssl ] - [ Online docs ]

Extension Openssl.

This extension binds functions of OpenSSL library for symmetric and asymmetric encryption and decryption, PBKDF2 , PKCS7 , PKCS12 , X509 and other cryptographic operations. In addition to that it provides implementation of TLS streams.

<?php 
// $data and $signature are assumed to contain the data and the signature

// fetch public key from certificate and ready it
$pubkeyid openssl_pkey_get_public("file://src/openssl-0.9.6/demos/sign/cert.pem");

// state whether signature is okay or not
$ok openssl_verify($data$signature$pubkeyid);
if (
$ok == 1) {
    echo 
"good";
} elseif (
$ok == 0) {
    echo 
"bad";
} else {
    echo 
"ugly, error checking signature";
}
// free the key from memory
openssl_free_key($pubkeyid);
?>



See also ext/OpenSSL, OpenSSL

ext/pcre

[Since 0.8.4] - [ -P Extensions/Extpcre ] - [ Online docs ]

Extension ext/pcre. PCRE stands for Perl Compatible Regular Expression. It is a standard PHP extension.

<?php 
$zip_code $_GET['zip'];

// Canadian Zip code H2M 3J1
$zip_ca '/^([a-zA-Z]\d[a-zA-Z])\ {0,1}(\d[a-zA-Z]\d)$/';

// French Zip code  75017
$zip_fr '/^\d{5}$/';

// Chinese Zip code  590615
$zip_cn '/^\d{6}$/';

var_dump(preg_match($_GET['zip']));
?>



See also Regular Expressions (Perl-Compatible)

ext/pdo

[Since 0.8.4] - [ -P Extensions/Extpdo ] - [ Online docs ]

Generic extension PDO.

The PHP Data Objects (PDO) extension defines a lightweight, consistent interface for accessing databases in PHP.

<?php 
/* Execute a prepared statement by passing an array of values */
$sql 'SELECT name, colour, calories
    FROM fruit
    WHERE calories < :calories AND colour = :colour'
;
$sth $dbh->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150':colour' => 'red'));
$red $sth->fetchAll();
$sth->execute(array(':calories' => 175':colour' => 'yellow'));
$yellow $sth->fetchAll();
?>



See also PHP Data Object

ext/pgsql

[Since 0.8.4] - [ -P Extensions/Extpgsql ] - [ Online docs ]

Extension PostGreSQL.

PostgreSQL is an open source descendant of this original Berkeley code. It provides SQL92/SQL99 language support, transactions, referential integrity, stored procedures and type extensibility.

<?php 
// Connect to a database named 'mary'
$dbconn pg_connect('dbname=mary');

// Prepare a query for execution
$result pg_prepare($dbconn'my_query''SELECT * FROM shops WHERE name = $1');

// Execute the prepared query.  Note that it is not necessary to escape
// the string 'Joe's Widgets' in any way
$result pg_execute($dbconn'my_query', array('Joe\'s Widgets'));

// Execute the same prepared query, this time with a different parameter
$result pg_execute($dbconn'my_query', array('Clothes Clothes Clothes'));
?>



See also PostgreSQL, PostgreSQL: The world's most advanced open source database

ext/phar

[Since 0.8.4] - [ -P Extensions/Extphar ] - [ Online docs ]

Extension phar.

The phar extension provides a way to put entire PHP applications into a single file called a phar (PHP Archive) for easy distribution and installation.

<?php 
try {
    
$p = new Phar('/path/to/my.phar'0'my.phar');
    
$p['myfile.txt'] = 'hi';
    
$file $p['myfile.txt'];
    
var_dump($file->isCompressed(Phar::BZ2));
    
$p['myfile.txt']->compress(Phar::BZ2);
    
var_dump($file->isCompressed(Phar::BZ2));
} catch (
Exception $e) {
    echo 
'Create/modify operations on my.phar failed: '$e;
}
?>



See also phar

ext/posix

[Since 0.8.4] - [ -P Extensions/Extposix ] - [ Online docs ]

Extension POSIX.

Ext/posix contains an interface to those functions defined in the IEEE 1003.1 (POSIX.1) standards document which are not accessible through other means.

<?php 
posix_kill(999459,SIGKILL);
echo 
'Your error returned was '.posix_get_last_error(); //Your error was ___
?>



See also 1003.1-2008 - IEEE Standard for Information Technology - Portable Operating System Interface (POSIX(R))

ext/readline

[Since 0.8.4] - [ -P Extensions/Extreadline ] - [ Online docs ]

Extension readline.

The readline functions implement an interface to the GNU Readline library. These are functions that provide editable command lines.

<?php 
//get 3 commands from user
for ($i=0$i 3$i++) {
        
$line readline("Command: ");
        
readline_add_history($line);
}

//dump history
print_r(readline_list_history());

//dump variables
print_r(readline_info());
?>



See also ext/readline, The GNU Readline Library

ext/reflection

[Since 0.8.4] - [ -P Extensions/Extreflection ] - [ Online docs ]

Extension Reflection.

PHP comes with a complete reflection API that adds the ability to reverse-engineer classes, interfaces, functions, methods and extensions. Additionally, the reflection API offers ways to retrieve doc comments for functions, classes and methods.

<?php 
/**
 * A simple counter
 *
 * @return    int
 */
function counter1()
{
    static 
$c 0;
    return ++
$c;
}

/**
 * Another simple counter
 *
 * @return    int
 */
$counter2 = function()
{
    static 
$d 0;
    return ++
$d;

};

function 
dumpReflectionFunction($func)
{
    
// Print out basic information
    
printf(
        
PHP_EOL.'===> The %s function '%s''.PHP_EOL.
        
'     declared in %s'.PHP_EOL.
        
'     lines %d to %d'.PHP_EOL,
        
$func->isInternal() ? 'internal' 'user-defined',
        
$func->getName(),
        
$func->getFileName(),
        
$func->getStartLine(),
        
$func->getEndline()
    );

    
// Print documentation comment
    
printf('---> Documentation:'.PHP_EOL.' %s',PHP_EOLvar_export($func->getDocComment(), 1));

    
// Print static variables if existant
    
if ($statics $func->getStaticVariables())
    {
        
printf('---> Static variables: %s',PHP_EOLvar_export($statics1));
    }
}

// Create an instance of the ReflectionFunction class
dumpReflectionFunction(new ReflectionFunction('counter1'));
dumpReflectionFunction(new ReflectionFunction($counter2));
?>



See also Reflection

ext/sem

[Since 0.8.4] - [ -P Extensions/Extsem ] - [ Online docs ]

Extension Semaphore, Shared Memory and IPC.

This module provides wrappers for the System V IPC family of functions. It includes semaphores, shared memory and inter-process messaging (IPC).

<?php 
$key         ftok(__FILE__,'a');
$semaphore   sem_get($key);
sem_acquire($semaphore);
sem_release($semaphore);
sem_remove($semaphore);
?>


See also Semaphore, Shared Memory and IPC.

ext/session

[Since 0.8.4] - [ -P Extensions/Extsession ] - [ Online docs ]

Extension ext/session.

Session support in PHP consists of a way to preserve certain data across subsequent accesses.

<?php 
session_start();
if (!isset(
$_SESSION['count'])) {
  
$_SESSION['count'] = 0;
} else {
  
$_SESSION['count']++;
}
?>



See also Session

ext/shmop

[Since 0.8.4] - [ -P Extensions/Extshmop ] - [ Online docs ]

Extension ext/shmop.

Shmop is an easy to use set of functions that allows PHP to read, write, create and delete Unix shared memory segments.

<?php 
// Create a temporary file and return its path
$tmp tempnam('/tmp''PHP');

// Get the file token key
$key ftok($tmp'a');

// Attach the SHM resource, notice the cast afterwards
$id shm_attach($key);

if (
$id === false) {
    die(
'Unable to create the shared memory segment');
}

// Cast to integer, since prior to PHP 5.3.0 the resource id 
// is returned which can be exposed when casting a resource
// to an integer
$id = (integer) $id;
?>



See also Semaphore, Shared Memory and IPC

ext/simplexml

[Since 0.8.4] - [ -P Extensions/Extsimplexml ] - [ Online docs ]

Extension SimpleXML .

The SimpleXML extension provides a very simple and easily usable toolset to convert XML to an object that can be processed with normal property selectors and array iterators.

<?php 
$xml = <<<'XML'
<?xml version='1.0' standalone='yes' ? >
<movies>
 <movie>
  <title>PHP: Behind the Parser</title>
  <characters>
   <character>
    <name>Ms. Coder</name>
    <actor>Onlivia Actora</actor>
   </character>
   <character>
    <name>Mr. Coder</name>
    <actor>El Act&#211;r</actor>
   </character>
  </characters>
  <plot>
   So, this language. It's like, a programming language. Or is it a
   scripting language? All is revealed in this thrilling horror spoof
   of a documentary.
  </plot>
  <great-lines>
   <line>PHP solves all my web problems</line>
  </great-lines>
  <rating type="thumbs">7</rating>
  <rating type="stars">5</rating>
 </movie>
</movies>
XML;

$movies = new SimpleXMLElement($xml);

echo 
$movies->movie[0]->plot;
?>



See also SimpleXML

ext/snmp

[Since 0.8.4] - [ -P Extensions/Extsnmp ] - [ Online docs ]

Extension SNMP.

The SNMP extension provides a very simple and easily usable toolset for managing remote devices via the Simple Network Management Protocol.

<?php 
$nameOfSecondInterface snmp3_get('localhost''james''authPriv''SHA''secret007''AES''secret007''IF-MIB::ifName.2');
?>


See also Net SNMP and SNMP.

ext/soap

[Since 0.8.4] - [ -P Extensions/Extsoap ] - [ Online docs ]

Extension SOAP.

The SOAP extension can be used to write SOAP Servers and Clients. It supports subsets of » SOAP 1.1, » SOAP 1.2 and » WSDL 1.1 specifications.

<?php 
$client = new SoapClient("some.wsdl");

$client = new SoapClient("some.wsdl", array('soap_version'   => SOAP_1_2));

$client = new SoapClient("some.wsdl", array('login'          => "some_name",
                                            
'password'       => "some_password"));
?>


See also SOAP, SOAP specifications

ext/sockets

[Since 0.8.4] - [ -P Extensions/Extsockets ] - [ Online docs ]

Extension socket.

The socket extension implements a low-level interface to the socket communication functions based on the popular BSD sockets, providing the possibility to act as a socket server as well as a client.

<?php 
//Example #2 Socket example: Simple TCP/IP client
//From the PHP manual

error_reporting(E_ALL);

echo 
"<h2>TCP/IP Connection</h2>\n";

/* Get the port for the WWW service. */
$service_port getservbyname('www''tcp');

/* Get the IP address for the target host. */
$address gethostbyname('www.example.com');

/* Create a TCP/IP socket. */
$socket socket_create(AF_INETSOCK_STREAMSOL_TCP);
if (
$socket === false) {
    echo 
'socket_create() failed: reason: ' socket_strerror(socket_last_error()) . PHP_EOL;
} else {
    echo 
'OK.'.PHP_EOL;
}

echo 
'Attempting to connect to '$address' on port '$service_port'...';
$result socket_connect($socket$address$service_port);
if (
$result === false) {
    echo 
'socket_connect() failed.\nReason: ($result) ' socket_strerror(socket_last_error($socket)) . '\n';
} else {
    echo 
'OK.'.PHP_EOL;
}

$in ""HEAD HTTP/1.1\r\n"";
$in .= ""Hostwww.example.com\r\n"";
$in .= ""ConnectionClose\r\n\r\n"";
$out '';

echo 
'Sending HTTP HEAD request...';
socket_write($socket$instrlen($in));
echo 
"OK.\n";

echo 
'Reading response:\n\n';
while (
$out socket_read($socket2048)) {
    echo 
$out;
}

echo 
'Closing socket...';
socket_close($socket);
echo 
'OK.\n\n';
?>



See also Sockets

ext/spl

[Since 0.8.4] - [ -P Extensions/Extspl ] - [ Online docs ]

SPL extension.

The Standard PHP Library (SPL) is a collection of interfaces and classes that are meant to solve common problems.

<?php 
// Example with FilesystemIterator
$files = new FilesystemIterator('/path/to/dir');
foreach(
$files as $file) {
    echo 
$file->getFilename() . PHP_EOL;
}
?>


See also Standard PHP Library (SPL)

ext/sqlite

[Since 0.11.3] - [ -P Extensions/Extsqlite ] - [ Online docs ]

Extension Sqlite 2.

Support for SQLite version 2 databases. The support for this version of Sqlite has ended. It is recommended to use SQLite3 .

<?php 
if ($db sqlite_open('mysqlitedb'0666$sqliteerror)) { 
    
sqlite_query($db'CREATE TABLE foo (bar varchar(10))');
    
sqlite_query($db'INSERT INTO foo VALUES ("fnord")');
    
$result sqlite_query($db'select bar from foo');
    
var_dump(sqlite_fetch_array($result)); 
} else {
    die(
$sqliteerror);
}
?>


See also ext/sqlite, SQLite

ext/sqlite3

[Since 0.8.4] - [ -P Extensions/Extsqlite3 ] - [ Online docs ]

Extension Sqlite3.

Support for SQLite version 3 databases.

<?php 
$db = new SQLite3('mysqlitedb.db');

$results $db->query('SELECT bar FROM foo');
while (
$row $results->fetchArray()) {
    
var_dump($row);
}
?>



See also ext/sqlite3, Sqlite

ext/ssh2

[Since 0.8.4] - [ -P Extensions/Extssh2 ] - [ Online docs ]

Extension ext/ssh2.

<?php 
/* Notify the user if the server terminates the connection */
function my_ssh_disconnect($reason$message$language) {
  
printf("Server disconnected with reason code [%d] and message: %s\n",
         
$reason$message);
}

$methods = array(
  
'kex' => 'diffie-hellman-group1-sha1',
  
'client_to_server' => array(
    
'crypt' => '3des-cbc',
    
'comp' => 'none'),
  
'server_to_client' => array(
    
'crypt' => 'aes256-cbc,aes192-cbc,aes128-cbc',
    
'comp' => 'none'));

$callbacks = array('disconnect' => 'my_ssh_disconnect');

$connection ssh2_connect('shell.example.com'22$methods$callbacks);
if (!
$connection) die('Connection failed');
?>


See also SSH2 functions, ext/ssh2 on PECL

ext/standard

[Since 0.8.4] - [ -P Extensions/Extstandard ] - [ Online docs ]

Standards PHP functions.

This is not a real PHP extension : it covers the core functions.

<?php 
/*
Our php.ini contains the following settings:

display_errors = On
register_globals = Off
post_max_size = 8M
*/

echo 'display_errors = ' ini_get('display_errors') . PHP_EOL;
echo 
'register_globals = ' ini_get('register_globals') . PHP_EOL;
echo 
'post_max_size = ' ini_get('post_max_size') . PHP_EOL;
echo 
'post_max_size+1 = ' . (ini_get('post_max_size')+1) . PHP_EOL;
echo 
'post_max_size in bytes = ' return_bytes(ini_get('post_max_size'));

function 
return_bytes($val) {
    
$val trim($val);
    
$last strtolower($val[strlen($val)-1]);
    switch(
$last) {
        
// The 'G' modifier is available since PHP 5.1.0
        
case 'g':
            
$val *= 1024;
        case 
'm':
            
$val *= 1024;
        case 
'k':
            
$val *= 1024;
    }

    return 
$val;
}
?>



See also PHP Options/Info Functions

ext/tidy

[Since 0.8.4] - [ -P Extensions/Exttidy ] - [ Online docs ]

Extension Tidy.

Tidy is a binding for the Tidy HTML clean and repair utility which allows you to not only clean and otherwise manipulate HTML documents, but also traverse the document tree.

<?php 
`ob_start() <https://www.php.net/ob_start>`_;
?>

a html document
<?php 
$html = `ob_get_clean() <https://www.php.net/ob_get_clean>`_;

// Specify configuration
$config = array(
           
'indent'         => true,
           
'output-xhtml'   => true,
           
'wrap'           => 200);

// Tidy
$tidy = new tidy;
$tidy->parseString($html$config'utf8');
$tidy->cleanRepair();

// Output
echo $tidy;
?>



See also Tidy, HTML-tidy

ext/tokenizer

[Since 0.8.4] - [ -P Extensions/Exttokenizer ] - [ Online docs ]

Extension Tokenizer.

The Tokenizer functions provide an interface to the PHP tokenizer embedded in the Zend Engine.

<?php 
/*
* T_ML_COMMENT does not exist in PHP 5.
* The following three lines define it in order to
* preserve backwards compatibility.
*
* The next two lines define the PHP 5 only T_DOC_COMMENT,
* which we will mask as T_ML_COMMENT for PHP 4.
*/
if (!defined('T_ML_COMMENT')) {
   
define('T_ML_COMMENT'T_COMMENT);
} else {
   
define('T_DOC_COMMENT'T_ML_COMMENT);
}

$source file_get_contents('example.php');
$tokens token_get_all($source);

foreach (
$tokens as $token) {
   if (
is_string($token)) {
       
// simple 1-character token
       
echo $token;
   } else {
       
// token array
       
list($id$text) = $token;

       switch (
$id) { 
           case 
T_COMMENT
           case 
T_ML_COMMENT// we\'ve defined this
           
case T_DOC_COMMENT// and this
               // no action on comments
               
break;

           default:
               
// anything else -> output 'as is'
               
echo $text;
               break;
       }
   }
}
?>



See also tokenizer

ext/wddx

[Since 0.8.4] - [ -P Extensions/Extwddx ] - [ Online docs ]

Extension WDDX.

The Web Distributed Data Exchange, or WDDX, is a free, open XML-based technology that allows Web applications created with any platform to easily exchange data with one another over the Web.

<?php 
echo wddx_serialize_value("PHP to WDDX packet example""PHP packet");
?>


See also Wddx on PHP, WDDX

ext/xdebug

[Since 0.8.4] - [ -P Extensions/Extxdebug ] - [ Online docs ]

Xdebug extension.

The Xdebug is a extension PHP which provides debugging and profiling capabilities.

<?php 
class Strings
{
    static function 
fix_string($a)
    {
        echo
            
xdebug_call_class().
            
"::".
            
xdebug_call_function().
            
" is called at ".
            
xdebug_call_`file() <https://www.php.net/file>`_.
            
":".
            
xdebug_call_line();
    }
}

$ret Strings::fix_string'Derick' );
?>



See also Xdebug

ext/xmlreader

[Since 0.8.4] - [ -P Extensions/Extxmlreader ] - [ Online docs ]

Extension XMLReader.

The XMLReader extension is an XML Pull parser. The reader acts as a cursor going forward on the document stream and stopping at each node on the way.

<?php 
$xmlreader = new XMLReader();
    
$xmlreader->xml("<xml><div>Content</div></xml>");
    
$xmlreader->read();
    
$xmlreader->read();
    
$xmlreader->readString();
?>



See also xmlreader

ext/xmlrpc

[Since 0.8.4] - [ -P Extensions/Extxmlrpc ] - [ Online docs ]

Extension ext/xmlrpc.

This extension can be used to write XML-RPC servers and clients.

<?php 
$request xmlrpc_encode_request('method', array(123));
$context stream_context_create(array('http' => array(
    
'method' => 'POST',
    
'header' => 'Content-Type: text/xml',
    
'content' => $request
)));
$file file_get_contents('http://www.example.com/xmlrpc'false$context);
$response xmlrpc_decode($file);
if (
$response && xmlrpc_is_fault($response)) {
    
trigger_error('xmlrpc: '.$response['faultString'].' ('.$response['faultCode']));
} else {
    
print_r($response);
}
?>



See also XML-RPC

ext/xmlwriter

[Since 0.8.4] - [ -P Extensions/Extxmlwriter ] - [ Online docs ]

Extension ext/xmlwriter.

The XMLWriter extension wraps the libxml xmlWriter API inside PHP.

<?php 
$xw xmlwriter_open_memory();
xmlwriter_set_indent($xwTRUE);
xmlwriter_start_document($xwNULL'UTF-8');
xmlwriter_start_element($xw'root');
xmlwriter_write_attribute_ns($xw'prefix''''http://www.php.net/uri');
xmlwriter_start_element($xw'elem1');
xmlwriter_write_attribute($xw'attr1''first');
xmlwriter_end_element($xw);
xmlwriter_full_end_element($xw);
xmlwriter_end_document($xw);
$output xmlwriter_flush($xwtrue);
print 
$output;
// write attribute_ns without start_element first
$xw xmlwriter_open_memory();
var_dump(xmlwriter_write_attribute_ns($xw'prefix''id''http://www.php.net/uri''elem1'));
print 
xmlwriter_output_memory($xw);
?>



See also XMLWriter and Module xmlwriter from libxml2

ext/xsl

[Since 0.8.4] - [ -P Extensions/Extxsl ] - [ Online docs ]

Extension XSL.

The XSL extension implements the XSL standard, performing XSLT transformations using the libxslt library.

<?php 
// Example from the PHP manual

$xmldoc = new DOMDocument();
$xsldoc = new DOMDocument();
$xsl = new XSLTProcessor();

$xmldoc->loadXML('fruits.xml');
$xsldoc->loadXML('fruits.xsl');

libxml_use_internal_errors(true);
$result $xsl->importStyleSheet($xsldoc);
if (!
$result) {
    foreach (
libxml_get_errors() as $error) {
        echo 
"Libxml error: {$error->message}\n";
    }
}
libxml_use_internal_errors(false);

if (
$result) {
    echo 
$xsl->transformToXML($xmldoc);
}
?>



See also XSL extension

ext/yaml

[Since 0.8.4] - [ -P Extensions/Extyaml ] - [ Online docs ]

Extension YAML.

This extension implements the YAML Ain't Markup Language (YAML) data serialization standard. Parsing and emitting are handled by the LibYAML library.

<?php 
$addr = array(
    
'given' => 'Chris',
    
'family'=> 'Dumars',
    
'address'=> array(
        
'lines'=> '458 Walkman Dr.
        Suite #292'
,
        
'city'=> 'Royal Oak',
        
'state'=> 'MI',
        
'postal'=> 48046,
      ),
  );
$invoice = array (
    
'invoice'=> 34843,
    
'date'=> '2001-01-23',
    
'bill-to'=> $addr,
    
'ship-to'=> $addr,
    
'product'=> array(
        array(
            
'sku'=> 'BL394D',
            
'quantity'=> 4,
            
'description'=> 'Basketball',
            
'price'=> 450,
          ),
        array(
            
'sku'=> 'BL4438H',
            
'quantity'=> 1,
            
'description'=> 'Super Hoop',
            
'price'=> 2392,
          ),
      ),
    
'tax'=> 251.42,
    
'total'=> 4443.52,
    
'comments'=> 'Late afternoon is best. Backup contact is Nancy Billsmer @ 338-4338.',
    );

// generate a YAML representation of the invoice
$yaml yaml_emit($invoice);
var_dump($yaml);

// convert the YAML back into a PHP variable
$parsed yaml_parse($yaml);

// check that roundtrip conversion produced an equivalent structure
var_dump($parsed == $invoice);
?>




See also YAML

ext/zip

[Since 0.8.4] - [ -P Extensions/Extzip ] - [ Online docs ]

Extension ext/zip.

This extension enables you to transparently read or write ZIP compressed archives and the files inside them.

<?php 
$zip = new ZipArchive();
$filename './test112.zip';

if (
$zip->open($filenameZipArchive::CREATE)!==TRUE) {
    exit(
'cannot open <$filename>');
}

$zip->addFromString('testfilephp.txt' time(), '#1 This is a test string added as testfilephp.txt.'.PHP_EOL);
$zip->addFromString('testfilephp2.txt' time(), '#2 This is a test string added as testfilephp2.txt.'.PHP_EOL);
$zip->addFile($thisdir '/too.php','/testfromfile.php');
echo 
'numfiles: ' $zip->numFiles PHP_EOL;
echo 
'status:' $zip->status PHP_EOL;
$zip->close();
?>



See also Zip

ext/zlib

[Since 0.8.4] - [ -P Extensions/Extzlib ] - [ Online docs ]

Extension ext/zlib.

<?php 
$filename tempnam('/tmp''zlibtest') . '.gz';
echo 
"<html>\n<head></head>\n<body>\n<pre>\n";
$s "Only a test, test, test, test, test, test, test, test!\n";

// open file for writing with maximum compression
$zp gzopen($filename'w9');

// write string to file
gzwrite($zp$s);

// close file
gzclose($zp);
?>


See also Zlib

Closures Glossary

[Since 0.8.4] - [ -P Functions/Closures ] - [ Online docs ]

List of all the closures in the code.

<?php 
// A closure is also a unnamed function
$closure = function ($arg) { return 'A'.strtolower($arg); }
?>



See also The Closure Class

Empty Function

[Since 0.8.4] - [ -P Functions/EmptyFunction ] - [ Online docs ]

Function or method whose body is empty.

Such functions or methods are rarely useful. As a bare minimum, the function should return some useful value, even if constant.

A method is considered empty when it contains nothing, or contains expressions without impact.

<?php 
// classic empty function
function emptyFunction() {}

class 
bar {
    
// classic empty method
    
function emptyMethod() {}

    
// classic empty function
    
function emptyMethodWithParent() {}
}

class 
barbar extends bar {
    
// NOT an empty method : it overwrites the parent method
    
function emptyMethodWithParent() {}
}
?>


Methods which overwrite another methods are omitted. Methods which are the concrete version of an abstract method are considered.

Functions Glossary

[Since 0.8.4] - [ -P Functions/Functionnames ] - [ Online docs ]

List of all the defined functions in the code.

<?php 
// A function
function aFunction() {}

// Closures (not reported)
$closure = function ($arg) {  }

// Methods
class foo {
    function 
aMethod() {}
}
?>


Recursive Functions

[Since 0.8.4] - [ -P Functions/Recursive ] - [ Online docs ]

Recursive functions are functions that calls itself.

<?php 
// a recursive function ; it calls itself
function factorial($n) {
    if (
$n == 1) { return 1; }
    
    return 
factorial($n 1) * $n;
}
?>


Functions, methods and closures are identified as recursive. Higher level of recursion are not detected (function a() calls function b(), calls function a(), etc.).

Redeclared PHP Functions

[Since 0.8.4] - [ -P Functions/RedeclaredPhpFunction ] - [ Online docs ]

Function that bear the same name as a PHP function, and that are declared.

This is useful when managing backward compatibility, like emulating an old function, or preparing for newer PHP versions, like emulating new upcoming function.

<?php 
if (version_compare(PHP_VERSION7.0) > 0) {
    function 
split($separator$string) {
        return 
explode($separator$string);
    }
}

print_rsplit(' ''2 3'));
?>

Typehints

[Since 0.8.4] - [ -P Functions/Typehints ] - [ Online docs ]

List of all the types (classes or scalar) used in Typehinting.

<?php 
// here, array, myObject and string are all typehints.
function foo(array $arraymyObject $xstring $string) {

}
?>



See also Type declarations

Methods Without Return

[Since 0.8.4] - [ -P Functions/WithoutReturn ] - [ Online docs ]

List of all the functions, closures, methods that have no explicit return.

Functions with the void or never returntypes, are omitted.

<?php 
// With return null : Explicitly not returning
function withExplicitReturn($a 1) {
    
$a++;
    return 
null;
}

// Without indication
function withoutExplicitReturn($a 1) {
    
$a++;
}

// With return type void : Explicitly not returning
function withExplicitReturnType($a 1) : void {
    
$a++;
}
?>



See also return

Empty Interfaces

[Since 0.8.4] - [ -P Interfaces/EmptyInterface ] - [ Online docs ]

Empty interfaces are a code smell. Interfaces should contains at least a method or a constant, and not be totally empty.

<?php 
// an empty interface
interface empty {}

// an normal interface
interface normal {
    public function 
i() ;
}

// a constants interface
interface constantsOnly {
    const 
FOO 1;
}
?>




See also Empty interfaces are bad practice, Blog : Are empty interfaces code smell?

Interfaces Names

[Since 0.8.4] - [ -P Interfaces/Interfacenames ] - [ Online docs ]

List of all the defined interfaces in the code.

<?php 
// interfaceName is reported
interface interfaceName {
    function 
interfaceMethod() ; 
}
?>

Aliases

[Since 0.8.4] - [ -P Namespaces/Alias ] - [ Online docs ]

List of all aliases used, to alias namespaces.

<?php 
// This is an alias
use stdClass as aClass;

// This is not an alias : it is not explicit
use stdClass;

trait 
{
    
// This is not an alias, it's a trait usage
    
use otherTrait;
}
?>


See also .

See also Using namespaces: Aliasing/Importing, A Complete Guide to PHP Namespaces

Namespaces Glossary

[Since 0.8.4] - [ -P Namespaces/Namespacesnames ] - [ Online docs ]

List of all the defined namespaces in the code, using the namespace keyword.

<?php 
// One reported namespace
namespace one\name\space {}

// This global namespace is reported, as it is explicit
namespace { }
?>


Global namespaces are mentioned when they are explicitly used.

Autoloading

[Since 0.8.4] - [ -P Php/AutoloadUsage ] - [ Online docs ]

Usage of the autoloading feature of PHP.

<?php 
spl_autoload_register('my_autoloader');

// Old way to autoload. Deprecated in PHP 7.2
function __autoload($class ) {}
?>


Defining the __autoload() function is obsolete since PHP 7.2.


See also __autoload

Goto Names

[Since 0.8.4] - [ -P Php/Gotonames ] - [ Online docs ]

List of all goto labels used in the code.

<?php 
GOTO_NAME_1

// reports the usage of GOTO_NAME_1
goto GOTO_NAME_1;

UNUSED_GOTO_NAME_1:
?>



See also goto

__halt_compiler

[Since 0.8.4] - [ -P Php/Haltcompiler ] - [ Online docs ]

__halt_compiler() usage.

<?php 
// open this file
$fp fopen(__FILE__'r');

// seek file pointer to data
fseek($fp__COMPILER_HALT_OFFSET__);

// and output it
var_dump(stream_get_contents($fp));

// the end of the script execution
__halt_compiler(); the installation data (egtargzPHPetc.)
?>


See also __halt_compiler

Incompilable Files

[Since 0.8.4] - [ -P Php/Incompilable ] - [ Online docs ]

Files that cannot be compiled, and, as such, be run by PHP. Scripts are linted against various versions of PHP.

This is usually undesirable, as all code must compile before being executed. It may be that such files are not compilable because they are not yet ready for an upcoming PHP version.

<?php 
// Can't compile this : Print only accepts one argument
print $a$b$c;
?>


Code that is not compilable with older PHP versions means that the code is breaking backward compatibility : good or bad is project decision.

When the code is used as a template for PHP code generation, for example at installation time, it is recommended to use a distinct file extension, so as to distinguish them from actual PHP code.

Labels

[Since 0.8.4] - [ -P Php/Labelnames ] - [ Online docs ]

List of all labels used in the code.

<?php 
// A is label. 
goto A:

A:

// A label may be used by several gotos.
goto A:
?>


Throw

[Since 0.8.4] - [ -P Php/ThrowUsage ] - [ Online docs ]

List of thrown exceptions.

<?php 
if ($divisor === 0) {
    
// Throw native exception
    
throw new DivisionByZeroError("Shouldn't divide by one");
}

if (
$divisor === 1) {
    
// Throw custom exception
    
throw new DontDivideByOneException("Shouldn't divide by one");
}
?>




See also Exceptions

Trigger Errors

[Since 0.8.4] - [ -P Php/TriggerErrorUsage ] - [ Online docs ]

List of situations where user errors are triggered.

PHP errors are triggered with trigger_error().

<?php 
if ($divisor == 0) {
    
trigger_error('Cannot divide by zero'E_USER_ERROR);
}
?>



See also trigger_error

Caught Expressions

[Since 0.8.4] - [ -P Php/TryCatchUsage ] - [ Online docs ]

List of caught exceptions.

<?php 
// This analyzer reports MyException and Exception
try {
    
doSomething();
} catch (
MyException $e) {
    
fixIt();
} catch (
\Exception $e) {
    
fixIt();
}
?>



See also Exceptions

error_reporting() With Integers

[Since 0.8.4] - [ -P Structures/ErrorReportingWithInteger ] - [ Online docs ]

Using named constants with error_reporting is strongly encouraged to ensure compatibility for future versions. As error levels are added, the range of integers increases, so older integer-based error levels will not always behave as expected. (Adapted from the documentation).

<?php 
// This is ready for PHP next version
error_reporting(E_ALL & ~E_DEPRECATED & ~E_STRICT & ~E_NOTICE & ~E_WARNING);

// This is not ready for PHP next version
error_reporting(2047);

// -1 and 0 are omitted, as they will be valid even is constants changes.
error_reporting(-1);
error_reporting(0);
?>


See also directive error_reporting and
error_reporting.

Eval() Usage

[Since 0.8.4] - [ -P Structures/EvalUsage ] - [ Online docs ]

Using eval() is evil.

Using eval() is bad for performances (compilation time), for caches (it won't be compiled), and for security (if it includes external data).

<?php 
// Avoid using incoming data to build the `eval() <https://www.php.net/eval>`_ expression : any filtering error leads to PHP injection
    
$mathExpression $_GET['mathExpression']; 
    
$mathExpression preg_replace('#[^0-9+\-*/\(/)]#is'''$mathExpression); // expecting 1+2
    
$literalCode '$a = '.$mathExpression.';';
    eval(
$literalCode);
    echo 
$a;

    
// If the code code given to `eval() <https://www.php.net/eval>`_ is known at compile time, it is best to put it inline
    
$literalCode '`phpinfo() <https://www.php.net/phpinfo>`_;';
    eval(
$literalCode);
?>


Most of the time, it is possible to replace the code by some standard PHP, like variable variable for accessing a variable for which you have the name.
At worse, including a pregenerated file is faster and cacheable.

There are several situations where eval() is actually the only solution :

For PHP 7.0 and later, it is important to put eval() in a try..catch expression.


See also eval, The Land Where PHP Uses `eval() `_

Exit() Usage

[Since 0.8.4] - [ -P Structures/ExitUsage ] - [ Online docs ]

Using exit or die() in the code makes the code untestable (it will break unit tests). Moreover, if there is no reason or string to display, it may take a long time to spot where the application is stuck.

<?php 
// Throw an exception, that may be caught somewhere
throw new \Exception('error');

// Dying with error message. 
die('error');

function 
foo() {
    
//exiting the function but not dying
    
if (somethingWrong()) {
        return 
true;
    }
}
?>


Try exiting the function/class with return, or throw exception that may be caught later in the code.

Forgotten Whitespace

[Since 0.8.4] - [ -P Structures/ForgottenWhiteSpace ] - [ Online docs ]

Forgotten whitespaces only bring misery to the code.

White spaces have been left at either end of a file : before the PHP opening tag, or after the closing tag.

Usually, such whitespaces are forgotten, and may end up summoning the infamous 'headers already sent' error. It is better to remove them.

<?php 
// This script has no forgotten whitespace, not at the beginning
    
function foo() {}

    
// This script has no forgotten whitespace, not at the end
?>


See also How to fix Headers already sent error in PHP.

Iffectations

[Since 0.8.4] - [ -P Structures/Iffectation ] - [ Online docs ]

Affectations that appears in a condition.

Iffectations are a way to do both a test and an affectations.
They may also be typos, such as if ($x = 3) { ... }, leading to a constant condition.

<?php 
// an iffectation : assignation in a If condition
if($connexion mysql_connect($host$user$pass)) {
    
$res mysql_query($connexion$query);
}

// Iffectation may happen in while too.
while($row mysql_fetch($res)) {
    
$store[] = $row;
}
?>


Multiply By One

[Since 0.8.4] - [ -P Structures/MultiplyByOne ] - [ Online docs ]

Multiplying by 1 is a fancy type cast.

If it is used to type cast a value to number, then casting (int) or (float) is clearer. This behavior may change with PHP 7.1, which has unified the behavior of all hidden casts.

<?php 
// Still the same value than $m, but now cast to integer or float
$m $m 1

// Still the same value than $m, but now cast to integer or float
$n *= 1

// make typecasting clear, and merge it with the producing call.
$n = (int) $n;
?>


See also Type Juggling

@ Operator

[Since 0.8.4] - [ -P Structures/Noscream ] - [ Online docs ]

@ is the 'no scream' operator : it suppresses error output.

<?php 
// Set x with incoming value, or else null. 
$x = @$_GET['x'];
?>


This operator is actually very slow : it will process the error all the way up, and finally decide not to display it. It is often faster to check the conditions first, then run the method without @ .

You may also set display_error to 0 in the php.ini : this will avoid user's error display, but will keep the error in the PHP logs, for later processing.

The only situation where @ is useful is when a native PHP function displays errors messages when error happens and there is no way to check it from the code.

This is the case with fopen(), stream_socket_server(), token_get_all().


See also Error Control Operators, Five reasons why the shut-op operator should be avoided

Not Not

[Since 0.8.4] - [ -P Structures/NotNot ] - [ Online docs ]

Double not makes a boolean, not a true .

This is a wrong casting to boolean. PHP supports (boolean) to do the same, faster and cleaner.

<?php 
// Explicit code
    
$b = (boolean) $x
    
$b = (bool) $x

    
// Wrong type casting
    
$b = !!$x;
?>



See also Logical Operators, Type Juggling

include_once() Usage

[Since 0.8.4] - [ -P Structures/OnceUsage ] - [ Online docs ]

Usage of include_once() and require_once(). Those functions should be avoided for performances reasons.

<?php 
// Including a library. 
include 'lib/helpers.inc';

// Including a library, and avoiding double inclusion
include_once 'lib/helpers.inc';
?>


Try using autoload for loading classes, or use include() or require() and make it possible to include several times the same file without errors.

Using Short Tags

[Since 0.8.4] - [ -P Structures/ShortTags ] - [ Online docs ]

The code makes use of short tags. Short tags are the following : . A full scripts looks like that : .

It is recommended to avoid using short tags, and use standard PHP tags. This makes PHP code compatible with XML standards. Short tags used to be popular, but have lost it.


See also PHP Tags

Strpos()-like Comparison

[Since 0.8.4] - [ -P Structures/StrposCompare ] - [ Online docs ]

The result of that function may be mistaken with an error.

strpos(), along with several PHP native functions, returns a string position, starting at 0, or false, in case of failure.

<?php 
// This is the best comparison
if (strpos($string'a') === false) { }

// This is OK, as 2 won't be mistaken with false
if (strpos($string'a') == 2) { }

// strpos is one of the 26 functions that may behave this way
if (preg_match($regex$string)) { } 

// This works like above, catching the value for later reuse
if ($a strpos($string'a')) { }

// This misses the case where 'a' is the first char of the string
if (strpos($string'a')) { }

// This misses the case where 'a' is the first char of the string, just like above
if (strpos($string'a') == 0) { }
?>


It is recommended to check the result of strpos() with === or !==, so as to avoid confusing 0 and false.

This analyzer list all the strpos()-like functions that are directly compared with == or !=. preg_match(), when its first argument is a literal, is omitted : this function only returns NULL in case of regex error.

The full list is the following :



In PHP 8.0, str_contains() will do the expected job of strpos(), with less confusion.


See also strpos not working correctly

Throws An Assignement

[Since 0.8.4] - [ -P Structures/ThrowsAndAssign ] - [ Online docs ]

It is possible to throw an exception, and, in the same time, assign this exception to a variable.

However, the variable will never be used, as the exception is thrown, and any following code is not executed, unless the exception is caught in the same scope.

<?php 
// $e is useful, though not by much
    
$e = new() Exception();
    throw 
$e;

    
// $e is useless
    
throw $e = new Exception();
?>


var_dump()... Usage

[Since 0.8.4] - [ -P Structures/VardumpUsage ] - [ Online docs ]

var_dump(), print_r() or var_export() should not be left in any production code. They are debugging functions.

<?php 
if ($error) {
    
// Debugging usage of var_dump
    // And major security problem 
    
var_dump($query);
    
    
// This is OK : the $query is logged, and not displayed
    
$this->log(print_r($querytrue));
}
?>


They may be tolerated during development time, but must be removed so as not to have any chance to be run in production.

__toString() Throws Exception

[Since 0.8.4] - [ -P Structures/toStringThrowsException ] - [ Online docs ]

Magical method __toString() can't throw exceptions.

In fact, __toString() may not let an exception pass. If it throw an exception, but must catch it. If an underlying method throws an exception, it must be caught.

<?php 
class myString {
    private 
$string null;
    
    public function 
__construct($string) {
        
$this->string $string;
    }
    
    public function 
__toString() {
        
// Do not throw exceptions in __toString
        
if (!is_string($this->string)) {
            throw new 
Exception("$this->string is not a string!!");
        }
        
        return 
$this->string;
    }
}
?>


A fatal error is displayed, when an exception is not intercepted in the __toString() function.


See also __toString()

Binary Glossary

[Since 0.8.4] - [ -P Type/Binary ] - [ Online docs ]

List of all the integer values using the binary format.

<?php 
$a 0b10;
$b 0B0101;
?>



See also Integer syntax

Email Addresses

[Since 0.8.4] - [ -P Type/Email ] - [ Online docs ]

List of all the email addresses that were found in the code.

Emails are detected with regex : [_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})

<?php 
$email 'contact@exakat.io';
?>


Heredoc Delimiter Glossary

[Since 0.8.4] - [ -P Type/Heredoc ] - [ Online docs ]

List of all the delimiters used to build a Heredoc string.

In the example below, EOD is the delimiter.

<?php 
$a = <<<EOD
heredoc
EOD;
?>



See also Heredoc

Hexadecimal Glossary

[Since 0.8.4] - [ -P Type/Hexadecimal ] - [ Online docs ]

List of all the integer values, written in the hexadecimal format.

<?php 
$hexadecimal 0x10;

$anotherHexadecimal =0XAF;
?>



See also Integer Syntax

Md5 Strings

[Since 0.8.4] - [ -P Type/Md5String ] - [ Online docs ]

List of all the MD5 values hard coded in the application.

MD5 values are detected as hexadecimal strings, of length 32. No attempt at recognizing the origin value is made, so any such strings, including dummy '11111111111111111111111111111111' are reported.

<?php 
// 32 
   
$a '0cc175b9c0f1b6a831c399e269771111';
?>



See also MD5

Nowdoc Delimiter Glossary

[Since 0.8.4] - [ -P Type/Nowdoc ] - [ Online docs ]

List of all the delimiters used to build a Nowdoc string.

<?php 
$nowdoc = <<<'EOD'

EOD;
?>



See also Nowdoc, Heredoc

Octal Glossary

[Since 0.8.4] - [ -P Type/Octal ] - [ Online docs ]

List of all the integer values using the octal format : an integer starting with an initial 0.

<?php 
$a 1234// decimal number
  
$a 0123// octal number (equivalent to 83 decimal)

  // silently valid for PHP 5.x
  
$a 01283// octal number (equivalent to 10 decimal)
?>


Putting an initial 0 is often innocuous, but in PHP, 0755 and 755 are not the same. The second is actually 1363 in octal, and will not provide the expected privileges.


See also Integers

URL List

[Since 0.8.4] - [ -P Type/Url ] - [ Online docs ]

List of all the URL addresses that were found in the code.

<?php 
// the first argument is recognized as an URL
ftp_connect('http://www.example.com/'$port$timeout);

// the string argument  is recognized as an URL
$source 'https://www.other-example.com/';
?>



See also Uniform Resource Identifier

Variable References

[Since 0.8.4] - [ -P Variables/References ] - [ Online docs ]

Variables that are references.

<?php 
$a '1'// not a reference
$b = &$a// a reference
?>



See also References

Static Variables

[Since 0.8.4] - [ -P Variables/StaticVariables ] - [ Online docs ]

In PHP, variables may be static. They will survive after the function execution end, and will be available at the next function run. They are distinct from globals, which are available application wide, and from static properties, which are tied to a class of objects.

<?php 
function foo() {
    
// static variable
    
static $count 0;
    
    echo ++
$count;
}

class 
bar {
    
// This is not a static variable : 
    // it is a static property
    
static $property 1;
}
?>


See also Using static variables

Variables With Long Names

[Since 0.8.4] - [ -P Variables/VariableLong ] - [ Online docs ]

This analysis collects all variables with more than 20 characters longs. This may be configured with the variableLength parameter.

<?php 
// Quite a long variable name
$There_is nothing_wrong_with_long_variable_names_They_tend_to_be_rare_and_that_make_them_noteworthy 1;
?>


PHP has not limitation on variable name size. While short name are often obscure, long names are usually better. Yet, there exists a limit to convenient variable name length.


See also Basics

Non Ascii Variables

[Since 0.8.4] - [ -P Variables/VariableNonascii ] - [ Online docs ]

PHP allows certain characters in variable names. The variable name must only include letters, figures, underscores and ASCII characters from 128 to 255.

In practice, letters outside the scope of a-zA-Z0-9 are rare, and require more care when editing the code or passing it from OS to OS.

<?php 
class 人 {
    
// An actual working class in PHP.
    
public function __construct() {
        echo 
__CLASS__;
    }
}

$人民 = new ();
?>



See also Variables

Used Once Variables

[Since 0.8.4] - [ -P Variables/VariableUsedOnce ] - [ Online docs ]

This is the list of used once variables.

<?php 
// The variables below never appear again in the code
$writtenOnce 1;

foo($readOnce);
?>


Such variables are useless. Variables must be used at least twice : once for writing, once for reading, at least. It is recommended to remove them.

In special situations, variables may be used once :

+ PHP predefined variables, as they are already initialized. They are omitted in this analyze.
+ Interface function's arguments, since the function has no body; They are omitted in this analyze.
+ Dynamically created variables ($$x, ${$this->y} or also using extract), as they are runtime values and can't be determined at static code time. They are reported for manual review.
+ Dynamically included files will provide in-scope extra variables.

This rule counts variables at the application level, and not at a method scope level.

See also class

Variable Variables

[Since 0.8.4] - [ -P Variables/VariableVariables ] - [ Online docs ]

A variable variable takes the value of a variable and treats that as the name of a variable.

PHP has the ability to dynamically use a variable.

<?php 
// Normal variable
$a 'b';
$b 'c';

// Variable variable
$d = $$b;

// Variable variable in string
$d "$\{$b\}";
?>


They are also called 'dynamic variable'.


See also Variable variables

Abstract Class Usage

[Since 0.8.4] - [ -P Classes/Abstractclass ] - [ Online docs ]

List of all abstract classes being used.

<?php 
abstract class foo {
    function 
foobar(); 
}

class 
bar extends foo {
    
// extended method
    
function foobar() {
        
// doSomething()
    
}

    
// extra method
    
function barbar() {
        
// doSomething()
    
}
}
?>



See also Classes abstraction

Abstract Methods Usage

[Since 0.8.4] - [ -P Classes/Abstractmethods ] - [ Online docs ]

List of all abstract methods being used.

<?php 
// abstract class
abstract class foo {
    
// abstract method
    
function foobar(); 
}

class 
bar extends foo {
    
// extended abstract method
    
function foobar() {
        
// doSomething()
    
}

    
// extra method
    
function barbar() {
        
// doSomething()
    
}
}
?>



See also Classes abstraction

Clone Usage

[Since 0.8.4] - [ -P Classes/CloningUsage ] - [ Online docs ]

List of all clone situations.

<?php 
$dateTime = new DateTime();
    echo (clone 
$dateTime)->format('Y');
?>



See also Object cloning

Bad Constants Names

[Since 0.8.4] - [ -P Constants/BadConstantnames ] - [ Online docs ]

PHP's manual recommends that developer do not use constants with the convention __NAME__ . Those are reserved for PHP future use.

For example, __TRAIT__ recently appeared in PHP, as a magic constant. In the future, other may appear.

<?php 
const __MY_APP_CONST__ 1;

const 
__MY_APP_CONST__ 1;

define('__MY_OTHER_APP_CONST__'2);
?>


The analyzer will report any constant which name is __.*.__ , or even _.*_ (only one underscore).


See also Constants

Variable Constants

[Since 0.8.4] - [ -P Constants/VariableConstant ] - [ Online docs ]

Variable constants are constants whose value is accessed via the function constant(). Otherwise, there is no way to dynamically access a constant (aka, when the developer has the name of the constant as a incoming parameter, and it requires the value of it).

<?php 
const 'constant_value';

$constant_name 'A';

$variableConstant constant($constant_name);
?>



See also `constant() `_

Empty Traits

[Since 0.8.4] - [ -P Traits/EmptyTrait ] - [ Online docs ]

List of all empty trait defined in the code.

<?php 
// empty trait
trait { }

// Another empty trait
trait t2 {
    use 
t
}
?>


Such traits may be reserved for future use. They may also be forgotten, and dead code.

Redefined PHP Traits

[Since 0.8.4] - [ -P Traits/Php ] - [ Online docs ]

List of all traits that bears name of a PHP trait. Although, at the moment (PHP 8.1), there are no PHP trait defined.

Traits Usage

[Since 0.8.4] - [ -P Traits/TraitUsage ] - [ Online docs ]

Usage of traits in the code.

<?php 
trait {
    function 
t() {
        echo 
'I\'m in t';
    }
}

class 
foo {
    use 
t;
}

$x = new foo();
$x->t();
?>



See also Traits

Trait Names

[Since 0.8.4] - [ -P Traits/Traitnames ] - [ Online docs ]

List all the trait's names, found in the code.

<?php 
// This trait is called 't'
trait {}
?>



See also Traits

PHP Alternative Syntax

[Since 0.8.4] - [ -P Php/AlternativeSyntax ] - [ Online docs ]

Identify the usage of alternative syntax in the code, for If then, Switch, While, For and Foreach.

<?php 
// Normal syntax
if ($a == 1) { 
    print 
$a;
}

// Alternative syntax : identical to the previous one.
if ($a == 1) : 
    print 
$a;
endif;
?>



See also Alternative syntax

Short Syntax For Arrays

[Since 0.8.4] - [ -P Arrays/ArrayNSUsage ] - [ Online docs ]

Arrays written with the new short syntax.

PHP 5.4 introduced the new short syntax, with square brackets. The previous syntax, based on the array() keyword is still available.

<?php 
// All PHP versions array
$a = array(123);

// PHP 5.4+ arrays
$a = [123];
?>



See also Array

Inclusions

[Since 0.8.4] - [ -P Structures/IncludeUsage ] - [ Online docs ]

List of all inclusions. Inclusions are made with include(), include_once(), require() and require_once().

<?php 
include 'library.php';

// display is a function defined in 'library.php';
display('Message');
?>


See also Include, Require

ext/file

[Since 0.8.4] - [ -P Extensions/Extfile ] - [ Online docs ]

Filesystem functions from standard.

Extension that handle access to file on the file system.

<?php 
$row 1;
if ((
$handle fopen('test.csv''r')) !== FALSE) {
    while ((
$data fgetcsv($handle1000',')) !== FALSE) {
        
$num count($data);
        echo 
'<p> $num fields in line $row: <br /></p>'.PHP_EOL;
        
$row++;
        for (
$c=0$c $num$c++) {
            echo 
$data[$c] . '<br />'.PHP_EOL;
        }
    }
    
fclose($handle);
}
?>


See also filesystem.

Use With Fully Qualified Name

[Since 0.8.4] - [ -P Namespaces/UseWithFullyQualifiedNS ] - [ Online docs ]

Use statement doesn't require a fully qualified name.

PHP manual recommends not to use fully qualified name (starting with \) when using the 'use' statement : they are "the leading backslash is unnecessary and not recommended, as import names must be fully qualified, and are not processed relative to the current namespace".

<?php 
// Recommended way to write a use statement.
use  A\B\C\D as E;

// No need to use the initial \
use \A\B\C\D as F;
?>


ext/array

[Since 0.8.4] - [ -P Extensions/Extarray ] - [ Online docs ]

Core functions processing arrays.

These functions manipulate arrays in various ways. Arrays are essential for storing, managing, and operating on sets of variables.

This is not a real extension : it is a documentation section, that helps classifying the functions.

<?php 
function odd($var)
{
    
// returns whether the input integer is odd
    
return($var 1);
}

function 
even($var)
{
    
// returns whether the input integer is even
    
return(!($var 1));
}

$array1 = array('a'=>1'b'=>2'c'=>3'd'=>4'e'=>5);
$array2 = array(6789101112);

echo 
'Odd :'.PHP_EOL;
print_r(array_filter($array1'odd'));
echo 
'Even:'.PHP_EOL;
print_r(array_filter($array2'even'));
?>



See also Arrays

ext/info

[Since 0.8.4] - [ -P Extensions/Extinfo ] - [ Online docs ]

PHP Options and Information.

These functions enable you to get a lot of information about PHP itself, e.g. runtime configuration, loaded extensions, version and much more.

<?php 
/*
Our php.ini contains the following settings:

display_errors = On
register_globals = Off
post_max_size = 8M
*/

echo 'display_errors = ' ini_get('display_errors') . "\n";
echo 
'register_globals = ' ini_get('register_globals') . "\n";
echo 
'post_max_size = ' ini_get('post_max_size') . "\n";
echo 
'post_max_size+1 = ' . (ini_get('post_max_size')+1) . "\n";
echo 
'post_max_size in bytes = ' return_bytes(ini_get('post_max_size'));

function 
return_bytes($val) {
    
$val trim($val);
    
$last strtolower($val[strlen($val)-1]);
    switch(
$last) {
        
// The 'G' modifier is available since PHP 5.1.0
        
case 'g':
            
$val *= 1024;
        case 
'm':
            
$val *= 1024;
        case 
'k':
            
$val *= 1024;
    }

    return 
$val;
}
?>



See also PHP Options And Information

ext/math

[Since 0.8.4] - [ -P Extensions/Extmath ] - [ Online docs ]

Core functions that provides math standard functions.

This is not a real extension : it is a documentation section, that helps sorting the functions.

<?php 
echo decbin(12) . PHP_EOL;
echo 
decbin(26);
?>


See also Mathematical Functions.

$HTTP_RAW_POST_DATA Usage

[Since 0.8.4] - [ -P Php/RawPostDataUsage ] - [ Online docs ]

$HTTP_RAW_POST_DATA is deprecated, and should be replaced by php://input .

$HTTP_RAW_POST_DATA is deprecated since PHP 5.6.

It is possible to prepare code to this lack of feature by setting always_populate_raw_post_data to -1.

<?php 
// PHP 5.5 and older
$postdata $HTTP_RAW_POST_DATA;

// PHP 5.6 and more recent
$postdata file_get_contents(php://input);
?>


See also $HTTP_RAW_POST_DATA variable.

Useless Instructions

[Since 0.8.4] - [ -P Structures/UselessInstruction ] - [ Online docs ]

Those instructions are useless, or contains useless parts.

For example, an addition whose result is not stored in a variable, or immediately used, does nothing : it is actually performed, and the result is lost. Just plain lost. In fact, PHP might detect it, and optimize it away.

Here the useless instructions that are spotted :

<?php 
// Concatenating with an empty string is useless.
$string 'This part '.$is.' useful but '.$not.'';

// This is a typo, that PHP turns into a constant, then a string, then nothing.
continue;

// Empty string in a concatenation
$a 'abc' '';

// Returning expression, whose result is not used (additions, comparisons, properties, closures, new without =, ...)
2;

// Returning post-incrementation
function foo($a) {
    return 
$a++;
}

// `array_replace() <https://www.php.net/array_replace>`_ with only one argument
$replaced array_replace($array);
// `array_replace() <https://www.php.net/array_replace>`_ is OK with ... 
$replaced array_replace(...$array);

// @ operator on source array, in foreach, or when assigning literals
$array = @array(1,2,3);

// Multiple comparisons in a for loop : only the last is actually used.
for($i 0$j 0$j 10$i 20; ++$j, ++$i) {
    print 
$i.' '.$j.PHP_EOL;
}

// Counting the keys and counting the array is the same.
$c count(array_keys($array))

//array_keys already provides an array with only unique values, as they were keys in a previous array
$d array_unique(array_keys($file['messages']))

// No need for assignation inside the ternary operator
$closeQuote $openQuote[3] === "'" substr($openQuote4, -2) : $closeQuote substr($openQuote3);
?>


Abstract Static Methods

[Since 0.8.4] - [ -P Classes/AbstractStatic ] - [ Online docs ]

Methods cannot be both abstract and static. Static methods belong to a class, and will not be overridden by the child class. For normal methods, PHP will start at the object level, then go up the hierarchy to find the method. With static, it is necessary to mention the name, or use Late Static Binding, with self or static. Hence, it is useless to have an abstract static method : it should be a static method.

A child class is able to declare a method with the same name than a static method in the parent, but those two methods will stay independent.

This is not the case anymore in PHP 7.0+.

<?php 
abstract class foo {
    
// This is not possible
    
static abstract function bar() ;
}
?>



See also Why does PHP 5.2+ disallow abstract static class methods?

Invalid Constant Name

[Since 0.8.4] - [ -P Constants/InvalidName ] - [ Online docs ]

There is a naming convention for PHP constants names.

According to PHP's manual, constant names, ' A valid constant name starts with a letter or underscore, followed by any number of letters, numbers, or underscores.'.

Constant, must follow this regex : /[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*/ .

In particular when defined using define() function, no error is produced. When using const , on the other hand, the

<?php 
define('+3'1); // wrong constant! 

echo constant('+3'); // invalid constant access
?>



See also Constants

Multiple Constant Definition

[Since 0.8.4] - [ -P Constants/MultipleConstantDefinition ] - [ Online docs ]

Some constants are defined several times in your code. This will lead to a fatal error, if they are defined during the same execution.

Multiple definitions may happens at bootstrap, when the application code is collecting information about the current environment. It may also happen at inclusion time, which one set of constant being loaded, while other definition are not, avoiding conflict. Both are false positive.

<?php 
// OS is defined twice. 
if (PHP_OS == 'Windows') {
    
define('OS''Win');
} else {
    
define('OS''Other');
}
?>



See also class

Wrong Optional Parameter

[Since 0.8.4] - [ -P Functions/WrongOptionalParameter ] - [ Online docs ]

Wrong placement of optional parameters.

PHP parameters are optional when they defined with a default value, like this :

<?php 
function x($arg 1) {
        
// PHP code here
    
}
?>


When a function have both compulsory and optional parameters, the compulsory ones should appear first, and the optional should appear last :

<?php 
function x($arg$arg2 2) {
        
// PHP code here
    
}
?>


PHP solves this problem at runtime, assign values in the same other, but will miss some of the default values and emits warnings.

It is better to put all the optional parameters at the end of the method's signature.

Optional parameter wrongly placed are now a Notice in PHP 8.0. The only previous case that is allowed in PHP 8.0 and also in this analysis, is when the null value is used as default for typed arguments.


See also Function arguments

Use === null

[Since 0.8.4] - [ -P Php/IsnullVsEqualNull ] - [ Online docs ]

It is faster to use === null than the function is_null().

<?php 
// Operator === is faster
if ($a === null) {

}

// Function call is slow 
if (is_null($a)) {

}
?>


This is a micro-optimisation. And being used frequently, and in loops, it may yield visible speed up.


See also is_null

Assertions

[Since 0.8.4] - [ -P Php/AssertionUsage ] - [ Online docs ]

Usage of assertions, to add checks within PHP code.

Assertions should be used as a debugging feature only. You may use them for sanity-checks that test for conditions that should always be TRUE and that indicate some programming errors if not or to check for the presence of certain features like extension functions or certain system limits and features.

<?php 
function foo($string) {
    
assert(!empty($string), 'An empty string was provided!');
    
    echo 
'['.$string.']';
}
?>



See also assert

$this Is Not An Array

[Since 0.8.4] - [ -P Classes/ThisIsNotAnArray ] - [ Online docs ]

$this variable represents the current object and it is not an array.

This is unless the class (or its parents) has the ArrayAccess interface, or extends ArrayObject or SimpleXMLElement .

<?php 
// $this is an array
class Foo extends ArrayAccess {
    function 
bar() {
        ++
$this[3];
    }
}

// $this is not an array
class Foo2 {
    function 
bar() {
        ++
$this[3];
    }
}
?>


See also ArrayAccess, ArrayObject, The Basics

One Variable String

[Since 0.8.4] - [ -P Type/OneVariableStrings ] - [ Online docs ]

These strings only contains one variable or property or array.

<?php 
$a 0;
$b "$a"// This is a one-variable string

// Better way to write the above
$b = (string) $a;

// Alternatives : 
$b2 "$a[1]"// This is a one-variable string
$b3 "$a->b"// This is a one-variable string
$c "d";
$d "D";
$b4 "{$$c}";
$b5 "{$a->foo()}";
?>


When the goal is to convert a variable to a string, it is recommended to use the type casting (string) operator : it is then clearer to understand the conversion. It is also marginally faster, though very little.


See also Strings, Type Juggling

Cast Usage

[Since 0.8.4] - [ -P Php/CastingUsage ] - [ Online docs ]

List of all cast usage.

PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used.

<?php 
if (is_int($_GET['x'])) {
    
$number = (int) $_GET['x'];
} else {
    
error_display('a wrong value was provided for "x"');
}
?>


Until PHP 7.2, a (unset) operator was available. It had the same role as unset() `_ as a function.


See also Type Juggling, unset

Function Subscripting

[Since 0.8.4] - [ -P Structures/FunctionSubscripting ] - [ Online docs ]

It is possible to use the result of a methodcall directly as an array, without storing the result in a temporary variable.

This works, given that the method actually returns an array.

This syntax was not possible until PHP 5.4. Until then, it was compulsory to store the result in a variable first. Although this is now superfluous, it has been a standard syntax in PHP, and is still being used.

<?php 
function foo() {
    return array(
=> 'a''b''c');
}

echo 
foo()[1]; // displays 'a';

// Function subscripting, the old way
function foo() {
    return array(
=> 'a''b''c');
}

$x foo();
echo 
$x[1]; // displays 'a';
?>


Storing the result in a variable is still useful if the result is actually used more than once.


See also Accessing array elements with square bracket syntax

Nested Loops

[Since 0.8.4] - [ -P Structures/NestedLoops ] - [ Online docs ]

Nested loops happens when a loop (while, do..while, for, foreach), is used inside another loop.

<?php 
// Nested loops
foreach($array as $a) {
    foreach (
$letters as $b) {
        
// This is performed count($array) * count($letters) times. 
        
doSomething();
    }
}
?>


Such structure tends to require a lot of processing, as the size of both loops have to be multiplied to estimate the actual payload. They should be avoided as much as possible. This may no be always possible, though.

Nested loops are worth a check for performances reasons, as they will process a lot of times the same instructions.

[Since 0.8.4] - [ -P Php/EchoTagUsage ] - [ Online docs ]

Usage of the short echo tab, , that echo's directly the following content.

?>

Static Methods Can't Contain $this

[Since 0.8.4] - [ -P Classes/StaticContainsThis ] - [ Online docs ]

Static methods are also called class methods : they may be called even if the class has no instantiated object. Thus, the local variable $this won't exist, PHP will set it to NULL as usual.

<?php 
class foo {
    
// Static method may access other static methods, or property, or none. 
    
static function staticBar() {
        
// This is not possible in a static method
        
return self::otherStaticBar() . static::$staticProperty;
    }

    static function 
bar() {
        
// This is not possible in a static method
        
return $this->property;
    }
}
?>


Either this is not a static method, which is fixed by removing the static keyword, or replace all $this mention by static properties Class::$property .


See also `Static Keyword `Static Keyword

While(List() = Each())

[Since 0.8.4] - [ -P Structures/WhileListEach ] - [ Online docs ]

This code structure is quite old : it should be replace by the more modern and efficient foreach.

This structure is deprecated since PHP 7.2. It may disappear in the future.

<?php 
while(list($key$value) = each($array)) {
        
doSomethingWith($key) and $value();
    }

    foreach(
$array as $key => $value) {
        
doSomethingWith($key) and $value();
    }
?>



See also PHP RFC: Deprecations for PHP 7.2 : Each()

Several Instructions On The Same Line

[Since 0.8.4] - [ -P Structures/OneLineTwoInstructions ] - [ Online docs ]

Usually, instructions do not share their line : one instruction, one line.

This is good for readability, and help at understanding the code. This is especially important when fast-reading the code to find some special situation, where such double-meaning line way have an impact.

<?php 
switch ($x) {
    
// Is it a fallthrough or not ? 
    
case 1:
        
doSomething(); break;

    
// Easily spotted break.
    
case 1:
        
doSomethingElse(); 
        break;

    default : 
        
doDefault(); 
        break;
}
?>



See also Object Calisthenics, rule # 5

Multiples Identical Case

[Since 0.8.4] - [ -P Structures/MultipleDefinedCase ] - [ Online docs ]

Some cases are defined multiple times, but only one will be processed. Check the list of cases, and remove the extra one.

Exakat tries to find the value of the case as much as possible, and ignore any dynamic cases (using variables).

<?php 
const 1;

case (
$x) {
    case 

        break;
    case 
true:    // This is a duplicate of the previous
        
break; 
    case 
0:   // This is a duplicate of the previous
        
break; 
    case 
1.0 :    // This is a duplicate of the previous
        
break; 
    case 
:      // The A constant is actually 1
        
break; 
    case 
$y  :    // This is not reported.
        
break; 
    default:
        
}
?>

Switch Without Default

[Since 0.8.4] - [ -P Structures/SwitchWithoutDefault ] - [ Online docs ]

Always use a default statement in switch() and match().

Switch statements hold a number of 'case' that cover all known situations, and a 'default' one which is executed when all other options are exhausted.

For Match statements, a missing default will lead to the UnhandledMatchError exception being raised. On the other hand, the switch statement will simply exit without action nor alert.

<?php 
// Missing default
switch($format) {
    case 
'gif' 
        
processGif();
        break 
1;
    
    case 
'jpeg' 
        
processJpeg();
        break 
1;
        
    case 
'bmp' :
        throw new 
UnsupportedFormat($format);
}
// In case $format is not known, then switch is ignored and no processing happens, leading to preparation errors


// switch with default
switch($format) {
    case 
'text' 
        
processText();
        break 
1;
    
    case 
'jpeg' 
        
processJpeg();
        break 
1;
        
    case 
'rtf' :
        throw new 
UnsupportedFormat($format);
        
    default :
        throw new 
UnknownFileFormat($format);
}
// In case $format is not known, an exception is thrown for processing
?>


Most of the time, switch() do need a default case, so as to catch the odd situation where the 'value is not what it was expected'. This is a good place to catch unexpected values, to set a default behavior.

See also UnhandledMatchError

$this Belongs To Classes Or Traits

[Since 0.8.4] - [ -P Classes/ThisIsForClasses ] - [ Online docs ]

The pseudo-variable $this must be used inside a class or trait, or bound closures.

$this variable represents the current object, inside a class or trait scope

It is a pseudo-variable, and should be used within class's or trait's methods and not outside. It should also not be used in static methods.

PHP 7.1 is stricter and check for $this at several situations.

This analysis also re

<?php 
// as an argument
function foo($this) {
    
// Using global
    
global $this;
    
// Using static (not a property)
    
static $this;
    
    
// Can't unset it
    
unset($this);
    
    try {
        
// inside a foreach
        
foreach($a as $this) {  }
        foreach(
$a as $this => $b) {  }
        foreach(
$a as $b => $this) {  }
    } catch (
Exception $this) {
        
// inside a catch
    
}
    
    
// with Variable Variable
    
$a this;
    $
$a 42;
}

class 
foo {
    function 
bar() {
        
// Using references
        
$a =& $this;
        
$a 42;
        
        
// Using `extract() <https://www.php.net/extract>`_, `parse_str() <https://www.php.net/parse_str>`_ or similar functions
        
extract([this => 42]);  // throw new Error(Cannot re-assign $this)
        
var_dump($this);
    }

    static function 
__call($name$args) {
        
// Using __call
        
var_dump($this); // prints object(C)#1 (0) {}, php-7.0 printed NULL
        
$this->test();   // prints ops
    
}

}
?>



See also class

Nested Ternary

[Since 0.8.4] - [ -P Structures/NestedTernary ] - [ Online docs ]

Ternary operators should not be nested too deep.

They are a convenient instruction to apply some condition, and avoid a if() structure. It works best when it is simple, like in a one liner.

However, ternary operators tends to make the syntax very difficult to read when they are nested. It is then recommended to use an if() structure, and make the whole code readable.

<?php 
// Simple ternary expression
echo ($a == $b $c) ;

// Nested ternary expressions
echo ($a === $d === $b $d $d === $e $c) ;
echo (
$a === $d === $f ===$g $h $d $d === $e $i === $j $k) ;

//Previous expressions, written as a if / Then expression
if ($a === 1) {
    if (
$d === 2) {
        echo 
$b;
    } else {
        echo 
$d;
    }
} else {
    if (
$d === 3) {
        echo 
$e;
    } else {
        echo 
$c;
    }
}

if (
$a === 1) {
    if (
$d === 2) {
        if (
$f === 4) {
            echo 
$g;
        } else {
            echo 
$h;
        }
    } else {
        echo 
$d;
    }
} else {
    if (
$d === 3) {
        echo 
$e;
    } else {
        if (
$i === 5) {
            echo 
$j;
        } else {
            echo 
$k;
        }
    }
}
?>


This is a separate analysis from PHP's preventing nested ternaries without parenthesis.


See also Nested Ternaries are Great, Php/NestedTernaryWithoutParenthesis

Non-constant Index In Array

[Since 0.8.4] - [ -P Arrays/NonConstantArray ] - [ Online docs ]

Undefined constants revert as strings in Arrays. They are also called barewords .

In $array[index] , PHP cannot find index as a constant, but, as a default behavior, turns it into the string index .

This default behavior raise concerns when a corresponding constant is defined, either using define() or the const keyword (outside a class). The definition of the index constant will modify the behavior of the index, as it will now use the constant definition, and not the 'index' string.

<?php 
// assign 1 to the element index in $array
// index will fallback to string
$array[index] = 1
//PHP Notice:  Use of undefined constant index - assumed 'index'

echo $array[index];      // display 1 and the above error
echo "$array[index]";    // display 1
echo "$array['index']";  // Syntax error


define('index'2);
 
 
// now 1 to the element 2 in $array
 
$array[index] = 1;
?>


It is recommended to make index a real string (with ' or "), or to define the corresponding constant to avoid any future surprise.

Note that PHP 7.2 removes the support for this feature.

See also PHP RFC: Deprecate and Remove Bareword (Unquoted) Strings, Syntax

Undefined Constants

[Since 0.8.4] - [ -P Constants/UndefinedConstants ] - [ Online docs ]

Constants definition can't be located.

Those constants are not defined in the code, and will raise errors, or use the fallback mechanism of being treated like a string.

<?php 
const 1;
define('B'2);

// here, C is not defined in the code and is reported
echo A.B.C;
?>


It is recommended to define them all, or to avoid using them.


See also Constants

Instantiating Abstract Class

[Since 0.8.4] - [ -P Classes/InstantiatingAbstractClass ] - [ Online docs ]

PHP cannot instantiate an abstract class.

The classes are actually abstract classes, and should be derived into a concrete class to be instantiated.

<?php 
abstract class Foo {
    protected 
$a;
}

class 
Bar extends Foo {
    protected 
$b;
}

// instantiating a concrete class.
new Bar();

// instantiating an abstract class.
// In real life, this is not possible also because the definition and the instantiation are in the same file
new Foo();
?>



See also Class Abstraction

Class, Interface, Enum Or Trait With Identical Names

[Since 0.8.4] - [ -P Classes/CitSameName ] - [ Online docs ]

The following names are used at the same time for classes, interfaces or traits. For example,

<?php 
class a     /* some definitions */ }
    interface 
/* some definitions */ }
    trait 
a     /* some definitions */ }
    enum 
a      /* some definitions */ // PHP 8.1
?>


Even if they are in different namespaces, identical names makes classes easy to confuse. This is often solved by using alias at import time : this leads to more confusion, as a class suddenly changes its name.

Internally, PHP use the same list for all classes, interfaces and traits. As such, it is not allowed to have both a trait and a class with the same name.

In PHP 4, and PHP 5 before namespaces, it was not possible to have classes with the same name. They were simply included after a check.

Empty Try Catch

[Since 0.8.4] - [ -P Structures/EmptyTryCatch ] - [ Online docs ]

The code does try, then catch errors but do no act upon the error.

<?php 
try { 
    
doSomething();
} catch (
Throwable $e) {
    
// ignore this
}
?>


At worst, the error should be logged, so as to measure the actual usage of the catch expression.

catch( Exception $e) (PHP 5) or catch(Throwable $e) with empty catch block should be banned. They ignore any error and proceed as if nothing happened. At worst, the event should be logged for future analysis.

See also Empty Catch Clause.

ext/pcntl

[Since 0.8.4] - [ -P Extensions/Extpcntl ] - [ Online docs ]

Extension for process control.

Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a web server environment and unexpected results may happen if any Process Control functions are used within a web server environment.

<?php 
declare(ticks=1);

$pid pcntl_fork();
if (
$pid == -1) {
     die(
'could not fork'); 
} else if (
$pid) {
     exit(); 
// we are the parent 
} else {
     
// we are the child
}

// detatch from the controlling terminal
if (posix_setsid() == -1) {
    die(
'could not detach from terminal');
}

// setup signal handlers
pcntl_signal(SIGTERM'sig_handler');
pcntl_signal(SIGHUP'sig_handler');

// loop forever performing tasks
while (1) {

    
// do something interesting here

}

function 
sig_handler($signo
{

     switch (
$signo) {
         case 
SIGTERM:
             
// handle shutdown tasks
             
exit;
             break;
         case 
SIGHUP:
             
// handle restart tasks
             
break;
         default:
             
// handle all other signals
     
}

}
?>


See also Process Control

Undefined Classes

[Since 0.8.4] - [ -P Classes/UndefinedClasses ] - [ Online docs ]

Those classes are used in the code, but there are no definition for them.

This may happens under normal conditions, if the application makes use of an unsupported extension, that defines extra classes;
or if some external libraries, such as PEAR, are not provided during the analysis.

<?php 
// FPDF is a classic PDF class, that is usually omitted by Exakat. 
$o = new FPDF();

// Exakat reports undefined classes in instanceof
// PHP ignores them
if ($o instanceof SomeClass) {
    
// doSomething();
}

// Classes may be used in typehint too
function foo(TypeHintClass $x) {
    
// doSomething();
}
?>


This analysis also checks in attributes.

ext/redis

[Since 0.8.4] - [ -P Extensions/Extredis ] - [ Online docs ]

Extension ext/redis.

The phpredis extension provides an API for communicating with the Redis key-value store.

<?php 
$redis = new Redis();
$redis->connect('127.0.0.1'6379);

$redis->setOption(Redis::OPT_SERIALIZERRedis::SERIALIZER_NONE);    // don't serialize data
$redis->setOption(Redis::OPT_SERIALIZERRedis::SERIALIZER_PHP);    // use built-in serialize/unserialize
$redis->setOption(Redis::OPT_SERIALIZERRedis::SERIALIZER_IGBINARY);    // use igBinary serialize/unserialize

$redis->setOption(Redis::OPT_PREFIX'myAppName:');    // use custom prefix on all keys

/* Options for the SCAN family of commands, indicating whether to abstract
   empty results from the user.  If set to SCAN_NORETRY (the default), phpredis
   will just issue one SCAN command at a time, sometimes returning an empty
   array of results.  If set to SCAN_RETRY, phpredis will retry the scan command
   until keys come back OR Redis returns an iterator of zero
*/
$redis->setOption(Redis::OPT_SCANRedis::SCAN_NORETRY);
$redis->setOption(Redis::OPT_SCANRedis::SCAN_RETRY);
?>




See also A PHP extension for Redis, Redis

Htmlentities Calls

[Since 0.8.4] - [ -P Structures/Htmlentitiescall ] - [ Online docs ]

htmlentities() and htmlspecialchars() are used to prevent injecting special characters in HTML code. As a bare minimum, they take a string and encode it for HTML.

The second argument of the functions is the type of protection. The protection may apply to quotes or not, to HTML 4 or 5, etc. It is highly recommended to set it explicitly.

The third argument of the functions is the encoding of the string. In PHP 5.3, it is ISO-8859-1 , in 5.4, was UTF-8 , and in 5.6, it is now default_charset, a php.ini configuration that has the default value of UTF-8 . It is highly recommended to set this argument too, to avoid distortions from the configuration.

<?php 
$str 'A quote is <b>bold</b>';

// Outputs, without depending on the php.ini: A &#039;quote&#039; is &lt;b&gt;bold&lt;/b&gt; 
echo htmlentities($strENT_QUOTES'UTF-8');

// Outputs, while depending on the php.ini: A quote is &lt;b&gt;bold&lt;/b&gt;
echo htmlentities($str);
?>


Also, note that arguments 2 and 3 are constants and string, respectively, and should be issued from the list of values available in the manual. Other values than those will make PHP use the default values.

See also htmlentities and htmlspecialchars.

Undefined Class Constants

[Since 0.8.4] - [ -P Classes/UndefinedConstants ] - [ Online docs ]

Class constants that are used, but never defined. This should yield a fatal error upon execution, but no feedback at compile level.

This analysis takes into account native PHP class constants, extensions and stubs. It also disambiguate enumeration cases.

<?php 
class foo {
    const 
1;
}

// here, C is not defined in the code and is reported
echo foo::A.foo::B.foo::C;
?>


Constants are searched in the typed class or interface and its parent. They are not searched in the children, since the children are not necesseraly available. In particular, one of the children may not define the constant, and when such child is used, it will satisfy the type, but not the constant definition.


See also Class constants

Used Once Variables (In Scope)

[Since 0.8.4] - [ -P Variables/VariableUsedOnceByContext ] - [ Online docs ]

This is the list of used once variables, scope by scope. Those variables are used once in a function, a method, a class or a namespace. In any case, this means the variable is read or written, while it should be used at least twice.

Static and global variables are omitted here : they may be used multiple times by having the method being called multiple times.

Blind variables, which are defined in a foreach() structure, are also omitted : the loop will use them multiple time, assigning different values each time.

Parameters that are inherited from parent classes' methods are also omitted : they are imposed by the structure, and cannot be avoided.

<?php 
function foo() {
    
// The variables below never appear twice, inside foo()
    
$writtenOnce 1;

    
foo($readOnce);
    
// They do appear again in other functions, or in global space. 
}

function 
bar() {
    
$writtenOnce 1;
    
foo($readOnce);
}
?>


Undefined Functions

[Since 0.8.4] - [ -P Functions/UndefinedFunctions ] - [ Online docs ]

Some functions are called, but not defined in the code. This means that the functions are probably defined in a missing library, or in an extension. If not, this will yield a Fatal error at execution.

<?php 
// Undefined function 
foo($a);

// valid function, as it belongs to the ext/yaml extension
$parsed yaml_parse($yaml);

// This function is not defined in the a\b\c namespace, nor in the global namespace
a\b\c\foo();
?>



See also Functions

Deprecated PHP Functions

[Since 0.8.4] - [ -P Php/Deprecated ] - [ Online docs ]

The following functions are deprecated. It is recommended to stop using them now and replace them with a durable equivalent.

Note that these functions may be still usable : they generate warning that help tracking their usage in the log. To eradicate their usage, watch the logs, and update any deprecated warning. This way, the code won't be stuck when the function is actually removed from PHP.

<?php 
// This is the current function
list($day$month$year) = explode('/''08/06/1995');

// This is deprecated
list($day$month$year) = split('/''08/06/1995');
?>


Dangling Array References

[Since 0.8.4] - [ -P Structures/DanglingArrayReferences ] - [ Online docs ]

Always unset a referenced-variable used in a loop.

It is highly recommended to unset blind variables when they are set up as references after a loop.

<?php 
$array = array(1,2,3,4);

foreach(
$array as &$a) {
    
$a += 1;
}
// This only unset the reference, not the value
unset($a);


// Dangling array problem
foreach($array as &$a) {
    
$a += 1;
}
//$array === array(3,4,5,6);

// This does nothing (apparently)
// $a is already a reference, even if it doesn't show here.
foreach($array as $a) {}
//$array === array(3,4,5,5);
?>


When omitting this step, the next loop that will also require this variable will deal with garbage values, and produce unexpected results.

See also : No Dangling Reference,
PHP foreach pass-by-reference: Do it right, or better not at all,
How does PHP 'foreach' actually work?,
References and foreach.

ext/cyrus

[Since 0.8.4] - [ -P Extensions/Extcyrus ] - [ Online docs ]

Extension ext/cyrus.

The Cyrus IMAP server is electronic mail server software developed by Carnegie Mellon University.

<?php 
$connexion cyrus_connect ('localhost');
?>


See also Cyrus and Cyrus IMAP server.

ext/sqlsrv

[Since 0.8.4] - [ -P Extensions/Extsqlsrv ] - [ Online docs ]

Extension for Microsoft SQL Server Driver.

The SQLSRV extension allows you to access Microsoft SQL Server and SQL Azure databases when running PHP on Windows.

<?php 
$serverName 'serverName\sqlexpress';
$connectionInfo = array( 'Database'=>'dbName''UID'=>'username''PWD'=>'password' );
$conn sqlsrv_connect$serverName$connectionInfo);
if( 
$conn === false ) {
     die( 
print_rsqlsrv_errors(), true));
}

$sql 'INSERT INTO Table_1 (id, data) VALUES (?, ?)';
$params = array(1'some data');

$stmt sqlsrv_query$conn$sql$params);
if( 
$stmt === false ) {
     die( 
print_rsqlsrv_errors(), true));
}
?>


See also Microsoft SQL Server Driver and PHP Driver for SQL Server Support for LocalDB.

Queries In Loops

[Since 0.8.4] - [ -P Structures/QueriesInLoop ] - [ Online docs ]

Avoid querying databases in a loop.

Querying an external database in a loop usually leads to performances problems. This is also called the 'n + 1 problem'.

This problem applies also to prepared statement : when such statement are called in a loop, they are slower than one-time large queries.

It is recommended to reduce the number of queries by making one query, and dispatching the results afterwards. This is true with SQL databases, graph queries, LDAP queries, etc.

<?php 
// Typical N = 1 problem : there will be as many queries as there are elements in $array
$ids = array(1,2,3,5,6,10);

$db = new SQLite3('mysqlitedb.db');

// all the IDS are merged into the query at once
$results $db->query('SELECT bar FROM foo WHERE id  in ('.implode(','$id).')');
while (
$row $results->fetchArray()) {
    
var_dump($row);
}


// Typical N = 1 problem : there will be as many queries as there are elements in $array
$ids = array(1,2,3,5,6,10);

$db = new SQLite3('mysqlitedb.db');

foreach(
$ids as $id) {
    
$results $db->query('SELECT bar FROM foo WHERE id = '.$id);
    while (
$row $results->fetchArray()) {
        
var_dump($row);
    }
}
?>


This optimisation is not always possible : for example, some SQL queries may not be prepared, like DROP TABLE or DESC . UPDATE commands often update one row at a time, and grouping such queries may be counter-productive or unsafe.

Var Keyword

[Since 0.8.4] - [ -P Classes/OldStyleVar ] - [ Online docs ]

Var was used in PHP 4 to mark properties as public. Nowadays, new keywords are available : public, protected, private. Var is equivalent to public.

It is recommended to avoid using var, and explicitly use the new keywords.

<?php 
class foo {
    public 
$bar 1;
    
// Avoid var
    //var $bar = 1; 
}
?>



See also Visibility

Native Alias Functions Usage

[Since 0.8.4] - [ -P Functions/AliasesUsage ] - [ Online docs ]

PHP manual recommends to avoid function aliases.

Some PHP native functions have several names, and both may be used the same way. However, one of the names is the main name, and the others are aliases. Aliases may be removed or change or dropped in the future. Even if this is not forecast, it is good practice to use the main name, instead of the aliases.

<?php 
// official way to count an array
$n count($array);

// official way to count an array
$n sizeof($array);
?>


Aliases are compiled in PHP, and do not provide any performances over the normal function.

Aliases are more likely to be removed later, but they have been around for a long time.


See also List of function aliases

Uses Default Values

[Since 0.8.4] - [ -P Functions/UsesDefaultArguments ] - [ Online docs ]

Default values are provided to methods so as to make it convenient to use. However, with new versions, those values may change. For example, in PHP 5.4, htmlentities() switched from Latin1 to UTF-8 default encoding.

<?php 
$string Eu não sou o pão;

echo 
htmlentities($string);

// PHP 5.3 : Eu n&Atilde;&pound;o sou o p&Atilde;&pound;o
// PHP 5.4 : Eu n&atilde;o sou o p&atilde;o

// Stable across versions
echo htmlentities($string'UTF8');
?>


As much as possible, it is recommended to use explicit values in those methods, so as to prevent from being surprise at a future PHP evolution.

This analyzer tend to report a lot of false positives, including usage of count(). Count() indeed has a second argument for recursive counts, and a default value. This may be ignored safely.

Wrong Number Of Arguments

[Since 0.8.4] - [ -P Functions/WrongNumberOfArguments ] - [ Online docs ]

Those functioncalls are made with too many or too few arguments.

When the number arguments is wrong for native functions, PHP emits a warning.
When the number arguments is too small for custom functions, PHP raises an exception.
When the number arguments is too high for custom functions, PHP ignores the arguments. Such arguments should be handled with the variadic operator, or with func_get_args() family of functions.

<?php 
echo strtoupper('This function is''ignoring arguments');
//Warning: `strtoupper() <https://www.php.net/strtoupper>`_ expects exactly 1 parameter, 2 given in Command line code on line 1

echo `strtoupper() <https://www.php.net/strtoupper>`_;
//Warning: `strtoupper() <https://www.php.net/strtoupper>`_ expects exactly 1 parameter, 0 given in Command line code on line 1

function foo($argument) {}
echo 
foo();
//Fatal error: Uncaught ArgumentCountError: Too few arguments to function foo(), 0 passed in /Users/famille/Desktop/analyzeG3/test.php on line 10 and exactly 1 expected in /Users/famille/Desktop/analyzeG3/test.php:3

echo foo('This function is''ignoring arguments');
?>


It is recommended to check the signature of the methods, and fix the arguments.

Hardcoded Passwords

[Since 0.8.4] - [ -P Functions/HardcodedPasswords ] - [ Online docs ]

Hardcoded passwords in the code.

Hardcoding passwords is a bad idea. Not only it make the code difficult to change, but it is an information leak. It is better to hide this kind of information out of the code.

<?php 
$ftp_server '300.1.2.3';   // yes, this doesn't exists, it's an example
$conn_id ftp_connect($ftp_server); 

// login with username and password
$login_result ftp_login($conn_id'login''password');
?>



See also 10 GitHub Security Best Practices, Git How-To: Remove Your Password from a Repository

Unresolved Classes

[Since 0.8.4] - [ -P Classes/UnresolvedClasses ] - [ Online docs ]

The following classes are instantiated in the code, but their definition couldn't be found.

<?php 
class Foo extends Bar {
    private function 
foobar() {
        
// here, parent is not resolved, as Bar is not defined in the code.
        
return parent::$prop;
    }
}
?>


Ellipsis Usage

[Since 0.8.4] - [ -P Php/EllipsisUsage ] - [ Online docs ]

Usage of the ellipsis keyword. The keyword is three dots : ... . It is also named variadic or splat operator.

It may be in function definitions, either in functioncalls.

... allows for packing or unpacking arguments into an array.

<?php 
$args = [123];
foo(...$args); 
// Identical to foo(1,2,3);

function bar(...$a) {
    
// Identical to : $a = `func_get_args() <https://www.php.net/func_get_args>`_;
}
?>



See also PHP RFC: Syntax for variadic functions, PHP 5.6 and the Splat Operator, Variable-length argument lists

Useless Constructor

[Since 0.8.4] - [ -P Classes/UselessConstructor ] - [ Online docs ]

Class constructor that have empty bodies are useless. They may be removed, if they are not called.

<?php 
class {
    function 
__construct() {
        
// Do nothing
    
}
}

class 
extends {
    
// Useful constructor, as it prevents usage of the parent
    
function __construct() {
        
// Do nothing
    
}
}
?>

Implements Is For Interface

[Since 0.8.4] - [ -P Classes/ImplementIsForInterface ] - [ Online docs ]

With class heritage, implements should be used for interfaces, and extends with classes.

PHP defers the implements check until execution : the code in example does lint, but won,t run.

<?php 
class {
    function 
foo() {}
}

interface 
{
    function 
foo();
}

// Use implements with an interface
class implements {}

// Implements is for an interface, not a class
class implements {}
?>

Use const

[Since 0.8.4] - [ -P Constants/ConstRecommended ] - [ Online docs ]

The const keyword may be used to define constant, just like the define() function.

When defining a constant, it is recommended to use 'const' when the features of the constant are not dynamical (name or value are known at compile time).
This way, constant will be defined at compile time, and not at execution time.

<?php 
//Do
  
const 1;
  
// Don't 
  
define('A'1);
?>


define() function is useful when the constant is not known at compile time, or when case sensitivity is necessary.

<?php 
// Read $a in database or config file
  
define('A'$a);

  
// Read $a in database or config file
  
define('B'1true);
  echo 
b;
?>



See also Syntax

Unresolved Use

[Since 0.8.4] - [ -P Namespaces/UnresolvedUse ] - [ Online docs ]

The following use instructions cannot be resolved to a known class, interface, trait, constant or function. They should be dropped or fixed.

A known class, interface, trait, constant or function is defined in PHP (standard), an extension, a stub or the current code.

<?php 
namespace {
    
// class B is defined
    
class {}
    
// class C is not defined
}

namespace 
X/{

    use 
A/B;  // This use is valid
    
use A/C;  // This use point to nothing.

    
new B();
    new 
C();
}
?>


Use expression are options for the current namespace.


See also Using namespaces: Aliasing/Importing

Undefined Parent

[Since 0.8.4] - [ -P Classes/UndefinedParentMP ] - [ Online docs ]

List of properties and methods that are accessed using parent keyword but are not defined in the parent classes.

This may compile but, eventually yields a fatal error during execution.

<?php 
class theParent {
    
// No bar() method
    // private bar() method is not accessible to theChild 
}

class 
theChild extends theParent {
    function 
foo() {
        
// bar is defined in theChild, but not theParent
        
parent::bar();
    }
    
    function 
bar() {
    
    }
}
?>


Note that if the parent is defined using extends someClass but someClass is not available in the tested code, it will not be reported : it may be in composer, another dependency, or just missing.

See also parent.

Undefined static:: Or self::

[Since 0.8.4] - [ -P Classes/UndefinedStaticMP ] - [ Online docs ]

The identified property or method are undefined. self and static refer to the current class, or one of its parent or trait.

<?php 
class {
    static public function 
definedStatic() {}
    private 
definedStatic 1;
    
    public function 
method() {
        
self::definedStatic();
        
self::undefinedStatic();

        static::
definedStatic;
        static::
undefinedStatic;
    }
}
?>



See also Late Static Bindings

Accessing Private

[Since 0.8.4] - [ -P Classes/AccessPrivate ] - [ Online docs ]

List of calls to private properties/methods that will compile but yield some fatal error upon execution.

<?php 
class {
    private 
$a;
}

class 
extends {
    function 
c() {
        
$this->a;
    }
}
?>

Access Protected Structures

[Since 0.8.4] - [ -P Classes/AccessProtected ] - [ Online docs ]

It is not allowed to access protected properties, methods or constants from outside the class or its relatives.

<?php 
class foo {
    protected 
$bar 1;
}

$foo = new Foo();
$foo->bar 2;
?>



See also Visibility., Understanding The Concept Of Visibility In Object Oriented PHP

Parent, Static Or Self Outside Class

[Since 0.8.4] - [ -P Classes/PssWithoutClass ] - [ Online docs ]

Parent, static and self keywords must be used within a class or a trait. They make no sense outside a class or trait scope, as self and static refers to the current class and parent refers to one of parent above.

PHP 7.0 and later detect some of their usage at compile time, and emits a fatal error.

<?php 
class {
    const 
1;
    
    function 
foo() {
        
// self is \x
        
echo self::Y;
    }
}

const 
1;
// This lint but won't anymore
echo self::Z;
?>


Static may be used in a function or a closure, but not globally.

ext/0mq

[Since 0.8.4] - [ -P Extensions/Extzmq ] - [ Online docs ]

Extension ext/zmq for 0mq .

ØMQ is a software library that lets you quickly design and implement a fast message-based application.

<?php 
// Example from https://github.com/kuying/ZeroMQ/blob/d80dcc3dc1c14a343ca90bbd656b98fd55366548/zguide/examples/PHP/msgqueue.php
    /*
     *  Simple message queuing broker
     *  Same as request-reply broker but using QUEUE device
     * @author Ian Barber <ian(dot)barber(at)gmail(dot)com>
     */
    
$context = new ZMQContext();
    
//  Socket facing clients
    
$frontend $context->getSocket(ZMQ::SOCKET_ROUTER);
    
$frontend->bind(tcp://*:5559);
    //  Socket facing services
    
$backend $context->getSocket(ZMQ::SOCKET_DEALER);
    
$backend->bind(tcp://*:5560);
    //  Start built-in device
    
new ZMQDevice($frontend$backend);
?>



See also ZeroMQ, ZMQ

ext/memcache

[Since 0.8.4] - [ -P Extensions/Extmemcache ] - [ Online docs ]

Extension Memcache.

Memcache module provides handy procedural and object oriented interface to memcached, highly effective caching daemon, which was especially designed to decrease database load in dynamic web applications.

<?php 
$memcache = new Memcache;
$memcache->connect('localhost'11211) or die ('Could not connect');

$version $memcache->getVersion();
echo 
'Server\'s version: '.$version.'<br/>';

$tmp_object = new stdClass;
$tmp_object->str_attr 'test';
$tmp_object->int_attr 123;

$memcache->set('key'$tmp_objectfalse10) or die ('Failed to save data at the server');
echo 
'Store data in the cache (data will expire in 10 seconds)<br/>';

$get_result $memcache->get('key');
echo 
'Data from the cache:<br/>';

var_dump($get_result);
?>


See also Memcache on PHP and memcached.

ext/memcached

[Since 0.8.4] - [ -P Extensions/Extmemcached ] - [ Online docs ]

Extension ext-memcached.

This extension uses the libmemcached library to provide an API for communicating with memcached servers. It also provides a session handler (`memcached`).

<?php 
$m = new Memcached();
$m->addServer('localhost'11211);

$m->set('foo'100);
var_dump($m->get('foo'));
?>



See also ext/memcached manual, memcached

Dynamic Function Call

[Since 0.8.4] - [ -P Functions/Dynamiccall ] - [ Online docs ]

Mark a functioncall made with a variable name.

<?php 
// function definition
function foo() {}

// function name is in a variable, as a string.
$var 'foo'

// dynamic call of a function
$var();

call_user_func($var);
?>


Has Variable Arguments

[Since 0.8.4] - [ -P Functions/VariableArguments ] - [ Online docs ]

Indicates if this function or method accept an arbitrary number of arguments, based on func_get_args(), func_get_arg() and func_num_args() usage.

<?php 
// Fixed number of arguments
function fixedNumberOfArguments($a$b) {
    if (`
func_num_args() <https://www.php.net/func_num_args>`2) {
        
$c = `func_get_args() <https://www.php.net/func_get_args>`_;
        
array_shift($c); // $a
        
array_shift($c); // $b
    
}
    
// do something
}

// Fixed number of arguments
function fixedNumberOfArguments($a$b$c 1) {}
?>


Multiple Catch

[Since 0.8.4] - [ -P Structures/MultipleCatch ] - [ Online docs ]

Indicates if a try structure have several catch statement.

<?php 
// This try has several catch
try {
    
doSomething();
} catch (
RuntimeException $e) {
    
processRuntimeException();
} catch (
OtherException $e) {
    
processOtherException();
}
?>

Dynamically Called Classes

[Since 0.8.4] - [ -P Classes/VariableClasses ] - [ Online docs ]

Indicates if a class is called dynamically.

<?php 
// This class is called dynamically
class {
    const 
CONSTANTE 1;
}

$classe 'X';

$x = new $classe();

echo 
$x::CONSTANTE;
?>


Conditioned Function

[Since 0.8.4] - [ -P Functions/ConditionedFunctions ] - [ Online docs ]

Indicates if a function is defined only if a condition is met.

<?php 
// This is a conditioned function. 
// it only exists if the PHP binary doesn't have it already.
if (!function_exists('join')) {
    function 
join($glue$array) {
        return 
implode($glue$array);
    }

}
?>


Conditioned Constants

[Since 0.8.4] - [ -P Constants/ConditionedConstants ] - [ Online docs ]

Indicates if a constant will be defined only if a condition is met.

<?php 
if (time() > 1519629617) {
    
define('MY_CONST'false);
} else {
    
define('MY_CONST'time() - 1519629617);
}
?>

Is Generator

[Since 0.8.4] - [ -P Functions/IsGenerator ] - [ Online docs ]

Mark as such functions or methods that are using yield and yield from.

<?php 
function generator() {
    yield from 
generator2();
    
    return 
3;
}

function 
generator2() {
    yield 
1;
    yield 
2;
}
?>


See also Generators overview

Try With Finally

[Since 0.8.4] - [ -P Structures/TryFinally ] - [ Online docs ]

Indicates if a try use a finally statement.

<?php 
try {
    
$a doSomething();
} catch (
Throwable $e) {
    
// Fix the problem
} finally {
    
// remove $a anyway
    
unset($a);
}
?>



See also Exceptions

Dereferencing String And Arrays

[Since 0.8.4] - [ -P Structures/DereferencingAS ] - [ Online docs ]

PHP allows the direct dereferencing of strings and arrays.

This was added in PHP 5.5. There is no need anymore for an intermediate variable between a string and array (or any expression generating such value) and accessing an index.

<?php 
$x = array(4,5,6); 
$y $x[2] ; // is 6

May be replaced by 
$y 
= array(4,5,6)[2];
$y = [4,5,6][2];
?>


list() May Omit Variables

[Since 0.8.4] - [ -P Structures/ListOmissions ] - [ Online docs ]

Simply omit any unused variable in a list() call.

list() is the only PHP function that accepts to have omitted arguments. If the following code makes no usage of a listed variable, just omit it.

<?php 
// No need for '2', so no assignation
    
list ($a, , $b) = array(123);
    
    
// works with PHP 7.1 short syntax
    
[$a, , $b] = array(123);

    
// No need for '2', so no assignation
    
list ($a$c$b) = array(123);
?>


See also list.

Or Die

[Since 0.8.4] - [ -P Structures/OrDie ] - [ Online docs ]

Classic old style failed error management.

<?php 
// In case the connexion fails, this kills the current script
mysql_connect('localhost'$user$pass) or die();
?>


Interrupting a script will leave the application with a blank page, will make your life miserable for testing. Just don't do that.

See also pg_last_error or
PDO::exec.

Constant Scalar Expressions

[Since 0.8.4] - [ -P Structures/ConstantScalarExpression ] - [ Online docs ]

Define constant with the result of static expressions. This means that constants may be defined with the const keyword, with the help of various operators but without any functioncalls.

This feature was introduced in PHP 5.6. It also supports array(), and expressions in arrays.

Those expressions (using simple operators) may only manipulate other constants, and all values must be known at compile time.

<?php 
// simple definition
const 1;

// constant scalar expression
const 3;

// constant scalar expression
const = [** 3'3' => B];
?>


See also Constant Scalar Expressions.

Written Only Variables

[Since 0.8.4] - [ -P Variables/WrittenOnlyVariable ] - [ Online docs ]

Those variables are being written, but never read. This way, they are useless and should be removed, or read at some point.

<?php 
// $a is used multiple times, but never read
$a 'a';
$a .= 'b';

$b 3
//$b is actually read once
$a .= $b 3;
?>

Must Return Methods

[Since 0.8.4] - [ -P Functions/MustReturn ] - [ Online docs ]

The following methods are expected to return a value that will be used later. Without return, they are useless.

Methods that must return are : __get(), __isset(), __sleep(), __toString(), __set_state(), __invoke(), __debugInfo().

Methods that may not return, but are often expected to : __call(), __callStatic().

<?php 
class foo {
    public function 
__isset($a) {
        
// returning something useful
        
return isset($this->$var[$a]);
    }

    public function 
__get($a) {
        
$this->$a++;
        
// not returning... 
    
}

    public function 
__call($name$args) {
        
$this->$name(...$args);
        
// not returning anything, but that's OK
    
}

}
?>



Empty Instructions

[Since 0.8.4] - [ -P Structures/EmptyLines ] - [ Online docs ]

Empty instructions are part of the code that have no instructions.

This may be trailing semi-colon or empty blocks for if-then structures.

Comments that explains the reason of the situation are not taken into account.

<?php 
$condition 3;;;;
    if (
$condition) { }
?>


ext/imagick

[Since 0.8.4] - [ -P Extensions/Extimagick ] - [ Online docs ]

Extension Imagick for PHP.

Imagick is a native php extension to create and modify images using the ImageMagick API.

<?php 
header('Content-type: image/jpeg');

$image = new Imagick('image.jpg');

// If 0 is provided as a width or height parameter,
// aspect ratio is maintained
$image->thumbnailImage(1000);

echo 
$image;
?>



See also Imagick for PHP, Imagick

ext/oci8

[Since 0.8.4] - [ -P Extensions/Extoci8 ] - [ Online docs ]

Extension ext/oci8.

OCI8 gives access Oracle Database 12c, 11g, 10g, 9i and 8i.

<?php 
$conn oci_connect('hr''welcome''localhost/XE');
if (!
$conn) {
    
$e oci_error();
    
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}

// Prepare the statement
$stid oci_parse($conn'SELECT * FROM departments');
if (!
$stid) {
    
$e oci_error($conn);
    
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}

// Perform the logic of the query
$r oci_execute($stid);
if (!
$r) {
    
$e oci_error($stid);
    
trigger_error(htmlentities($e['message'], ENT_QUOTES), E_USER_ERROR);
}

// Fetch the results of the query
print '<table border='1'>' PHP_EOL;
while (
$row oci_fetch_array($stidOCI_ASSOC+OCI_RETURN_NULLS)) {
    print 
'<tr>' PHP_EOL;
    foreach (
$row as $item) {
        print 
'    <td>' . ($item !== null htmlentities($itemENT_QUOTES) : '&nbsp;') . '</td>' PHP_EOL;
    }
    print 
'</tr>' PHP_EOL;
}
print 
'</table>' PHP_EOL;

oci_free_statement($stid);
oci_close($conn);
?>


See also Oracle OCI8 and Oracle.

Overwritten Exceptions

[Since 0.8.4] - [ -P Exceptions/OverwriteException ] - [ Online docs ]

In catch blocks, it is good practice to avoid overwriting the incoming exception, as information about the exception will be lost.

<?php 
try {
    
doSomething();
} catch (
SomeException $e) { 
    
// $e is overwritten 
    
$e = new anotherException($e->getMessage()); 
    throw 
$e;
} catch (
SomeOtherException $e) { 
    
// $e is chained with the next exception 
    
$e = new Exception($e->getMessage(), 0$e); 
    throw 
$e;
}
?>

Foreach Reference Is Not Modified

[Since 0.8.4] - [ -P Structures/ForeachReferenceIsNotModified ] - [ Online docs ]

Foreach statement may loop using a reference, especially when the loop has to change values of the array it is looping on.

In the spotted loop, reference are used but never modified. They may be removed.

<?php 
$letters range('a''z');

// $letter is not used here
foreach($letters as &$letter) {
    
$alphabet .= $letter;
}

// $letter is actually used here
foreach($letters as &$letter) {
    
$letter strtoupper($letter);
}
?>


ext/imap

[Since 0.8.4] - [ -P Extensions/Extimap ] - [ Online docs ]

Extension ext/imap.

This extension operate with the IMAP protocol, as well as the NNTP, POP3 and local mailbox access methods.

<?php 
$mbox imap_open('{imap.example.org}''username''password'OP_HALFOPEN)
      or die(
'can't connect' . imap_last_error());

$list = imap_list($mbox, '
{imap.example.org}', '*');
if (is_array($list)) {
    foreach ($list as $val) {
        echo imap_utf7_decode($val) . PHP_EOL;
    }
} else {
    echo '
imap_list failed' . imap_last_error() . PHP_EOL;
}

imap_close($mbox);
?>


See also IMAP.

Overwritten Class Constants

[Since 0.8.4] - [ -P Classes/OverwrittenConst ] - [ Online docs ]

Those class constants are overwriting a parent class's constant. This may lead to confusion, as the value of the constant may change depending on the way it is called.

<?php 
class foo {
    const 
1;
}

class 
bar extends foo {
    const 
2;
    
    function 
x() {
        
// depending on the access to C, value is different.
        
print self::C.' '.static::C.' '.parent::C;
    }
}
?>


Dynamic Class Constant

[Since 0.8.4] - [ -P Classes/DynamicConstantCall ] - [ Online docs ]

Dynamic calls to class constants.

Constant may be dynamically called with the constant() function.

<?php 
// Dynamic access to 'E_ALL'
    
echo constant('E_ALL');
    
    interface 
{
        const 
MY_CONSTANT  1;
    }

    
// Dynamic access to 'E_ALL'
    
echo constant('i::MY_CONSTANT');
?>


Dynamic Methodcall

[Since 0.8.4] - [ -P Classes/DynamicMethodCall ] - [ Online docs ]

Dynamic calls to class methods.

<?php 
class {
    static public function 
foo() {}
           public function 
bar() {}
}

$staticmethod 'foo';
// dynamic static method call to x::foo()
x::$staticmethod();

$method 'bar';
// dynamic method call to bar()
$object = new x();
$object->$method();
?>


Dynamic New

[Since 0.8.4] - [ -P Classes/DynamicNew ] - [ Online docs ]

Dynamic instantiation of classes. It happens when the name of the class is an executable expression, and, as such, only known at execution time.

<?php 
$classname foo();  
    
$object = new $classname();
    
    
$object = new (foo());
?>



Dynamic Property

[Since 0.8.4] - [ -P Classes/DynamicPropertyCall ] - [ Online docs ]

Dynamic access to class property. This is when the the name of the property is stored in a variable (or other container), rather than statically provided.

<?php 
class {
    static public 
$foo 1;
           public 
$bar 2;
}

$staticproperty 'foo';
// dynamic static property call to x::$foo
echo x::${$staticproperty};

$property 'bar';
// dynamic property call to bar()
$object = new x();
$object->$property 4;
?>



See also class

Don't Change Incomings

[Since 0.8.4] - [ -P Structures/NoChangeIncomingVariables ] - [ Online docs ]

PHP hands over a lot of information using special variables like $_GET, $_POST, etc... Modifying those variables and those values inside variables means that the original content is lost, while it will still look like raw data, and, as such, will be untrustworthy.

<?php 
// filtering and keeping the incoming value. 
$_DATA'id'] = (int) $_GET['id'];

// filtering and changing the incoming value. 
$_GET['id'] = strtolower($_GET['id']);
?>


It is recommended to put the modified values in another variable, and keep the original one intact.

Dynamic Classes

[Since 0.8.4] - [ -P Classes/DynamicClass ] - [ Online docs ]

Dynamic calls of classes.

<?php 
class {
    static function 
staticMethod() {}
}

$class 'x';
$class::staticMethod();
?>


Compared Comparison

[Since 0.8.4] - [ -P Structures/ComparedComparison ] - [ Online docs ]

Usually, comparison are sufficient, and it is rare to have to compare the result of comparison. Check if this two-stage comparison is really needed.

<?php 
if ($a === strpos($string$needle) > 2) {}

// the expression above apply precedence : 
// it is equivalent to : 
if (($a === strpos($string$needle)) > 2) {}
?>



See also Operators Precedence

Useless Return

[Since 0.8.4] - [ -P Functions/UselessReturn ] - [ Online docs ]

The spotted functions or methods have a return statement, but this statement is useless. This is the case for constructor and destructors, whose return value are ignored or inaccessible.

When return is void, and the last element in a function, it is also useless.

<?php 
class foo {
    function 
__construct() {
        
// return is not used by PHP
        
return 2;
    }
}

function 
bar(&$a) {
    
$a++;
    
// The last return, when empty, is useless
    
return;
}
?>

Multiple Classes In One File

[Since 0.8.4] - [ -P Classes/MultipleClassesInFile ] - [ Online docs ]

It is regarded as a bad practice to store several classes in the same file. This is usually done to make life of __autoload() easier.

It is often unexpected to find class foo in the bar.php file. This is also the case for interfaces and traits.

<?php 
// three classes in the same file
class foo {}
class 
bar {}
class 
foobar{}
?>


One good reason to have multiple classes in one file is to reduce include time by providing everything into one nice include.

See also Is it a bad practice to have multiple classes in the same file?.

File Uploads

[Since 0.8.4] - [ -P Structures/FileUploadUsage ] - [ Online docs ]

This code makes usage of file upload features of PHP.

Upload file feature is detected through the usage of specific functions :

<?php 
$uploaddir '/var/www/uploads/';
$uploadfile $uploaddir basename($_FILES['userfile']['name']);

echo 
'<pre>';
if (
move_uploaded_file($_FILES['userfile']['tmp_name'], $uploadfile)) {
    echo 
'File is valid, and was successfully uploaded.'.PHP_EOL;
} else {
    echo 
'Possible file upload attack!'.PHP_EOL;
}

echo 
'Here is some more debugging info:';
print_r($_FILES);

print 
'</pre>';
?>



See also Handling file uploads

Unused Classes

[Since 0.8.4] - [ -P Classes/UnusedClass ] - [ Online docs ]

The following classes are never explicitly used in the code.

Note that this may be valid in case the current code is a library or framework, since it defines classes that are used by other (unprovided) codes.
Also, this analyzer may find classes that are, in fact, dynamically loaded.

<?php 
class unusedClasss {}
class 
usedClass {}

$y = new usedClass();
?>



See also class

ext/intl

[Since 0.8.4] - [ -P Extensions/Extintl ] - [ Online docs ]

Extension international.

Internationalization extension (further is referred as Intl) is a wrapper for ICU library, enabling PHP programmers to perform various locale-aware operations including but not limited to formatting, transliteration, encoding conversion, calendar operations, UCA-conformant collation, locating text boundaries and working with locale identifiers, timezones and graphemes.

<?php 
$coll = new Collator('en_US');
$al   $coll->getLocale(Locale::ACTUAL_LOCALE);
echo 
Actual locale$al\n;

$formatter = new NumberFormatter('en_US'NumberFormatter::DECIMAL);
echo 
$formatter->format(1234567);
?>



See also Internationalization Functions

Dynamic Code

[Since 0.8.4] - [ -P Structures/DynamicCode ] - [ Online docs ]

List of instructions that were left during analysis, as they rely on dynamic data.

<?php 
// Dynamic call to 'method';
$name 'method';
$object->$name();

// Hard coded call to 'method';
$object->method();
?>


Any further analysis will need to start from here.

See also Variable functions.

Unpreprocessed Values

[Since 0.8.4] - [ -P Structures/Unpreprocessed ] - [ Online docs ]

Preprocessing values is the preparation of values before PHP executes the code.

There is no macro language in PHP, that prepares the code before compilation, bringing some comfort and short syntax. Most of the time, one uses PHP itself to preprocess data.

For example :

<?php 
$days_en 'monday,tuesday,wednesday,thursday,friday,saturday,sunday';
    
$days_zh '星期-,星期二,星期三,星期四,星期五,星期六,星期日';

    
$days explode(','$lang === 'en' $days_en $days_zh);
?>


could be written

<?php 
if ($lang === 'en') {
        
$days = ['monday''tuesday''wednesday''thursday''friday''saturday''sunday'];
    } else {
        
$days = ['星期-''星期二''星期三''星期四''星期五''星期六''星期日'];
    }
?>


and avoid preprocessing the string into an array first.

Preprocessing could be done anytime the script includes all the needed values to process the expression.

ext/pspell

[Since 0.8.4] - [ -P Extensions/Extpspell ] - [ Online docs ]

Extension pspell.

These functions allow you to check the spelling of a word and offer suggestions.

<?php 
$pspell_link pspell_new('en');

if (
pspell_check($pspell_link'testt')) {
    echo 
'This is a valid spelling';
} else {
    echo 
'Sorry, wrong spelling';
}
?>



See also Pspell, pspell

No Direct Access

[Since 0.8.4] - [ -P Structures/NoDirectAccess ] - [ Online docs ]

This expression protects files against direct access. It will kill the process if it realizes this is not supposed to be directly accessed.

Those expressions are used in applications and framework, to prevent direct access to definition files.

<?php 
// CONSTANT_EXEC is defined in the main file of the application
  
defined('CONSTANT_EXEC') or die('Access not allowed'); : Constant used!
?>

ext/opcache

[Since 0.8.4] - [ -P Extensions/Extopcache ] - [ Online docs ]

Extension opcache.

OPcache improves PHP performance by storing precompiled script bytecode in shared memory, thereby removing the need for PHP to load and parse scripts on each request.

<?php 
echo opcache_compile_file('/var/www/index.php');

print_r(opcache_get_status());
?>


See also OPcache functions.

ext/expect

[Since 0.8.4] - [ -P Extensions/Extexpect ] - [ Online docs ]

Extension Expect.

This extension allows to interact with processes through PTY . You may consider using the expect:// wrapper with the filesystem functions which provide a simpler and more intuitive interface.

<?php 
ini_set('expect.loguser''Off');

$stream fopen('expect://ssh root@remotehost uptime''r');

$cases = array (
    array (
=> 'password:'=> PASSWORD)
);

switch (
expect_expectl ($stream$cases)) {
    case 
PASSWORD:
        
fwrite ($stream'password'.PHP_EOL);
        break;
 
    default:
        die (
'Error was occurred while connecting to the remote host!'.PHP_EOL);
}

while (
$line fgets($stream)) {
      print 
$line;
}
fclose ($stream);
?>


See also expect.

Undefined Properties

[Since 0.8.4] - [ -P Classes/UndefinedProperty ] - [ Online docs ]

List of properties that are not explicitly defined in the class, its parents or traits.

<?php 
class foo {
    
// property definition
    
private bar 2;
    
    function 
foofoo() {
        
// $this->bar is defined in the class
        // $this->barbar is NOT defined in the class
        
return $this->bar $this->barbar;
    }
}
?>


It is possible to spot unidentified properties by using the PHP's magic methods __get and __set . Even if the class doesn't use magic methods, any call to an undefined property will be directed to those methods, and they can be used as a canary, warning that the code is missing a definition.

<?php 
trait NoUnefinedProperties {
    function 
__get($name) {
        
assert(false"Attempt to read the $name property, on the class ".__CLASS__;
    }

    function 
__set($name$value) {
        
assert(false"Attempt to read the $name property, on the class ".__CLASS__;
    }
}
?>


In PHP 8.2, undefined properties are reported as deprecated. They will be a Fatal Error in PHP 9.0.


See also Properties

ext/parsekit

[Since 0.8.4] - [ -P Extensions/Extparsekit ] - [ Online docs ]

Extension Parsekit.

These functions allow runtime analysis of opcodes compiled from PHP scripts.

<?php 
var_dump(parsekit_compile_file('hello_world.php'$errorsPARSEKIT_SIMPLE));
?>


See also Parsekit.

ext/gettext

[Since 0.8.4] - [ -P Extensions/Extgettext ] - [ Online docs ]

Extension Gettext.

The gettext functions implement an NLS (Native Language Support) API which can be used to internationalize your PHP applications.

<?php 
// Set language to German
putenv('LC_ALL=de_DE');
setlocale(LC_ALL'de_DE');

// Specify location of translation tables
bindtextdomain('myPHPApp''./locale');

// Choose domain
textdomain('myPHPApp');

// Translation is looking for in ./locale/de_DE/LC_MESSAGES/myPHPApp.mo now

// Print a test message
echo gettext('Welcome to My PHP Application');

// Or use the alias _() for gettext()
echo _('Have a nice day');
?>



See also Gettext, ext/gettext

Short Open Tags

[Since 0.8.4] - [ -P Php/ShortOpenTagRequired ] - [ Online docs ]

Usage of short open tags is discouraged. The following files were found to be impacted by the short open tag directive at compilation time. They must be reviewed to ensure no <? tags are found in the code.

Strict Comparison With Booleans

[Since 0.8.4] - [ -P Structures/BooleanStrictComparison ] - [ Online docs ]

Strict comparisons prevent from mistaking an error with a false.

Boolean values may be easily mistaken with other values, especially when the function may return integer or boolean as a normal course of action.

It is encouraged to use strict comparison === or !== when booleans are involved in a comparison.

<?php 
// distinguish between : $b isn't in $a, and, $b is at the beginning of $a 
if (strpos($a$b) === 0) {
    
doSomething();
}

// DOES NOT distinguish between : $b isn't in $a, and, $b is at the beginning of $a 
if (strpos($a$b)) {
    
doSomething();
}

// will NOT mistake 1 and true
$a = array(012true);
if (
in_array($atruetrue)) {
    
doSomething();
}

// will mistake 1 and true
$a = array(012true);
if (
in_array($atrue)) {
    
doSomething();
}
?>


switch() structures always uses `==` comparisons. Since PHP 8.0, it is possible to use match() to have strict comparisons.

Native function in_array() has a third parameter to make it use strict comparisons.

Lone Blocks

[Since 0.8.4] - [ -P Structures/LoneBlock ] - [ Online docs ]

Any grouped code without a commanding structure is useless.

Blocks are compulsory when defining a structure, such as a class or a function. They are most often used with flow control instructions, like if then or switch.

Blocks are also valid syntax that group several instructions together, though they have no effect at all, except confuse the reader. Most often, it is a ruin from a previous flow control instruction, whose condition was removed or commented. They should be removed.

<?php 
// Lone block
    //foreach($a as $b) 
    
{
        
$b++;
    }
?>


$this Is Not For Static Methods

[Since 0.8.4] - [ -P Classes/ThisIsNotForStatic ] - [ Online docs ]

Static methods shouldn't use $this variable.

$this variable represents an object, the current object. It is not compatible with a static method, which may operate without any object.

While executing a static method, $this is actually set to NULL.

<?php 
class foo {
    static 
$staticProperty 1;

    
// Static methods should use static properties
    
static public function `count() <https://www.php.net/count>`{
        return 
self::$staticProperty++;
    }
    
    
// Static methods can't use $this
    
static public function bar() {
        return 
$this->a;   // No $this usage in a static method
    
}
}
?>


See also Static Keyword.

Super Global Usage

[Since 0.8.4] - [ -P Php/SuperGlobalUsage ] - [ Online docs ]

Spot usage of Super global variables, such as $_GET, $_POST or $_REQUEST.

<?php 
echo htmlspecialchars($_GET['name'], UTF-8);
?>



See also Superglobals

Global Usage

[Since 0.8.4] - [ -P Structures/GlobalUsage ] - [ Online docs ]

List usage of globals variables, with global keywords or direct access to $GLOBALS.

<?php 
$a 1/* global scope */ 

function test()

    echo 
$a/* reference to local scope variable */ 


test();
?>

It is recommended to avoid using global variables, at it makes it very difficult to track changes in values across the whole application.

See also Variable scope.

Logical Should Use Symbolic Operators

[Since 0.8.4] - [ -P Php/LogicalInLetters ] - [ Online docs ]

Logical operators come in two flavors : and / &&, || / or, ^ / xor. However, they are not exchangeable, as && and and have different precedence.

<?php 
// Avoid lettered operator, as they have lower priority than expected
$a $b and $c;
// $a === 3 because equivalent to ($a = $b) and $c;

// safe way to write the above : 
$a = ($b and $c);

$a $b && $c;
// $a === 1
?>


It is recommended to use the symbol operators, rather than the letter ones.

See also Logical Operators.

Could Use self

[Since 0.8.4] - [ -P Classes/ShouldUseSelf ] - [ Online docs ]

self keyword refers to the current class, or any of its parents. Using it is just as fast as the full class name, it is as readable and it is will not be changed upon class or namespace change.

It is also routinely used in traits : there, self represents the class in which the trait is used, or the trait itself.

<?php 
class {
    const 
FOO 1;
    
    public function 
bar() {
        return 
self::FOO;
// same as return x::FOO;
    
}
}
?>



See also Scope Resolution Operator (::)

Catch Overwrite Variable

[Since 0.8.4] - [ -P Structures/CatchShadowsVariable ] - [ Online docs ]

The try/catch structure uses some variables that are also in use in this scope. In case of a caught exception, the exception will be put in the catch variable, and overwrite the current value, loosing some data.

<?php 
// variables and caught exceptions are distinct
$argument 1;
try {
    
methodThatMayRaiseException($argument);
} (
Exception $e) {
    
// here, $e has been changed to an exception.
}

// variables and caught exceptions are overlapping
$e 1;
try {
    
methodThatMayRaiseException();
} (
Exception $e) {
    
// here, $e has been changed to an exception.
}
?>


It is recommended to use another name for these catch variables.

Namespaces

[Since 0.8.4] - [ -P Namespaces/NamespaceUsage ] - [ Online docs ]

Inventory of all namespaces.

Deep Definitions

[Since 0.8.4] - [ -P Functions/DeepDefinitions ] - [ Online docs ]

Structures, such as functions, classes, interfaces, traits, etc. may be defined anywhere in the code, including inside functions. This is legit code for PHP.

Since the availability of autoload, with spl_register_autoload(), there is no need for that kind of code. Structures should be defined, and accessible to the autoloading. Inclusions and deep definitions should be avoided, as they compel code to load some definitions, while autoloading will only load them if needed.

<?php 
class {
    function 
init() {
        
// myFunction is defined when and only if X::init() is called.
        
if (!function_exists('myFunction'){
            function 
myFunction($a) {
                return 
$a 1;
            }
        })
    }
}
?>


Functions are excluded from autoload, but shall be gathered in libraries, and not hidden inside other code.

Constants definitions are tolerated inside functions : they may be used for avoiding repeat, or noting the usage of such function.

Definitions inside a if/then statement, that include PHP version check are accepted here.


See also Autoloading Classes

Not Definitions Only

[Since 0.8.4] - [ -P Files/NotDefinitionsOnly ] - [ Online docs ]

Files should only include definitions (class, functions, traits, interfaces, constants), or global instructions, but not both.

<?php 
// This whole script is a file

// It contains definitions and global code
class foo {
    static public 
$foo null;
}
//This can be a singleton creation
foo::$foo = new foo();

trait 
{}

class 
bar {}
?>


Within this context, globals, use, and namespaces instructions are not considered a warning.

Repeated print()

[Since 0.8.4] - [ -P Structures/RepeatedPrint ] - [ Online docs ]

Always merge several print or echo in one call.

It is recommended to use echo with multiple arguments, or a concatenation with print, instead of multiple calls to print echo, when outputting several blob of text.

<?php 
//Write : 
  
echo 'a'$b'c';
  print 
'a' $b 'c';

//Don't write :  
  
print 'a';
  print 
$b;
  print 
'c';
?>


Avoid Parenthesis With Language Construct

[Since 0.8.4] - [ -P Structures/PrintWithoutParenthesis ] - [ Online docs ]

Avoid Parenthesis for language construct. Languages constructs are a few PHP native elements, that looks like functions but are not.

Among other distinction, those elements cannot be directly used as variable function call, and they may be used with or without parenthesis.

<?php 
// normal usage of include
include 'file.php';

// This looks like a function and is not
include('file2.php');
?>


The usage of parenthesis actually give some feeling of comfort, it won't prevent PHP from combining those argument with any later operators, leading to unexpected results.

Even if most of the time, usage of parenthesis is legit, it is recommended to avoid them.

Objects Don't Need References

[Since 0.8.4] - [ -P Structures/ObjectReferences ] - [ Online docs ]

There is no need to add references to parameters for objects, as those are always passed by reference when used as arguments.

Reference operator is needed when the object are replaced inside the method with a new value (or a clone), as whole. Calls to methods or property modifications do not require extra reference.

Reference operator is also needed when one of the types is scalar : this include null, and the hidden null type : that is when the default value is null.

This rule applies to arguments in methods, and to foreach() blind variables.

<?php 
$object = new stdClass();
    
$object->name 'a';
    
    
foo($object);
    print 
$object->name// Name is 'b'
    
    // No need to make $o a reference
    
function foo(&$o) {
        
$o->name 'b';
    }

    
// $o is assigned inside the function : the parameter must have a &, or the new object won't make it out of the foo3 scope
    
function foo3(&$o) {
        
$o = new stdClass;
    }

    
$array = array($object);
    foreach(
$array as &$o) { // No need to make this a reference
        
$o->name 'c';
    }
?>



See also Passing by reference

Lost References

[Since 0.8.4] - [ -P Variables/LostReferences ] - [ Online docs ]

Either avoid references, or propagate them correctly.

When assigning a referenced variable with another reference, the initial reference is lost, while the intend was to transfer the content.

<?php 
function foo(&$lostReference, &$keptReference)
{
    
$c 'c';

    
// $lostReference was a reference to $bar, but now, it is a reference to $c
    
$lostReference =& $c;
    
// $keptReference was a reference to $bar : it is still now, though it contains the actual value of $c now
    
$keptReference $c;
}

$bar 'bar';
$bar2 'bar';
foo($bar$bar2); 

//displays bar c, instead of bar bar
print $bar' '.$bar2;
?>


Do not reassign a reference with another reference. Assign new content to the reference to change its value.

Constants Created Outside Its Namespace

[Since 0.8.4] - [ -P Constants/CreatedOutsideItsNamespace ] - [ Online docs ]

Constants Created Outside Its Namespace.

Using the define() function, it is possible to create constant outside their namespace, but using the fully qualified namespace.

<?php 
namespace A\B {
    
// define A\B\C as 1
    
define('C'1);
}

namespace 
D\E {
    
// define A\B\C as 1, while outside the A\B namespace
    
define('A\B\C'1);
}
?>


However, this makes the code confusing and difficult to debug. It is recommended to move the constant definition to its namespace.

Fully Qualified Constants

[Since 0.8.4] - [ -P Namespaces/ConstantFullyQualified ] - [ Online docs ]

Constants defined with their namespace.

When defining constants with define() function, it is possible to include the actual namespace :

<?php 
define('a\b\c'1);
?>


However, the name should be fully qualified without the initial \. Here, \a\b\c constant will never be accessible as a namespace constant, though it will be accessible via the constant() function.

Also, the namespace will be absolute, and not a relative namespace of the current one.

Never Used Properties

[Since 0.8.4] - [ -P Classes/PropertyNeverUsed ] - [ Online docs ]

Properties that are never used. They are defined in a class or a trait, but they never actually used.

Properties are considered used when they are used locally, in the same class as their definition, or in a parent class : a parent class is always included with the current class.

On the other hand, properties which are defined in a class, but only used in children classes is considered unused, since children may also avoid using it.

<?php 
class foo {
    public 
$usedProperty 1;

    
// Never used anywhere
    
public $unusedProperty 2;
    
    function 
bar() {
        
// Used internally
        
++$this->usedProperty;
    }
}

class 
foo2  extends foo {
    function 
bar2() {
        
// Used in child class
        
++$this->usedProperty;
    }
}

// Used externally
++$this->usedProperty;
?>


No Real Comparison

[Since 0.8.4] - [ -P Type/NoRealComparison ] - [ Online docs ]

Avoid comparing decimal numbers with ==, ===, !==, !=. Real numbers have an error margin which is random, and makes it very difficult to match even if the compared value is a literal.

PHP uses an internal representation in base 2 : any number difficult to represent with this base (like 0.1 or 0.7) will have a margin of error.

<?php 
$a 1/7;
$b 2.0;

// 7 * $a is a real, not an integer
var_dump$a === 1);

// rounding error leads to wrong comparison
var_dump( (0.1 0.7) * 10 == 8);
// although
var_dump( (0.1 0.7) * 10);
// displays 8

// precision formula to use with reals. Adapt 0.0001 to your precision needs
var_dumpabs(((0.1 0.7) * 10) - 8) < 0.0001);
?>


Use precision formulas with abs() to approximate values with a given precision, or avoid reals altogether.

See also Floating point numbers.

Should Use Local Class

[Since 0.8.4] - [ -P Classes/ShouldUseThis ] - [ Online docs ]

Methods should use the defining class, or be functions.

Methods should use $this with another method or a property, or call parent:: . Static methods should call another static method, or a static property.
Methods which are overwritten by a child class are omitted : the parent class act as a default value for the children class, and this is correct.

<?php 
class foo {
    public function 
__construct() {
        
// This method should do something locally, or be removed.
    
}
}

class 
bar extends foo {
    private 
$a 1;
    
    public function 
__construct() {
        
// Calling parent:: is sufficient
        
parent::__construct();
    }

    public function 
barbar() {
        
// This is acting on the local object
        
$this->a++;
    }

    public function 
barfoo($b) {
        
// This has no action on the local object. It could be a function or a closure where needed
        
return $b;
    }
}
?>


Note that a method using a class constant is not considered as using the local class, for this analyzer.

Usage Of class_alias()

[Since 0.8.4] - [ -P Classes/ClassAliasUsage ] - [ Online docs ]

class_alias creates dynamically an alias for classes.

<?php 
class foo { }

class_alias('foo''bar');

$a = new foo;
$b = new bar;

// the objects are the same
var_dump($a == $b$a === $b);
var_dump($a instanceof $b);

// the classes are the same
var_dump($a instanceof foo);
var_dump($a instanceof bar);

var_dump($b instanceof foo);
var_dump($b instanceof bar);
?>



See also class_alias

ext/apache

[Since 0.8.4] - [ -P Extensions/Extapache ] - [ Online docs ]

Extension Apache.

These functions are only available when running PHP as an Apache module.

<?php 
$ret apache_getenv(SERVER_ADDR);
  echo 
$ret;
?>



See also Extension Apache, Apache server

ext/eaccelerator

[Since 0.8.4] - [ -P Extensions/Exteaccelerator ] - [ Online docs ]

Extension Eaccelerator.

eAccelerator is a free open-source PHP accelerator & optimizer.

See also Eaccelerator and eaccelerator/eaccelerato.

ext/fpm

[Since 0.8.4] - [ -P Extensions/Extfpm ] - [ Online docs ]

Extension FPM, FastCGI Process Manager.

FPM (FastCGI Process Manager) is an alternative PHP FastCGI implementation with some additional features (mostly) useful for heavy-loaded sites.

<?php 
echo $text;
    
fastcgi_finish_request( );
?>


See also FastCGI Process Manager.

ext/iis

[Since 0.8.4] - [ -P Extensions/Extiis ] - [ Online docs ]

Extension IIS Administration.

It provides functions to administrate Microsoft Internet Information Server (IIS).

<?php 
$path iis_get_server_by_path('/path/to/root/folder/')
?>


This extension is available for Windows only.

See also IIS Administration.

ext/wincache

[Since 0.8.4] - [ -P Extensions/Extwincache ] - [ Online docs ]

Extension Wincache.

The Wincache extension for PHP is a PHP accelerator that is used to increase the speed of PHP applications running on Windows and Windows Server.

<?php 
$fp fopen('/tmp/lock.txt''r+');
if (
wincache_lock(“lock_txt_lock”)) { // do an exclusive lock
    
ftruncate($fp0); // truncate file
    
fwrite($fp'Write something here\n');
    
wincache_unlock(“lock_txt_lock”); // release the lock
} else {
    echo 
'Couldn't get the lock!';
}
fclose($fp);
?>


See also WinCache Homepage.

No Direct Call To Magic Method

[Since 0.8.4] - [ -P Classes/DirectCallToMagicMethod ] - [ Online docs ]

PHP features magic methods, which are methods related to operators.

Magic methods, such as __get(), related to =, or __clone(), related to clone , are supposed to be used in an object environment, and not with direct call.

It is recommended to use the magic method with its intended usage, and not to call it directly. For example, typecast to string instead of calling the __toString() method.

<?php 
// Write
  
print $x->a;
// instead of 
  
print $x->__get('a'); 

class 
Foo {
    private 
$b secret;

    public function 
__toString() {
        return 
strtoupper($this->b);
    }
}

$bar = new Foo();
echo (string) 
$bar;
?>


Accessing those methods in a static way is also discouraged.


See also Magical PHP: __call

String May Hold A Variable

[Since 0.8.4] - [ -P Type/StringHoldAVariable ] - [ Online docs ]

Strings that contains a variable, yet are not interpolated.

Single quotes and Nowdoc syntax may include $ signs. They are treated as literals, and not replaced with a variable value.

However, there are some potential variables in those strings, making it possible for an error : the variable was forgotten and will be published as such. It is worth checking the content and make sure those strings are not variables.

<?php 
$a 2;

// Explicit variable, but literal effect is needed
echo '$a is '.$a;

// One of the variable has been forgotten
echo '$a is $a';

// $CAD is not a variable, rather a currency unit
$total 12;
echo 
$total.' $CAD';

// $CAD is not a variable, rather a currency unit
$total 12;

// Here, $total has been forgotten
echo <<<'TEXT'
$total $CAD
TEXT;
?>

Echo With Concat

[Since 0.8.4] - [ -P Structures/EchoWithConcat ] - [ Online docs ]

Optimize your echo 's by avoiding concatenating at echo time, but serving all argument separated. This will save PHP a memory copy.

If values, literals and variables, are small enough, this won't have visible impact. Otherwise, this is less work and less memory waste.

<?php 
echo $a' b '$c;
?>


instead of

<?php 
echo  $a ' b ' $c;
  echo 
$a b $c;
?>


It is a micro-optimisation.

Unused Global

[Since 0.8.4] - [ -P Structures/UnusedGlobal ] - [ Online docs ]

A global keyword is used in a method, yet the variable is not actually used. This makes PHP import values for nothing, or may create interference

<?php 
function foo() {
        global 
bar;
        
        return 
1;
    }
?>


Useless Global

[Since 0.8.4] - [ -P Structures/UselessGlobal ] - [ Online docs ]

Global are useless in two cases. First, on super-globals, which are always globals, like $_GET; secondly, on variables that are not used.

<?php 
// $_POST is already a global : it is in fact a global everywhere
global $_POST;

// $unused is useless
function foo() {
    global 
$used$unused;
    
    ++
$used;
}
?>


Also, PHP has superglobals, a special team of variables that are always available, whatever the context.
They are : $GLOBALS, $_SERVER, $_GET, $_POST, $_FILES, $_COOKIE, $_SESSION, $_REQUEST and $_ENV.

Preprocessable

[Since 0.8.4] - [ -P Structures/ShouldPreprocess ] - [ Online docs ]

The following expression are made of literals or already known values : they may be fully calculated before running PHP.

<?php 
// Building an array from a string
$name 'PHP'.' '.'7.2';

// Building an array from a string
$list explode(',''a,b,c,d,e,f');

// Calculating a power
$kbytes $bytes pow(210);

// This will never change
$name ucfirst(strtolower('PARIS'));
?>


By doing so, this will reduce the amount of work of PHP.

Useless Final

[Since 0.8.4] - [ -P Classes/UselessFinal ] - [ Online docs ]

When a class is declared final, all of its methods are also final by default.

There is no need to declare them individually final.

<?php 
final class foo {
        
// Useless final, as the whole class is final
        
final function method() { }
    }

    class 
bar {
        
// Useful final, as the whole class is not final
        
final function method() { }
    }
?>



See also Final Keyword, When to declare final

Use Constant

[Since 0.8.4] - [ -P Structures/UseConstant ] - [ Online docs ]

Some functioncalls have a constant equivalent, that is faster to execute than calling the function.

This applies to the following functions :

  • pi() : replace with `M_PI`
  • phpVersion() : replace with `PHP_VERSION`
  • php_sapi_name() : replace with `PHP_SAPI_NAME`

<?php 
// recommended way 
echo PHP_VERSION;

// slow version
echo php_version();
?>



See also PHP why `pi() and M_PI `_

Resources Usage

[Since 0.8.4] - [ -P Structures/ResourcesUsage ] - [ Online docs ]

List of situations that are creating resources.

<?php 
// This functioncall creates a resource to use
    
$fp fopen('/tmp/file.txt''r');
    
    if (!
is_resource($fp)){
        
thrown new RuntimeException('Could not open file.txt');
    }
?>


Useless Unset

[Since 0.8.4] - [ -P Structures/UselessUnset ] - [ Online docs ]

There are situations where trying to remove a variable is actually useless.

PHP ignores any command that tries to unset a global variable, a static variable, or a blind variable from a foreach loop.

This is different from the garbage collector, which is run on its own schedule. It is also different from an explicit unset, aimed at freeing memory early : those are useful.

<?php 
function foo($a) {
    
// unsetting arguments is useless
    
unset($a);
    
    global 
$b;
    
// unsetting global variable has no effect 
    
unset($b);

    static 
$c;
    
// unsetting static variable has no effect 
    
unset($c);
    
    foreach(
$d as &$e){
        
// unsetting a blind variable is useless
        
(unset) $e;
    }
    
// Unsetting a blind variable AFTER the loop is good.
    
unset($e);
}
?>



See also unset

Buried Assignation

[Since 0.8.4] - [ -P Structures/BuriedAssignation ] - [ Online docs ]

Those assignations are buried in the code, and placed in unexpected situations.

They are difficult to spot, and may be confusing. It is advised to place them in a more visible place.

<?php 
// $b may be assigned before processing $a
$a $c && ($b 2);

// Display property p immeiately, but also, keeps the object for later
echo ($o = new x)->p;

// legit syntax, but the double assignation is not obvious.
for($i 2$j 3$j 10$j++) {
    
}
?>


No array_merge() In Loops

[Since 0.8.4] - [ -P Performances/ArrayMergeInLoops ] - [ Online docs ]

array_merge() is memory intensive : every call will duplicate the arguments in memory, before merging them.

To handle arrays that may be quite big, it is recommended to avoid using array_merge() in a loop. Instead, one should use array_merge() with as many arguments as possible, making the merge a on time call.

<?php 
// A large multidimensional array
$source = ['a' => ['a''b'/*...*/],
           
'b' => ['b''c''d'/*...*/],
           
/*...*/
           
];

// Faster way
$b = array();
foreach(
$source as $key => $values) {
    
//Collect in an array
    
$b[] = $values;
}

// One call to array_merge
$b call_user_func_array('array_merge'$b);
// or with variadic
$b call_user_func('array_merge', ..$b);

// Fastest way (with above example, without checking nor data pulling)
$b call_user_func_array('array_merge'array_values($source))
// or
$b call_user_func('array_merge', ...array_values($source))

// Slow way to merge it all
$b = array();
foreach(
$source as $key => $values) {
    
$b array_merge($b$values);
}
?>


Note that array_merge_recursive() and file_put_contents() are affected and reported the same way.


See also Speed up `array_merge() `_

Useless Parenthesis

[Since 0.8.4] - [ -P Structures/UselessParenthesis ] - [ Online docs ]

Situations where parenthesis are not necessary, and may be removed.

Parenthesis group several elements together, and allows for a more readable expression. They are used with logical and mathematical expressions. They are necessary when the precedence of the operators are not the intended execution order : for example, when an addition must be performed before the multiplication.

Sometimes, the parenthesis provide the same execution order than the default order : they are deemed useless, from the PHP point of view. Yet, they may add readability to the code. In special circonstances, they may also protect the code from evolution in the precedence of operators : for example, 1 + 2 . '.' . 3 + 4; has different results between PHP 8 and PHP 7.

<?php 
if ( ($condition) ) {}
    while( (
$condition) ) {}
    do 
$a++; while ( ($condition) );
    
    switch ( (
$a) ) {}
    
$y = (1);
    (
$y) == (1);
    
    
f(($x));

    
// = has precedence over == 
    
($a $b) == $c;
    
    (
$a++);
    
    
// No need for parenthesis in default values
    
function foo($c = ( 2) ) {}
?>



See also Operators Precedence

Shell Usage

[Since 0.8.4] - [ -P Structures/ShellUsage ] - [ Online docs ]

List of shell calls to system.

<?php 
// Using backtick operator
    
$a = `ls -hla`;
    
    
// Using one of PHP native or extension functions
    
$a shell_exec('ls -hla');
    
$b \pcntl_exec('/path/to/command');
?>



See also shell_exec, Execution Operators

File Usage

[Since 0.8.4] - [ -P Structures/FileUsage ] - [ Online docs ]

The application makes usage of files on the system (read, write, delete, etc.).

Files usage is based on the usage of file functions.

<?php 
$fp fopen('/tmp/file.txt''w+');
    
// ....
?>



See also filesystem

Mail Usage

[Since 0.8.4] - [ -P Structures/MailUsage ] - [ Online docs ]

Report usage of mail from PHP.

The analysis is based on mail() function and various classes used to send mail.

<?php 
// The message
$message Line 1\r\nLine 2\r\nLine 3;

// In case any of our lines are larger than 70 characters, we should use `wordwrap() <https://www.php.net/wordwrap>`_
$message wordwrap($message70\r\n);

// Send
mail('caffeinated@example.com''My Subject'$message);
?>


See also mail.

Dynamic Calls

[Since 0.8.4] - [ -P Structures/DynamicCalls ] - [ Online docs ]

List of dynamic calls. They will probably need to be reviewed manually.

<?php 
$a 'b';

// Dynamic call of a constant
echo constant($a);

// Dynamic variables
$$a 2;
echo 
$b;

// Dynamic call of a function
$a('b'); 

// Dynamic call of a method
$object->$a('b'); 

// Dynamic call of a static method
A::$a('b');
?>


Unresolved Instanceof

[Since 0.8.4] - [ -P Classes/UnresolvedInstanceof ] - [ Online docs ]

The instanceof operator doesn't confirm if the compared class exists.

It checks if an variable is of a specific class. However, if the referenced class doesn't exist, because of a bug, a missed inclusion or a typo, the operator always fails, without a warning.

<?php 
namespace {
    class 
{}
    
    
// This is OK, as C is defined in X
    
if ($o instanceof C) { }

    
// This is not OK, as C is not defined in global
    // instanceof respects namespaces and use expressions
    
if ($o instanceof \C) { }

    
// This is not OK, as undefinedClass
    
if ($o instanceof undefinedClass) { }

    
// This is not OK, as $class is now a full namespace. It actually refers to \c, which doesn't exist
    
$class 'C';
    if (
$o instanceof $class) { }
}
?>


Make sure the following classes are well defined.


See also Instanceof

Use PHP Object API

[Since 0.8.4] - [ -P Php/UseObjectApi ] - [ Online docs ]

OOP API is the modern version of the PHP API.

When PHP offers the alternative between procedural and OOP api for the same features, it is recommended to use the OOP API.

Often, this least to more compact code, as methods are shorter, and there is no need to bring the resource around. Lots of new extensions are directly written in OOP form too.

OOP / procedural alternatives are available for mysqli, tidy, cairo, finfo, and some others.

<?php 
/// OOP version
$mysqli = new mysqli(localhostmy_usermy_passwordworld);

/* check connection */
if ($mysqli->connect_errno) {
    
printf(Connect failed: %s\n$mysqli->connect_error);
    exit();
}

/* Create table doesn't return a resultset */
if ($mysqli->query(CREATE TEMPORARY TABLE myCity LIKE City) === TRUE) {
    
printf(Table myCity successfully created.\n);
}

/* Select queries return a resultset */
if ($result $mysqli->query(SELECT Name FROM City LIMIT 10)) {
    
printf(Select returned %d rows.\n$result->num_rows);

    
/* free result set */
    
$result->close();
}
?>


<?php 
/// Procedural version
$link mysqli_connect(localhostmy_usermy_passwordworld);

/* check connection */
if (mysqli_connect_errno()) {
    
printf(Connect failed: %s\nmysqli_connect_error());
    exit();
}

/* Create table doesn't return a resultset */
if (mysqli_query($linkCREATE TEMPORARY TABLE myCity LIKE City) === TRUE) {
    
printf(Table myCity successfully created.\n);
}
?>


Unthrown Exception

[Since 0.8.4] - [ -P Exceptions/Unthrown ] - [ Online docs ]

List of exceptions that are defined in the code but never thrown. They are probably dead code.

<?php 
//This exception is defined but never used in the code.
class myUnusedException extends \Exception {}

//This exception is defined and used in the code.
class myUsedException extends \Exception {}

throw new 
myUsedException('I was called');
?>


Old Style __autoload()

[Since 0.8.4] - [ -P Php/oldAutoloadUsage ] - [ Online docs ]

Avoid __autoload(), only use spl_register_autoload().

__autoload() is deprecated since PHP 7.2 and possibly removed in later versions. spl_register_autoload() was introduced in PHP 5.1.0.

__autoload() may only be declared once, and cannot be modified later. This creates potential conflicts between libraries that try to set up their own autoloading schema.

On the other hand, spl_register_autoload() allows registering and de-registering multiple autoloading functions or methods.

<?php 
// Modern autoloading.
function myAutoload($class){}
spl_register_autoload('myAutoload');

// Old style autoloading.
function __autoload($class){}
?>


Do not use the old __autoload() function, but rather the new spl_register_autoload() function.

See also Autoloading Classe.

Altering Foreach Without Reference

[Since 0.8.4] - [ -P Structures/AlteringForeachWithoutReference ] - [ Online docs ]

Foreach() loop that could use a reference as value.

When using a foreach loop that modifies the original source, it is recommended to use referenced variables, rather than access the original value with $source[$index].

Using references is then must faster, and easier to read.

<?php 
// Using references in foreach
foreach($source as $key => &$value) {
    
$value newValue($value$key);
}

// Avoid foreach : use array_map
$source array_walk($source'newValue');
    
// Here, $key MUST be the second argument or newValue

// Slow version to update the array
foreach($source as $key => &$value) {
    
$source[$key] = newValue($value$key);
}
?>


array_walk() and array_map() are also alternative to prevent the use of foreach(), when $key is not used.

See also foreach.

Test Class

[Since 0.8.4] - [ -P Classes/TestClass ] - [ Online docs ]

Those are test classes, based on popular UT frameworks.

Mark Callable

[Since 0.8.4] - [ -P Functions/MarkCallable ] - [ Online docs ]

Guess what literals are actually a callable structure.

Use Pathinfo

[Since 0.8.4] - [ -P Php/UsePathinfo ] - [ Online docs ]

Use pathinfo() function instead of string manipulations.

pathinfo() is more efficient and readable and string functions.

<?php 
$filename '/path/to/file.php';

// With `pathinfo() <https://www.php.net/pathinfo>`_;
$details pathinfo($filename);
print 
$details['extension'];  // also capture php

// With string functions (other solutions possible)
$ext substr($filename, - strpos(strreverse($filename), '.')); // Capture php
?>


When the path contains UTF-8 characters, pathinfo() may strip them. There, string functions are necessary.

Should Use Existing Constants

[Since 0.8.4] - [ -P Functions/ShouldUseConstants ] - [ Online docs ]

The following functions have related constants that should be used as arguments, instead of scalar literals, such as integers or strings.

<?php 
// The file is read and new lines are ignored.
$lines file('file.txt'FILE_IGNORE_NEW_LINES)

// What is this doing, with 2 ? 
$lines file('file.txt'2);
?>



See also Bitmask Constant Arguments in PHP

Hash Algorithms

[Since 0.8.4] - [ -P Php/HashAlgos ] - [ Online docs ]

There is a long but limited list of hashing algorithm available to PHP. The one found doesn't seem to be existing.

<?php 
// This hash has existed in PHP. Check with hash_algos() if it is available on your system. 
echo hash('ripmed160''The quick brown fox jumped over the lazy dog.');

// This hash doesn't exist
echo hash('ripemd160''The quick brown fox jumped over the lazy dog.');
?>


See also hash_algos.

ext/dio

[Since 0.8.4] - [ -P Extensions/Extdio ] - [ Online docs ]

Extension DIO : Direct Input Output.

PHP supports the direct io functions as described in the Posix Standard (Section 6) for performing I/O functions at a lower level than the C-Language stream I/O functions

<?php 
$fd dio_open('/dev/ttyS0'O_RDWR O_NOCTTY O_NONBLOCK);

dio_close($fd);
?>


See also DIO.

No Parenthesis For Language Construct

[Since 0.8.4] - [ -P Structures/NoParenthesisForLanguageConstruct ] - [ Online docs ]

Some PHP language constructs, such are include , require , include_once , require_once , print , echo don't need parenthesis. They accept parenthesis, but it is may lead to strange situations.

<?php 
// This is an attempt to load 'foo.inc', or kill the script
include('foo.inc') or die();
// in fact, this is read by PHP as : include 1 
// include  'foo.inc' or die();
?>


It it better to avoid using parenthesis with echo , print , return , throw , yield , yield from , include , require , include_once , require_once .


See also ON PHP LANGUAGE CONSTRUCTS AND PARENTHESES, include

No Hardcoded Path

[Since 0.8.4] - [ -P Structures/NoHardcodedPath ] - [ Online docs ]

It is not recommended to use hardcoded literals when designating files. Full paths are usually tied to one file system organization. As soon as the organisation changes or must be adapted to any external constraint, the path is not valid anymore.

Either use __FILE__ and __DIR__ to make the path relative to the current file; use a DOC_ROOT as a configuration constant that will allow the moving of the script to another folder; finally functions like sys_get_temp_dir() produce a viable temporary folder.

Relative paths are relative to the current execution directory, and not the current file. This means they may differ depending on the location of the start of the application, and are sensitive to chdir() and chroot() usage.

<?php 
// This depends on the current executed script
    
file_get_contents('token.txt');

    
// Exotic protocols are ignored
    
file_get_contents('jackalope://file.txt');

    
// Some protocols are ignored : http, https, ftp, ssh2, php (with memory)
    
file_get_contents('http://www.php.net/');
    
file_get_contents('php://memory/');
    
    
// `glob() <https://www.php.net/glob>`_ with special chars * and ? are not reported
    
glob('./*/foo/bar?.txt');
    
// `glob() <https://www.php.net/glob>`_ without special chars * and ? are reported
    
glob('/foo/bar/');
?>


No Hardcoded Port

[Since 0.8.4] - [ -P Structures/NoHardcodedPort ] - [ Online docs ]

When connecting to a remove server, port is an important information. It is recommended to make this configurable (with constant or configuration), to as to be able to change this value without changing the code.

<?php 
// Both configurable IP and hostname
    
$connection ssh2_connect($_ENV['SSH_HOST'], $_ENV['SSH_PORT'], $methods$callbacks);
    
    
// Both hardcoded IP and hostname
    
$connection ssh2_connect('shell.example.com'22$methods$callbacks);

    if (!
$connection) die('Connection failed');
?>


ext/phalcon

[Since 0.8.4] - [ -P Extensions/Extphalcon ] - [ Online docs ]

Extension Phalcon : High Performance PHP Framework.

Phalcon's autoload examples from the docs : Tutorial 1: Let’s learn by example

<?php 
use Phalcon\Loader;

// ...

$loader = new Loader();

$loader->registerDirs(
    [
        ../
app/controllers/,
        ../
app/models/,
    ]
);

$loader->register();
?>


See also PhalconPHP.

Use Constant As Arguments

[Since 0.8.4] - [ -P Functions/UseConstantAsArguments ] - [ Online docs ]

Some methods and functions are defined to be used with constants as arguments. Those constants are made to be meaningful and readable, keeping the code maintenable. It is recommended to use such constants as soon as they are documented.

<?php 
// Turn off all error reporting
// 0 and -1 are accepted 
error_reporting(0);

// Report simple running errors
error_reporting(E_ERROR E_WARNING E_PARSE);

// The first argument can be one of INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, or INPUT_ENV.
$search_html filter_input(INPUT_GET'search'FILTER_SANITIZE_SPECIAL_CHARS);

// sort accepts one of SORT_REGULAR, SORT_NUMERIC, SORT_STRING, SORT_LOCALE_STRING, SORT_NATURAL
// SORT_FLAG_CASE may be added, and combined with SORT_STRING or SORT_NATURAL
sort($fruits);
?>


Here is the list of functions that use a unique PHP constant as argument :

+ array_change_key_case()
+ array_multisort()
+ array_unique()
+ count()
+ dns_get_record()
+ easter_days()
+ extract()
+ filter_input()
+ filter_var()
+ fseek()
+ get_html_translation_table()
+ gmp_div_q()
+ gmp_div_qr()
+ gmp_div_r()
+ html_entity_decode()
+ htmlspecialchars_decode()
+ http_build_query()
+ http_parse_cookie()
+ http_parse_params()
+ http_redirect()
+ http_support()
+ parse_ini_file()
+ parse_ini_string()
+ parse_url()
+ pathinfo()
+ pg_select()
+ posix_access()
+ round()
+ scandir()
+ socket_read()
+ str_pad()
+ trigger_error()

Here is the list of functions that use a combination of PHP native constants as argument.

+ arsort()
+ asort()
+ error_reporting()
+ filter_input()
+ filter_var()
+ get_html_translation_table()
+ htmlentities()
+ htmlspecialchars()
+ http_build_url()
+ jdtojewish()
+ krsort()
+ ksort()
+ pg_result_status()
+ phpcredits()
+ phpinfo()
+ preg_grep()
+ preg_match()
+ preg_split()
+ rsort()
+ runkit_import()
+ sort()
+ stream_socket_client()
+ stream_socket_server()

Implied If

[Since 0.8.4] - [ -P Structures/ImpliedIf ] - [ Online docs ]

It is confusing to emulate if/then with boolean operators.

It is possible to emulate a if/then structure by using the operators 'and' and 'or'. Since optimizations will be applied to them :
when the left operand of 'and' is false, the right one is not executed, as its result is useless;
when the left operand of 'or' is true, the right one is not executed, as its result is useless;

However, such structures are confusing. It is easy to misread them as conditions, and ignore an important logic step.

<?php 
// Either connect, or die
mysql_connect('localhost'$user$pass) or die();

// Defines a constant if not found. 
defined('SOME_CONSTANT') and define('SOME_CONSTANT'1);

// Defines a default value if provided is empty-ish 
// Warning : this is 
$user $_GET['user'] || 'anonymous';
?>


It is recommended to use a real 'if then' structures, to make the condition readable.

Overwritten Literals

[Since 0.8.4] - [ -P Variables/OverwrittenLiterals ] - [ Online docs ]

The same variable is assigned a literal twice. It is possible that one of the assignation is too much.

This analysis doesn't take into account the distance between two assignations : it may report false positives when the variable is actually used for several purposes, and, as such, assigned twice with different values.

<?php 
function foo() {
    
// Two assignations in a short sequence : one is too many.
    
$a 1;
    
$a 2;
    
    for(
$i 0$i 10$i++) {
        
$a += $i;
    }
    
$b $a;
    
    
// New assignation. $a is now used as an array. 
    
$a = array(0);
}
?>

Assign Default To Properties

[Since 0.8.4] - [ -P Classes/MakeDefault ] - [ Online docs ]

Properties may be assigned default values at declaration time. Such values may be later modified, if needed.

<?php 
class foo {
    private 
$propertyWithDefault 1;
    private 
$propertyWithoutDefault;
    private 
$propertyThatCantHaveDefault;
    
    public function 
__construct() {
        
// Skip this extra line, and give the default value above
        
$this->propertyWithoutDefault 1;

        
// Static expressions are available to set up simple computation at definition time.
        
$this->propertyWithoutDefault OtherClass::CONSTANT 1;

        
// Arrays, just like scalars, may be set at definition time
        
$this->propertyWithoutDefault = [1,2,3];

        
// Objects or resources can't be made default. That is OK.
        
$this->propertyThatCantHaveDefault fopen('/path/to/file.txt');
        
$this->propertyThatCantHaveDefault = new Fileinfo();
    }
}
?>


Default values will save some instructions in the constructor, and makes the value obvious in the code.
See also PHP Default parameters

No Public Access

[Since 0.8.4] - [ -P Classes/NoPublicAccess ] - [ Online docs ]

The properties below are declared with public access, but are never used publicly. They can be made protected or private.

<?php 
class foo {
    public 
$bar 1;            // Public, and used in public space
    
public $neverInPublic 3;  // Public, but never used in outside the class
    
    
function bar() {
        
$neverInPublic++;
    }
}

$x = new foo();
$x->bar 3;
$x->bar();
?>

Composer Usage

[Since 0.8.4] - [ -P Composer/UseComposer ] - [ Online docs ]

Mark the usage of composer, mostly by having a composer.json file.
See also Composer

Composer's autoload

[Since 0.8.4] - [ -P Composer/Autoload ] - [ Online docs ]

Report if this code is using the autoload from Composer.

Should Chain Exception

[Since 0.8.4] - [ -P Structures/ShouldChainException ] - [ Online docs ]

Chain exception to provide more context.

When catching an exception and rethrowing another one, it is recommended to chain the exception : this means providing the original exception, so that the final recipient has a chance to track the origin of the problem. This doesn't change the thrown message, but provides more information.

Note : Chaining requires PHP > 5.3.0.

<?php 
try {
        throw new 
Exception('Exception 1'1);
    } catch (
\Exception $e) {
        throw new 
Exception('Exception 2'2$e); 
        
// Chaining here. 

    
}
?>



See also Exception::__construct, What are the best practices for catching and re-throwing exceptions?

Useless Interfaces

[Since 0.8.4] - [ -P Interfaces/UselessInterfaces ] - [ Online docs ]

The interfaces below are defined and are implemented by some classes.

However, they are never used to enforce an object's class in the code, using instanceof or in a typehint.
As they are currently used, those interfaces may be removed without change in behavior.

<?php 
// only defined interface but never enforced
    
interface {};
    class 
implements {}
?>


Interfaces should be used in Typehint or with the instanceof operator.

<?php 
interface {};
    
    function 
foo(i $arg) { 
        
// Now, $arg is always an 'i'
    
}
    
    function 
bar($arg) { 
        if (!(
$arg instanceof i)) {
            
// Now, $arg is always an 'i'
        
}
    }
?>


Undefined Interfaces

[Since 0.8.4] - [ -P Interfaces/UndefinedInterfaces ] - [ Online docs ]

Some typehints or instanceof that are relying on undefined interfaces or classes. They will always return false. Any condition based upon them are dead code.

<?php 
class var implements undefinedInterface {
    
// If undefinedInterface is undefined, this code lints but doesn't run
}

if (
$o instanceof undefinedInterface) {
    
// This is silent dead code
}

function 
foo(undefinedInterface $a) {
    
// This is dead code
    // it will probably be discovered at execution
}
?>



See also Object interfaces, Type declarations, Instanceof

Concrete Visibility

[Since 0.8.4] - [ -P Interfaces/ConcreteVisibility ] - [ Online docs ]

Methods that implements an interface in a class must be public.

PHP does lint this, unless the interface and the class are in the same file. At execution, it stops immediately with a Fatal error : 'Access level to c::iPrivate() must be public (as in class i) ';

<?php 
interface {
    function 
iPrivate() ;
    function 
iProtected() ;
    function 
iPublic() ;
}

class 
implements {
    
// Methods that implements an interface in a class must be public.  
    
private function iPrivate() {}
    protected function 
iProtected() {}
    public function 
iPublic() {}
}
?>




See also Interfaces

ext/apcu

[Since 0.8.4] - [ -P Extensions/Extapcu ] - [ Online docs ]

Extension APCU .

APCu is APC stripped of opcode caching. The Alternative PHP Cache (APC) is a free and open opcode cache for PHP. Its goal is to provide a free, open, and robust framework for caching and optimizing PHP intermediate code.

<?php 
$bar 'BAR';
apcu_add('foo'$bar);
var_dump(apcu_fetch('foo'));
echo 
\n;
$bar 'NEVER GETS SET';
apcu_add('foo'$bar);
var_dump(apcu_fetch('foo'));
echo 
\n;
?>



See also APCU, ext/apcu, krakjoe/apcu

Double Instructions

[Since 0.8.4] - [ -P Structures/DoubleInstruction ] - [ Online docs ]

Twice the same call in a row. This is worth a check.

<?php 
// repetition of the same command, with the same effect each time. 
$a array_merge($b$c);
$a array_merge($b$c);

// false positive : commands are identical, but the effect is compounded 
$a array_merge($a$c);
$a array_merge($a$c);
?>

Should Use Prepared Statement

[Since 0.8.4] - [ -P Security/ShouldUsePreparedStatement ] - [ Online docs ]

Modern databases provides support for prepared statement : it separates the query from the processed data and raise significantly the security.

Building queries with concatenations is not recommended, though not always avoidable. When possible, use prepared statements.

<?php 
/* Execute a prepared statement by passing an array of values */

$sql 'SELECT name, colour, calories
    FROM fruit
    WHERE calories < :calories AND colour = :colour'
;
$sth $conn->prepare($sql, array(PDO::ATTR_CURSOR => PDO::CURSOR_FWDONLY));
$sth->execute(array(':calories' => 150':colour' => 'red'));
$red $sth->fetchAll();
?>


Same code, without preparation :

<?php 
$sql 'SELECT name, color, calories FROM fruit WHERE calories < '.$conn-quote(150).' AND colour = '.$conn->quotes('red').' ORDER BY name';
    
$sth $conn->query($sql) as $row);
}
?>



See also Prepared Statements, PHP MySQLi Prepared Statements Tutorial to Prevent SQL Injection, The Best Way to Perform MYSQLI Prepared Statements in PHP

Print And Die

[Since 0.8.4] - [ -P Structures/PrintAndDie ] - [ Online docs ]

Die() also prints.

When stopping a script with die(), it is possible to provide a message as first argument, that will be displayed at execution. There is no need to make a specific call to print or echo.

<?php 
//  die may do both print and die.
echo 'Error message';
die();

//  exit may do both print and die.
print 'Error message';
exit;

//  exit cannot print integers only : they will be used as status report to the system.
print 'Error message';
exit 
1;
?>


Unchecked Resources

[Since 0.8.4] - [ -P Structures/UncheckedResources ] - [ Online docs ]

Resources are created, but never checked before being used. This is not safe.

Always check that resources are correctly created before using them.

<?php 
// always check that the resource is created correctly
$fp fopen($d,'r');
if (
$fp === false) {
    throw new 
Exception('File not found');

$firstLine fread($fp);

// This directory is not checked : the path may not exist and return false
$uncheckedDir opendir($pathToDir);
while(
readdir($uncheckedDir)) {
    
// do something()
}

// This file is not checked : the path may not exist or be unreadable and return false
$fp fopen($pathToFile);
while(
$line freads($fp)) {
    
$text .= $line;
}

// unsafe one-liner : using bzclose on an unchecked resource
bzclose(bzopen('file'));
?>



See also resources

ext/trader

[Since 0.8.4] - [ -P Extensions/Exttrader ] - [ Online docs ]

Extension trader.

The trader extension is a free open source stock library based on TA-Lib. It's dedicated to trading software developers requiring to perform technical analysis of financial market data.

<?php 
// get_data() reads the data from a source 
var_dump(trader_avgprice(
    
get_data(open$data0),
    
get_data(high$data0),
    
get_data(low$data0),
    
get_data(close$data0)
));
?>



See also trader (PECL), 'TA-lib _, `ext/trader

ext/mailparse

[Since 0.8.4] - [ -P Extensions/Extmailparse ] - [ Online docs ]

Extension mailparse.

Mailparse is an extension for parsing and working with email messages. It can deal with RFC 822 (MIME) and RFC 2045 (MIME) compliant messages.

<?php 
$mail mailparse_msg_create();
mailparse_msg_parse($mail$mailInString);
$parts mailparse_msg_get_structure($mail); 

foreach(
$parts as $part) { 
    
$section mailparse_msg_get_part($mail$part); 
    
$info mailparse_msg_get_part_data($section); 
}
?>



See also Mailparse

ext/mail

[Since 0.8.4] - [ -P Extensions/Extmail ] - [ Online docs ]

Extension for mail.

The mail() function allows you to send mail.

<?php 
// The message
$message "Line 1\r\nLine 2\r\nLine 3";

// In case any of our lines are larger than 70 characters, we should use `wordwrap() <https://www.php.net/wordwrap>`_
$message wordwrap($message70"\r\n");

// Send
mail('caffeinated@example.com''My Subject'$message);
?>


See also Mail related functions.

No Hardcoded Ip

[Since 0.8.4] - [ -P Structures/NoHardcodedIp ] - [ Online docs ]

Do not leave hard coded IP in your code.

It is recommended to move such configuration in external files or databases, for each update.
This may also come handy when testing.

<?php 
// This IPv4 is hardcoded. 
$ip '183.207.224.50';
// This IPv6 is hardcoded. 
$ip '2001:0db8:85a3:0000:0000:8a2e:0370:7334';

// This looks like an IP
$thisIsNotAnIP '213.187.99.50';
$thisIsNotAnIP '2133:1387:9393:5330';
?>


127.0.0.1 , ::1 and ::0 are omitted, and not considered as a violation.

See also Use of Hardcoded IPv4 Addresses and
Never hard code sensitive information.

Else If Versus Elseif

[Since 0.8.4] - [ -P Structures/ElseIfElseif ] - [ Online docs ]

Always use elseif instead of else and if.

"The keyword elseif SHOULD be used instead of else if so that all control keywords look like single words". Quoted from the PHP-FIG documentation

<?php 
// Using elseif 
if ($a == 1) { doSomething(); }
elseif (
$a == 2) { doSomethingElseIf(); }
else { 
doSomethingElse(); }

// Using else if 
if ($a == 1) { doSomething(); }
else if (
$a == 2) { doSomethingElseIf(); }
else { 
doSomethingElse(); }

// Using else if, no {}
if ($a == 1)  doSomething(); 
else if (
$a == 2doSomethingElseIf(); 
else  
doSomethingElse();
?>


See also elseif/else if.

Unset In Foreach

[Since 0.8.4] - [ -P Structures/UnsetInForeach ] - [ Online docs ]

Unset applied to the variables of a foreach loop are useless. Those variables are copies and not the actual value. Even if the value is a reference, unsetting it has no effect on the original array : the only effect may be indirect, on elements inside an array, or on properties inside an object.

<?php 
// When unset is useless
$array = [123];
foreach(
$array as $a) {
    unset(
$a);
}

print_r($array); // still [1, 2, 3]

foreach($array as $b => &$a) {
    unset(
$a);
}

print_r($array); // still [1, 2, 3]

// When unset is useful
$array = [ [ 'c' => 1] ]; // Array in array
foreach($array as &$a) {
    unset(&
$a['c']);
}

print_r($array); // now [ ['c' => null] ]
?>


Could Be Static

[Since 0.8.4] - [ -P Structures/CouldBeStatic ] - [ Online docs ]

This global is only used in one function or method. It may be called 'static', instead of global. This allows you to keep the value between call to the function, but will not be accessible outside this function.

<?php 
function foo( ) {
    static 
$variableIsReservedForX// only accessible within foo( ), even between calls.
    
global $variableIsGlobal;       //      accessible everywhere in the application
}
?>

Multiple Class Declarations

[Since 0.8.4] - [ -P Classes/MultipleDeclarations ] - [ Online docs ]

It is possible to declare several times the same class in the code. PHP will not mention it until execution time, since declarations may be conditional.

<?php 
$a 1;

// Conditional declaration
if ($a == 1) {
    class 
foo {
        function 
method() { echo 'class 1';}
    }
} else {
    class 
foo {
        function 
method() { echo 'class 2';}
    }
}

(new 
foo())->method();
?>


It is recommended to avoid declaring several times the same class in the code. The best practice is to separate them with namespaces, they are for here for that purpose. In case those two classes are to be used interchangeably, the best is to use an abstract class or an interface.
See also class

Empty Namespace

[Since 0.8.4] - [ -P Namespaces/EmptyNamespace ] - [ Online docs ]

Declaring a namespace in the code and not using it for structure declarations or global instructions is useless.

Using simple style :

<?php 
namespace Y;

class 
foo {}


namespace 
X;
// This is useless
?>


Using bracket-style syntax :

<?php 
namespace {
    
// This is useless
}

namespace 
{

    class 
foo {}

}
?>



Could Use Short Assignation

[Since 0.8.4] - [ -P Structures/CouldUseShortAssignation ] - [ Online docs ]

Use short assignment operator, to speed up code, and keep syntax clear.

Some operators, like * or +, have a compact and fast 'do-and-assign' version. They looks like a compacted version for = and the operator. This syntax is good for readability, and saves some memory in the process.

Depending on the operator, not all permutations of arguments are possible.

Addition and short assignation of addition have a different set of features when applied to arrays. Do not exchange one another in that case.

<?php 
$a 10 $a;
$a += 10;

$b $b 1;
$b -= 1;

$c $c 2;
$c *= 2;

$d $d 3;
$d /= 3;

$e $e 4;
$e %= 4;

$f $f 5;
$f |= 5;

$g $g 6;
$g &= 6;

$h $h 7;
$h ^= 7;

$i $i >> 8;
$i >>= 8;

$j $j << 9;
$j <<= 9;

// PHP 7.4 and more recent
$l $l ?? 'value';
$l ??= 'value';
?>


Short operators are faster than the extended version, though it is a micro-optimization.


See also Assignation Operators

Useless Abstract Class

[Since 0.8.4] - [ -P Classes/UselessAbstract ] - [ Online docs ]

Those classes are marked 'abstract' and they are never extended. This way, they won't be instantiated nor used.

Abstract classes that have only static methods are omitted here : one usage of such classes are Utilities classes, which only offer static methods.

<?php 
// Never extended class : this is useless
abstract class foo {}

// Extended class
abstract class bar {
    public function 
barbar() {}
}

class 
bar2 extends bar {}

// Utility class : omitted here
abstract class bar {
    public static function 
barbar() {}
}
?>


Scalar Typehint Usage

[Since 0.8.4] - [ -P Php/ScalarTypehintUsage ] - [ Online docs ]

Spot usage of scalar type hint : int , float , boolean and string .

Scalar typehint are PHP 7.0 and more recent. Some, like object , is 7.2.

Scalar typehint were not supported in PHP 5 and older. Then, the typehint is treated as a class name.

<?php 
function withScalarTypehint(string $x) {}

function 
withoutScalarTypehint(someClass $x) {}
?>



See also PHP RFC: Scalar Type Hints, Type declarations

Return Typehint Usage

[Since 0.8.4] - [ -P Php/ReturnTypehintUsage ] - [ Online docs ]

Spot usage of return typehint. It is a PHP 7.0 feature.

Return typehint were introduced in PHP 7.0, and are backward incompatible with PHP 5.x.

<?php 
function foo($a) : stdClass {
    return new 
\stdClass();
}
?>


See also RFC: Return Type Declarations and
Return Type Declarations.

ext/ob

[Since 0.8.4] - [ -P Extensions/Extob ] - [ Online docs ]

Extension Output Buffering Control.

The Output Control functions allow you to control when output is sent from the script.

<?php 
`ob_start() <https://www.php.net/ob_start>`_;
echo 
Hello\n;

setcookie(cookienamecookiedata);

`
ob_end_flush() <https://www.php.net/ob_end_flush>`_;
?>



See also Output Buffering Control.

Static Loop

[Since 0.8.4] - [ -P Structures/StaticLoop ] - [ Online docs ]

Static loop may be preprocessed.

It looks like the following loops are static : the same code is executed each time, without taking into account loop variables.

<?php 
// Static loop
$total 0;
for(
$i 0$i 10$i++) {
    
$total += $i;
}

// The above loop may be replaced by (with some math help)
$total 10 * (10  1) / 2;

// Non-Static loop (the loop depends on the size of the array)
$n count($array);
for(
$i 0$i $n$i++) {
    
$total += $i;
}
?>


It is possible to create loops that don't use any blind variables, though this is fairly rare. In particular, calling a method may update an internal pointer, like next() or SimpleXMLIterator::next() .

It is recommended to turn a static loop into an expression that avoid the loop. For example, replacing the sum of all integers by the function $n * ($n + 1) / 2 , or using array_sum().

This analysis doesn't detect usage of variables with compact .

Pre-increment

[Since 0.8.4] - [ -P Performances/PrePostIncrement ] - [ Online docs ]

When possible, use the pre-increment operator ( ++$i or --$i ) instead of the post-increment operator ( $i++ or $i-- ).

The latter needs an extra memory allocation that costs about 10% of performances.

<?php 
// ++$i should be preferred over $i++, as current value is not important
for($i 0$i <10; ++$i) {
    
// do Something
}

// ++$b and $b++ have different impact here, since $a will collect $b + 1 or $b, respectively.
$a $b++;
?>


This is a micro-optimisation. However, its usage is so widespread, including within loops, that it may eventually have an significant impact on execution time. As such, it is recommended to adopt this rule, and only consider changing legacy code as they are refactored for other reasons.

Only Variable Returned By Reference

[Since 0.8.4] - [ -P Structures/OnlyVariableReturnedByReference ] - [ Online docs ]

Function can't return literals by reference.

When a function returns a reference, it is only possible to return variables, properties or static properties.

Anything else, like literals or static expressions, yield a warning at execution time.

<?php 
// Can't return a literal number
function &foo() {
    return 
+ `rand() <https://www.php.net/rand>`_;
}

// bar must return values that are stored in a 
function &bar() {
    
$a + `rand() <https://www.php.net/rand>`_;
    return 
$a;
}
?>

ext/geoip

[Since 0.8.4] - [ -P Extensions/Extgeoip ] - [ Online docs ]

Extension geoip for PHP.

The GeoIP extension allows the localisation of an IP address.

<?php 
$org geoip_org_by_name('www.example.com');
if (
$org) {
    echo 
'This host IP is allocated to: ' $org;
}
?>



See also GeoIP

ext/event

[Since 0.8.4] - [ -P Extensions/Extevent ] - [ Online docs ]

Extension event.

This is an extension to efficiently schedule I/O, time and signal based events using the best I/O notification mechanism available for specific platform. This is a port of libevent to the PHP infrastructure.

<?php 
// Read callback
function readcb($bev$base) {
    
//$input = $bev->input; //$bev->getInput();

    //$pos = $input->search('TTP');
    
$pos $bev->input->search('TTP');

    while ((
$n $bev->input->remove($buf1024)) > 0) {
        echo 
$buf;
    }
}

// Event callback
function eventcb($bev$events$base) {
    if (
$events EventBufferEvent::CONNECTED) {
        echo 
'Connected.';
    } elseif (
$events & (EventBufferEvent::ERROR EventBufferEvent::EOF)) {
        if (
$events EventBufferEvent::ERROR) {
            echo 
'DNS error: '$bev->getDnsErrorString(), PHP_EOL;
        }

        echo 
'Closing'.PHP_EOL;
        
$base->exit();
        exit(
'Done'.PHP_EOL);
    }
}

if (
$argc != 3) {
    echo <<<EOS
Trivial HTTP 0.x client
Syntax: php 
{$argv[0]} [hostname] [resource]
Example: php 
{$argv[0]} www.google.com /

EOS;
    exit();
}

$base = new EventBase();

$dns_base = new EventDnsBase($baseTRUE); // We'll use async DNS resolving
if (!$dns_base) {
    exit(
'Failed to init DNS Base'.PHP_EOL);
}

$bev = new EventBufferEvent($base/* use internal socket */ NULL,
    
EventBufferEvent::OPT_CLOSE_ON_FREE EventBufferEvent::OPT_DEFER_CALLBACKS,
    
'readcb'/* writecb */ NULL'eventcb'
);
if (!
$bev) {
    exit(
'Failed creating bufferevent socket'.PHP_EOL);
}

//$bev->setCallbacks('readcb', /* writecb */ NULL, 'eventcb', $base);
$bev->enable(Event::READ Event::WRITE);

$output $bev->output//$bev->getOutput();
if (!$output->add(
    
'GET '.$argv[2].' HTTP/1.0'."\r\n".
    
'Host: '.$argv[1]."\r\n".
    
'Connection: Close'.\r\n\r\n
)) {
    exit(
'Failed adding request to output buffer\n');
}

if (!
$bev->connectHost($dns_base$argv[1], 80EventUtil::AF_UNSPEC)) {
    exit(
'Can\'t connect to host '.$argv[1].PHP_EOL);
}

$base->dispatch();
?>



See also Event, libevent

ext/amqp

[Since 0.8.4] - [ -P Extensions/Extamqp ] - [ Online docs ]

Extension amqp .

PHP AMQP Binding Library`. This is an interface with the `RabbitMQ AMQP client library. It is a C language AMQP client library for use with version 2.0 and more recent of the `RabbitMQ` broker.

<?php 
$cnn = new AMQPConnection();
$cnn->connect();
echo 
'Used channels: '$cnn->getUsedChannels(), PHP_EOL;
$ch = new AMQPChannel($cnn);
echo 
'Used channels: '$cnn->getUsedChannels(), PHP_EOL;
$ch = new AMQPChannel($cnn);
echo 
'Used channels: '$cnn->getUsedChannels(), PHP_EOL;
$ch null;
echo 
'Used channels: '$cnn->getUsedChannels(), PHP_EOL;
?>



See also PHP AMQP Binding Library

ext/gearman

[Since 0.8.4] - [ -P Extensions/Extgearman ] - [ Online docs ]

Extension Gearman.

Gearman is a generic application framework for farming out work to multiple machines or processes.

<?php 
# Create our client object.
$gmclient= new GearmanClient();

# Add default server (localhost).
$gmclient->addServer();

echo 
'Sending job'.PHP_EOL;

# Send reverse job
do
{
  
$result $gmclient->doNormal('reverse''Hello!');

  
# Check for various return packets and errors.
  
switch($gmclient->returnCode())
  {
    case 
GEARMAN_WORK_DATA:
      echo 
'Data: '.$result PHP_EOL;;
      break;
    case 
GEARMAN_WORK_STATUS:
      list(
$numerator$denominator)= $gmclient->doStatus();
      echo 
'Status: '.$numerator.'/'.$denominator.' complete'PHP_EOL;
      break;
    case 
GEARMAN_WORK_FAIL:
      echo 
'Failed\n';
      exit;
    case 
GEARMAN_SUCCESS:
      echo 
'Success: $result\n';
      break;
    default:
      echo 
'RET: ' $gmclient->returnCode() . PHP_EOL;
      exit;
  }
}
while(
$gmclient->returnCode() != GEARMAN_SUCCESS);
?>



See also Gearman on PHP, Gearman

ext/com

[Since 0.8.4] - [ -P Extensions/Extcom ] - [ Online docs ]

Extension COM and .Net (Windows).

COM is an acronym for 'Component Object Model'; it is an object orientated layer (and associated services) on top of DCE RPC (an open standard) and defines a common calling convention that enables code written in any language to call and interoperate with code written in any other language (provided those languages are COM aware).

<?php 
$domainObject = new COM(WinNT://Domain); 
foreach ($domainObject as $obj) { 
   echo 
$obj->Name . <br />; 
}
?>


See also COM and .Net (Windows).

ext/gmagick

[Since 0.8.4] - [ -P Extensions/Extgmagick ] - [ Online docs ]

Extension gmagick.

Gmagick is a php extension to create, modify and obtain meta information of images using the GraphicsMagick API.

<?php 
//Instantiate a new Gmagick object
$image = new Gmagick('example.jpg');

//Make thumbnail from image loaded. 0 for either axes preserves aspect ratio
$image->thumbnailImage(1000);

//Create a border around the image, then simulate how the image will look like as an oil painting
//Note the chaining of mutator methods which is supported in gmagick
$image->borderImage(yellow88)->oilPaintImage(0.3);

//Write the current image at the current state to a file
$image->write('example_thumbnail.jpg');
?>


See also PHP gmagick and
gmagick.

ext/ibase

[Since 0.8.4] - [ -P Extensions/Extibase ] - [ Online docs ]

Extensions Interbase and Firebird .

Firebird is a relational database offering many ISO SQL-2003 features that runs on Linux, Windows, and a variety of Unix platforms.

<?php 
$host 'localhost:/path/to/your.gdb';

$dbh ibase_connect($host$username$password);
$stmt 'SELECT * FROM tblname';

$sth ibase_query($dbh$stmt) or die(ibase_errmsg());
?>


See also Firebase / Interbase and Firebird.

ext/inotify

[Since 0.8.4] - [ -P Extensions/Extinotify ] - [ Online docs ]

Extension inotify.

The Inotify extension gives access to the Linux kernel subsystem that acts to extend filesystems to notice changes to the filesystem, and report those changes to applications.

<?php 
// Open an inotify instance
$fd inotify_init();

// Watch __FILE__ for metadata changes (e.g. mtime)
$watch_descriptor inotify_add_watch($fd__FILE__IN_ATTRIB);

// generate an event
touch(__FILE__);

// Read events
$events inotify_read($fd);
print_r($events);

// The following methods allows to use inotify functions without blocking on inotify_read():

// - Using `stream_select() <https://www.php.net/stream_select>`_ on $fd:
$read = array($fd);
$write null;
$except null;
stream_select($read,$write,$except,0);

// - Using `stream_set_blocking() <https://www.php.net/stream_set_blocking>`_ on $fd
stream_set_blocking($fd0);
inotify_read($fd); // Does no block, and return false if no events are pending

// - Using inotify_queue_len() to check if event queue is not empty
$queue_len inotify_queue_len($fd); // If > 0, inotify_read() will not block

// Stop watching __FILE__ for metadata changes
inotify_rm_watch($fd$watch_descriptor);

// Close the inotify instance
// This may have closed all watches if this was not already done
fclose($fd);
?>


See also ext/inotify manual, inotify

ext/proctitle

[Since 0.8.4] - [ -P Extensions/Extproctitle ] - [ Online docs ]

Extension proctitle.

This extension allows changing the current process', and thread, name on Linux and *BSD systems. This is useful when using pcntl_fork() to identify running processes in process list

<?php 
setproctitle('myscript');
?>


See also proctitle.

ext/wikidiff2

[Since 0.8.4] - [ -P Extensions/Extwikidiff2 ] - [ Online docs ]

Extension wikidiff2.

Wikidiff2 is a PHP and HHVM module that provides the external diff engine for MediaWiki.

<?php 
$x = <<<EOT
foo bar
baz
quux
bang
EOT;

$y = <<<EOT
foo test
baz
test
bang
EOT;

print 
wikidiff2_inline_diff$x$y);
?>


See also wikidiff2 and wikidiff2 (C ext).

ext/xdiff

[Since 0.8.4] - [ -P Extensions/Extxdiff ] - [ Online docs ]

Extension xdiff.

xdiff extension enables you to create and apply patch files containing differences between different revisions of files.

<?php 
$old_version 'my_script-1.0.php';
$patch 'my_script.patch';

$errors xdiff_file_patch($old_version$patch'my_script-1.1.php');
if (
is_string($errors)) {
   echo 
'Rejects:'.PHP_EOL;
   echo 
$errors;
}
?>


See also libxdiff

ext/libevent

[Since 0.8.4] - [ -P Extensions/Extlibevent ] - [ Online docs ]

Extension libevent.

Libevent is a library that provides a mechanism to execute a callback function when a specific event occurs on a file descriptor or after a timeout has been reached.

<?php 
function print_line($fd$events$arg)
{
    static 
$max_requests 0;

    
$max_requests++;

    if (
$max_requests == 10) {
        
// exit loop after 10 writes
        
event_base_loopexit($arg[1]);
    }

    
// print the line
    
echo  fgets($fd);
}

// create base and event
$base event_base_new();
$event event_new();

$fd STDIN;

// set event flags
event_set($event$fdEV_READ EV_PERSIST'print_line', array($event$base));
// set event base
event_base_set($event$base);

// enable event
event_add($event);
// start event loop
event_base_loop($base);
?>


See also libevent and Libevent ext.

ext/ev

[Since 0.8.4] - [ -P Extensions/Extev ] - [ Online docs ]

Extension ev.

ext/ev is a high performance full-featured event loop written in C.

<?php 
// Create and start timer firing after 2 seconds
$w1 = new EvTimer(20, function () {
    echo 
'2 seconds elapsed'.PHP_EOL;
});

// Create and launch timer firing after 2 seconds repeating each second
// until we manually stop it
$w2 = new EvTimer(21, function ($w) {
    echo 
'is called every second, is launched after 2 seconds'.PHP_EOL;
    echo 
'iteration = 'Ev::iteration(), PHP_EOL;

    
// Stop the watcher after 5 iterations
    
Ev::iteration() == and $w->stop();
    
// Stop the watcher if further calls cause more than 10 iterations
    
Ev::iteration() >= 10 and $w->stop();
});

// Create stopped timer. It will be inactive until we start it ourselves
$w_stopped EvTimer::createStopped(105, function($w) {
    echo 
'Callback of a timer created as stopped'.PHP_EOL;

    
// Stop the watcher after 2 iterations
    
Ev::iteration() >= and $w->stop();
});

// Loop until Ev::stop() is called or all of watchers stop
Ev::run();

// Start and look if it works
$w_stopped->start();
echo 
'Run single iteration'.PHP_EOL;
Ev::run(Ev::RUN_ONCE);

echo 
'Restart the second watcher and try to handle the same events, but don\'t block'.PHP_EOL;
$w2->again();
Ev::run(Ev::RUN_NOWAIT);

$w = new EvTimer(100, function() {});
echo 
'Running a blocking loop'.PHP_EOL;
Ev::run();
echo 
'END'.PHP_EOL;
?>


See also Ev and libev.

ext/php-ast

[Since 0.8.4] - [ -P Extensions/Extast ] - [ Online docs ]

PHP-AST extension (PHP 7.0 +).

<?php 
$code = <<<'EOC'
<?php
$var = 42;
EOC;

var_dump(ast\parse_code($code$version=50));
?>



See also ext/ast, Extension exposing PHP 7 abstract syntax tree, Introduction of PHP parse and its application in hyperf

ext/xml

[Since 0.8.4] - [ -P Extensions/Extxml ] - [ Online docs ]

Extension xml (Parser).

This PHP extension implements support for James Clark's expat in PHP. This toolkit lets you parse, but not validate, XML documents.

<?php 
$file data.xml;
$depth = array();

function 
startElement($parser$name$attrs)
{
    global 
$depth;

    if (!isset(
$depth[$parser])) {
        
$depth[$parser] = 0;
    }

    for (
$i 0$i $depth[$parser]; $i++) {
        echo ;
    }
    echo 
$name\n;
    
$depth[$parser]++;
}

function 
endElement($parser$name)
{
    global 
$depth;
    
$depth[$parser]--;
}

$xml_parser xml_parser_create();
xml_set_element_handler($xml_parserstartElementendElement);
if (!(
$fp fopen($filer))) {
    die(
could not open XML input);
}

while (
$data fread($fp4096)) {
    if (!
xml_parse($xml_parser$datafeof($fp))) {
        die(
sprintf(XML error: %s at line %d,
                    
xml_error_string(xml_get_error_code($xml_parser)),
                    
xml_get_current_line_number($xml_parser)));
    }
}
xml_parser_free($xml_parser);
?>



See also XML Parser

ext/xhprof

[Since 0.8.4] - [ -P Extensions/Extxhprof ] - [ Online docs ]

Extension xhprof.

XHProf is a light-weight hierarchical and instrumentation based profiler.

<?php 
xhprof_enable(XHPROF_FLAGS_CPU XHPROF_FLAGS_MEMORY);

for (
$i 0$i <= 1000$i++) {
    
$a $i $i;
}

$xhprof_data xhprof_disable();

$XHPROF_ROOT '/tools/xhprof/';
include_once 
$XHPROF_ROOT '/xhprof_lib/utils/xhprof_lib.php';
include_once 
$XHPROF_ROOT '/xhprof_lib/utils/xhprof_runs.php';

$xhprof_runs = new XHProfRuns_Default();
$run_id $xhprof_runs->save_run($xhprof_data'xhprof_testing');

echo 
'http://localhost/xhprof/xhprof_html/index.php?run={$run_id}&source=xhprof_testing'.PHP_EOL;
?>



See also XHprof Documentation, ext/apcu

Indices Are Int Or String

[Since 0.8.4] - [ -P Structures/IndicesAreIntOrString ] - [ Online docs ]

Indices in an array notation such as $array['indice'] may only be integers or string.

Boolean, Null or float will be converted to their integer or string equivalent.

<?php 
$a = [true => 1,
          
1.0  => 2,
          
1.2  => 3,
          
1    => 4,
          
'1'  => 5,
          
0.8  => 6,
          
0x1  => 7,
          
01   => 8,
          
          
null  => 1,
          
''    => 2,
          
          
false => 1,
          
0     => 2,

          
'0.8' => 3,
          
'01'  => 4,
          
'2a'  => 5
          
];
          
    
print_r($a);

/*
The above displays
Array
(
    [1] => 8
    [0] => 2
    [] => 2
    [0.8] => 3
    [01] => 4
    [2a] => 5
)
*/
?>


Decimal numbers are rounded to the closest integer; Null is transtyped to '' (empty string); true is 1 and false is 0; Integers in strings are transtyped, while partial numbers or decimals are not analyzed in strings.

As a general rule of thumb, only use integers or strings that don\'t look like integers.

This analyzer may find constant definitions, when available.

Note also that PHP detects integer inside strings, and silently turn them into integers. Partial and octal numbers are not transformed.

<?php 
$a = [1      => 1,
          
'2'    => 2,
          
'011'  => 9// octal number
          
'11d'  => 11// partial number 
          
];
          
    
var_dump($a);

/*
The above displays
array(4) {
  [1]=>
  int(1)
  [2]=>
  int(2)
  [011]=>
  int(9)
  [11d]=>
  int(11)
}*/
?>


See also Arrays syntax.

Should Typecast

[Since 0.8.4] - [ -P Type/ShouldTypecast ] - [ Online docs ]

When typecasting, it is better to use the casting operator, such as (int) or (bool) .

Functions such as intval() or settype() are always slower.

<?php 
// Fast version
$int = (int) $X;

// Slow version
$int intval($X);

// Convert to base 8 : can't use (int) for that
$int intval($X8);
?>


This is a micro-optimisation, although such conversion may be use multiple times, leading to a larger performance increase.

Note that intval() may also be used to convert an integer to another base. Intval() called with 2 arguments are skipped by this rule.

No Self Referencing Constant

[Since 0.8.4] - [ -P Classes/NoSelfReferencingConstant ] - [ Online docs ]

It is not possible to use a constant to define itself in a class. It yields a fatal error at runtime.

The PHP error reads : Cannot declare self-referencing constant 'self::C2' . Unlike PHP which is self-referencing, self referencing variables can't have a value : just don't use that.

<?php 
class 
        const 
C1 1;         // fully defined constant
        
const C2 self::C2;  // self referencing constant
        
const C3 a::C3 2// self referencing constant
    
}
?>


The code may access an already declared constant with self or with its class name.

<?php 
class 
        const 
C1 1
        const 
C2 a::C1
    }
?>


This error is not detected by linting. It is only detected at instantiation time : if the class is not used, it won't appear.

No Direct Usage

[Since 0.8.4] - [ -P Structures/NoDirectUsage ] - [ Online docs ]

The results of the following functions shouldn't be used directly, but checked first.

For example, glob() returns an array, unless some error happens, in which case it returns a boolean (false). In such case, however rare it is, plugging glob() directly in a foreach() loops will yield errors.

<?php 
// Used without check : 
    
foreach(glob('.') as $file) { /* do Something */ }.
    
    
// Used without check : 
    
$files glob('.');
    if (!
is_array($files)) {
        foreach(
$files as $file) { /* do Something */ }.
    }
?>

Break Outside Loop

[Since 0.8.4] - [ -P Structures/BreakOutsideLoop ] - [ Online docs ]

Starting with PHP 7, break or continue that are outside a loop (for, foreach(), do...while(), while()) or a switch() statement won't compile anymore.

It is not possible anymore to include a piece of code inside a loop that will then break.

<?php 
// outside a loop : This won't compile
    
break 1
    
    foreach(
$array as $a) {
        break 
1// Compile OK

        
break 2// This won't compile, as this break is in one loop, and not 2
    
}

    foreach(
$array as $a) {
        foreach(
$array2 as $a2) {
            break 
2// OK in PHP 5 and 7
        
}
    }
?>



Else Usage

[Since 0.8.4] - [ -P Structures/ElseUsage ] - [ Online docs ]

Else should be avoided by various means. For example, defaulting values before, or short-circuiting the method as soon as the condition is not met.

<?php 
// $a is always set
$a 'default';
if (
$condition) {
    
$a foo($condition);
}

// Don't use else for default : set default before
if ($condition) {
    
$a foo($condition);
} else {
    
$a 'default';
}

// Use then to exit 
if ( ! $condition) {
    return;
}
$a foo($condition);

// don't use else to return
if ($condition) {
    
$a foo($condition);
} else {
    return;
}
?>



See also Avoid Else, Return Early, Why does clean code forbid else expression

Avoid Substr() One

[Since 0.8.4] - [ -P Structures/NoSubstrOne ] - [ Online docs ]

Use array notation $string[$position] to reach a single byte in a string.

There are two ways to access a byte in a string : substr() and $v[$pos] .

The second style is more readable. It may be up to four times faster, though it is a micro-optimization. It is recommended to use it.

PHP 7.1 also introduces the support of negative offsets as string index : negative offset are also reported.

<?php 
$string 'ab人cde';

echo 
substr($string$pos1);
echo 
$string[$pos];

echo 
mb_substr($string$pos1);

// when $pos = 1
// displays bbb
// when $pos = 2
// displays ??人
?>


Beware that substr() and $v[$pos] are similar, while mb_substr() is not. The first function works on bytes, while the latter works on characters.

Anonymous Classes

[Since 0.8.4] - [ -P Classes/Anonymous ] - [ Online docs ]

Anonymous classes.

<?php 
// Anonymous class, available since PHP 7.0
$object = new class { function __construct() { echo __METHOD__; } };
?>



See also Anonymous classes

Coalesce

[Since 0.8.4] - [ -P Php/Coalesce ] - [ Online docs ]

Usage of coalesce operator.

Note that the coalesce operator is a special case of the ternary operator.

<?php 
// Coalesce operator, since PHP 5.3
$a $b ?: 'default value';

// Equivalent to $a = $b ? $b : 'default value';
?>


See also Ternary Operator

Double Assignation

[Since 0.8.4] - [ -P Structures/DoubleAssignation ] - [ Online docs ]

This happens when a container (variable, property, array index) is assigned with values twice in a row. One of them is probably a debug instruction, that was forgotten.

<?php 
// Normal assignation
$a 1;

// Double assignation
$b 2;
$b 3;
?>

Empty List

[Since 0.8.4] - [ -P Php/EmptyList ] - [ Online docs ]

Empty list() are not allowed anymore in PHP 7. There must be at least one variable in the list call.

<?php 
//Not accepted since PHP 7.0
list() = array(1,2,3);

//Still valid PHP code
list(,$x) = array(1,2,3);
?>


Directives Usage

[Since 0.8.4] - [ -P Php/DirectivesUsage ] - [ Online docs ]

List of the directives mentioned in the code.

<?php 
//accessing the configuration to change it
ini_set('timelimit', -1);

//accessing the configuration to check it
ini_get('safe_mode');
?>


See also `ini_set() `_

Useless Brackets

[Since 0.8.4] - [ -P Structures/UselessBrackets ] - [ Online docs ]

Standalone brackets have no use. Brackets are used to delimit a block of code, and are used by control statements. They may also be used to protect variables in strings.

Standalone brackets may be a left over of an old instruction, or a misunderstanding of the alternative syntax.

<?php 
// The following brackets are useless : they are a leftover from an older instruction
// if (DEBUG) 
{
    
$a 1;
}

// Here, the extra brackets are useless
for($a 2$a 5$a++) : {
    
$b++;
} endfor;
?>

preg_replace With Option e

[Since 0.8.4] - [ -P Structures/pregOptionE ] - [ Online docs ]

preg_replace() supported the /e option until PHP 7.0. It allowed the use of eval()'ed expression as replacement. This has been dropped in PHP 7.0, for security reasons.

preg_replace() with /e option may be replaced with preg_replace_callback() and a closure, or preg_replace_callback_array() and an array of closures.

<?php 
// preg_replace with /e
$string 'abcde';

// PHP 5.6 and older usage of /e
$replaced preg_replace('/c/e''strtoupper($0)'$string);

// PHP 7.0 and more recent
// With one replacement
$replaced preg_replace_callback('/c/', function ($x) { return strtoupper($x[0]); }, $string);

// With several replacements, preventing multiple calls to preg_replace_callback
$replaced preg_replace_callback_array(array('/c/' => function ($x) { return strtoupper($x[0]); },
                                              
'/[a-b]/' => function ($x) { return strtolower($x[0]); }), $string);
?>


eval() Without Try

[Since 0.8.4] - [ -P Structures/EvalWithoutTry ] - [ Online docs ]

eval() `_ emits a ParseError exception with PHP 7 and later. Catching this exception is the recommended way to handle errors when using the eval() `_ function.

<?php 
$code 'This is no PHP code.';

//PHP 5 style
eval($code);
// Ends up with a Fatal error, at execution time

//PHP 7 style
try {
    eval(
$code);
} catch (
ParseError $e) {
    
cleanUpAfterEval();
}
?>


Note that it will catch situations where eval() `_ is provided with code that can't be used, but it will not catch security problems. Avoid using eval() `_ with incoming data.

Global In Global

[Since 0.8.4] - [ -P Structures/GlobalInGlobal ] - [ Online docs ]

List of global variables. There are the global variables, defined with the global keyword, and the implicit global variables, defined in the global scope.

<?php 
global $explicitGlobal// in global namespace
    
    
$implicitGlobal 1// in global namespace, variables are automatically global
    
    
function foo() {
        global 
$explicitGlobalInFoo// in functions, globals must be declared with global
    
}
?>


See also Variable Scope.

ext/fann

[Since 0.8.4] - [ -P Extensions/Extfann ] - [ Online docs ]

Extension FANN : Fast Artificial Neural Network.

PHP binding for FANN library which implements multi-layer artificial neural networks with support for both fully connected and sparsely connected networks.

<?php 
$num_input 2;
$num_output 1;
$num_layers 3;
$num_neurons_hidden 3;
$desired_error 0.001;
$max_epochs 500000;
$epochs_between_reports 1000;

$ann fann_create_standard($num_layers$num_input$num_neurons_hidden$num_output);

if (
$ann) {
    
fann_set_activation_function_hidden($annFANN_SIGMOID_SYMMETRIC);
    
fann_set_activation_function_output($annFANN_SIGMOID_SYMMETRIC);

    
$filename dirname(__FILE__) . '/xor.data';
    if (
fann_train_on_file($ann$filename$max_epochs$epochs_between_reports$desired_error))
        
fann_save($anndirname(__FILE__) . '/xor_float.net');

    
fann_destroy($ann);
}
?>



See also extension FANN, PHP-ML, Rubix ML, lib FANN

Relay Function

[Since 0.8.4] - [ -P Functions/RelayFunction ] - [ Online docs ]

Relay function only delegate workload to another one.

Relay functions and methods are delegating the actual work to another function or method. They do not have any impact on the results, besides exposing another name for the same feature.

<?php 
function myStrtolower($string) {
    return 
\strtolower($string);
}
?>


Relay functions are typical of transition API, where an old API have to be preserved until it is fully migrated. Then, they may be removed, so as to reduce confusion, and simplify the API.

func_get_arg() Modified

[Since 0.8.4] - [ -P Functions/funcGetArgModified ] - [ Online docs ]

func_get_arg() and func_get_args() used to report the calling value of the argument until PHP 7. Since PHP 7, it is reporting the value of the argument at calling time, which may have been modified by a previous instruction.

<?php 
function x($a) {
    
$a++;
    print 
func_get_arg(0);
}

x(0);
?>


This code will display 1 in PHP 7, and 0 in PHP 5.

Use Web

[Since 0.8.4] - [ -P Php/UseWeb ] - [ Online docs ]

The code is used in web environment.

The web usage is identified through the usage of the superglobals.

<?php 
// Accessing $_GET is possible when PHP is used in a web server.
$x filter_validate($_GET['x'], FILTER_EMAIL);
?>


Use Cli

[Since 0.8.4] - [ -P Php/UseCli ] - [ Online docs ]

Signal the usage of code in CLI mode, through the usage of `$argv` and `$argc` variables.

<?php 
// Characteristics of CLI usage 
getopt(abcd);
?>

Avoid get_class()

[Since 0.8.4] - [ -P Structures/UseInstanceof ] - [ Online docs ]

get_class() should be replaced with the instanceof operator to check the class of an object.

get_class() only compares the full namespace name of the object's class, while instanceof actually resolves the name, using the local namespace and aliases.

<?php 
use Stdclass as baseClass;
    
    function 
foo($arg) {
        
// Slow and prone to namespace errors
        
if (get_class($arg) === 'Stdclass') {
            
// doSomething()
        
}
    }

    function 
bar($arg) {
        
// Faster, and uses aliases.
        
if ($arg instanceof baseClass) {
            
// doSomething()
        
}
    }
?>



See also get_class, Instanceof

Silently Cast Integer

[Since 0.8.4] - [ -P Type/SilentlyCastInteger ] - [ Online docs ]

Those are integer literals that are cast to a float when running PHP. They are too big for the current PHP version, and PHP resorts to cast them into a float, which has a much larger capacity but a lower precision.

Compare your literals to PHP_MAX_INT (typically 9223372036854775807 ) and PHP_MIN_INT (typically -9223372036854775808 ).
This applies to binary ( 0b10101 ...), octal ( 0123123 ...) and hexadecimal ( 0xfffff ...) too.

<?php 
echo 0b1010101101010110101011010101011010101011010101011010101011010111;
//6173123008118052203
echo 0b10101011010101101010110101010110101010110101010110101010110101111;
//1.2346246016236E+19

echo 0123123123123123123123;
//1498121094048818771
echo 01231231231231231231231;
//1.1984968752391E+19

echo 0x12309812311230;
//5119979279159856
echo 0x12309812311230fed;
//2.0971435127439E+19

echo 9223372036854775807//PHP_MAX_INT
//9223372036854775807
echo 9223372036854775808;
9.2233720368548E+18?>



See also Integer overflow

Error Messages

[Since 0.8.4] - [ -P Structures/ErrorMessages ] - [ Online docs ]

Error message when an error is reported in the code. Those messages will be read by whoever is triggering the error, and it has to be helpful.

It is a good exercise to read the messages out of context, and try to understand what is about.

<?php 
// Not so helpful messages
die('Here be monsters');
exit(
'An error happened');
throw new 
Exception('Exception thrown at runtime');
?>


Error messages are spotted via die, exit or throw.

Timestamp Difference

[Since 0.8.4] - [ -P Structures/TimestampDifference ] - [ Online docs ]

Avoid adding or subtracting quantities of seconds to measure time.

time() , microtime() `_ or DateTime::format('U') provide timestamps, which are the number of seconds since January, 1rst, 1970 . They shouldn't be used to calculate duration or another date by adding an amount of seconds.

Those functions are subject to variations, depending on system clock variations, such as daylight saving time difference (every spring and fall, one hour variation), or leap seconds, happening on June, 30th or December 31th , as announced by IERS.

<?php 
// Calculating tomorow, same hour, the wrong way
// tomorrow is not always in 86400s, especially in countries with daylight saving 
$tomorrow time()  + 86400

// Good way to calculate tomorrow
$datetime = new DateTime('tomorrow');
?>


When the difference may be rounded to a larger time unit (rounding the difference to days, or several hours), the variation may be ignored safely.

When the difference is very small, it requires a better way to measure time difference, such as `Ticks '_,
`ext/hrtime '_, or including a check on the actual time zone ( ini_get() `_ with 'date.timezone').


See also PHP DateTime difference – it’s a trap!, PHP Daylight savings bug?

Php7 Relaxed Keyword

[Since 0.8.4] - [ -P Php/Php7RelaxedKeyword ] - [ Online docs ]

Most of the traditional PHP keywords may be used inside classes, trait or interfaces.

<?php 
// Compatible with PHP 7.0 + 
class foo {
    
// as is a PHP 5 keyword
    
public function as() {
    
    }
}
?>


This was not the case in PHP 5, and will yield parse errors.

See also Loosening Reserved Word Restrictions.

ext/pecl_http

[Since 0.8.4] - [ -P Extensions/Exthttp ] - [ Online docs ]

Extension HTTP.

This HTTP extension aims to provide a convenient and powerful set of functionalities for one of PHP major applications.

It eases handling of HTTP URL, headers and messages, provides means for negotiation of a client's preferred content type, language and charset, as well as a convenient way to send any arbitrary data with caching and resuming capabilities.

It provides powerful request functionality with support for parallel requests.

<?php 
$client = new http\Client;
$client->setSslOptions(array("verifypeer" => true));
$client->addSslOptions(array("verifyhost" => 2));

$client->enqueue($req = new http\Client\Request("GET""https://twitter.com/"));
$client->s`end() <https://www.php.net/end>`_;
$ti = (array) $client->getTransferInfo($req);
var_dump($ti);
?>


See also ext-http and
pecl_http.

Unused Parameter

[Since 0.8.4] - [ -P Functions/UnusedArguments ] - [ Online docs ]

Those parameters are not used in the method or function.

Unused parameters should be removed in functions : they are dead code.

Unused parameters also should be removed from methods, though there may have external reasons for them to stay. In particular, they might be defined in a parent class, or an interface, and cannot be removed.

<?php 
// $unused is in the signature, but not used. 
function foo($unused$b$c) {
    return 
$b $c;
}

interface 
{
    function 
goo($a);
}

class 
implements {
    
// goo signature comes from the interface
    
function goo($a) {
        return 
3;
    }
}
?>


Uses Environment

[Since 0.8.4] - [ -P Php/UsesEnv ] - [ Online docs ]

Spot usage of $_ENV and getenv() putenv() functions that will fetch data from the environment.

<?php 
// Take some configuration from the environment
$secret_key getenv('secret_key');
?>


Switch To Switch

[Since 0.8.4] - [ -P Structures/SwitchToSwitch ] - [ Online docs ]

The following structures are based on if / elseif / else. Since they have more than three conditions (not withstanding the final else), it is recommended to use the switch structure, so as to make this more readable.

On the other hand, switch() structures with less than 3 elements should be expressed as a if / else structure.

Note that if condition that uses strict typing (=== or !==) can't be converted to switch() as the latter only performs == or != comparisons.

<?php 
if ($a == 1) {

} elseif (
$a == 2) {

} elseif (
$a == 3) {

} elseif (
$a == 4) {

} else {

}

// Better way to write long if/else lists
switch ($a) {
    case 

        
doSomething(1);
        break 
1;
    
    case 

        
doSomething(2);
        break 
1;

    case 

        
doSomething(3);
        break 
1;

    case 

        
doSomething(4);
        break 
1;
    
    default :
        
doSomething();
        break 
1;
}
?>


Note that simple switch statement, which compare a variable to a literal are optimised in PHP 7.2 and more recent. This gives a nice performance boost, and keep code readable.


See also PHP 7.2's switch optimisations, Is Your Code Readable By Humans? Cognitive Complexity Tells You

Wrong Parameter Type

[Since 0.8.4] - [ -P Php/InternalParameterType ] - [ Online docs ]

The expected parameter is not of the correct type. Check PHP documentation to know which is the right format to be used.

<?php 
// `substr() <https://www.php.net/substr>`_ shouldn't work on integers.
// the first argument is first converted to string, and it is 123456.
echo substr(12345604); // display 1234

// `substr() <https://www.php.net/substr>`_ shouldn't work on boolean
// the first argument is first converted to string, and it is 1, and not t
echo substr(true01); // displays 1

// `substr() <https://www.php.net/substr>`_ works correctly on strings.
echo substr(12345604);
?>


Redefined Methods

[Since 0.8.4] - [ -P Classes/RedefinedMethods ] - [ Online docs ]

Redefined methods are overwritten methods. Those methods are defined in different classes that are part of the same classes hierarchy.

Protected and public redefined methods replace each other. Private methods are kept separated, and depends on the caller to be distinguished.

<?php 
class foo {
    function 
method() {
        return 
1;
    }
}

class 
bar extends foo {
    function 
method() {
        return 
2;
    }
}
?>



See also Object Inheritance

Wrong fopen() Mode

[Since 0.8.4] - [ -P Php/FopenMode ] - [ Online docs ]

Wrong file opening for fopen().

fopen() has a few modes, as described in the documentation : 'r', 'r+', for reading; 'w', 'w+' for writing; 'a', 'a+' for appending; 'x', 'x+' for modifying; 'c', 'c+' for writing and locking, 't' for text files and windows only.
An optional 'b' may be used to make the fopen() call more portable and binary safe. Another optional 't' may be used to make the fopen() call process automatically text input : this one should be avoided.

<?php 
// open the file for reading, in binary mode
$fp fopen('/tmp/php.txt''rb');

// New option e in PHP 7.0.16 and 7.1.2 (beware of compatibility)
$fp fopen('/tmp/php.txt''rbe');

// Unknown option x
$fp fopen('/tmp/php.txt''rbx');
?>


Any other values are not understood by PHP.

Is CLI Script

[Since 0.8.4] - [ -P Files/IsCliScript ] - [ Online docs ]

Mark a file as a CLI script, based on the usage of #!.

PHP Bugfixes

[Since 0.8.4] - [ -P Php/MiddleVersion ] - [ Online docs ]

This is the list of features, used in the code, that also received a bug fix in recent PHP versions.

Negative Power

[Since 0.8.4] - [ -P Structures/NegativePow ] - [ Online docs ]

The power operator ** has higher precedence than the sign operators + and -.

This means that -2 ** 2 == -4. It is in fact, -(2 ** 2).

When using negative power, it is clearer to add parenthesis or to use the pow() function, which has no such ambiguity :

<?php 
// -2 to the power of 2 (a square)
pow(-22) == 4;

// minus 2 to the power of 2 (a negative square)
-** == -(** 2) == 4;
?>

Already Parents Interface

[Since 0.8.4] - [ -P Interfaces/AlreadyParentsInterface ] - [ Online docs ]

The same interface is implemented by a class and one of its children.

That way, the child doesn't need to implement the interface, nor define its methods to be an instance of the interface.

<?php 
interface 
    function 
i();
}

class 
implements {
    function 
i() {
        return 
__METHOD__;
    }
}

// This implements is useless. 
class AB extends implements {
    
// No definition for function i()
}

// Implements i is understated
class AB extends {
    
// redefinition of the i method
    
function i() {
        return 
__METHOD__.' ';
    }
}

$x = new AB;
var_dump($x instanceof i);
// true

$x = new AC;
var_dump($x instanceof i);
// true
?>


This analysis may report classes which do not explicitly implements any interfaces : the issue is then coming from the parents.

Use random_int()

[Since 0.8.4] - [ -P Php/BetterRand ] - [ Online docs ]

rand() and mt_rand() should be replaced with random_int().

At worse, rand() should be replaced with mt_rand(), which is a drop-in replacement and srand() by mt_srand().

random_int() replaces rand(), and has no seeding function like srand().

Other sources of entropy that should be replaced by random_int() : microtime(), uniqid(), time(). Those a often combined with hashing functions and mixed with other sources of entropy, such as a salt.

<?php 
// Avoid using this
$random rand(010);

// Drop-in replacement
$random mt_rand(010);

// Even better but different : 
// valid with PHP 7.0+
try {
    
$random random_int(010);
} catch (
\Exception $e) {
    
// process case of not enoug random values
}

// This is also a source of entropy, based on `srand() <https://www.php.net/srand>`_
// random_int() is a drop-in replacement here
$a sha256(`uniqid() <https://www.php.net/uniqid>`_);
?>


Since PHP 7, random_int() along with random_bytes(), provides cryptographically secure pseudo-random bytes, which are good to be used
when security is involved. openssl_random_pseudo_bytes() may be used when the OpenSSL extension is available.


See also CSPRNG, OpenSSL

Can't Extend Final

[Since 0.8.4] - [ -P Classes/CantExtendFinal ] - [ Online docs ]

It is not possible to extend final classes.

Since PHP fails with a fatal error, this means that the extending class is probably not used in the rest of the code. Check for dead code.

<?php 
// File Foo
    
final class foo {
        public final function 
bar() {
            
// doSomething
        
}
    }
?>


In a separate file :

<?php 
// File Bar
    
class bar extends foo {
    
    }
?>



See also Final Keyword

Ternary In Concat

[Since 0.8.4] - [ -P Structures/TernaryInConcat ] - [ Online docs ]

Ternary and coalesce operator have higher priority than dot '.' for concatenation. This means that :

<?php 
// print B0CE as expected  
  
print 'B'.$b.'C'. ($b 'D') : 'E';

  
// print E, instead of B0CE
  
print 'B'.$b.'C'$b 'D' 'E';

  print 
'B'.$b.'C'$b 'D' 'E';
?>


prints actually 'E' , instead of the awaited 'B0CE' .

To be safe, always add parenthesis when using ternary operator with concatenation.


See also Operator Precedence

Using $this Outside A Class

[Since 0.8.4] - [ -P Classes/UsingThisOutsideAClass ] - [ Online docs ]

$this is a special variable, that should only be used in a class context.

Until PHP 7.1, $this may be used as an argument in a function or a method, a global, a static : while this is legit, it sounds confusing enough to avoid it.

<?php 
function foo($this) {
    echo 
$this;
}

// A closure can be bound to an object at later time. It is valid usage.
$closure = function ($x) {
    echo 
$this->foo($x);
}
?>


Starting with PHP 7.1, the PHP engine check thoroughly that $this is used in an appropriate manner, and raise fatal errors in case it isn't.

Yet, it is possible to find $this outside a class : if the file is included inside a class, then $this will be recognized and validated. If the file is included outside a class context, it will yield a fatal error : Using $this when not in object context .


See also Closure::bind, The Basics

ext/tokyotyrant

[Since 0.8.4] - [ -P Extensions/Exttokyotyrant ] - [ Online docs ]

Extension for Tokyo Tyrant.

tokyo_tyrant extension provides a wrapper for Tokyo Tyrant client libraries.

<?php 
$tt = new TokyoTyrant("localhost");
$tt->put("key""value");
echo 
$tt->get("key");
?>


See also tokyo_tyrant, Tokyo cabinet

ext/v8js

[Since 0.8.4] - [ -P Extensions/Extv8js ] - [ Online docs ]

Extension v8js.

This extension embeds the V8 Javascript Engine into PHP.

<?php 
$v8 = new V8Js();

/* basic.js */
$JS = <<< EOT
len = print('Hello' + ' ' + 'World!' + '\n');
len;
EOT;

try {
  
var_dump($v8->executeString($JS'basic.js'));
} catch (
V8JsException $e) {
  
var_dump($e);
}
?>



See also V8 Javascript Engine Integration, V8 Javascript Engine for PHP, pecl v8js

Yield Usage

[Since 0.8.4] - [ -P Php/YieldUsage ] - [ Online docs ]

Usage of generators, with yield keyword.

Yield was introduced in PHP 5.5, and is backward incompatible.

<?php 
function prime() {
    
$primes = [235711131719];
    foreach(
$primes as $prime) {
        yield 
$prime;
    }
}
?>



See also Generator Syntax, Deal with Memory Gently using Yield in PHP, Understanding PHP Generators

Yield From Usage

[Since 0.8.4] - [ -P Php/YieldFromUsage ] - [ Online docs ]

Usage of generator delegation, with yield from keyword.

In PHP 7, generator delegation allows you to yield values from another Generator , Traversable object, or array by using the yield from .

Yield from was introduced in PHP 7.1, and is backward incompatible.

<?php 
// Yield delegation
function foo() {
    yield from 
bar();
}

function 
bar() {
    yield 
1;
}
?>


See also Generator Syntax, Understanding PHP Generators

Pear Usage

[Since 0.8.4] - [ -P Php/PearUsage ] - [ Online docs ]

Pear Usage : list of Pear packages in use.

<?php 
require_once('MDB2.php');
    
$dsn 'mysql://user:pass@host';
    
$mdb2 = &MDB2::factory($dsn);
    
$mdb2->setFetchMode(MDB2_FETCHMODE_ASSOC);
?>


See also PEAR.

Undefined Trait

[Since 0.8.4] - [ -P Traits/UndefinedTrait ] - [ Online docs ]

Those are undefined, traits .

When the using class or trait is instantiated, PHP emits a a fatal error.

<?php 
use Composer/Component/someTrait as externalTrait;

trait 
{
    function 
foo() {}
}

// This class uses trait that are all known
class hasOnlyDefinedTrait {
    use 
texternalTrait;
}

// This class uses trait that are unknown
class hasUndefinedTrait {
    use 
unknownTraittexternalTrait;
}
?>


Trait which are referenced in a `use` expression are omitted: they are considered part of code that is probably outside the current code, either omitted or in external component.

No Hardcoded Hash

[Since 0.8.4] - [ -P Structures/NoHardcodedHash ] - [ Online docs ]

Hash should never be hardcoded.

Hashes may be MD5, SHA1, SHA512, Bcrypt or any other. Such values must be easily changed, for security reasons, and the source code is not the safest place to hide it.

<?php 
// Those strings may be sha512 hashes. 
    // it is recomemdned to check if they are static or should be put into configuration
    
$init512 = array( // initial values for SHA512
        
'6a09e667f3bcc908''bb67ae8584caa73b''3c6ef372fe94f82b''a54ff53a5f1d36f1'
    );

    
// strings which are obvious conversion are ignored 
    
$decimal intval('87878877'12);
?>


See also Salted Password Hashing - Doing it Right and
Hash-Buster.

Identical Conditions

[Since 0.8.4] - [ -P Structures/IdenticalConditions ] - [ Online docs ]

These logical expressions contain members that are identical.

This means those expressions may be simplified.

<?php 
// twice $a
if ($a || $b || $c || $a) {  }

// Hiding in parenthesis is bad
if (($a) ^ ($a)) {}

// expressions may be large
if ($a === && === $a) {}
?>

Unkown Regex Options

[Since 0.8.4] - [ -P Structures/UnknownPregOption ] - [ Online docs ]

Regex support in PHP accepts the following list of options : eimsuxADJSUX .

All other letter used as option are not supported : depending on the situation, they may be ignored or raise an error.

<?php 
// all options are available
if (preg_match('/\d+/isA'$string$results)) { }

// p and h are not regex options, p is double
if (preg_match('/\d+/php'$string$results)) { }
?>



See also Pattern Modifiers

No Choice

[Since 0.8.4] - [ -P Structures/NoChoice ] - [ Online docs ]

A conditional structure is being used, but both alternatives are the same, leading to the illusion of choice.

Either the condition is useless, and may be removed, or the alternatives need to be distinguished.

<?php 
if ($condition == 2) {
    
doSomething();
} else {
    
doSomething();
}

$condition == ?     doSomething() :     doSomething();
?>


Common Alternatives

[Since 0.8.4] - [ -P Structures/CommonAlternatives ] - [ Online docs ]

In the following conditional structures, expressions were found that are common to both 'then' and 'else'. It may be interesting, though not always possible, to put them both out of the conditional, and reduce line count.

<?php 
if ($c == 5) {
    
$b strtolower($b[2]); 
    
$a++;
} else {
    
$b strtolower($b[2]); 
    
$b++;
}
?>


may be rewritten in :

<?php 
$b strtolower($b[2]); 
if (
$c == 5) {
    
$a++;
} else {
    
$b++;
}
?>


Logical Mistakes

[Since 0.8.4] - [ -P Structures/LogicalMistakes ] - [ Online docs ]

Avoid logical mistakes within long expressions.

Sometimes, the logic is not what it seems. It is important to check the actual impact of every part of the logical expression. Do not hesitate to make a table with all possible cases. If those cases are too numerous, it may be time to rethink the whole expression.

<?php 
// Always true
if ($a != || $a != 2) { } 

// $a == 1 is useless
if ($a == || $a != 2) {}

// Always false
if ($a == && $a == 2) {}

// $a != 2 is useless
if ($a == && $a != 2) {}
?>


Inspired by an article from Andrey Karpov .


See also Logical Expressions in C/C++. Mistakes Made by Professionals

ext/lua

[Since 0.8.4] - [ -P Extensions/Extlua ] - [ Online docs ]

Extension Lua.

'Lua is a powerful, fast, light-weight, embeddable scripting language.' This extension embeds the lua interpreter and offers an OO-API to lua variables and functions.

<?php 
$lua = new Lua();
$lua->eval(<<<CODE
    print(2);
CODE
);
?>



See also ext/lua manual, LUA

Uncaught Exceptions

[Since 0.8.4] - [ -P Exceptions/UncaughtExceptions ] - [ Online docs ]

The following exceptions are thrown in the code, but are never caught.

<?php 
// This exception is throw, but not caught. It will lead to a fatal error.
if ($message check_for_error()) {
    throw new 
My\Exception($message);
}

// This exception is throw, and caught. 
try {
    if (
$message check_for_error()) {
        throw new 
My\Exception($message);
    }
} catch (
\Exception $e) {
    
doSomething();
}
?>


Either they will lead to a Fatal Error, or they have to be caught by an including application. This is a valid behavior for libraries, but is not for a final application.


See also Structuring PHP Exceptions

Same Conditions In Condition

[Since 0.8.4] - [ -P Structures/SameConditions ] - [ Online docs ]

At least two consecutive if/then structures use identical conditions. The latter will probably be ignored.

This analysis returns false positive when there are attempt to fix a situation, or to call an alternative solution.

Conditions that are shared between if structures, but inside a logical OR expression are also detected.

<?php 
if ($a == 1) { doSomething(); }
elseif (
$b == 1) { doSomething(); }
elseif (
$c == 1) { doSomething(); }
elseif (
$a == 1) { doSomething(); }
else {}

// Also works on if then else if chains
if ($a == 1) { doSomething(); }
else if (
$b == 1) { doSomething(); }
else if (
$c == 1) { doSomething(); }
else if (
$a == 1) { doSomething(); }
else {}

// Also works on if then else if chains
// Here, $a is common and sufficient in both conditions
if ($a || $b) { doSomething(); } 
elseif (
$a || $c) { doSomethingElse(); } 

// This sort of situation generate false postive. 
$config load_config_from_commandline();
if (empty(
$config)) {
    
$config load_config_from_`file() <https://www.php.net/file>`_;
    if (empty(
$config)) {
        
$config load_default_config();
    }
}
?>

Return True False

[Since 0.8.4] - [ -P Structures/ReturnTrueFalse ] - [ Online docs ]

These conditional expressions return true/false, depending on the condition. This may be simplified by dropping the control structure altogether.

<?php 
if (version_compare($a$b) >= 0) {
    return 
true;
} else {
    return 
false;
}
?>


This may be simplified with :

<?php 
return version_compare($a$b) >= 0;
?>


This may be applied to assignations and ternary operators too.

<?php 
if (version_compare($a$b) >= 0) {
    
$a true;
} else {
    
$a false;
}

$a version_compare($a$b) >= false true;
?>


Useless Switch

[Since 0.8.4] - [ -P Structures/UselessSwitch ] - [ Online docs ]

This switch has only one case. It may very well be replaced by a ifthen structure.

<?php 
switch($a) {
    case 
1:
        
doSomething();
        break;
}

// Same as 

if ($a == 1) {
    
doSomething();
}
?>



Could Use __DIR__

[Since 0.8.4] - [ -P Structures/CouldUseDir ] - [ Online docs ]

Use __DIR__ constant to access the current file's parent directory.

Avoid using dirname() on __FILE__.

<?php 
// Better way
$fp fopen(__DIR__.'/myfile.txt''r');

// compatible, but slow way
$fp fopen(dirname(__FILE__).'/myfile.txt''r');

// Since PHP 5.3
assert(dirname(__FILE__) == __DIR__);
?>


__DIR__ has been introduced in PHP 5.3.0.

See also Magic Constants.

Should Use Coalesce

[Since 0.8.4] - [ -P Php/ShouldUseCoalesce ] - [ Online docs ]

PHP 7 introduced the ?? operator, that replaces longer structures to set default values when a variable is not set.

<?php 
// Fetches the request parameter user and results in 'nobody' if it doesn't exist
$username $_GET['user'] ?? 'nobody';
// equivalent to: $username = isset($_GET['user']) ? $_GET['user'] : 'nobody';
 
// Calls a hypothetical model-getting function, and uses the provided default if it fails
$model Model::get($id) ?? $default_model;
// equivalent to: if (($model = Model::get($id)) === NULL) { $model = $default_model; }
?>


Sample extracted from PHP docs Isset Ternary.


See also New in PHP 7: null coalesce operator

Make Global A Property

[Since 0.8.4] - [ -P Classes/MakeGlobalAProperty ] - [ Online docs ]

Calling global (or $GLOBALS) in methods is slower and less testable than setting the global to a property, and using this property.

Using properties is slightly faster than calling global or $GLOBALS, though the gain is not important.

Setting the property in the constructor (or in a factory), makes the class easier to test, as there is now a single point of configuration.

<?php 
// Wrong way
class fooBad {
    function 
x() {
        global 
$a;
        
$a->do();
        
// Or $GLOBALS['a']->do();
    
}
}

class 
fooGood {
    private 
$bar null;
    
    function 
__construct() {
        global 
$bar
        
$this->bar $bar;
        
// Even better, do this via arguments
    
}
    
    function 
x() {
        
$this->a->do();
    }
}
?>


List With Keys

[Since 0.8.4] - [ -P Php/ListWithKeys ] - [ Online docs ]

Setting keys when using list() is a PHP 7.1 feature.

<?php 
// PHP 7.1 and later only
list('a' => $a'b' => $b) = ['b' => 1'c' => 2'a' => 3];
?>

If With Same Conditions

[Since 0.8.4] - [ -P Structures/IfWithSameConditions ] - [ Online docs ]

Successive If / then structures that have the same condition may be either merged or have one of the condition changed.

<?php 
if ($a == 1) {
    
doSomething();
}

if (
$a == 1) {
    
doSomethingElse();
}

// May be replaced by 
if ($a == 1) {
    
doSomething();
    
doSomethingElse();
}
?>


Note that if the values used in the condition have been modified in the first if/then structure, the two distinct conditions may be needed.

<?php 
// May not be merged
if ($a == 1) {
    
// Check that this is really the situation
    
$a checkSomething();
}

if (
$a == 1) {
    
doSomethingElse();
}
?>


ext/suhosin

[Since 0.8.4] - [ -P Extensions/Extsuhosin ] - [ Online docs ]

Suhosin extension.

Suhosin (pronounced 'su-ho-shin') is an advanced protection system for PHP installations. It was designed to protect servers and users from known and unknown flaws in PHP applications and the PHP core.

Suhosin was a PHP 5 extension, and it has been ported to PHP 7 and 8, as a separate but eponymous project.

<?php 
// sha256 is a ext/suhosin specific function
$sha256 sha256($string);
?>



See also Suhosin.org, Suhosin snuffleupagus

Throw Functioncall

[Since 0.8.4] - [ -P Exceptions/ThrowFunctioncall ] - [ Online docs ]

The throw keyword expects to use an exception. Calling a function to prepare that exception before throwing it is possible, but forgetting the new keyword is also possible.

<?php 
// Forgotten new
throw \RuntimeException('error!');

// Code is OK, function returns an exception
throw getException(ERROR_TYPE'error!');

function 
getException(ERROR_TYPE$message) {
    return new 
\RuntimeException($messsage);
}
?>


When the new keyword is forgotten, then the class constructor is used as a function name, and now exception is emitted, but an Undefined function fatal error is emitted.

Can't Disable Function

[Since 0.8.4] - [ -P Security/CantDisableFunction ] - [ Online docs ]

This is the list of potentially dangerous PHP functions being used in the code, such as exec() or fsockopen().

eval() is not reported here, as it is not a PHP function, but a language construct : it can't be disabled.

<?php 
// This script uses ftp_connect(), therefore, this function shouldn't be disabled. 
$ftp ftp_connect($host21);

// This script doesn't use imap_open(), therefore, this function may be disabled.
?>


This analysis is the base for suggesting values for the disable_functions directive.

Functions Using Reference

[Since 0.8.4] - [ -P Functions/FunctionsUsingReference ] - [ Online docs ]

Functions and methods using references in their signature.

<?php 
function usingReferences( &$a) {}

class 
foo {
    public function 
methodUsingReferences($b, &$c 1) {}
}
?>


Use Instanceof

[Since 0.8.4] - [ -P Classes/UseInstanceof ] - [ Online docs ]

The instanceof operator is a more precise alternative to is_object() `_ . It is also faster.

instanceof checks for an variable to be of a class or its parents or the interfaces it implements.
Once instanceof has been used, the actual attributes available (properties, constants, methods) are known, unlike with is_object() `_ .

Last, instanceof may be upgraded to Typehint, by moving it to the method signature.

<?php 
class Foo {

    
// Don't use is_object
    
public function bar($o) {
        if (!
is_object($o)) { return false; } // Classic argument check
        
return $o->method();
    }

    
// use instanceof
    
public function bar($o) {
        if (
$o instanceof myClass) {  // Now, we know which methods are available
            
return $o->method();
        }
        
        return 
false; } // Default behavior
    
}

    
// use of typehinting
    // in case $o is not of the right type, exception is raised automatically
    
public function bar(myClass $o) {
        return 
$o->method();
    }
}
?>


instanceof and is_object() `_ may not be always interchangeable. Consider using isset() on a known property for a simple check on objects. You may also consider is_string(), is_integer() or is_scalar(), in particular instead of !is_object() .

The instanceof operator is also faster than the is_object() `_ functioncall.

See also Type Operators, is_object

List Short Syntax

[Since 0.8.4] - [ -P Php/ListShortSyntax ] - [ Online docs ]

Usage of short syntax version of list().

<?php 
// PHP 7.1 short list syntax
// PHP 7.1 may also use key => value structures with list
[$a$b$c] = ['2'3'4'];

// PHP 7.0 list syntax
list($a$b$c) = ['2'3'4'];
?>

Results May Be Missing

[Since 0.8.4] - [ -P Structures/ResultMayBeMissing ] - [ Online docs ]

preg_match() may return empty values, if the search fails. It is important to check for the existence of results before assigning them to another variable, or using it.

<?php 
preg_match('/PHP ([0-9\.]+) /'$res$r);
    
$s $r[1];
    
// $s may end up null if preg_match fails.
?>


Since PHP 7.2, it is possible to use the PREG_UNMATCHED_AS_NULL constant in the flag parameter to avoid this.

Use Nullable Type

[Since 0.8.4] - [ -P Php/UseNullableType ] - [ Online docs ]

The code uses nullable type, available since PHP 7.1.

Nullable Types are an option to type hint : they allow the passing value to be null, or another type.

According to the authors of the feature : 'It is common in many programming languages including PHP to allow a variable to be of some type or null. This null often indicates an error or lack of something to return.'

<?php 
function foo(?string $a 'abc') : ?string {
    return 
$a.b;
}
?>



See also Type declarations, PHP RFC: Nullable Types

Always Positive Comparison

[Since 0.8.4] - [ -P Structures/NeverNegative ] - [ Online docs ]

Some PHP native functions, such as count(), strlen(), or abs() only returns positive or null values.

When comparing them to 0, the following expressions are always true and should be avoided.

<?php 
$a = [123];

var_dump(count($a) >= 0);
var_dump(count($a) < 0);
?>

Multiple Exceptions Catch()

[Since 0.8.4] - [ -P Exceptions/MultipleCatch ] - [ Online docs ]

It is possible to have several distinct exceptions class caught by the same catch, preventing code repetition.

This is a new feature since PHP 7.1.

<?php 
// PHP 7.1 and more recent
try {  
    throw new 
someException(); 
} catch (
Single $s) {
    
doSomething();
} catch (
oneType anotherType $s) {
    
processIdentically();
} finally {

}

// PHP 7.0 and older
try {  
    throw new 
someException(); 
} catch (
Single $s) {
    
doSomething();
} catch (
oneType $s) {
    
processIdentically();
} catch (
anotherType $s) {
    
processIdentically();
} finally {

}
?>


This is a backward incompatible feature of PHP 7.1.

Empty Blocks

[Since 0.8.4] - [ -P Structures/EmptyBlocks ] - [ Online docs ]

Full empty block, part of a control structures.

It is recommended to remove those blocks, so as to reduce confusion in the code.

<?php 
foreach($foo as $bar) ; // This block seems erroneous
    
$foobar++;

if (
$a === $b) {
    
doSomething();
} else {
    
// Empty block. Remove this
}

// Blocks containing only empty expressions are also detected
for($i 0$i 10$i++) {
    ;
}

// Although namespaces are not control structures, they are reported here
namespace A;
namespace 
B;
?>


Throw In Destruct

[Since 0.8.4] - [ -P Classes/ThrowInDestruct ] - [ Online docs ]

According to the manual, Attempting to throw an exception from a destructor (called in the time of script termination) causes a fatal error.

The destructor may be called during the lifespan of the script, but it is not certain. If the exception is thrown later, the script may end up with a fatal error.

Thus, it is recommended to avoid throwing exceptions within the __destruct method of a class.

<?php 
// No exception thrown
class Bar 
    function 
__construct() {
        throw new 
Exception('__construct');
    }

    function 
__destruct() {
        
$this->cleanObject();
    }
}

// Potential crash
class Foo 
    function 
__destruct() {
        throw new 
Exception('__destruct');
    }
}
?>



See also Constructors and Destructors

Use System Tmp

[Since 0.8.4] - [ -P Structures/UseSystemTmp ] - [ Online docs ]

It is recommended to avoid hardcoding the temporary file. It is better to rely on the system's temporary folder, which is accessible with sys_get_temp_dir().

<?php 
// Where the tmp is : 
file_put_contents(`sys_get_temp_dir() <https://www.php.net/sys_get_temp_dir>`_.'/tempFile.txt'$content);


// Avoid hard-coding tmp folder : 
// On Linux-like systems
file_put_contents('/tmp/tempFile.txt'$content);

// On Windows systems
file_put_contents('C:\WINDOWS\TEMP\tempFile.txt'$content);
?>



See also PHP: When is /tmp not /tmp?

Dependant Trait

[Since 0.8.4] - [ -P Traits/DependantTrait ] - [ Online docs ]

Traits should be autonomous. It is recommended to avoid depending on methods or properties that should be in the using class.

The following traits make usage of methods and properties, static or not, that are not defined in the trait. This means the host class must provide those methods and properties, but there is no way to enforce this.

This may also lead to dead code : when the trait is removed, the host class have unused properties and methods.

<?php 
// autonomous trait : all it needs is within the trait
trait {
    private 
$p 0;
    
    function 
foo() {
        return ++
$this->p;
    }
}

// dependant trait : the host class needs to provide some properties or methods
trait t2 {
    function 
foo() {
        return ++
$this->p;
    }
}

class 
{
    use 
t2;
    
    private 
$p 0;
}
?>



See also Classes/DependantAbstractClass

Hidden Use Expression

[Since 0.8.4] - [ -P Namespaces/HiddenUse ] - [ Online docs ]

The use expression for namespaces should always be at the beginning of the namespace block.

It is where everyone expect them, and it is less confusing than having them at various levels.

<?php 
// This is visible 
use A;

class 
{}

// This is hidden 
use as D;

class 
extends {
    use 
traitT// This is a use for a trait

    
function foo() {
        
// This is a use for a closure
        
return function ($a) use ($b) {}
    }
}
?>


Should Make Alias

[Since 0.8.4] - [ -P Namespaces/ShouldMakeAlias ] - [ Online docs ]

Long names should be aliased.

Aliased names are easy to read at the beginning of the script; they may be changed at one point, and update the whole code at the same time.
Finally, short names makes the rest of the code readable.

<?php 
namespace x\y\z;

use 
a\b\c\d\e\f\g as Object;

// long name, difficult to read, prone to change.
new a\b\c\d\e\f\g();

// long name, difficult to read, prone to silent dead code if namespace change.
if ($o instanceof a\b\c\d\e\f\g) {
    
}

// short names Easy to update all at once.
new Object();
if (
$o instanceof Object) {
    
}
?>

Multiple Identical Trait Or Interface

[Since 0.8.4] - [ -P Classes/MultipleTraitOrInterface ] - [ Online docs ]

There is no need to use the same trait, or implements the same interface more than once.

Up to PHP 7.4, this doesn't raise any warning. Traits are only imported once, and interfaces may be implemented as many times as wanted.

Since PHP 7.4, multiple implementations of the same interface in one class is reported at compilation time. It is possible to repeat the implementation in various levels of a class hierarchy (aka, same implements in a class and a parent).

<?php 
class foo {
    use 
aTraitaTraitaTrait;
    use 
aTrait;
}

class 
bar implements anInterfaceanInterfaceanInterface {

}
?>


See also Interfaces/AlreadyParentsInterface

Multiple Alias Definitions

[Since 0.8.4] - [ -P Namespaces/MultipleAliasDefinitions ] - [ Online docs ]

Some aliases are representing different classes across the repository. This leads to potential confusion.

Across an application, it is recommended to use the same namespace for one alias. Failing to do this lead to the same keyword to represent different values in different files, with different behavior. Those are hard to find bugs.

<?php 
namespace {
    use 
d\d// aka D
}

// Those are usually in different files, rather than just different namespaces.

namespace {
    use 
b\c as D// also D. This could be named something else
}
?>

Nested Ifthen

[Since 0.8.4] - [ -P Structures/NestedIfthen ] - [ Online docs ]

Three levels of ifthen is too much. The method should be split into smaller functions.

<?php 
function foo($a$b) {
    if (
$a == 1) {
        
// Second level, possibly too much already
        
if ($b == 2) {
            
        }
    }
}

function 
bar($a$b$c) {
    if (
$a == 1) {
        
// Second level. 
        
if ($b == 2) {
            
// Third level level. 
            
if ($c == 3) {
                
// Too much
            
}
        }
    }
}
?>


See also Structures/TooManyIf

Cast To Boolean

[Since 0.8.4] - [ -P Structures/CastToBoolean ] - [ Online docs ]

This expression may be reduced by casting to boolean type.

<?php 
$variable $condition == 'met' 0;
// Same as 
$variable = (bool) $condition == 'met';

$variable $condition == 'met' 1;
// Same as (Note the condition inversion)
$variable = (bool) $condition != 'met';
// also, with an indentical condition
$variable = !(bool) $condition == 'met';

// This also works with straight booleans expressions
$variable $condition == 'met' true false;
// Same as 
$variable $condition == 'met';
?>


Failed Substr Comparison

[Since 0.8.4] - [ -P Structures/FailingSubstrComparison ] - [ Online docs ]

The extracted string must be of the size of the compared string.

This is also true for negative lengths.

<?php 
// Possible comparison : strings and substr results are the same
if (substr($a03) === 'abc') { }
if (
substr($b43) === 'abc') { }

// Always failing : substr will probably provide a longer string
if (substr($a03) === 'ab') { }
if (
substr($a3, -3) === 'ab') { }

// Omitted in this analysis
if (substr($a03) !== 'ab') { }
?>


This rule raise a false positive when the variable is already smaller than the expected substr() results.

This rule doesn't apply to mb_substr() and iconv_substr() : those functions use the character size, not the byte size.

Should Make Ternary

[Since 0.8.5] - [ -P Structures/ShouldMakeTernary ] - [ Online docs ]

Ternary operators are the best when assigning values to a variable.

This way, they are less verbose, compatible with assignation and easier to read.

<?php 
// verbose if then structure
    
if ($a == 3) {
        
$b 2;
    } else {
        
$b 3;
    }

    
// compact ternary call
    
$b = ($a == 3) ? 3;

    
// verbose if then structure
    // Works with short assignations and simple expressions
    
if ($a != 3) {
        
$b += $a 4;
    } else {
        
$b += 3;
    }

    
// compact ternary call
    
$b += ($a != 3) ? $a 3;
?>



See also Ternary Operator, Shorthand comparisons in PHP

Unused Returned Value

[Since 0.8.5] - [ -P Functions/UnusedReturnedValue ] - [ Online docs ]

The function called returns a value, which is ignored.

Usually, this is a sign of dead code, or a missed check on the results of the functioncall. At times, it may be a valid call if the function has voluntarily no return value.

It is recommended to add a check on the return value, or remove the call.

<?php 
// simplest form
function foo() {
    return 
1;
}

foo();

// In case of multiple return, any one that returns something means that return value is meaningful
function bar() {
    if (
rand(01)) {
        return 
1;
    } else {
        return ;
    }
}

bar();
?>


Note that this analysis ignores functions that return void (same meaning that PHP 7.1 : return ; or no return in the function body).


Modernize Empty With Expression

[Since 0.8.6] - [ -P Structures/ModernEmpty ] - [ Online docs ]

empty() accepts expressions as argument. This feature was added in PHP 5.5.

There is no need to store the expression in a variable before testing, unless it is reused later.

<?php 
// PHP 5.5+ `empty() <https://www.php.net/empty>`_ usage
if (empty(foo($b $c))) {
    
doSomethingWithoutA();
}

// Compatible `empty() <https://www.php.net/empty>`_ usage
$a foo($b $c);
if (empty(
$a)) {
    
doSomethingWithoutA();
}

// $a2 is reused, storage is legit
$a2 strtolower($b $c);
if (empty(
$a2)) {
    
doSomething();
} else {
    echo 
$a2;
}
?>



See also empty() _, empty() _ supports arbitrary expressions

Use Positive Condition

[Since 0.8.6] - [ -P Structures/UsePositiveCondition ] - [ Online docs ]

Whenever possible, use a positive condition.

Positive conditions are easier to understand, and lead to less understanding problems.
Negative conditions are not reported when else is not present.

<?php 
// This is a positive condition
if ($a == 'b') {
    
doSomething();
} else {
    
doSomethingElse();
}

if (!empty(
$a)) {
    
doSomething();
} else {
    
doSomethingElse();
}

// This is a negative condition
if ($a == 'b') {
    
doSomethingElse();
} else {
    
doSomething();
}

// No need to force $a == 'b' with empty else
if ($a != 'b') {
    
doSomethingElse();
}
?>


See also Double negatives should not not be avoided, How To Write Conditional Statements in PHP

Drop Else After Return

[Since 0.8.6] - [ -P Structures/DropElseAfterReturn ] - [ Online docs ]

Avoid else clause when the then clause returns, but not the else. And vice-versa.

This way, the else block disappears, and is now the main sequence of the function.

This is also true if else has a return, and then not. When doing so, don't forget to reverse the condition.

<?php 
// drop the else
if ($a) {
    return 
$a;
} else {
    
doSomething();
}

// drop the then
if ($b) {
    
doSomething();
} else {
    return 
$a;
}

// return in else and then
if ($a3) {
    return 
$a;
} else {
    
$b doSomething();
    return 
$b;
}
?>

Use ::Class Operator

[Since 0.8.7] - [ -P Classes/UseClassOperator ] - [ Online docs ]

Use ::class to hardcode class names, instead of strings.

This is actually faster than strings, which are parsed at execution time, while ::class is compiled, making it faster to execute.

::class operator is also able to handle use expressions, including aliases and local namespace. The code is easier to maintain. For example, the target class's namespace may be renamed, without changing the ::class , while the string must be updated.

::class operator works with self and static keywords.

<?php 
namespace foo\bar;

use 
foo\bar\X as B;

class 
{}

$className '\foo\bar\X';

$className foo\bar\X::class;

$className B\X;

$object = new $className;
?>


This is not possible when building the name of the class with concatenation.

This is a micro-optimization. This also helps static analysis, as it gives more information at compile time to analyse.


See also ::class

ext/rar

[Since 0.8.7] - [ -P Extensions/Extrar ] - [ Online docs ]

Extension RAR.

Rar is a powerful and effective archiver created by Eugene Roshal. This extension gives you possibility to read Rar archives but doesn't support writing Rar archives, because this is not supported by the UnRar library and is directly prohibited by its license.

<?php 
$arch RarArchive::open(example.rar);
if (
$arch === FALSE)
    die(
Cannot open example.rar);

$entries $arch->getEntries();
if (
$entries === FALSE)
    die(
Cannot retrieve entries);
?>



See also Rar archiving, rarlabs

Don't Echo Error

[Since 0.8.7] - [ -P Security/DontEchoError ] - [ Online docs ]

It is recommended to avoid displaying error messages directly to the browser.

PHP's uses the display_errors directive to control display of errors to the browser. This must be kept to off when in production.

<?php 
// Inside a 'or' test
mysql_connect('localhost'$user$pass) or die(mysql_error());

// Inside a if test
$result pg_query$db$query );
if( !
$result )
{
    echo 
Erreur SQL: . pg_error();
    exit;
}

// Changing PHP configuration
ini_set('display_errors'1);
// This is also a security error : 'false' means actually true.
ini_set('display_errors''false');
?>


Error messages should be logged, but not displayed.


See also Error reporting, List of php.ini directives

Useless Type Casting

[Since 0.8.7] - [ -P Structures/UselessCasting ] - [ Online docs ]

There is no need to cast already typed values.

<?php 
// trim always returns a string : cast is useless
$a = (string) trim($b);

// strpos doesn't always returns an integer : cast is useful
$a = (boolean) strpos($b$c);

// comparison don't need casting, nor parenthesis
$c = (bool) ($b 2);

function 
foo(array $a) {
    foreach((array) 
$a as $b) {
        
// doSomething
    
}
}
?>


Typed values, such as properties, do not have to be cast again, as the engine always ensures their type.

Typed arguments are variables : after the initial check at method call time, they might change value and type. Those extra cast may then carry some value, although changing the type of an incoming value is not recommended.


See also Type juggling, Structures/MultipleTypeVariable

No isset() With empty()

[Since 0.8.7] - [ -P Structures/NoIssetWithEmpty ] - [ Online docs ]

empty() actually does the job of isset() too.

From the manual : No warning is generated if the variable does not exist. That means empty() is essentially the concise equivalent to !isset($var) || $var == false. The main difference is that isset() only works with variables, while empty() works with other structures, such as constants.

<?php 
// Enough validation
if (!empty($a)) {
    
doSomething();
}

// Too many tests
if (isset($a) && !empty($a)) {
    
doSomething();
}
?>



See also Isset, empty

Useless Check

[Since 0.8.9] - [ -P Structures/UselessCheck ] - [ Online docs ]

There is no need to check the size of an array content before using foreach. Foreach() applies a test on the source, and skips the loop if no element is found.

<?php 
// Checking for type is good. 
if (is_array($array)) {
    foreach(
$array as $a) {
        
doSomething($a);
    }
}

// Foreach on empty arrays doesn't start. Checking is useless
if (!empty($array)) {
    foreach(
$array as $a) {
        
doSomething($a);
    }
}
?>


This analysis checks for conditions with sizeof() and count(). Conditions with isset() and empty() are omitted : they also check for the variable existence, and thus, offer extra coverage.

See also foreach.

Bail Out Early

[Since 0.8.9] - [ -P Structures/BailOutEarly ] - [ Online docs ]

When using conditions, it is recommended to quit in the current context, and avoid else clause altogether.

The main benefit is to make clear the method applies a condition, and stop immediately when it is not satisfied.
The main sequence is then focused on the actual code.

This works with the break , continue , throw and goto keywords too, depending on situations.

<?php 
// Bailing out early, low level of indentation
function foo1($a) {
    if (
$a 0) {
        return 
false;
    } 
    
    
$a++;
    return 
$a;
}

// Works with continue too
foreach($array as $a => $b) {
    if (
$a 0) {
        continue 
false;
    } 
    
    
$a++;
    return 
$a;
}

// No need for else
function foo2($a) {
    if (
$a 0) {
        return 
false;
    } else {
        
$a++;
    }
    
    return 
$a;
}

// No need for else : return goes into then. 
function foo3($a) {
    if (
$a 0) {
        
$a++;
    } else {
        return 
false;
    }
    
    return 
$a;
}

// Make a return early, and make the condition visible.
function foo3($a) {
    if (
$a 0) {
        
$a++;
        
methodcall();
        
functioncall();
    } 
}
?>




See also Avoid nesting too deeply and return early (part 1), Avoid nesting too deeply and return early (part 2)

Dont Change The Blind Var

[Since 0.8.9] - [ -P Structures/DontChangeBlindKey ] - [ Online docs ]

When using a foreach(), the blind variables hold a copy of the original value. It is confusing to modify them, as it seems that the original value may be changed.

When actually changing the original value, use the reference in the foreach definition to make it obvious, and save the final reassignation.

When the value has to be prepared before usage, then save the filtered value in a separate variable. This makes the clean value obvious, and preserve the original value for a future usage.

<?php 
// $bar is duplicated and kept 
$foo = [123];
foreach(
$foo as $bar) {
    
// $bar is updated but its original value is kept
    
$nextBar $bar 1;
    print 
$bar ' => ' . ($nextBar) . PHP_EOL;
    
foobar($nextBar);
}

// $bar is updated and lost
$foo = [123];
foreach(
$foo as $bar) {
    
// $bar is updated but its final value is lost
    
print $bar ' => ' . (++$bar) . PHP_EOL;
    
// Now that $bar is reused, it is easy to confuse its value
    
foobar($bar);
}

// $bar is updated and kept
$foo = [123];
foreach(
$foo as &$bar) {
    
// $bar is updated and keept
    
print $bar ' => ' . (++$bar) . PHP_EOL;
    
foobar($bar);
}
?>

Avoid Using stdClass

[Since 0.9.1] - [ -P Php/UseStdclass ] - [ Online docs ]

stdClass is the default class for PHP. It is instantiated when PHP needs to return a object, but no class is specifically available.

It is recommended to avoid instantiating this class. Some PHP or frameworks functions, such as json_encode(), do return them : this is fine, although it is reported here.

<?php 
$json '{a:1,b:2,c:3}';
$object json_decode($json);
// $object is a stdClass, as returned by json_decode

// Fast building of $o
$a = [];
$a['a'] = 1;
$a['b'] = 2;
$a['c'] = 3;
json_encode( (object) $a);

// Slow building of $o
$o = new stdClass();
$o->1;
$o->2;
$o->3;
json_encode($o);
?>


If you need a stdClass object, it is faster to build it as an array, then cast it, than instantiate stdClass . This is a micro-optimisation.

ext/nsapi

[Since 0.9.2] - [ -P Extensions/Extnsapi ] - [ Online docs ]

NSAPI specific functions calls.

These functions are only available when running PHP as a NSAPI module in Netscape/iPlanet/Sun webservers.

<?php 
// This scripts depends on ext/nsapi
if (ini_get('nsapi.read_timeout') < 60) {
    
doSomething();
}
?>



See also Sun, iPlanet and Netscape servers on Sun Solaris

ext/newt

[Since 0.9.2] - [ -P Extensions/Extnewt ] - [ Online docs ]

Newt PHP CLI extension.

This is a PHP language extension for RedHat Newt library, a terminal-based window and widget library for writing applications with user friendly interface.

<?php 
newt_init ();
newt_cls ();

newt_draw_root_text (00Test Mode Setup Utility 1.12);
newt_push_help_line (null);

newt_get_screen_size ($rows$cols);

newt_open_window ($rows/2-17$cols/2-103417Choose a Tool);

$form newt_form ();

$list newt_listbox (3210);

foreach (array (
    
Authentication configuration,
    
Firewall configuration,
    
Mouse configuration,
    
Network configuration,
    
Printer configuration,
    
System services) as $l_item)
{
    
newt_listbox_add_entry ($list$l_item$l_item);
}

$b1 newt_button (512Run Tool);
$b2 newt_button (2112Quit);

newt_form_add_component ($form$list);
newt_form_add_components ($form, array($b1$b2));

newt_refresh ();
newt_run_form ($form);

newt_pop_window ();
newt_pop_help_line ();
newt_finished ();
newt_form_destroy ($form);
?>


See also Newt.

ext/ncurses

[Since 0.9.2] - [ -P Extensions/Extncurses ] - [ Online docs ]

Extension ncurses (CLI).

ncurses (new curses) is a free software emulation of curses in System V Rel 4.0 (and above).

<?php 
ncurses_init();
ncurses_start_color();
ncurses_init_pair(1NCURSES_COLOR_GREENNCURSES_COLOR_BLACK);
ncurses_init_pair(2NCURSES_COLOR_RED,   NCURSES_COLOR_BLACK);
ncurses_init_pair(3NCURSES_COLOR_WHITENCURSES_COLOR_BLACK);
ncurses_color_set(1);
ncurses_addstr('OK   ');
ncurses_color_set(3);
ncurses_addstr('Success!'.PHP_EOL);
ncurses_color_set(2);
ncurses_addstr('FAIL ');
ncurses_color_set(3);
ncurses_addstr('Success!'.PHP_EOL);
?>


See also Ncurses Terminal Screen Control and Ncurses.

Use Composer Lock

[Since 0.9.2] - [ -P Composer/UseComposerLock ] - [ Online docs ]

Reports if the composer.lock was committed to the archive.
See also Composer

Too Many Local Variables

[Since 0.9.2] - [ -P Functions/TooManyLocalVariables ] - [ Online docs ]

Too many local variables were found in the methods. When over 15 variables are found in such a method, a violation is reported.

Local variables exclude globals (imported with global) and arguments. Local variable include static variables.

When too many variables are used in a function, it is a code smells. The function is trying to do too much and needs extra space for juggling.
Beyond 15 variables, it becomes difficult to keep track of their name and usage, leading to confusion, overwriting or hijacking.

<?php 
// This function is OK : 3 vars are arguments, 3 others are globals.
function a20a3g3($a1$a2$a3) {
    global 
$a4$a5$a6;
    
    
$a1  1;
    
$a2  2;
    
$a3  ;
    
$a4  ;
    
$a5  ;
    
$a6  ;
    
$a7  ;
    
$a8  ;
    
$a9  ;
    
$a10 10;
    
$a11  11;
    
$a12  12;
    
$a13  13 ;
    
$a14  14 ;
    
$a15  15 ;
    
$a16  16 ;
    
$a17  17 ;
    
$a18  18 ;
    
$a19  19 ;
    
$a20 20;

}

// This function has too many variables
function a20() {
    
    
$a1  1;
    
$a2  2;
    
$a3  ;
    
$a4  ;
    
$a5  ;
    
$a6  ;
    
$a7  ;
    
$a8  ;
    
$a9  ;
    
$a10 10;
    
$a11  11;
    
$a12  12;
    
$a13  13 ;
    
$a14  14 ;
    
$a15  15 ;
    
$a16  16 ;
    
$a17  17 ;
    
$a18  18 ;
    
$a19  19 ;
    
$a20 20;

}
?>


Illegal Name For Method

[Since 0.9.2] - [ -P Classes/WrongName ] - [ Online docs ]

PHP has reserved usage of methods starting with __ for magic methods. It is recommended to avoid using this prefix, to prevent confusions.

<?php 
class foo{
    
// Constructor
    
function __construct() {}

    
// Constructor's typo
    
function __constructor() {}

    
// Illegal function name, even as private
    
private function __bar() {}
}
?>


See also Magic Methods.

String

[Since 0.9.4] - [ -P Extensions/Extstring ] - [ Online docs ]

Strings in PHP. Strings are part of the core of PHP, and are not a separate extension.

<?php 
$str Mary Had A Little Lamb and She LOVED It So;
$str strtolower($str);

echo 
$str// Prints mary had a little lamb and she loved it so
?>



See also String functions

ext/mhash

[Since 0.9.4] - [ -P Extensions/Extmhash ] - [ Online docs ]

Extension mhash (obsolete since PHP 5.3.0).

This extension provides functions, intended to work with mhash.

<?php 
$input 'what do ya want for nothing?';
$hash mhash(MHASH_MD5$input);
echo 
'The hash is ' bin2hex($hash) . '<br />'.PHP_EOL;
$hash mhash(MHASH_MD5$input'Jefe');
echo 
'The hmac is ' bin2hex($hash) . '<br />'.PHP_EOL;
?>


See also Extension mhash.

ext/mongodb

[Since 0.9.5] - [ -P Extensions/Extmongodb ] - [ Online docs ]

Extension MongoDb.

Do not mistake with extension Mongo, the previous version.

Mongodb driver supports both PHP and HHVM and is developed atop the libmongoc and libbson libraries.

<?php 
require 'vendor/autoload.php'// include Composer's autoloader

$client = new MongoDB\Client(mongodb://localhost:27017);
$collection $client->demo->beers;

$result $collection->insertOne( [ 'name' => 'Hinterland''brewery' => 'BrewDog' ] );

echo 
Inserted with Object ID {$result->getInsertedId()};
?>


See also MongoDB driver.

Long Arguments

[Since 0.9.7] - [ -P Structures/LongArguments ] - [ Online docs ]

Long arguments should be put in variable, to preserve readability.

When literal arguments are too long, they break the hosting structure by moving the next argument too far on the right. Whenever possible, long arguments should be set in a local variable to keep the readability.

<?php 
// Now the call to foo() is easier to read.
$reallyBigNumber = <<<BIGNUMBER
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
BIGNUMBER
foo($reallyBigNumber2'12345678901234567890123456789012345678901234567890');

// where are the next arguments ? 
foo('123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890'2'123456789012345678901234567890123456789012345678901234567890');

// This is still difficult to read
foo(<<<BIGNUMBER
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
BIGNUMBER
2'123456789012345678901234567890123456789012345678901234567890');
?>


Literal strings and heredoc strings, including variables, that are over 50 chars longs are reported here.

Assigned Twice

[Since 0.9.8] - [ -P Variables/AssignedTwiceOrMore ] - [ Online docs ]

The same variable is assigned twice in the same function.

While this is possible and quite common, it is also a good practice to avoid changing a value from one literal to another. It is far better to assign the new value to

Incremental changes to a variables are not reported here.

<?php 
function foo() {
    
// incremental changes of $a;
    
$a 'a';
    
$a++;
    
$a uppercase($a);
    
    
$b 1;
    
$c bar($b);
    
// B changed its purpose. Why not call it $d? 
    
$b = array(1,2,3);
    
    
// This is some forgotten debug
    
$e $config->getSomeList();
    
$e = array('OneElement');
}
?>


Error_Log() Usage

[Since 0.10.0] - [ -P Php/ErrorLogUsage ] - [ Online docs ]

Usage of error_log() function. This leads to checking the configuration of error_log in the PHP configuration directives.

<?php 
error_log(logging message\n);
?>

No Boolean As Default

[Since 0.10.0] - [ -P Functions/NoBooleanAsDefault ] - [ Online docs ]

Default values should always be set up with a constant name.

Class constants and constants improve readability when calling the methods or comparing values and statuses.

<?php 
const CASE_INSENSITIVE true;
const 
CASE_SENSITIVE false;

function 
foo($case_insensitive true) {
    
// doSomething()
}

// Readable code 
foo(CASE_INSENSITIVE);
foo(CASE_SENSITIVE);


// unreadable code  : is true case insensitive or case sensitive ? 
foo(true);
foo(false);
?>



See also FlagArgument, Clean code: The curse of a boolean parameter

SQL queries

[Since 0.10.1] - [ -P Type/Sql ] - [ Online docs ]

SQL queries, detected in literal strings.

SQL queries are detected with keywords, inside literals or concatenations.

<?php 
// SQL in a string
$query 'SELECT name FROM users WHERE id = 1';

// SQL in a concatenation
$query 'SELECT name FROM '.$table_users.' WHERE id = 1';

// SQL in a Heredoc
$query = <<<SQL
SELECT name FROM $table_users WHERE id = 1
SQL;
?>


ext/libsodium

[Since 0.10.2] - [ -P Extensions/Extlibsodium ] - [ Online docs ]

Extension for libsodium : in PECL until PHP 7.2, and in core ever since.

The Sodium crypto library (libsodium) is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more.

Sodium supports a variety of compilers and operating systems, including Windows (with MinGW or Visual Studio, x86 and x64), iOS and Android.

The design choices emphasize security, and "magic constants" have clear rationales.

<?php 
// Example from the docs : https://paragonie.com/book/pecl-libsodium/read/06-hashing.md#crypto-generichash

// Fast, unkeyed hash function.
// Can be used as a secure replacement for MD5
$h \Sodium\crypto_generichash('msg');

// Fast, keyed hash function.
// The key can be of any length between \Sodium\CRYPTO_GENERICHASH_KEYBYTES_MIN
// and \Sodium\CRYPTO_GENERICHASH_KEYBYTES_MAX, in bytes.
// \Sodium\CRYPTO_GENERICHASH_KEYBYTES is the recommended length.
$h \Sodium\crypto_generichash('msg'$key);

// Fast, keyed hash function, with user-chosen output length, in bytes.
// Output length can be between \Sodium\CRYPTO_GENERICHASH_BYTES_MIN and
// \Sodium\CRYPTO_GENERICHASH_BYTES_MAX.
// \Sodium\CRYPTO_GENERICHASH_BYTES is the default length.
$h \Sodium\crypto_generichash('msg'$key64);
?>



See also PHP extension for libsodium, Using Libsodium in PHP Projects

Forgotten Thrown

[Since 0.10.2] - [ -P Exceptions/ForgottenThrown ] - [ Online docs ]

An exception is instantiated, but not thrown.

<?php 
class MyException extends \Exception { }

if (
$error !== false) {
    
// This looks like 'throw' was omitted
    
new MyException();
}
?>

Multiple Alias Definitions Per File

[Since 0.10.3] - [ -P Namespaces/MultipleAliasDefinitionPerFile ] - [ Online docs ]

Avoid aliasing the same name with different aliases. This leads to confusion.

<?php 
// first occurrence
use name\space\ClasseName;

// when this happens, several other uses are mentioned

// name\space\ClasseName has now two names
use name\space\ClasseName as anotherName;
?>



See also `Namespaces/MultipleAliasDefinition`_

__DIR__ Then Slash

[Since 0.10.3] - [ -P Structures/DirThenSlash ] - [ Online docs ]

__DIR__ must be concatenated with a string starting with /.

The magic constant __DIR__ holds the name of the current directory, without final /. When it is used to build path, then the following path fragment must start with /. Otherwise, two directories names will be merged together.

<?php 
// __DIR__ = /a/b/c
// $filePath = /a/b/c/g.php

// /a/b/c/d/e/f.txt : correct path
echo __DIR__.'/d/e/f.txt';
echo 
dirname($filePath).'/d/e/f.txt';

// /a/b/cd/e/f.txt : most probably incorrect path
echo __DIR__.'d/e/f.txt';
echo 
dirname($filePath).'d/e/f.txt';
?>


self, parent, static Outside Class

[Since 0.10.3] - [ -P Classes/NoPSSOutsideClass ] - [ Online docs ]

self, parent and static should be called inside a class or trait. PHP lint won't report those situations.

self, parent and static may be used in a trait : their actual value will be only known at execution time, when the trait is used.

<?php 
// In the examples, self, parent and static may be used interchangeably

// This raises a Fatal error
//Fatal error: Uncaught Error: Cannot access static:: when no class scope is active
new static();

// static calls
echo self::CONSTANTE;
echo 
self::$property;
echo 
self::method();

// as a type hint
function foo(static $x) {
    
doSomething();
}

// as a instanceof
if ($x instanceof static) {
    
doSomething();
}
?>


Such syntax problem is only revealed at execution time : PHP raises a Fatal error.

The origin of the problem is usually a method that was moved outside a class, at least temporarily.


See also Scope Resolution Operator (::)

Used Once Property

[Since 0.10.3] - [ -P Classes/UsedOnceProperty ] - [ Online docs ]

Property used once in their defining class.

Properties used in one method only may be used several times, and read only. This may be a class constant. Such properties are meant to be overwritten by an extending class, and that's possible with class constants.

Setting properties with default values is a good way to avoid littering the code with literal values, and provide a single point of update (by extension, or by hardcoding) for all those situations. A constant is definitely better suited for this task.

<?php 
class foo {
    private 
$defaultCols '*';
    
cont DEFAULT_COLUMNS '*';

    
// $this->defaultCols holds a default value. Should be a constant.
    
function bar($table$cols) {
        
// This is necessary to activate usage of default values
        
if (empty($cols)) {
            
$cols $this->defaultCols;
        }
        
$res $this->query('SELECT '.$cols.' FROM '.$table);
        
// ....
    
}

    
// Upgraded version of bar, with default values
    
function bar2($table$cols self::DEFAULT_COLUMNS) {
        
$res $this->query('SELECT '.$cols.' FROM '.$table);
        
// .....
    
}
}
?>

Property Used In One Method Only

[Since 0.10.3] - [ -P Classes/PropertyUsedInOneMethodOnly ] - [ Online docs ]

Properties should be used in several methods. When a property is used in only one method, this should have be of another shape.

Properties used in one method only may be used several times, and read only. This may be a class constant. Such properties are meant to be overwritten by an extending class, and that's possible with class constants.

Properties that read and written may be converted into a variable, static to the method. This way, they are kept close to the method, and do not pollute the object's properties.

<?php 
class foo {
    private 
$once 1;
    const 
ONCE 1;
    private 
$counter 0;
    
    function 
bar() {
        
// $this->once is never used anywhere else. 
        
someFunction($this->once);
        
someFunction(self::ONCE);   // Make clear that it is a 
    
}

    function 
bar2() {
        static 
$localCounter 0;
        
$this->counter++;
        
        
// $this->once is only used here, for distinguising calls to someFunction2
        
if ($this->counter 10) { // $this->counter is used only in bar2, but it may be used several times
            
return false;
        }
        
someFunction2($this->counter);

        
// $localCounter keeps track for all the calls
        
if ($localCounter 10) { 
            return 
false;
        }
        
someFunction2($localCounter);
    }
}
?>


Note : properties used only once are not returned by this analysis. They are omitted, and are available in the analysis `Used Once Property`_.

ext/ds

[Since 0.10.4] - [ -P Extensions/Extds ] - [ Online docs ]

Extension Data Structures : Data structures.

<?php 
$vector = new \Ds\Vector();

$vector->push('a');
$vector->push('b''c');

$vector[] = 'd';

print_r($vector);
?>



See also Efficient data structures for PHP 7

No Need For Else

[Since 0.10.4] - [ -P Structures/NoNeedForElse ] - [ Online docs ]

Else is not needed when the Then ends with a break. A break may be the following keywords : break, continue, return, goto. Any of these send the execution somewhere in the code. The else block is then executed as the main sequence, only if the condition fails.

<?php 
function foo() {
    
// Else may be in the main sequence.
    
if ($a1) {
        return 
$a1;
    } else {
        
$a++;
    }

    
// Same as above, but negate the condition : if (!$a2) { return $a2; }
    
if ($a2) {
        
$a++;
    } else {
        return 
$a2;
    }

    
// This is OK
    
if ($a3) {
        return;
    }

    
// This has no break
    
if ($a4) {
        
$a++;
    } else {
        
$b++;
    }

    
// This has no else
    
if ($a5) {
        
$a++;
    }
}
?>



See also Object Calisthenics, rule # 2

Strange Name For Constants

[Since 0.10.5] - [ -P Constants/StrangeName ] - [ Online docs ]

Those constants looks like a typo from other names.

<?php 
// This code looks OK : DIRECTORY_SEPARATOR is a native PHP constant
$path $path DIRECTORY_SEPARATOR $file;

// Strange name DIRECOTRY_SEPARATOR
$path $path DIRECOTRY_SEPARATOR $file;
?>


Too Many Finds

[Since 0.10.5] - [ -P Classes/TooManyFinds ] - [ Online docs ]

Too many methods called 'find*' in this class. It is may be time to consider the Specification pattern.

<?php 
// quite a fishy interface
interface UserInterface {
    public function 
findByEmail($email);
    public function 
findByUsername($username);
    public function 
findByFirstName($firstname);
    public function 
findByLastName($lastname);
    public function 
findByName($name);
    public function 
findById($id);

    public function 
insert($user);
    public function 
update($user);
}
?>



See also On Taming Repository Classes in Doctrine, specifications

Use Cookies

[Since 0.10.6] - [ -P Php/UseCookies ] - [ Online docs ]

This code source uses cookies.

Cookie usage is spotted with the usage of setcookie(), setrawcookie() and header() with the 'Set-Cookie' header.

<?php 
header('Set-Cookie: '.$name.'='.$value.'; EXPIRES'.$date.';');

    
// From the PHP Manual : 
    
setcookie('TestCookie3'$valuetime()+3600'/~rasmus/''example.com'1);
?>



See also Cookies

Should Use SetCookie()

[Since 0.10.6] - [ -P Php/UseSetCookie ] - [ Online docs ]

Use setcookie() or setrawcookie(). Avoid using header() to do so, as the PHP native functions are more convenient and easier to spot during a refactoring.

setcookie() applies some encoding internally, for the value of the cookie and the date of expiration. Rarely, this encoding has to be skipped : then, use setrawencoding().

Both functions help by giving a checklist of important attributes to be used with the cookie.

<?php 
// same as below
setcookie(myCookie'chocolate'time()+3600, /, , truetrue);

// same as above. Slots for path and domain are omitted, but should be used whenever possible
header('Set-Cookie: myCookie=chocolate; Expires='.date('r', (time()+3600)).'; Secure; HttpOnly');
?>


See also Set-Cookie,
setcookie.

Check All Types

[Since 0.10.6] - [ -P Structures/CheckAllTypes ] - [ Online docs ]

When checking for type, avoid using else. Mention explicitly all tested types, and raise an exception when all available options have been exhausted : after all, this is when the code doesn't know how to handle the datatype.

PHP has a short list of scalar types : null, boolean, integer, real, strings, object, resource and array. When a variable is not holding one the the type, then it may be of any other type.

Most of the time, when using a simple is_string() / else test, this is relying on the conception of the code. By construction, the arguments may be one of two types : array or string.

What happens often is that in case of failure in the code (database not working, another class not checking its results), a third type is pushed to the structure, and it ends up breaking the execution.

The safe way is to check the various types all the time, and use the default case (here, the else) to throw exception() or test an assertion and handle the special case.

<?php 
// hasty version
if (is_array($argument)) {
    
$out $argument;
} else {
    
// Here, $argument is NOT an array. What if it is an object ? or a NULL ? 
    
$out = array($argument);
}

// Safe type checking : do not assume that 'not an array' means that it is the other expected type.
if (is_array($argument)) {
    
$out $argument;
} elseif (
is_string($argument)) {
    
$out = array($argument);
} else {
    
assert(false'$argument is not an array nor a string, as expected!');
}
?>


Using is_callable(), is_iterable() with this structure is fine : when variable is callable or not, while a variable is an integer or else.

Using a type test without else is also accepted here. This is a special treatment for this test, and all others are ignored. This aspect may vary depending on situations and projects.

Missing Cases In Switch

[Since 0.10.7] - [ -P Structures/MissingCases ] - [ Online docs ]

It seems that some cases are missing in this switch structure.

When comparing two different switch() structures, it appears that some cases are missing in one of them. The set of cases are almost identical, but one of the values are missing.

Switch() structures using strings as literals are compared in this analysis. When the discrepancy between two lists is below 25%, both switches are reported.

<?php 
// This switch operates on a, b, c, d and default 
switch($a) {
    case 
'a'doSomethingA(); break 1;
    case 
'b'doSomethingB(); break 1;
    case 
'c'doSomethingC(); break 1;
    case 
'd'doSomethingD(); break 1;
    default: 
doNothing();
}

// This switch operates on a, b, d and default 
switch($o->p) {
    case 
'a'doSomethingA(); break 1;
    case 
'b'doSomethingB(); break 1;

    case 
'd'doSomethingD(); break 1;
    default: 
doNothing();
}
?>


In the example, one may argue that the 'c' case is actually handled by the 'default' case. Otherwise, business logic may request that omission.

Group Use Declaration

[Since 0.10.7] - [ -P Php/GroupUseDeclaration ] - [ Online docs ]

The group use declaration is used in the code.

<?php 
// Adapted from the RFC documentation 
// Pre PHP 7 code
use some\name_space\ClassA;
use 
some\name_space\ClassB;
use 
some\name_space\ClassC as C;

use function 
some\name_space\fn_a;
use function 
some\name_space\fn_b;
use function 
some\name_space\fn_c;

use const 
some\name_space\ConstA;
use const 
some\name_space\ConstB;
use const 
some\name_space\ConstC;

// PHP 7+ code
use some\name_space\{ClassAClassBClassC as C};
use function 
some\name_space\{fn_afn_bfn_c};
use const 
some\name_space\{ConstAConstBConstC};
?>



See also Group Use Declaration RFC, Using namespaces: Aliasing/Importing

Repeated Regex

[Since 0.10.9] - [ -P Structures/RepeatedRegex ] - [ Online docs ]

Repeated regex should be centralized.

When a regex is repeatedly used in the code, it is getting harder to update.

<?php 
// Regex used several times, at least twice.
preg_match('/^abc_|^square$/i'$_GET['x']);

//.......

preg_match('/^abc_|^square$/i'$row['name']);

// This regex is dynamically built, so it is not reported.
preg_match('/^circle|^'.$x.'$/i'$string);

// This regex is used once, so it is not reported.
preg_match('/^circle|^square$/i'$string);
?>


Regex that are repeated at least once (aka, used twice or more) are reported. Regex that are dynamically build are not reported.

No Class In Global

[Since 0.10.9] - [ -P Php/NoClassInGlobal ] - [ Online docs ]

Avoid defining structures in Global namespace. Always prefer using a namespace. This will come handy later, either when publishing the code, or when importing a library, or even if PHP reclaims that name.

<?php 
// Code prepared for later
namespace Foo {
    class 
Bar {}
}

// Code that may conflict with other names.
namespace {
    class 
Bar {}
}
?>


Crc32() Might Be Negative

[Since 0.11.0] - [ -P Php/Crc32MightBeNegative ] - [ Online docs ]

crc32() may return a negative number, on 32 bits platforms.

According to the manual : Because PHP\'s integer type is signed many CRC32 checksums will result in negative integers on 32 bits platforms. On 64 bits installations, all crc32() results will be positive integers though.

<?php 
// display the checksum with %u, to make it unsigned
echo sprintf('%u'crc32($str));

// turn the checksum into an unsigned hexadecimal
echo dechex(crc32($str));

// avoid concatenating crc32 to a string, as it may be negative on 32bits platforms 
echo 'prefix'.crc32($str);
?>



See also `crc32() `_

Could Use str_repeat()

[Since 0.11.0] - [ -P Structures/CouldUseStrrepeat ] - [ Online docs ]

Use str_repeat() or str_pad() instead of making a loop.

Making a loop to repeat the same concatenation is actually much longer than using str_repeat(). As soon as the loop repeats more than twice, str_repeat() is much faster. With arrays of 30, the difference is significant, though the whole operation is short by itself.

<?php 
// This adds 7 'e' to $x
$x .= str_repeat('e'7);

// This is the same as above, 
for($a 3$a 10; ++$a) {
    
$x .= 'e';
}

// here, $default must contains 7 elements to be equivalent to the previous code
foreach($default as $c) {
    
$x .= 'e';
}
?>


Suspicious Comparison

[Since 0.11.0] - [ -P Structures/SuspiciousComparison ] - [ Online docs ]

The comparison seems to be misplaced.

A comparison happens in the last argument, while the actual function expect another type : this may be the case of a badly placed parenthesis.

<?php 
// trim expect a string, a boolean is given.
if (trim($str === '')){

}

// Just move the first closing parenthesis to give back its actual meaning
if (trim($str) === ''){

}
?>


Original idea by Vladimir Reznichenko.

Strings With Strange Space

[Since 0.11.0] - [ -P Type/StringWithStrangeSpace ] - [ Online docs ]

An invisible space may be mistaken for a normal space.

However, PHP does straight comparisons, and may fail at recognizing. This analysis reports when it finds such strange spaces inside strings.

PHP doesn't mistake space and tables for whitespace when tokenizing the code.

This analysis doesn't report Unicode Codepoint Notation : those are visible in the code.

<?php 
// PHP 7 notation, 
$a \u{3000};
$b = ;

// Displays false
var_dump($a === $b);
?>



See also Unicode spaces, disallow irregular whitespace (no-irregular-whitespace)

No Empty Regex

[Since 0.11.1] - [ -P Structures/NoEmptyRegex ] - [ Online docs ]

PHP regex don't accept empty regex, nor regex with alphanumeric delimiter.

Most of those errors happen at execution time, when the regex is build dynamically, but still may end empty. At compile time, such error are made when the code is not tested before commit.

<?php 
// No empty regex
preg_match(''$string$r); 

// Delimiter must be non-alphanumerical
preg_replace('1abc1'$string$r); 

// Delimiter must be non-alphanumerical
preg_replace('1'.$regex.'1'$string$r);
?>


See also PCRE and Delimiters.

Alternative Syntax Consistence

[Since 0.11.2] - [ -P Structures/AlternativeConsistenceByFile ] - [ Online docs ]

PHP allows for two syntax : the alternative syntax, and the classic syntax.

The classic syntax is almost always used. When used, the alternative syntax is used in templates.

This analysis reports files that are using both syntax at the same time. This is confusing.

<?php 
// Mixing both syntax is confusing.
foreach($array as $item) : 
    if (
$item 1) {
        print 
$item elements\n;
    } else {
        print 
$item element\n;
    }
endforeach;
?>


Randomly Sorted Arrays

[Since 0.11.2] - [ -P Arrays/RandomlySortedLiterals ] - [ Online docs ]

Those literal arrays are written in several places, but their items are in various orders.

This may reduce the reading and proofing of the arrays, and induce confusion. The random order may also be a residue of development : both arrays started with different values, but they grew overtime to handle the same items. The way they were written lead to the current order.

Unless order is important, it is recommended to always use the same order when defining literal arrays. This makes it easier to match different part of the code by recognizing one of its literal.

<?php 
// an array
$set = [1,3,5,9,10];

function 
foo() {
    
// an array, with the same values but different order, in a different context
    
$list = [1,3,5,10,9,];
}

// an array, with the same order than the initial one
$inits = [1,3,5,9,10];
?>


ext/sphinx

[Since 0.11.3] - [ -P Extensions/Extsphinx ] - [ Online docs ]

Extension for the Sphinx search server.

This extension provides bindings for Sphinx search client library.

<?php 
$s = new SphinxClient;
$s->setServer(localhost6712);
$s->setMatchMode(SPH_MATCH_ANY);
$s->setMaxQueryTime(3);

$result $s->query(test);

var_dump($result);
?>



See also Sphinx Client, Sphinx Search

Try With Multiple Catch

[Since 0.11.3] - [ -P Php/TryMultipleCatch ] - [ Online docs ]

Try may be used with multiple catch clauses.

<?php 
try { 
    
OneCatch(); 
} catch (
FirstException $e) {

}

try { 
    
TwoCatches(); 
} catch (
FirstException $e) {
} catch (
SecondException $e) {
}
?>



See also Exceptions

ext/grpc

[Since 0.11.3] - [ -P Extensions/Extgrpc ] - [ Online docs ]

Extension for GRPC : A high performance, open-source universal RPC framework.

<?php 
//https://github.com/grpc/grpc/blob/master/examples/php/greeter_client.php

require dirname(__FILE__).'/vendor/autoload.php';
// The following includes are needed when using protobuf 3.1.0
// and will suppress warnings when using protobuf 3.2.0+
@include_once dirname(__FILE__).'/helloworld.pb.php';
@include_once 
dirname(__FILE__).'/helloworld_grpc_pb.php';
function 
greet($name)
{
    
$client = new Helloworld\GreeterClient('localhost:50051', [
        
'credentials' => Grpc\ChannelCredentials::createInsecure(),
    ]);
    
$request = new Helloworld\HelloRequest();
    
$request->setName($name);
    list(
$reply$status) = $client->SayHello($request)->wait();
    
$message $reply->getMessage();
    return 
$message;
}
$name = !empty($argv[1]) ? $argv[1] : 'world';
echo 
greet($name).\n;
?>



See also GRPC, GRPC on PECL

Only Variable Passed By Reference

[Since 0.11.3] - [ -P Functions/OnlyVariablePassedByReference ] - [ Online docs ]

When an argument is expected by reference, it is compulsory to provide a container. A container may be a variable, an array, a property or a static property.

This may be linted by PHP, when the function definition is in the same file as the function usage. This is silently linted if definition and usage are separated, if the call is dynamical or made as a method.

<?php 
function foo(&$bar) { /**/ }

function &
bar() { /**/ }

// This is not possible : `strtolower() <https://www.php.net/strtolower>`_ returns a value
foo(strtolower($string));

// This is valid : bar() returns a reference
foo(bar($string));
?>


This analysis currently covers functioncalls and static methodcalls, but omits methodcalls.

See also Passing arguments by reference

No Return Used

[Since 0.11.3] - [ -P Functions/NoReturnUsed ] - [ Online docs ]

The return value of the following methods are never used. The return argument may be dropped from the code, as it is dead code.

This analysis supports functions and static methods, when a definition may be found. It doesn't support method calls.

<?php 
function foo($a 1) { return 1; }

foo();
foo();
foo();
foo();
foo();
foo();

// This function doesn't return anything. 
function foo2() { }

// The following function are used in an expression, thus the return is important
function foo3() {  return 1;}
function 
foo4() {  return 1;}
function 
foo5() {  return 1;}

foo3() + 1
$a foo4();
foo(foo5());
?>

Use Browscap

[Since 0.11.4] - [ -P Php/UseBrowscap ] - [ Online docs ]

Browscap is a browser database, accessible via get_browser().

Browscap is the 'Browser Capabilities Project'.

<?php 
echo $_SERVER['HTTP_USER_AGENT'] . \n\n;

$browser get_browser(nulltrue);
print_r($browser);
?>


See also browscap

Use Debug

[Since 0.11.4] - [ -P Structures/UseDebug ] - [ Online docs ]

The code source includes calls to debug functions.

The following debug functions and libraries are reported :


<?php 
// Example with Zend Debug
Zend\Debug\Debug::dump($var$label null$echo true);
?>


No Reference On Left Side

[Since 0.11.5] - [ -P Structures/NoReferenceOnLeft ] - [ Online docs ]

Do not use references as the right element in an assignation.

<?php 
$b 2;
$c 3;

$a = &$b $c;
// $a === 2 === $b;

$a $b $c;
// $a === 5
?>


This is the case for most situations : addition, multiplication, bitshift, logical, power, concatenation.
Note that PHP won't compile the code if the operator is a short operator (+=, .=, etc.), nor if the & is on the right side of the operator.


See also References Explained, Operator Precedence

Implemented Methods Must Be Public

[Since 0.11.5] - [ -P Classes/ImplementedMethodsArePublic ] - [ Online docs ]

Class methods that are defined in an interface must be public. They cannot be either private, nor protected.

This error is not reported by lint, but is reported at execution time.

<?php 
interface {
    function 
foo();
}

class 
{
    
// This method is defined in the interface : it must be public
    
protected function foo() {}
    
    
// other methods may be private
    
private function bar() {}
}
?>



See also Interfaces, Interfaces - the next level of abstraction

PSR-16 Usage

[Since 0.11.6] - [ -P Psr/Psr16Usage ] - [ Online docs ]

PSR-16 describes a simple yet extensible interface for a cache item and a cache driver. It is supported by an set of interfaces, that one may use in the code.

<?php 
namespace My\SimpleCache;

// MyCache implements the PSR-16 Simple cache.
// MyCache is more of a black hole than a real cache.
class MyCache implements Psr\SimpleCache\CacheInterface {
    public function 
get($key$default null) {}
    public function 
set($key$value$ttl null) {}
    public function 
delete($key) {}
    public function 
clear() {}
    public function 
getMultiple($keys$default null) {}
    public function 
setMultiple($values$ttl null) {}
    public function 
deleteMultiple($keys) {}
    public function 
has($key) {}
}
?>


See also PSR-16 : Common Interface for Caching Libraries.

PSR-7 Usage

[Since 0.11.6] - [ -P Psr/Psr7Usage ] - [ Online docs ]

PSR-7 describes common interfaces for representing HTTP messages as described in RFC 7230 and RFC 7231, and URI for use with HTTP messages as described in RFC 3986.

It is supported by an set of interfaces, that one may use in the code.

<?php 
namespace MyNamespace;

// MyServerRequest implements the PSR-7 ServerRequestInterface.
// MyServerRequest is more of a black hole than a real Server.
class MyServerRequest extends  \Psr\Http\Message\ServerRequestInterface  {
    public function 
getServerParams() {}
    public function 
getCookieParams() {}
    public function 
withCookieParams(array $cookies) {}
    public function 
getQueryParams() {}
    public function 
withQueryParams(array $query) {}
    public function 
getUploadedFiles() {}
    public function 
withUploadedFiles(array $uploadedFiles) {}
    public function 
getParsedBody() {}
    public function 
withParsedBody($data) {}
    public function 
getAttributes() {}
    public function 
getAttribute($name$default null) {}
    public function 
withAttribute($name$value) {}
    public function 
withoutAttribute($name) {}
}
?>



See also PSR-7 : HTTP message interfaces

PSR-6 Usage

[Since 0.11.6] - [ -P Psr/Psr6Usage ] - [ Online docs ]

PSR-6 is the cache standard for PHP.

The goal of PSR-6 is to allow developers to create cache-aware libraries that can be integrated into existing frameworks and systems without the need for custom development.

It is supported by an set of interfaces, that one may use in the code.

<?php 
namespace MyNamespace;

// MyCacheItem implements the PSR-7 CacheItemInterface.
// This MyCacheItem is more of a black hole than a real CacheItem.
class MyCacheItem implements \Psr\Cache\CacheItemInterface {
    public function 
getKey() {}
    public function 
get() {}
    public function 
isHit() {}
    public function 
set($value) {}
    public function 
expiresAt($expiration) {}
    public function 
expiresAfter($time) {}
}
?>


See also PSR-6 : Caching.

PSR-3 Usage

[Since 0.11.6] - [ -P Psr/Psr3Usage ] - [ Online docs ]

PSR-3 describes a common interface for logging libraries.

It is supported by an set of interfaces, that one may use in the code.

<?php 
namespace MyNamespace;

// MyLog implements the PSR-3 LoggerInterface.
// MyLog is more of a black hole than a real Log.
namespace ;

class 
MyLog implements \Psr\Log\LoggerInterface {
    public function 
emergency($message, array $context = array()) {}
    public function 
alert($message, array $context = array()) {}
    public function 
critical($message, array $context = array()) {}
    public function 
error($message, array $context = array()) {}
    public function 
warning($message, array $context = array()) {}
    public function 
notice($message, array $context = array()) {}
    public function 
info($message, array $context = array()) {}
    public function 
debug($message, array $context = array()) {}
    public function 
log($level$message, array $context = array()) {}
}
?>


See also PSR-3 : Logger Interface.

PSR-11 Usage

[Since 0.11.5] - [ -P Psr/Psr11Usage ] - [ Online docs ]

PSR-11 describes a common interface for dependency injection containers.

It is supported by an set of interfaces, that one may use in the code.

<?php 
namespace MyNamespace;

// MyContainerInterface implements the PSR-7 ServerRequestInterface.
// MyContainerInterface is more of a black hole than a real Container.
class MyContainerInterface implements \Psr\Container\ContainerInterface {
    public function 
get($id) {}
    public function 
has($id) {}
}
?>


See also PSR-11 : Dependency injection container.

PSR-13 Usage

[Since 0.11.6] - [ -P Psr/Psr13Usage ] - [ Online docs ]

PSR-13 describes a common interface for dependency injection containers.

It is supported by an set of interfaces, that one may use in the code.

<?php 
namespace MyNamespace;

// MyLink implements the PSR-13 LinkInterface.
// MyLink is more of a black hole than a real Container.
class MyLink implements LinkInterface {
    public function 
getHref() {}
    public function 
isTemplated() {}
    public function 
getRels() {}
    public function 
getAttributes() {}
}
?>


See also PSR-13 : Link definition interface.

Mixed Concat And Interpolation

[Since 0.11.5] - [ -P Structures/MixedConcatInterpolation ] - [ Online docs ]

Mixed usage of concatenation and string interpolation is error prone. It is harder to read, and leads to overlooking the concatenation or the interpolation.

<?php 
// Concatenation string
$a $b 'c' $d;

// Interpolation strings
$a = {$b}c{$d};   // regular form
$a = {$b}c$d;     // irregular form

// Mixed Concatenation and Interpolation string
$a = {$b}$d;
$a $b c$d;
$a $b c{$d};

// Mixed Concatenation and Interpolation string with constant
$a = {$b}CONSTANT;
?>


Fixing this issue has no impact on the output. It makes code less error prone.

There are some situations where using concatenation are compulsory : when using a constant, calling a function, running a complex expression or make use of the escape sequence. You may also consider pushing the storing of such expression in a local variable.

ext/stats

[Since 0.11.5] - [ -P Extensions/Extstats ] - [ Online docs ]

Statistics extension.

This extension contains few dozens of functions useful for statistical computations. It is a wrapper around 2 scientific libraries, namely DCDFLIB (Library of C routines for Cumulative Distributions Functions, Inverses, and Other parameters) by B. Brown & J. Lavato and RANDLIB by Barry Brown, James Lavato & Kathy Russell.

<?php 
$x = [ 1516861512121812201214, ];
$y = [ 17.241514.914.5186.2919.2318.697.2142.067.58,];

sprintf(%2.9fstats_covariance($a_1$a_2));
?>


See also Statistics, ext/stats

Too Many Injections

[Since 0.11.6] - [ -P Classes/TooManyInjections ] - [ Online docs ]

When a class is constructed with more than four dependencies, it should be split into smaller classes.

<?php 
// This class relies on 5 other instances. 
// It is probably doing too much.
class Foo {
    public function 
__construct(
            
A $a
            
B $b
            
C $c,
            
D $d
            E $e 
) {
        
$this->$a;
        
$this->$b;
        
$this->$d;
        
$this->$d;
        
$this->$e;
    }
}
?>



See also Dependency Injection Smells

Dependency Injection

[Since 0.11.6] - [ -P Patterns/DependencyInjection ] - [ Online docs ]

A dependency injection is a typehinted argument, that is stored in a property by the constructor.

<?php 
// Classic dependency injection 
class foo {
    private 
$bar;

    public function 
__construct(Bar $bar) {
        
$this->bar $bar;
    }

    public function 
doSomething($args) {
        return 
$this->bar->barbar($args);
    }
}

// Without typehint, this is not a dependency injection
class foo {
    private 
$bar;

    public function 
__construct($bar) {
        
$this->bar $bar;
    }
}
?>


See also Understanding Dependency Injection.

Courier Anti-Pattern

[Since 0.11.6] - [ -P Patterns/CourrierAntiPattern ] - [ Online docs ]

The courier anti-pattern is the storage of a dependency by a class, in order to create an instance that requires this dependency.

The class itself doesn't actually need this dependency, but has a dependency to a class that requires it.

<?php 
// The foo class requires bar
class Foo {
    public function 
__construct(Bar $b) {
    }
}

// Class A doesn't depends on Bar, but depends on Foo
// Class A never uses Bar, but only uses Foo.
class {
    private 
$courier;

    public function 
__construct(Bar $courier) {
        
$this->courier $courier;       
    }

    public function 
Afoo() {
        
$b = new Foo($this->courier);
    }

}
?>


The alternative here is to inject Foo instead of Bar.

See also Courier Anti-pattern.

ext/gender

[Since 0.11.6] - [ -P Extensions/Extgender ] - [ Online docs ]

Gender extension.

The Gender PHP extension is a port of the gender.c program originally written by Joerg Michael. Its main purpose is to find out the gender of firstnames, based on a database of over 40000 firstnames from 54 countries.

<?php 
namespace Gender;

$gender = new Gender;

 
$name 'Milene';
$country Gender::FRANCE;
 
$result $gender->get($name$country);

$data $gender->country($country);

switch(
$result) {
    case 
Gender::IS_FEMALE:
        
printf('The name %s is female in %s\n'$name$data['country']);
    break;

 
    case 
Gender::IS_MOSTLY_FEMALE:
        
printf('The name %s is mostly female in %s\n'$name$data['country']);
    break;

 
    case 
Gender::IS_MALE:
        
printf('The name %s is male in %s\n'$name$data['country']);
    break;

 
    case 
Gender::IS_MOSTLY_MALE:
        
printf('The name %s is mostly male in %s\n'$name$data['country']);
    break;

 
    case 
Gender::IS_UNISEX_NAME:
        
printf('The name %s is unisex in %s\n'$name$data['country']);
    break;

 
    case 
Gender::IS_A_COUPLE:
        
printf('The name %s is both male and female in %s\n'$name$data['country']);
    break;

 
    case 
Gender::NAME_NOT_FOUND:
        
printf('The name %s was not found for %s\n'$name$data['country']);
    break;

 
    case 
Gender::ERROR_IN_NAME:
        echo 
'There is an error in the given name!'.PHP_EOL;
    break;
 
    default:
        echo 
'An error occurred!'.PHP_EOL;
    break;

}
?>


See also ext/gender manual, genderReader

ext/judy

[Since 0.11.6] - [ -P Extensions/Extjudy ] - [ Online docs ]

The Judy extension.

PHP Judy is a PECL extension for the Judy C library implementing dynamic sparse arrays.

<?php 
$judy = new Judy(Judy::BITSET);
if (
$judy->getType() === judy_type($judy) &&
    
$judy->getType() === Judy::BITSET) {
    echo 
'Judy BITSET type OK'.PHP_EOL;
} else {
    echo 
'Judy BITSET type check fail'.PHP_EOL;
}
unset(
$judy);
?>


See also php-judy.

Could Make A Function

[Since 0.11.6] - [ -P Functions/CouldCentralize ] - [ Online docs ]

When a function is called across the code with the same arguments often enough, it should be turned into a local API.

This approach is similar to turning literals into constants : it centralize the value, it helps refactoring by updating it. It also makes the code more readable. Moreover, it often highlight common grounds between remote code locations.

The analysis looks for functions calls, and checks the arguments. When the calls occurs more than 4 times, it is reported.

<?php 
// str_replace is used to clean '&' from strings. 
// It should be upgraded to a central function
function foo($arg ) {
    
$arg str_replace('&'''$arg);
    
// do something with $arg
}

class 
{
    function 
bar($database ) {
        
$value $database->queryName();
        
$value str_replace('&'''$value);
        
// $value = removeAmpersand($value);
        // do something with $arg2
    
}
}

// helper function
function removeAmpersand($string) {
    return 
str_replace('&'''$string);
}
?>


See also Don't repeat yourself (DRY)

Forgotten Interface

[Since 0.11.7] - [ -P Interfaces/CouldUseInterface ] - [ Online docs ]

The following classes have been found implementing an interface's methods, though it doesn't explicitly implements this interface. This may have been forgotten.

<?php 
interface {
    function 
i(); 
}

// i is not implemented and declared
class foo {
    function 
i() {}
    function 
j() {}
}

// i is implemented and declared
class foo implements {
    function 
i() {}
    function 
j() {}
}
?>



See also Traits/CouldUseTrait

Yii usage

[Since 0.11.8] - [ -P Vendors/Yii ] - [ Online docs ]

This analysis reports usage of the Yii 2 framework.

This analysis targets Yii 2, not Yii 1.

<?php 
// A Yii controller
class SiteController extends \Yii\Web\Controller
{
    public function 
actionIndex()
    {
        
// ...
    
}
 
    public function 
actionContact()
    {
        
// ...
    
}
}
?>



See also Yii

Codeigniter usage

[Since 0.11.8] - [ -P Vendors/Codeigniter ] - [ Online docs ]

This analysis reports usage of the Codeigniter 4 framework.

Note : Code igniter 3 and older are not reported.

<?php 
// A code igniter controller
class Blog extends \App\Controllers\Home {

        public function 
index()
        {
                echo 
'Hello World!';
        }
}
?>



See also Codeigniter

Laravel usage

[Since 0.11.8] - [ -P Vendors/Laravel ] - [ Online docs ]

This analysis reports usage of the Laravel framework.

<?php 
namespace App\Http\Controllers;

use 
App\User;
use 
App\Http\Controllers\Controller;

class 
UserController extends Controller
{
    
/**
     * Show the profile for the given user.
     *
     * @param  int  $id
     * @return Response
     */
    
public function show($id)
    {
        return 
view('user.profile', ['user' => User::findOrFail($id)]);
    }
}
?>



See also Laravel

Symfony usage

[Since 0.11.8] - [ -P Vendors/Symfony ] - [ Online docs ]

This analysis reports usage of the Symfony framework.

<?php 
// src/AppBundle/Controller/LuckyController.php
namespace AppBundle\Controller;

use 
Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use 
Symfony\Component\HttpFoundation\Response;

class 
LuckyController
{
    
/**
     * @Route(/lucky/number)
     */
    
public function numberAction()
    {
        
$number mt_rand(0100);

        return new 
Response(
            
'<html><body>Lucky number: '.$number.'</body></html>'
        
);
    }
}
?>



See also Symfony

Wordpress usage

[Since 0.11.8] - [ -P Vendors/Wordpress ] - [ Online docs ]

This analysis reports usage of the Wordpress platform.

The current supported version is Wordpress 5.8.

<?php 
//Usage of the WP_http class from Wordpress
$rags = array(
   
'x' => '1',
   
'y' => '2'
);
$url 'http://www.example.com/';
$request = new WP_Http();
$result $request->request$url, array( 'method' => 'POST''body' => $body) );
?>



See also Wordpress

Ez cms usage

[Since 0.11.8] - [ -P Vendors/Ez ] - [ Online docs ]

This analysis reports usage of the Ez CMS.

<?php 
namespace My\Bundle\With\Controller;

use 
eZ\Bundle\EzPublishCoreBundle\Controller;
use 
Symfony\Component\HttpFoundation\Request;

class 
DemoController extends Controller {
    public function 
demoCreateContentAction(Request $request) {
        
//
    
}
}
?>



See also Ez

Joomla usage

[Since 0.11.8] - [ -P Vendors/Joomla ] - [ Online docs ]

This analysis reports usage of the Joomla CMS.

<?php 
// no direct access
defined('_JEXEC') or die('Restricted access');

jimport('joomla.application.component.controller');
JLoader::import('KBIntegrator'JPATH_PLUGINS DS 'kbi');

class 
MyController extends JController {
    function 
display($message) {
        echo 
$message;
    }
}
?>



See also Joomla

Non Breakable Space In Names

[Since 0.12.0] - [ -P Structures/NonBreakableSpaceInNames ] - [ Online docs ]

PHP allows non-breakable spaces in structures names, such as class, interfaces, traits, and variables.

This may be a nice trick to make names more readable outside code context, like long-named methods for tests.

<?php 
class class with non breakable spaces {}

class 
ClassWithoutNonBreakableSpaces {}
?>


Original post by Matthieu Napoli .
.

See also Using non-breakable spaces in test method names, PHP Variable Names

Multiple Functions Declarations

[Since 0.12.0] - [ -P Functions/MultipleDeclarations ] - [ Online docs ]

Some functions are declared multiple times in the code.

PHP accepts multiple definitions for the same functions, as long as they are not in the same file (linting error), or not included simultaneously during the execution.

This creates to several situations in which the same functions are defined multiple times : the function may be compatible with various PHP version, but their implementation may not. Or the function is part of a larger library, and sometimes only need without the rest of the library.

It is recommended to avoid having several functions with the same name in one repository. Turn those functions into methods and load them when needed.

<?php 
namespace {
    function 
foo() {}
}

// Other file
namespace {
    function 
foo() {}
    function 
bar() {}
}
?>


Avoid Optional Properties

[Since 0.12.0] - [ -P Classes/AvoidOptionalProperties ] - [ Online docs ]

Avoid optional properties, to prevent littering the code with existence checks.

When a property has to be checked once for existence, it is safer to check it each time. This leads to a decrease in readability and a lot of checks added to the code.

Either make sure the property is set with an actual object rather than with null, or use a null object. A null object offers the same interface than the expected object, but does nothing. It allows calling its methods, without running into a Fatal error, nor testing it.

<?php 
// Example is courtesy 'The Coding Machine' : it has been adapted from its original form. See link below.

class MyMailer {
    private 
$logger;

    public function 
__construct(LoggerInterface $logger null) {
        
$this->logger $logger;
    }

    private function 
sendMail(Mail $mail) {
        
// Since $this->logger may be null, it must be tested anytime it is used.
        
if ($this->logger) {
            
$this->logger->info('Mail successfully sent.');
        }
    }
}
?>


See also Avoid optional services as much as possible, The Null Object Pattern – Polymorphism in Domain Models, Practical PHP Refactoring: Introduce Null Object

ext/swoole

[Since 0.12.0] - [ -P Extensions/Extswoole ] - [ Online docs ]

Swoole : Production-Grade Async programming Framework for PHP.

Swoole is an event-driven asynchronous & concurrent networking communication framework with high performance written only in C for PHP.

<?php 
for($i 0$i 100$i++) {
    
Swoole\Coroutine::create(function() use ($i) {
        
$redis = new Swoole\Coroutine\Redis();
        
$res $redis->connect('127.0.0.1'6379);
        
$ret $redis->incr('coroutine');
        
$redis->close();
        if (
$i == 50) {
            
Swoole\Coroutine::create(function() use ($i) {
                
$redis = new Swoole\Coroutine\Redis();
                
$res $redis->connect('127.0.0.1'6379);
                
$ret $redis->set('coroutine_i'50);
                
$redis->close();
            });
        }
    });
}
?>


See also Swoole, Swoole src

Manipulates NaN

[Since 0.10.6] - [ -P Php/IsNAN ] - [ Online docs ]

This code handles Not-a-Number situations. Not-a-Number , also called NaN , happens when a calculation can't return an actual float.

<?php 
// acos returns a float, unless it is not possible.
$a acos(8);

var_dump(is_nan($a));
?>



See also Floats

Manipulates INF

[Since 0.10.6] - [ -P Php/IsINF ] - [ Online docs ]

This code handles INF situations. INF represents the infinity, when used in a float context. It happens when a calculation returns a number that is much larger than the maximum allowed float (not integer), or a number that is not a Division by 0.

<?php 
// pow returns INF, as it is equivalent to 1 / 0 ^ 2
$a pow(0,-2); // 

// exp returns an actual value, but won't be able to represent it as a float
$a exp(PHP_INT_MAX); 

// 0 ^ -1 is like 1 / 0 but returns INF.
$a pow(0, -1); 

var_dump(is_infinite($a));

// This yields a Division by zero exception
$a 0;
?>



See also Math predefined constants

Const Or Define

[Since 0.12.1] - [ -P Structures/ConstDefineFavorite ] - [ Online docs ]

const and define() `_ have the same functional use : create constants.

The analyzed code has less than 10% of one of them : for consistency reasons, it is recommended to make them all the same.

They are almost interchangeable, though not totally : define() `_ allows the creation of case-insensitive constants, while Const won\'t.

<?php 
// be consistent
const A1  ;
const 
A2  ;
const 
A3  ;
const 
A4  ;
const 
A5  ;
const 
A6  ;
const 
A7  ;
const 
A8  ;
const 
A9  ;
const 
A10 10;
const 
A11 11;

define('A12'12); // Be consistent, always use the same.
?>



See also define, const

strict_types Preference

[Since 0.12.2] - [ -P Php/DeclareStrict ] - [ Online docs ]

strict_types is a PHP mode where typehint are enforced strictly or weakly. By default, it is weak typing, allowing backward compatibility with previous versions.

This analysis reports if strict_types are used systematically or not. strict_types affects the calling file, not the definition file.

<?php 
// define strict_types
declare(strict_types 1);

foo(1);
?>



See also Strict typing

Declare strict_types Usage

[Since 0.12.1] - [ -P Php/DeclareStrictType ] - [ Online docs ]

Usage of strict_types . By default, PHP attempts to change the original type to match the type specified by the type-declaration. With an explicit strict_types declaration, PHP ensures that the incoming argument has the exact type.

strict_types were introduced in PHP 7.0.

<?php 
// Setting strict_types;
    
declare(strict_types 1);

    function 
foo(int $i) {
        echo 
$i;
    }

    
// Always valid : displays 1
    
foo(1);
    
// with strict types, this emits an error
    // without strict types, this displays 1
    
foo(1.7);
?>



See also declare

Encoding Usage

[Since 0.12.1] - [ -P Php/DeclareEncoding ] - [ Online docs ]

Usage of declare(encoding = );.

<?php 
// Setting encoding for the file;
    
declare(encoding 'UTF-8');
?>



See also declare

Ticks Usage

[Since 0.12.1] - [ -P Php/DeclareTicks ] - [ Online docs ]

Usage of declare(ticks = );.

<?php 
// Setting ticks value
    
declare(ticks 'UTF-8');
?>



See also declare

Mismatched Ternary Alternatives

[Since 0.12.1] - [ -P Structures/MismatchedTernary ] - [ Online docs ]

A ternary operator should yield the same type on both branches.

Ternary operator applies a condition, and yield two different results. Those results will then be processed by code that expects the same types. It is recommended to match the types on both branches of the ternary operator.

<?php 
// $object may end up in a very unstable state
$object = ($type == 'Type') ? new $type() : null;

//same result are provided by both alternative, though process is very different
$result = ($type == 'Addition') ? $a $b $a $b;

//Currently, this is omitted
$a 1;
$result = empty($condition) ? $a 'default value';
$result = empty($condition) ? $a getDefaultValue();
?>


ext/lapack

[Since 0.12.2] - [ -P Extensions/Extlapack ] - [ Online docs ]

Extension Lapack. LAPACK provides routines for solving systems of simultaneous linear equations, least-squares solutions of linear systems of equations, eigenvalue problems, and singular value problems.

<?php 
$a = array(
    array( 
1.44,  -7.84,  -4.39,   4.53),
    array(-
9.96,  -0.28,  -3.24,   3.83),
    array(-
7.55,   3.24,   6.27,  -6.64),
    array( 
8.34,   8.09,   5.28,   2.06),
    array( 
7.08,   2.52,   0.74,  -2.47),
    array(-
5.45,  -5.70,  -1.19,   4.70),
);

$b = array(
    array( 
8.58,   9.35),
    array( 
8.26,  -4.43),
    array( 
8.48,  -0.70),
    array(-
5.28,  -0.26),
    array( 
5.72,  -7.36),
    array( 
8.93,  -2.52),
);

$result Lapack::leastSquaresByFactorisation($a$b);
?>


See also Lapack and php-lapack.

Mismatched Default Arguments

[Since 0.12.3] - [ -P Functions/MismatchedDefaultArguments ] - [ Online docs ]

Arguments are relayed from one method to the other, and the arguments have different default values.

Although it is possible to have different default values, it is worth checking why this is actually the case.

<?php 
function foo($a null$b = array() ) {
    
// foo method calls directly bar. 
    // When argument are provided, it's OK
    // When argument are omited, the default value is not the same as the next method
    
bar($a$b);
}

function 
bar($c 1$d = array() ) {

}
?>


This analysis reports the original arguments. Starting from it, follow the usage of the argument in its method, and find calls to other methods.

This analysis omits reporting argument when one of them does not have a default value.

Mismatched Typehint

[Since 0.12.3] - [ -P Functions/MismatchedTypehint ] - [ Online docs ]

Relayed arguments don't have the same typehint.

Typehint acts as a filter method. When an object is checked with a first class, and then checked again with a second distinct class, the whole process is always false : $a can't be of two different classes at the same time.

<?php 
// Foo() calls bar()
function foo(A $aB $b) {
    
bar($a$b);
}

// $a is of A typehint in both methods, but 
// $b is of B then BB typehing
function bar(A $aBB $b) {

}
?>


Note : This analysis currently doesn't check generalisation of classes : for example, when B is a child of BB, it is still reported as a mismatch.

Scalar Or Object Property

[Since 0.12.3] - [ -P Classes/ScalarOrObjectProperty ] - [ Online docs ]

Property shouldn't use both object and scalar syntaxes. When a property may be an object, it is recommended to implement the Null Object pattern : instead of checking if the property is scalar, make it always object.

<?php 
class {
    public 
$display 'echo';
    
    function 
foo($string) {
        if (
is_string($this->display)) {
            echo 
$this->string;
        } elseif (
$this->display instanceof myDisplayInterface) {
            
$display->display();
        } else {
            print 
Error when displaying\n;
        }
    }
}

interface 
myDisplayInterface {
    public function 
display($string); // does the display in its own way
}

class 
nullDisplay implements myDisplayInterface {
    
// implements myDisplayInterface but does nothing
    
public function display($string) {}
}

class 
x2 {
    public 
$display null;
    
    public function 
__construct() {
        
$this->display = new nullDisplay();
    }
    
    function 
foo($string) {
        
// Keep the check, as $display is public, and may get wrong values
        
if ($this->display instanceof myDisplayInterface) {
            
$display->display();
        } else {
            print 
Error when displaying\n;
        }
    }
}

// Simple class for echo
class echoDisplay implements myDisplayInterface {
    
// implements myDisplayInterface but does nothing
    
public function display($string) {
        echo 
$string;
    }
}
?>


See also Null Object Pattern, The Null Object Pattern

Assign With And Precedence

[Since 0.12.4] - [ -P Php/AssignAnd ] - [ Online docs ]

The lettered logical operators yield to assignation. It may collect less information than expected.

It is recommended to use the &&, ^ and || operators, instead of and, or and xor, to prevent confusion.

<?php 
// The expected behavior is 
// The following are equivalent
 
$a =  $b  && $c;
 
$a = ($b && $c);

// The unexpected behavior is 
// The following are equivalent
 
$a $b  and $c;
(
$a $b) and $c;
?>



See also Operator Precedence

No Magic Method With Array

[Since 0.12.4] - [ -P Classes/NoMagicWithArray ] - [ Online docs ]

Magic method __set() doesn't work for array syntax.

When overloading properties, they can only be used for scalar values, excluding arrays. Under the hood, PHP uses __get() to reach for the name of the property, and doesn't recognize the following index as an array. It yields an error : Indirect modification of overloaded property.

<?php 
class {
    private 
$a;
    private 
$o = array();

    function 
__get($name) {
        return 
$this->o[$name];
    }
    
    function 
foo() {
        
// property b doesn't exists
        
$this->b['a'] = 3;
        
        
print_r($this);
    }

    
// This method has no impact on the issue
    
function __set($name$value) {
        
$this->o[$name] = $value;
    }
}

$c = new c();
$c->foo();
?>


It is possible to use the array syntax with a magic property : by making the __get returns an array, the syntax will actually extract the expected item in the array.

This is not reported by linting.

In this analysis, only properties that are found to be magic are reported. For example, using the b property outside the class scope is not reported, as it would yield too many false-positives.

See also Overload.

ext/xattr

[Since 0.12.4] - [ -P Extensions/Extxattr ] - [ Online docs ]

Extensions xattr.

The xattr extension allows for the manipulation of extended attributes on a filesystem.

<?php 
$file 'my_favourite_song.wav';
xattr_set($file'Artist''Someone');
xattr_set($file'My ranking''Good');
xattr_set($file'Listen count''34');

/* ... other code ... */

printf('You\'ve played this song %d times'xattr_get($file'Listen count'));
?>



See also xattr, Extended attributres

Logical To in_array

[Since 0.12.5] - [ -P Performances/LogicalToInArray ] - [ Online docs ]

Multiples exclusive comparisons may be replaced by in_array().

in_array() makes the alternatives more readable, especially when the number of alternatives is large. In fact, the list of alternative may even be set in a variable, and centralized for easier management.

Even two 'or' comparisons are slower than using a in_array() call. More calls are even slower than just two. This is a micro-optimisation : speed gain is low, and marginal. Code centralisation is a more significant advantage.

<?php 
// Set the list of alternative in a variable, property or constant. 
$valid_values = array(1234);
if (
in_array($a$valid_values) ) {
    
// doSomething()
}

if (
$a == || $a == || $a == || $a == 4) {
    
// doSomething()
}

// in_array also works with strict comparisons
if (in_array($a$valid_valuestrue) ) {
    
// doSomething()
}

if (
$a === || $a === || $a === || $a === 4) {
    
// doSomething()
}
?>



See also `in_array() `_

ext/rdkafka

[Since 0.12.8] - [ -P Extensions/Extrdkafka ] - [ Online docs ]

Extension for RDkafka.

PHP-rdkafka is a thin librdkafka binding providing a working PHP 5 / PHP 7 Kafka 0.8 / 0.9 / 0.10 client.

<?php 
$rk = new RdKafka\Producer();
$rk->setLogLevel(LOG_DEBUG);
$rk->addBrokers(10.0.0.1,10.0.0.2);
?>



See also Kafka client for PHP, librdkafka

ext/fam

[Since 0.12.8] - [ -P Extensions/Extfam ] - [ Online docs ]

File Alteration Monitor extension.

FAM monitors files and directories, notifying interested applications of changes.

ext/FAM is not available for Windows

<?php 
$fam fam_open('myApplication');
fam_monitor_directory($fam'/tmp');
fam_close($fam);
?>


See also File Alteration Monitor.

Pathinfo() Returns May Vary

[Since 0.12.11] - [ -P Php/PathinfoReturns ] - [ Online docs ]

pathinfo() function returns an array whose content may vary. It is recommended to collect the values after check, rather than directly.

<?php 
$file '/a/b/.c';
//$extension may be missing, leading to empty $filename and filename in $extension
list( $dirname$basename$extension$filename ) = array_valuespathinfo($file) );

//Use PHP 7.1 list() syntax to assign correctly the values, and skip `array_values() <https://www.php.net/array_values>`_
//This emits a warning in case of missing index
['dirname'   => $dirname
 
'basename'  => $basename
 
'extension' => $extension
 
'filename'  => $filename ] = pathinfo($file);
 
//This works without warning
$details pathinfo($file);
$dirname   $details['dirname'] ?? getpwd();
$basename  $details['basename'] ?? '';
$extension $details['extension'] ?? '';
$filename  $details['filename'] ?? '';
?>


The same applies to parse_url(), which returns an array with various index.

ext/parle

[Since 0.12.12] - [ -P Extensions/Extparle ] - [ Online docs ]

Extension Parser and Lexer.

The parle extension provides lexing and parsing facilities. The implementation is based on » Ben Hanson's libraries and requires a » C++14 capable compiler.

<?php 
use Parle\{TokenLexerLexerException};

/* name => id */
$token = array(
        
'EOI' => 0,
        
'COMMA' => 1,
        
'CRLF' => 2,
        
'DECIMAL' => 3,
);
/* id => name */
$token_rev array_flip($token);

$lex = new Lexer;
$lex->push("[\x2c]"$token['COMMA']);
$lex->push("[\r][\n]"$token['CRLF']);
$lex->push("[\d]+"$token['DECIMAL']);
$lex->build();

$in 0,1,2\r\n3,42,5\r\n6,77,8\r\n;

$lex->consume($in);

do {
        
$lex->advance();
        
$tok $lex->getToken();

        if (
Token::UNKNOWN == $tok->id) {
                throw new 
LexerException('Unknown token "'.$tok->value.'" at offset '.$tok->offset.'.');
        }

        echo 
'TOKEN: '$token_rev[$tok->id], PHP_EOL;
} while (
Token::EOI != $tok->id);
?>


See also Parsing and Lexing.

Regex Inventory

[Since 0.12.14] - [ -P Type/Regex ] - [ Online docs ]

All regular expressions used in the code. PHP relies on the PCRE extension to process them, with the functions preg_match(), preg_replace(), etc.

<?php 
// PCRE regex used with preg_match
preg_match('/[abc]+/'$string);

// Mbstring regex, in the arabic range
if(mb_ereg('[\x{0600}-\x{06FF}]'$text))
?>


mbstring regular expressions are also collected. POSIX regex are not listed : they were deprecated in PHP 7.0.


See also preg_match(), `ext/mbstring `_, `ext/pcre `_

Multiple Type Variable

[Since 0.12.15] - [ -P Structures/MultipleTypeVariable ] - [ Online docs ]

Avoid using the same variable with different types of data.

It is recommended to use different names for differently typed data, while processing them. This prevents errors where one believe the variable holds the former type, while it has already been cast to the later.

Incrementing variables, with math operations or concatenation, is OK : the content changes, but not the type. And casting the variable without storing it in itself is OK.

<?php 
// $x is an array
$x range('a''z');
// $x is now a string
$x join(''$x);
$c count($x); // $x is not an array anymore


// $letters is an array
$letters range('a''z');
// $alphabet is a string
$alphabet join(''$letters);

// Here, $letters is cast by PHP, but the variable is changed.
if ($letters) { 
    
$count count($letters); // $letters is still an array 
}
?>


Is Actually Zero

[Since 0.12.15] - [ -P Structures/IsZero ] - [ Online docs ]

This addition actually may be simplified because one term is actually negated by another.

This kind of error happens when the expression is very large : the more terms are included, the more chances are that some auto-annihilation happens.

This error may also be a simple typo : for example, calculating the difference between two consecutive terms.

<?php 
// This is quite obvious
$a 2;

// This is obvious too. This may be a typo-ed difference between two consecutive terms. 
// Could have been $c = $fx[3][4] - $fx[3][3] or $c = $fx[3][5] - $fx[3][4];
$c $fx[3][4] - $fx[3][4];

// This is less obvious
$a $b[3] - $c $d->foo(1,2,3) + $c $b[3];
?>


Unconditional Break In Loop

[Since 0.12.16] - [ -P Structures/UnconditionLoopBreak ] - [ Online docs ]

An unconditional break in a loop creates dead code. Since the break is directly in the body of the loop, it is always executed, creating a strange loop that can only run once.

Here, break may also be a return, a goto or a continue. They all branch out of the loop. Such statement are valid, but should be moderated with a condition.

<?php 
// return in loop should be in 
function summAll($array) {
    
$sum 0;
    
    foreach(
$array as $a) {
        
// Stop at the first error
        
if (is_string($a)) {
            return 
$sum;
        }
        
$sum += $a;
    }
    
    return 
$sum;
}

// foreach loop used to collect first element in array
function getFirst($array) {
    foreach(
$array as $a) {
        return 
$a;
    }
}
?>


Too Complex Expression

[Since 0.12.16] - [ -P Structures/ComplexExpression ] - [ Online docs ]

Long expressions should be broken in small chunks, to limit complexity.

Really long expressions tends to be error prone : either by typo, or by missing details. They are even harder to review, once the initially build of the expression is gone.

As a general rule, it is recommended to keep expressions short. The analysis include any expression that is more than 15 tokens large : variable and operators counts as one, properties, arrays count as two. Parenthesis are also counted.

PHP has no specific limit to expression size, so long expression are legal and valid. It is possible that the business logic requires a complex equation.

<?php 
// Why not calculate wordwrap size separatedly ? 
$a explode("\n"wordwrap($this->messagefloor($this->width imagefontwidth($this->fontsize)), "\n"));

// Longer but easier to read
$width floor($this->width imagefontwidth($this->fontsize)), "\n");
$a explode("\n"wordwrap($this->message$width);

// Here, some string building, including error management with @, is making the data quite complex.
fwrite($fp'HEAD ' . @$url['path'] . @$url['query'] . ' HTTP/1.0' "\r\n" 'Host: ' . @$url['host'] . "\r\n\r\n")

// Better validation of data. 
$http_header 'HEAD ';
if (isset(
$url['path'])) {
    
$http_header .= $url['path'];
}
if (isset(
$url['query'])) {
    
$http_header .= $url['query'];
}

$http_header .=  "\r\n";
if (isset(
$url['host'])) {
    
$http_header .= 'Host: ' $url['host'] . "\r\n\r\n";
}

fwrite($fp$http_header);
?>


Could Be Else

[Since 1.0.1] - [ -P Structures/CouldBeElse ] - [ Online docs ]

Merge opposition conditions into one if/then structure.

When two if/then structures follow each other, using a condition and its opposite, they may be merged into one.

<?php 
// Short version
if ($a == 1) {
    
$b 2;
} else {
    
$b 1;
}

// Long version
if ($a == 1) {
    
$b 2;
}

if (
$a != 1) {
    
$b 3;
}
?>


Next Month Trap

[Since 1.0.1] - [ -P Structures/NextMonthTrap ] - [ Online docs ]

Avoid using +1 month with strtotime().

strtotime() calculates the next month by incrementing the month number. For day number that do not exist from one month to the next, strtotime() fixes them by setting them in the next-next month.

This happens to January, March, May, July, August and October. January is also vulnerable for 29 (not every year), 30 and 31.

To use '+1 month', rely on 'first day of next month' or 'last day of next month' to extract the next month's name. For longer interfaces, start from 'first day of next month'.

<?php 
// Base date is October 31 => 10/31
// +1 month adds +1 to 10 => 11/31 
// Since November 31rst doesn't exists, it is corrected to 12/01. 
echo date('F'strtotime('+1 month',mktime(0,0,0,$i,31,2017))).PHP_EOL;

// Base date is October 31 => 10/31
echo date('F'strtotime('first day of next month',mktime(0,0,0,$i,31,2017))).PHP_EOL;
?>


Note that Datetime and DatetimeImmutable are also subject to the same trap.


See also It is the 31st again

Printf Number Of Arguments

[Since 1.0.1] - [ -P Structures/PrintfArguments ] - [ Online docs ]

The number of arguments provided to printf() or vprintf() doesn't match the format string.

Extra arguments are ignored, and are dead code as such. Missing arguments are reported with a warning, and nothing is displayed.

Omitted arguments produce an error.

<?php 
// not enough
printf(' a %s '$a1); 
// OK
printf(' a %s '$a1$a2); 
// too many
printf(' a %s '$a1$a2$a3); 

// not enough
sprintf(' a %s '$a1); 
// OK
\sprintf(' a %s '$a1$a2); 
// too many
sprintf(' a %s '$a1$a2$a3);
?>


See also printf and sprintf.

Drupal Usage

[Since 1.0.3] - [ -P Vendors/Drupal ] - [ Online docs ]

This analysis reports usage of the Drupal CMS. The report is based on the usage of Drupal namespace.

<?php 
namespace Drupal\example\Controller;

use 
Drupal\Core\Controller\ControllerBase;

/**
 * An example controller.
 */
class ExampleController extends ControllerBase {

  
/**
   * {@inheritdoc}
   */
  
public function content() {
    
$build = array(
      
'#type' => 'markup',
      
'#markup' => t('Hello World!'),
    );
    return 
$build;
  }

}
?>



See also Drupal

Ambiguous Static

[Since 1.0.3] - [ -P Classes/AmbiguousStatic ] - [ Online docs ]

Methods or properties with the same name, are defined static in one class, and not static in another. This is error prone, as it requires a good knowledge of the code to make it static or not.

Try to keep the methods simple and unique. Consider renaming the methods and properties to distinguish them easily. A method and a static method have probably different responsibilities.

<?php 
class {
    function 
mixedStaticMethod() {}
}

class 
{
    static function 
mixedStaticMethod() {}
}

/... 
a lot more code later .../

$c->mixedStaticMethod();
// or 
$c::mixedStaticMethod();
?>


Phalcon Usage

[Since 1.0.3] - [ -P Vendors/Phalcon ] - [ Online docs ]

This analysis reports usage of the Phalcon Framework. The report is based on the usage of Phalcon namespace, which may be provided by PHP code inclusion or the PHP extension.

<?php 
use Phalcon\Mvc\Application;

// Register autoloaders

// Register services

// Handle the request
$application = new Application($di);

try {
    
$response $application->handle();

    
$response->s`end() <https://www.php.net/end>`_;
} catch (
\Exception $e) {
    echo 
'Exception: '$e->getMessage();
}
?>



See also Phalcon

Fuel PHP Usage

[Since 1.0.3] - [ -P Vendors/Fuel ] - [ Online docs ]

This analysis reports usage of the Fuel PHP Framework.

<?php 
// file located in APPPATH/classes/presenter.php
class Presenter extends \Fuel\Core\Presenter
{
    
// namespace prefix
    
protected static $ns_prefix 'Presenter\';
}
?>


Do not confuse fuelPHP and fuelCMS


See also FuelPHP

Don't Send $this In Constructor

[Since 1.0.4] - [ -P Classes/DontSendThisInConstructor ] - [ Online docs ]

Don't use $this as an argument while in the __construct(). Until the constructor is finished, the object is not finished, and may be in an unstable state. Providing it to another code may lead to error.

This is true when the receiving structure puts the incoming object immediately to work, and don't store it for later use.

<?php 
// $this is only provided when Foo is constructed
class Foo {
    private 
$bar null;
    private 
$data = array();
    
    static public function 
build($data) {
        
$foo = new Foo($data);
        
// Can't build in one call. Must make it separate.
        
$foo->finalize();
    }

    private function 
__construct($data) {
        
// $this is provided too early
        
$this->data $data;
    }
    
    function 
finalize() {
        
$this->bar = new Bar($this);
    }
}

// $this is provided too early, leading to error in Bar
class Foo2 extends Foo {
    private 
$bar null;
    private 
$data = array();
    
    function 
__construct($data) {
        
// $this is provided too early
        
$this->bar = new Bar($this);
        
$this->data $data;
    }
}

class 
Bar {
    function 
__construct(Foo $foo) {
        
// the cache is now initialized with a wrong 
        
$this->cache $foo->getIt();
    }
}
?>



See also Don't pass this out of a constructor

Argon2 Usage

[Since 1.0.4] - [ -P Php/Argon2Usage ] - [ Online docs ]

Argon2 is an optionally compiled password hashing API.

Argon2 has been added to the password hashing API in PHP 7.2.

It is not available in older version. It also requires PHP to be compiled with the --with-password-argon2 option.

<?php 
// Hashing a password with argon2
$hash password_hash('password'PASSWORD_ARGON2I, ['memory_cost' => 1<<17
                                                     
'time_cost'   => PASSWORD_ARGON2_DEFAULT_TIME_COST
                                                     
'threads'     => PASSWORD_ARGON2_DEFAULT_THREADS]);
?>



See also Argon2 Password Hash

Crypto Usage

[Since 1.0.4] - [ -P Php/CryptoUsage ] - [ Online docs ]

Usage of cryptography and hashes functions.

The functions listed are the native PHP functions, and do not belong to a specific extension, like OpenSSL , mcrypt or mhash .

Cryptography and hashes are mainly used for storing sensitive data, such as passwords, or to verify authenticity of data. They may also be used for name-randomization with cache.

<?php 
if (md5($_POST['password']) === $row['password_hash']) {
    
user_login($user);
} else {
    
error('Wrong password');
}
?>



See also Cryptography Extensions

No get_class() With Null

[Since 1.0.4] - [ -P Structures/NoGetClassNull ] - [ Online docs ]

It is not possible to pass explicitly null to get_class() to get the current's class name. Since PHP 7.2, one must call get_class() without arguments to achieve that result.

<?php 
class {
  public function 
f() {
    
// Gets the classname
    
$classname get_class();

    
// Gets the classname and a warning
    
$classname get_class(null);
  }
}

$a = new A();
$a->f('get_class');
?>


Maybe Missing New

[Since 1.0.4] - [ -P Structures/MissingNew ] - [ Online docs ]

This functioncall looks like a class instantiation that is missing the new keyword.

Any function definition was found for that function, but a class with that name was. New is probably missing.

<?php 
// Functioncall
$a foo();

// Class definition
class foo {}
// Function definition
function foo {}


// Functioncall
$a BAR;

// Function definition
class bar {}
// Constant definition
const BAR 1;
?>


Unknown Pcre2 Option

[Since 1.0.4] - [ -P Php/UnknownPcre2Option ] - [ Online docs ]

PCRE2 supports different options, compared to PCRE1 . PCRE2 was adopted with PHP 7.3.

The S modifier : it used to tell PCRE to spend more time studying the regex, so as to be faster at execution. This is now the default behavior, and may be dropped from the regex.

The X modifier : X is still existing with PCRE2 , though it is now the default for PCRE2 , and not for PHP as time of writing. In particular, Any backslash in a pattern that is followed by a letter that has no special meaning causes an error, thus reserving these combinations for future expansion. . It is recommended to avoid using useless sequence \s in regex to get ready for that change. All the following letters gijkmoqyFIJMOTY . Note that clLpPuU are valid PRCE sequences, and are probably failing for other reasons.

<?php 
// \y has no meaning. With X option, this leads to a regex compilation error, and a failed test.
preg_match('/ye\y/'$string);
preg_match('/ye\y/X'$string);
?>



See also Pattern Modifiers, PHP RFC: PCRE2 migration

Type Array Index

[Since 1.0.4] - [ -P Type/ArrayIndex ] - [ Online docs ]

All literal index used in the code.

<?php 
// index is an index. it is read
$array['index'] = 1;

// another_index and second_level are read
$array[] = $array['another_index']['second_level'];

// variables index are not reported
$array[$variable] = 1;
?>


Incoming Variable Index Inventory

[Since 1.0.4] - [ -P Type/GPCIndex ] - [ Online docs ]

This collects all the index used in incoming variables : $_GET, $_POST, $_REQUEST, $_COOKIE.

<?php 
// x is collected
echo $_GET['x'];

// y is collected, but no z. 
echo $_POST['y']['z'];

// a is not collected
echo $_ENV['s'];
?>


ext/vips

[Since 1.0.4] - [ -P Extensions/Extvips ] - [ Online docs ]

Extension VIPS.

The VIPS image processing system is a very fast, multi-threaded image processing library with low memory needs.

<?php 
dl('vips.' PHP_SHLIB_SUFFIX);
    
$x vips_image_new_from_file($argv[1])[out];
    
vips_image_write_to_file($x$argv[2]);
?>



See also php-vips-ext, libvips, libvips adapter for PHP Imagine

Dl() Usage

[Since 1.0.4] - [ -P Php/DlUsage ] - [ Online docs ]

Dynamically load PHP extensions with dl().

<?php 
// dynamically loading ext/vips
    
dl('vips.' PHP_SHLIB_SUFFIX);
?>


See also dl.


See also dl

Parent First

[Since 1.0.5] - [ -P Classes/ParentFirst ] - [ Online docs ]

When calling parent constructor, always put it first in the __construct method.

It ensures the parent is correctly build before the child start using values.

<?php 
class father {
    protected 
$name null;
    
    function 
__construct() {
        
$this->name init();
    }
}

class 
goodSon {
    function 
__construct() {
        
// parent is build immediately, 
        
parent::__construct();
        echo 
my name is.$this->name;
    }
}

class 
badSon {
    function 
__construct() {
        
// This will fail.
        
echo my name is.$this->name;

        
// parent is build later, 
        
parent::__construct();
    }
}
?>


This analysis doesn't apply to Exceptions.

Environment Variables

[Since 1.0.5] - [ -P Variables/UncommonEnvVar ] - [ Online docs ]

Environment variables are used to interact with the hosting system.

They often provides configuration parameter that are set by the host of the application to be used.
That way, information is not hardcoded in the application, and may be changed at production.

<?php 
//ENVIRONMENT set the production context
if (getenv('ENVIRONMENT') === 'Production') {
    
$sshKey getenv('HOST_KEY');
} elseif (
getenv('ENVIRONMENT') === 'Developper') {
    
$sshKey 'NO KEY';
} else {
    
header('No website here.');
    die();
}
?>



See also $_ENV

Invalid Regex

[Since 1.0.5] - [ -P Structures/InvalidRegex ] - [ Online docs ]

The PCRE regex doesn't compile. It isn't a valid regex.

Several reasons may lead to this situation : syntax error, Unknown modifier, missing parenthesis or reference.

<?php 
// valid regex
preg_match('/[abc]/'$string);

// invalid regex (missing terminating ] for character class 
preg_match('/[abc/'$string);
?>


Regex are check with the Exakat version of PHP.

Dynamic regex are only checked for simple values. Dynamic values may eventually generate a compilation error.

Use Named Boolean In Argument Definition

[Since 1.0.6] - [ -P Functions/AvoidBooleanArgument ] - [ Online docs ]

Boolean in argument definitions is confusing.

It is recommended to use explicit constant names, instead. They are more readable. They also allow for easy replacement when the code evolve and has to replace those booleans by strings. This works even also with classes, and class constants.

<?php 
function flipImage($im$horizontal NO_HORIZONTAL_FLIP$vertical NO_VERTICAL_FLIP) { }

// with constants
const HORIZONTAL_FLIP true;
const 
NO_HORIZONTAL_FLIP true;
const 
VERTICAL_FLIP true;
const 
NO_VERTICAL_FLIP true;

rotateImage($imHORIZONTAL_FLIPNO_VERTICAL_FLIP);


// without constants 
function flipImage($im$horizontal false$vertical false) { }

rotateImage($imtruefalse);
?>



See also Improve Passing Booleans in PHP , Flag Argument, Improve Passing Booleans in PHP

Same Variable Foreach

[Since 1.0.5] - [ -P Structures/AutoUnsetForeach ] - [ Online docs ]

A foreach which uses its own source as a blind variable is actually broken.

Actually, PHP makes a copy of the source before it starts the loop. As such, the same variable may be used for both source and blind value.

Of course, this is very confusing, to see the same variables used in very different ways.

The source will also be destroyed immediately after the blind variable has been turned into a reference.

<?php 
$array range(010);
foreach(
$array as $array) {
    print 
$array.PHP_EOL;
}

print_r($array); // display number from 0 to 10.

$array range(010);
foreach(
$array as &$array) {
    print 
$array.PHP_EOL;
}

print_r($array); // display 10
?>


Never Called Parameter

[Since 1.0.6] - [ -P Functions/NeverUsedParameter ] - [ Online docs ]

When a parameter is never used at calltime. It always falls back to its default value : then, it may be turned into a local variable.

Parameter without a default value are reported by PHP, and are usually always filled.

<?php 
// $b may be turned into a local var, it is unused
function foo($a$b 1) {
    return 
$a $b;
}

// whenever foo is called, the 2nd arg is not mentioned
foo($a);
foo(3);
foo('a');
foo($c);
?>


This analysis checks for actual usage of the parameter, from the outside of the method. This is different from checking if the parameter is used inside the method.

ext/igbinary

[Since 1.0.6] - [ -P Extensions/Extigbinary ] - [ Online docs ]

Extension igbinary.

igbinary is a drop in replacement for the standard php serializer. Instead of time and space consuming textual representation, igbinary stores php data structures in compact binary form.

<?php 
$serialized igbinary_serialize($variable);
    
$unserialized igbinary_unserialize($serialized);
?>



See also igbinary

Identical On Both Sides

[Since 1.0.8] - [ -P Structures/IdenticalOnBothSides ] - [ Online docs ]

Operands should be different when comparing or making a logical combination. Of course, the value each operand holds may be identical. When the same operand appears on both sides of the expression, the result is know before execution.

<?php 
// Trying to confirm consistency
if ($login == $login) {
    
doSomething();
}

// Works with every operators
if ($object->login( ) !== $object->login()) {
    
doSomething();
}

if (
$sum >= $sum) {
    
doSomething();
}

//
if ($mask && $mask) {
    
doSomething();
}

if (
$mask || $mask) {
    
doSomething();
}
?>


Identical Consecutive Expression

[Since 1.0.8] - [ -P Structures/IdenticalConsecutive ] - [ Online docs ]

Identical consecutive expressions might be double code. They are worth being checked.

They may be a copy/paste with unmodified content. When the content has to be duplicated, it is recommended to avoid executing the expression again, and just access the cached result.

<?php 
$current  $array[$i];
$next     $array[$i 1];
$nextnext $array[$i 1]; // OOps, nextnext is wrong.

// Initialization
$previous foo($array[1]); // previous is initialized with the first value on purpose
$next     foo($array[1]); // the second call to foo() with the same arguments should be avoided
// the above can be rewritten as : 
$next     $previous// save the processing.

for($i 1$i 200; ++$i) {
    
$next doSomething();
}
?>


No Reference For Ternary

[Since 1.0.8] - [ -P Php/NoReferenceForTernary ] - [ Online docs ]

The ternary operator and the null coalescing operator are both expressions that only return values, and not a variable.

This means that any provided reference will be turned into its value. While this is usually invisible, it will raise a warning when a reference is expected. This is the case with methods returning a reference.

A PHP notice is generated when using a ternary operator or the null coalesce operator : Only variable references should be returned by reference . The notice is also emitted when returning objects.

This applies to methods, functions and closures.

<?php 
// This works
function &foo($a$b) { 
    if (
$a === 1) {
        return 
$b
    } else {
        return 
$a
    }
}

// This raises a warning, as the operator returns a value
function &foo($a$b) { return $a === $b $a; }
?>



See also Null Coalescing Operator, Ternary Operator

Unused Inherited Variable In Closure

[Since 1.0.11] - [ -P Functions/UnusedInheritedVariable ] - [ Online docs ]

Some closures forgot to make usage of inherited variables.

Closure have two separate set of incoming variables : the arguments (between parenthesis) and the inherited variables, in the 'use' clause. Inherited variables are extracted from the local environment at creation time, and keep their value until execution.

The reported closures are requesting some local variables, but do not make any usage of them. They may be considered as dead code.

<?php 
// In this closure, $y is forgotten, but $u is used.
$a = function ($y) use ($u) { return $u; };

// In this closure, $u is forgotten
$a = function ($y$z) use ($u) { return $u; };
?>


See also Anonymous functions.

Inclusion Wrong Case

[Since 1.1.1] - [ -P Files/InclusionWrongCase ] - [ Online docs ]

Inclusion should follow exactly the case of included files and path. This prevents the infamous case-sensitive filesystem bug, where files are correctly included in a case-insensitive system, and failed to be when moved to production.

<?php 
// There must exist a path called path/to and a file library.php with this case
include path/to/library.php;

// Error on the case, while the file does exist
include path/to/LIBRARY.php;

// Error on the case, on the PATH
include path/TO/library.php;
?>


See also include_once, about case sensitivity and inclusions.

Missing Include

[Since 1.1.2] - [ -P Files/MissingInclude ] - [ Online docs ]

The included files doesn't exists in the repository. The inclusions target a files that doesn't exist.

The analysis works with every type of inclusion : include(), require(), include_once() and require_once(). It also works with parenthesis when used as parameter delimiter.

The analysis doesn't take into account include_path . This may yield false positives.

<?php 
include 'non_existent.php';

// variables are not resolved. This won't be reported.
require ($path.'non_existent.php');
?>


Missing included files may lead to a fatal error, a warning or other error later in the execution.

Useless Referenced Argument

[Since 1.1.3] - [ -P Functions/UselessReferenceArgument ] - [ Online docs ]

The argument has a reference, but is only used for reading.

This is probably a development artefact that was forgotten. It is better to remove it.

This analysis also applies to foreach() loops, that declare the blind variable as reference, then use the variable as an object, accessing properties and methods. When a variable contains an object, there is no need to declare a reference : it is a reference automatically.

<?php 
function foo($a, &$b, &$c) {
    
// $c is passed by reference, but only read. The reference is useless.
    
$b $c $a;
    
// The reference is useful for $b
}

foreach (
$array as &$element) {
    
$element->method();
}
?>


See also Objects and references.

Fallback Function

[Since 1.1.4] - [ -P Functions/FallbackFunction ] - [ Online docs ]

A function that is called with its name alone, and whose definition is in the global scope.

<?php 
namespace {
    
// global definition
    
function foo() {}
}

namespace 
Bar {
    
// local definition
    
function foo2() {}
    
    
foo(); // definition is in the global namespace
    
foo2(); // definition is in the Bar namespace
}
?>



See also Using namespaces: fallback to global function/constant

Useless Catch

[Since 1.1.4] - [ -P Exceptions/UselessCatch ] - [ Online docs ]

A catch clause should handle the exception by doing something.

Among the task of a catch clause : log the exception, clean any mess that was introduced, fail graciously.

<?php 
function foo($a) {
    try {
        
$b doSomething($a);
    } catch (
Throwable $e) {
        
// No log of the exception : no one knows it happened.
        
        // return immediately ? 
        
return false;
    }
    
    
$b->complete();
    
    return 
$b;
}
?>



See also Exceptions, Best practices for PHP exception handling

Possible Infinite Loop

[Since 1.1.5] - [ -P Structures/PossibleInfiniteLoop ] - [ Online docs ]

Loops on files that can't be open results in infinite loop.

fgets(), and functions like fgetss(), fgetcsv(), fread(), return false when they finish reading, or can't access the file.

In case the file is not accessible, comparing the result of the reading to something that is falsy, leads to a permanent valid condition. The execution will only finish when the max_execution_time is reached.

<?php 
$file fopen('/path/to/file.txt''r');
// when `fopen() <https://www.php.net/fopen>`_ fails, the next loops is infinite
// `fgets() <https://www.php.net/fgets>`_ will always return false, and while will always be true. 
while($line fgets($file) != 'a') {
    
doSomething();
}
?>


It is recommended to check the file resources when they are opened, and always use === or !== to compare readings. feof() is also a reliable function here.

ext/hrtime

[Since 1.1.5] - [ -P Extensions/Exthrtime ] - [ Online docs ]

High resolution timing Extension.

The HRTime extension implements a high resolution `StopWatch` class. It uses the best possible API on different platforms which brings resolution up to nanoseconds. It also makes possible to implement a custom stopwatch using low level ticks delivered by the underlaying system.

<?php 
$c = new HRTime\StopWatch;

$c->start();
/* measure this code block execution */
for ($i 0$i 1024*1024$i++);
$c->stop();
$elapsed0 $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);

/* measurement is not running here*/
for ($i 0$i 1024*1024$i++);

$c->start();
/* measure this code block execution */
for ($i 0$i 1024*1024$i++);
$c->stop();
$elapsed1 $c->getLastElapsedTime(HRTime\Unit::NANOSECOND);

$elapsed_total $c->getElapsedTime(HRTime\Unit::NANOSECOND);
?>


See also ext/hrtime manual.

Test Then Cast

[Since 1.1.6] - [ -P Structures/TestThenCast ] - [ Online docs ]

A test is run on a value without a cast, and later the cast value is later used.

The cast may introduce a distortion to the value, and still lead to the unwanted situation. For example, comparing to 0, then later casting to an int. The comparison to 0 is done without casting, and as such, 0.1 is different from 0. Yet, (int) 0.1 is actually 0, leading to a Division by 0 error.

<?php 
// Here. $x may be different from 0, but (int) $x may be 0
$x 0.1;

if (
$x != 0) {
    
$y / (int) $x;
}

// Safe solution : check the cast value.
if ( (int) $x != 0) {
    
$y / (int) $x;
}
?>


Foreach On Object

[Since 1.1.6] - [ -P Php/ForeachObject ] - [ Online docs ]

Foreach on object looks like a typo. This is particularly true when both object and member are variables.

Foreach on an object member is a legit PHP syntax, though it is very rare : blind variables rarely have to be securing in an object to be processed.

<?php 
// This is the real thing
foreach($array as $o => $b) { 
    
doSomething();
}

// Looks suspicious
foreach($array as $o -> $b) { 
    
doSomething();
}
?>


ext/xxtea

[Since 1.1.7] - [ -P Extensions/Extxxtea ] - [ Online docs ]

Extension xxtea : XXTEA encryption algorithm extension for PHP.

XXTEA is a fast and secure encryption algorithm. This is a XXTEA extension for PHP.
It is different from the original XXTEA encryption algorithm. It encrypts and decrypts string instead of uint32 array, and the key is also string.

<?php 
// Example is extracted from the xxtea repository on github : tests/xxtea.phpt

$str 'Hello World! 你好,中国🇨🇳!';
$key '1234567890';
$base64 'D4t0rVXUDl3bnWdERhqJmFIanfn/6zAxAY9jD6n9MSMQNoD8TOS4rHHcGuE=';
$encrypt_data xxtea_encrypt($str$key);
$decrypt_data xxtea_decrypt($encrypt_data$key);
if (
$str == $decrypt_data && base64_encode($encrypt_data) == $base64) {
    echo 
'success!';
} else {
    echo 
base64_encode($encrypt_data);
    echo 
'fail!';
}
?>



See also PECL ext/xxtea, ext/xxtea on Github

ext/uopz

[Since 1.1.7] - [ -P Extensions/Extuopz ] - [ Online docs ]

Extension UOPZ : User Operations for Zend.

The uopz extension is focused on providing utilities to aid with unit testing PHP code.

It supports the following activities: Intercepting function execution, Intercepting object creation, Hooking into function execution, Manipulation of function statics, Manipulation of function flags, Redefinition of constants, Deletion of constants, Runtime creation of functions and methods,

<?php 
// The example is extracted from the UOPZ extension test suite : tests/001.phpt
class Foo {
    public function 
bar(int $arg) : int {
        return 
$arg;
    }
}
var_dump(uopz_set_return(Foo::class, 'bar'true));
$foo = new Foo();
var_dump($foo->bar(1));
uopz_set_return(Foo::class, 'bar', function(int $arg) : int {
    return 
$arg 2;
}, 
true);
var_dump($foo->bar(2));
try {
    
uopz_set_return(Foo::class, 'nope'1);
} catch(
Throwable $t) {
    
var_dump($t->getMessage());
}
class 
Bar extends Foo {}
try {
    
uopz_set_return(Bar::class, 'bar'null);
} catch (
Throwable $t) {
    
var_dump($t->getMessage());
}

    
uopz_set_something(Bar::class, 'bar'null);
?>



See also ext/uopz, User Operations for Zend

ext/varnish

[Since 1.1.7] - [ -P Extensions/Extvarnish ] - [ Online docs ]

Extension PHP for varnish.

Varnish Cache is an open source, state of the art web application accelerator. The extension makes it possible to interact with a running varnish instance through TCP socket or shared memory.

<?php 
$args = array(
        
VARNISH_CONFIG_HOST => '::1',
        
VARNISH_CONFIG_PORT => 6082,
        
VARNISH_CONFIG_SECRET => '5174826b-8595-4958-aa7a-0609632ad7ca',
        
VARNISH_CONFIG_TIMEOUT => 300,
    );
    
$va = new VarnishAdmin($args);
?>



See also ext/varnish, pecl/Varnish

ext/opencensus

[Since 1.1.7] - [ -P Extensions/Extopencensus ] - [ Online docs ]

Extension PHP for OpenCensus.

A stats collection and distributed tracing framework.

<?php 
opencensus_trace_begin('root', ['spanId' => '1234']);
opencensus_trace_add_annotation('foo');
opencensus_trace_begin('inner', []);
opencensus_trace_add_annotation('asdf', ['spanId' => '1234']);
opencensus_trace_add_annotation('abc');
opencensus_trace_finish();
opencensus_trace_finish();
$traces opencensus_trace_list();
echo 
Number of traces: . count($traces) . \n;
$span $traces[0];
print_r($span->timeEvents());
$span2 $traces[1];
print_r($span2->timeEvents());
?>



See also opencensus.

ext/leveldb

[Since 1.1.7] - [ -P Extensions/Extleveldb ] - [ Online docs ]

PHP Binding for LevelDB.

LevelDB is a fast key-value storage library written at Google that provides an ordered mapping from string keys to string values.

<?php 
$db = new LevelDB($leveldb_path);

$batch = new LevelDBWriteBatch();
$batch->set('batch_foo''batch_bar');
$batch->put('batch_foo2''batch_bar2');
$batch->delete('batch_foo');

$db->write($batch);

$batch->clear();
$batch->delete('batch_foo2');
$batch->set('batch_foo''batch again');
?>


See also ext/leveldb on Github and
Leveldb.

Property Could Be Local

[Since 1.1.7] - [ -P Classes/PropertyCouldBeLocal ] - [ Online docs ]

A property only used in one method may be turned into a local variable.

Public an protected properties are omitted here : they may be modified somewhere else, in the code. This analysis may be upgraded to support those properties, when tracking of such properties becomes available.

Classes where only one non-magic method is available are omitted.

Traits with private properties are processed the same way.

<?php 
class {
    private 
$foo 1;

    
// Magic method, and constructor in particular, are omitted.
    
function __construct($foo) {
        
$this->foo $foo;
    }
    
    function 
bar() {
        
$this->foo++;
        
        return 
$this->foo;
    }

    function 
barbar() {}
}
?>


ext/db2

[Since 1.1.8] - [ -P Extensions/Extdb2 ] - [ Online docs ]

Extension for IBM DB2, Cloudscape and Apache Derby.

This extension gives access to IBM DB2 Universal Database, IBM Cloudscape, and Apache Derby databases using the DB2 Call Level Interface (DB2 CLI).

<?php 
$conn db2_connect($database$user$password);

if (
$conn) {
    
$stmt db2_exec($conn'SELECT count(*) FROM animals');
    
$res db2_fetch_array$stmt );
    echo 
$res[0] . PHP_EOL;
    
    
// Turn AUTOCOMMIT off
    
db2_autocommit($connDB2_AUTOCOMMIT_OFF);
   
    
// Delete all rows from ANIMALS
    
db2_exec($conn'DELETE FROM animals');
    
    
$stmt db2_exec($conn'SELECT count(*) FROM animals');
    
$res db2_fetch_array$stmt );
    echo 
$res[0] . PHP_EOL;
    
    
// Roll back the DELETE statement
    
db2_rollback$conn );
    
    
$stmt db2_exec$conn'SELECT count(*) FROM animals' );
    
$res db2_fetch_array$stmt );
    echo 
$res[0] . PHP_EOL;
    
db2_close($conn);
}
?>


See also IBM Db2.

Too Many Native Calls

[Since 1.1.10] - [ -P Php/TooManyNativeCalls ] - [ Online docs ]

Avoid stuffing too many PHP native call inside another functioncall.

For readability reasons, or, more often, for edge case handling, it is recommended to avoid nesting too many PHP native calls.

This analysis reports any situation where more than 3 PHP native calls are nested.

<?php 
// Too many nested functions 
$cleanArray array_unique(array_keys(array_count_values(array_column($source'x'))));

// Avoid warning when source is empty
$extract array_column($source'x');
if (empty(
$extract)) {
    
$cleanArray = array();
} else {
    
$cleanArray array_unique(array_keys(array_count_values($extract)));
}

// This is not readable, although it is short. 
// It may easily get out of hand.
echo chr(80), chr(72), chr(80), chr(32), ' is great!';
?>


Don't Unset Properties

[Since 1.2.3] - [ -P Classes/DontUnsetProperties ] - [ Online docs ]

Don't unset properties. They would go undefined, and raise warnings of undefined properties, even though the property is explicitly defined in the original class.

When getting rid of a property, assign it to `null`. This keeps the property defined in the object, yet allows existence check without errors.

<?php 
class Foo {
    public 
$a 1;
}

$a = new Foo();

var_dump((array) $a) ;
// la propriété est reportée, et null
// ['a' => null]

unset($a->a);

var_dump((array) $a) ;
//Empty []

// Check if a property exists
var_dump($a->=== null);

// Same result as above, but with a warning
var_dump($a->=== null);
?>


This analysis works on properties and static properties. It also reports magic properties being unset.

Thanks for Benoit Burnichon for the original idea.

Strtr Arguments

[Since 1.2.3] - [ -P Php/StrtrArguments ] - [ Online docs ]

Strtr() replaces characters by others in a string. When using strings, strtr() replaces characters as long as they have a replacement. All others are ignored.

In particular, strtr() works on strings of the same size, and cannot be used to remove chars.

<?php 
$string 'abcde';
echo 
strtr($string'abc''AB');
echo 
strtr($string'ab''ABC');
// displays ABcde 
// c is ignored each time

// strtr can't remove a char
echo strtr($string'a''');
// displays a
?>


See also strtr.

Missing Parenthesis

[Since 1.2.6] - [ -P Structures/MissingParenthesis ] - [ Online docs ]

Add parenthesis to those expression to prevent bugs.

<?php 
// Missing some parenthesis!!
if (!$a instanceof Stdclass) {
    print 
Not\n;
} else {
    print 
Is\n;
}

// Could this addition be actually
$c = -$a $b;

// This one ? 
$c = -($a $b);
?>




See also Operators Precedence

Callback Function Needs Return

[Since 1.2.6] - [ -P Functions/CallbackNeedsReturn ] - [ Online docs ]

When used with array_map() functions, the callback must return something. This return may be in the form of a return statement, a global variable or a parameter with a reference. All those solutions extract information from the callback.

<?php 
// This filters each element
$filtered array_filter($array, function ($x) {return $x == 2; });

// This return void for every element
$filtered array_filter($array, function ($x) {return ; });

// costly `array_sum() <https://www.php.net/array_sum>`_
$sum 0;
$filtered array_filter($array, function ($x) use (&$sum) {$sum += $x; });

// costly `array_sum() <https://www.php.net/array_sum>`_
global $sum 0;
$filtered array_filter($array, function () {global $sum$sum += $x; });

// register_shutown_function() doesn't require any return
register_shutown_function(my_shutdown);
?>


The following functions are omitted, as they don't require the return :

+ forward_static_call_array()
+ forward_static_call()
+ register_shutdown_function()
+ register_tick_function()

Wrong Range Check

[Since 1.2.5] - [ -P Structures/WrongRange ] - [ Online docs ]

The interval check should use && and not ||.

<?php 
//interval correctly checked a is between 2 and 999
if ($a && $a 1000) {}

//interval incorrectly checked : a is 2 or more ($a < 1000 is never checked)
if ($a || $a 1000) {}
?>

ext/zookeeper

[Since 1.2.5] - [ -P Extensions/Extzookeeper ] - [ Online docs ]

Extension for Apache Zookeeper.

ZooKeeper is an Apache project that enables centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.

<?php 
$zookeeper = new Zookeeper('locahost:2181');
$path '/path/to/node';
$value 'nodevalue';
$zookeeper->set($path$value);

$r $zookeeper->get($path);
if (
$r)
  echo 
$r;
else
  echo 
'ERR';
?>



See also ext/zookeeper, Install Zookeeper PHP Extension, Zookeeper

ext/cmark

[Since 1.2.7] - [ -P Extensions/Extcmark ] - [ Online docs ]

Extension Cmark, for Common Mark.

cmark provides access to the reference implementation of CommonMark, a rationalized version of Markdown syntax with a specification.

<?php 
$text = new CommonMark\Node\Text;
$text->literal 'Hello World';
$document = new CommonMark\Node\Document;
$document->appendChild(
    (new 
CommonMark\Node\Paragraph)
        ->
appendChild($text));
echo 
CommonMark\Render\HTML($document);
?>



See also Cmark, ext/cmark

Can't Instantiate Class

[Since 1.2.8] - [ -P Classes/CantInstantiateClass ] - [ Online docs ]

When constructor is not public, it is not possible to instantiate such a class. Either this is a conception choice, or there are factories to handle that. Either way, it is not possible to call new on such class.

<?php 
//This is the way to go
$x X::factory();

//This is not possible
$x = new X();

class 
{
    
//This is also the case with proctected __construct
    
private function __construct() {}

    static public function 
factory() {
        return new 
X();
    }
}
?>



See also In a PHP5 class, when does a private constructor get called?, Named Constructors in PHP, PHP Constructor Best Practices And The Prototype Pattern

strpos() Too Much

[Since 1.2.8] - [ -P Performances/StrposTooMuch ] - [ Online docs ]

strpos() covers the whole string before reporting 0. If the expected string is expected be at the beginning, or a fixed place, it is more stable to use substr() for comparison.

The longer the haystack (the searched string), the more efficient is that trick. The string has to be 10k or more to have impact, unless it is in a loop.

<?php 
// This always reads the same amount of string
if (substr($html06) === '<html>') {

}

// When searching for a single character, checking with a known position ($string[$position]) is even faster
if ($html[0] === '<') {

}

// With `strpos() <https://www.php.net/strpos>`_, the best way is to search for something that exist, and use absence as worst case scenario 
if (strpos($html'<html>') > 0) {

} else {
    
// 
}

// When the search fails, the whole string has been read
if (strpos($html'<html>') === 0) {

}
?>


This applies to stripos() too.

Typehinted References

[Since 1.2.8] - [ -P Functions/TypehintedReferences ] - [ Online docs ]

Typehinted arguments have no need for references. Since they are only an object, they are already a reference.

In fact, adding the & on the argument definition may lead to error like Only variables should be passed by reference .

This applies to the object type hint, but not the the others, such as int or bool .

<?php 
// a class
    
class {
        public 
$a 3;
    }

    
// typehinted reference
    //function foo(object &$x) works too
    
function foo(&$x) {
        
$x->1;
    
        return 
$x;
    }

    
// Send an object 
    
$y foo(new X);

    
// This prints 1;
    
print $y->a;
?>



See also Passing by reference, Objects and references

Weak Typing

[Since 1.2.8] - [ -P Classes/WeakType ] - [ Online docs ]

The variable's validation is not enough to allow for a sophisticated usage. For example, the variable is checked for null, then used as an object or an array.

<?php 
if ($a !== null) {
    echo 
$a->b;
}
?>



See also From assumptions to assertions

Method Signature Must Be Compatible

[Since 1.2.9] - [ -P Classes/MethodSignatureMustBeCompatible ] - [ Online docs ]

Make sure methods signature are compatible.

PHP generates the infamous Fatal error at execution : Declaration of FooParent::Bar() must be compatible with FooChildren::Bar()

<?php 
class {
    function 
xa() {}
}

class 
xxx extends xx {
    function 
xa($a) {}
}
?>


Mismatch Type And Default

[Since 1.2.9] - [ -P Functions/MismatchTypeAndDefault ] - [ Online docs ]

The argument typehint and its default value don't match.

The code may lint and load, and even work when the arguments are provided. Though, PHP won't eventually execute it.

Most of the mismatch problems are caught by PHP at linting time. It displays the following error message : 'Argument 1 passed to foo() must be of the type integer, string given'.

The default value may be a constant (normal or class constant) : as such, PHP might find its value only at execution time, from another include. As such, PHP doesn't report anything about the situation at compile time.

The default value may also be a constant scalar expression : since PHP 7, some of the simple operators such as +, -, *, %, **, etc. are available to build default values. Among them, the ternary operator and Coalesce. Again, those expression may be only evaluated at execution time, when the value of the constants are known.

<?php 
// bad definition : the string is actually an integer
const STRING 3;

function 
foo(string $s STRING) {
    echo 
$s;
}

// works without problem
foo('string');

// Fatal error at compile time
foo();

// Fail only at execution time (missing D), and when default is needed
function foo2(string $s null : array()) {
    echo 
$s;
}
?>


PHP reports typehint and default mismatch at compilation time, unless there is a static expression that can't be resolved within the compiled file : then it is checked only at runtime, leading to a Fatal error.


See also Type declarations, Functions/WrongReturnedType, Functions/MismatchTypeAndDefault, Classes/WrongTypedPropertyInit

Check JSON

[Since 1.3.0] - [ -P Structures/CheckJson ] - [ Online docs ]

Check errors whenever JSON is encoded or decoded.

In particular, NULL is a valid decoded JSON response. If you want to avoid mistaking NULL for an error, it is recommended to call json_last_error .

<?php 
$encoded json_encode($incoming);
// Unless JSON must contains some non-null data, this mistakes NULL and error
if(json_last_error() != JSON_ERROR_NONE) {
    die(
'Error when encoding JSON');
}

$decoded json_decode($incoming);
// Unless JSON must contains some non-null data, this mistakes NULL and error
if($decoded === null) {
    die(
'ERROR');
}
?>


See also Option to make json_encode and json_decode throw exceptions on errors,
json_last_error.

Const Visibility Usage

[Since 1.3.0] - [ -P Classes/ConstVisibilityUsage ] - [ Online docs ]

Visibility for class constant controls the accessibility to class constant.

A public constant may be used anywhere in the code; a protected constant usage is restricted to the class and its relatives; a private constant is restricted to itself.

This feature was introduced in PHP 7.1. It is recommended to use explicit visibility, and, whenever possible, make the visibility private.

<?php 
class {
    public const 
1;
    protected const 
2;
    private const 
3;
    const 
4;
}

interface 
{
    public const 
1;
      const 
4;
}
?>



See also Class Constants, PHP RFC: Support Class Constant Visibility

Dont Mix ++

[Since 1.3.2] - [ -P Structures/DontMixPlusPlus ] - [ Online docs ]

++ operators, pre and post, have two distinct behaviors, and should be used separately.

When mixed in a larger expression, they are difficult to read, and may lead to unwanted behaviors.

<?php 
// Clear and defined behavior
    
$i++;
    
$a[$i] = $i;

    
// The index is also incremented, as it is used AFTP the incrementation
    // With $i = 2; $a is array(3 => 3)
    
$a[$i] = ++$i;

    
// $i is actually modified twice 
    
$i = --$i 1;
?>



See also EXP30-C. Do not depend on the order of evaluation for side effects

Can't Throw Throwable

[Since 1.3.3] - [ -P Exceptions/CantThrow ] - [ Online docs ]

Classes extending Throwable can't be thrown. The same applies to interfaces.

Although this code lints, PHP throws a Fatal error when executing or including it : Class fooThrowable cannot implement interface Throwable, extend Exception or Error instead .

<?php 
// This is the way to go
class fooException extends \Exception { }

// This is not possible and a lot of work
class fooThrowable implements \throwable { }
?>



See also Throwable, Exception, Error

Abstract Or Implements

[Since 1.3.3] - [ -P Classes/AbstractOrImplements ] - [ Online docs ]

A class must implements all abstract methods of it parent, or be abstract too.

While PHP lints this code, it won't execute it and stop with a Fatal Error : Class BA contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (A::aFoo) .

<?php 
abstract class Foo 
    abstract function 
FooBar();
}

// This is in another file : php -l would detect it right away

class FooFoo extends Foo 
    
// The method is not defined. 
    // The class must be abstract, just like Foo
}
?>



See also Class Abstraction

ext/eio

[Since 1.3.3] - [ -P Extensions/Exteio ] - [ Online docs ]

Extension EIO.

This is a PHP extension wrapping functions of the libeio library written by Marc Lehmann.

Libeio is a an asynchronous I/O library. Features basically include asynchronous versions of POSIX API(read, write, open, close, stat, unlink, fdatasync, mknod, readdir etc.); sendfile (native on Solaris, Linux, HP-UX, FreeBSD); readahead. libeio itself emulates the system calls, if they are not available on specific(UNIX-like) platform.

<?php 
$str      str_repeat('1'20);
$filename '/tmp/tmp_file' .`uniqid() <https://www.php.net/uniqid>`_;
@
unlink($filename);
touch($filename);
eio_open($filenameEIO_O_RDWRNULLEIO_PRI_DEFAULT, function($filename$fd) use ($str) {
    
eio_write($fd$strstrlen($str), 0null, function($fd$written) use ($str$filename) {
        
var_dump([
            
'written'  => $written,
            
'strlen'   => strlen($str),
            
'filesize' => filesize($filename),
            
'count'    => substr_count(file_get_contents($filename), '1')
            ]);
    }, 
$fd);
}, 
$filename);
eio_event_loop();
?>


See also libeio, PHP extension for libeio

Incompatible Signature Methods

[Since 1.3.3] - [ -P Classes/IncompatibleSignature ] - [ Online docs ]

Methods should have the same signature when being overwritten.

The same signatures means the children class must have :

+ the same name
+ the same visibility or less restrictive
+ the same typehint or removed
+ the same default value or removed
+ a reference like its parent

This problem emits a fatal error, for abstract methods, or a warning error, for normal methods. Yet, it is difficult to lint, because classes are often stored in different files. As such, PHP do lint each file independently, as unknown parent classes are not checked if not present. Yet, when executing the code, PHP lint the actual code and may encounter a fatal error.

<?php 
class {
    public function 
foo($a 1) {}
}

class 
ab extends {
    
// foo is overloaded and now includes a default value for $a
    
public function foo($a) {}
}
?>



See also Object Inheritance

Ambiguous Visibilities

[Since 1.3.4] - [ -P Classes/AmbiguousVisibilities ] - [ Online docs ]

The properties have the same name, but have different visibilities, across different classes.

While it is legit to have a property with the same name in different classes, it may easily lead to confusion. As soon as the context is need to understand if the property is accessible or not, the readability suffers.

It is recommended to handle the same properties in the same way across classes, even when the classes are not related.

<?php 
class person {
    public 
$name;
    private 
$address;
}

class 
gangster {
    private 
$name;
    public 
$nickname;
    private 
$address;
}

$someone Human::load(123);
echo 
'Hello, '.$someone->name;
?>



Undefined ::class

[Since 1.3.5] - [ -P Classes/UndefinedStaticclass ] - [ Online docs ]

::class doesn't check if a corresponding class exists.

::class must be checked with a call to class_exists(). Otherwise, it may lead to a Class 'foo' not found or even silent dead code : this happens also with Catch and instanceof commands with undefined classes. PHP doesn't raise an error in that case.

<?php 
class foo() {}

// prints foo
echo foo::class; 

// prints bar though bar doesn't exist.
echo bar::class;
?>



See also Class Constants

ext/lzf

[Since 1.3.5] - [ -P Extensions/Extlzf ] - [ Online docs ]

Extension LZF.

LZF is a very fast compression algorithm, ideal for saving space with only slight speed cost. It can be optimized for speed or space at the time of compilation.

<?php 
$compressed lzf_compress(This is test of LZF extension);

echo 
base64_encode($compressed);
?>



See also lzf, liblzf

ext/msgpack

[Since 1.3.5] - [ -P Extensions/Extmsgpack ] - [ Online docs ]

Extension msgPack.

This extension provide API for handling MessagePack serialization, both encoding and decoding.

<?php 
$serialized msgpack_serialize(array('a' => true'b' => 4));
    
$unserialized msgpack_unserialize($serialized);
?>



See also msgpack for PHP, MessagePack

Case Insensitive Constants

[Since 1.3.9] - [ -P Constants/CaseInsensitiveConstants ] - [ Online docs ]

PHP constants used to be able to be case insensitive, when defined with define() and the third argument.

This feature is deprecated since PHP 7.3 and is removed since PHP 8.0.

<?php 
// case sensitive
define('A'1);

// case insensitive
define('B'1true);

echo 
A;
// This is not possible
//echo a;

// both possible
echo B;
echo 
b;
?>



See also define

Handle Arrays With Callback

[Since 1.3.7] - [ -P Arrays/WithCallback ] - [ Online docs ]

Use functions like array_map().

<?php 
// Handles arrays with callback
$uppercase array_map('strtoupper'$source);

// Handles arrays with foreach
foreach($source as &$s) {
    
$s uppercase($s);
}
?>



See also array_map

Detect Current Class

[Since 1.3.8] - [ -P Php/DetectCurrentClass ] - [ Online docs ]

Detecting the current class should be done with `self::class` or `static::class` operator.

__CLASS__ may be replaced by self::class .
get_called_class() may be replaced by static::class .

__CLASS__ and get_called_class() are set to be deprecated in PHP 7.4.

<?php 
class {
    function 
foo() {
        echo 
__CLASS__.\n;          // X
        
echo self::class.\n;        // X
        
        
echo get_called_class().\n;  // Y
        
echo static::class.\n;       // Y
    
}
}

class 
extends {}

$y = new Y();
$y->foo();
?>



See also PHP RFC: Deprecations for PHP 7.4

Assert Function Is Reserved

[Since 1.3.9] - [ -P Php/AssertFunctionIsReserved ] - [ Online docs ]

Avoid defining an assert function in namespaces.

While they work fine when the assertions are active ( zend.assertions=1 ), calls to unqualified assert are optimized away when assertions are not active.

Since PHP 7.3, a fatal error is emitted : Defining a custom assert() function is deprecated, as the function has special semantics .

<?php 
//      Run this with zend.assertions=1 and 
// Then run this with zend.assertions=0

namespace Test {
    function `
assert() <https://www.php.net/assert>`{
        global 
$foo;

        
$foo true;
    }
}

namespace 
Test {
    `
assert() <https://www.php.net/assert>`_;

    
var_dump(isset($foo));
}
?>


See also assert, User-defined assert function is optimized away with zend.assertions=-1

Could Be Abstract Class

[Since 1.3.9] - [ -P Classes/CouldBeAbstractClass ] - [ Online docs ]

An abstract class is never instantiated, and has children class that are. As such, a 'parent' class that is never instantiated by itself, but has its own children instantiated could be marked as abstract.

That will prevent new code to try to instantiate it.

<?php 
// Example code would actually be split over multiple files.


// That class could be abstract
class motherClass {}

// Those classes shouldn't be abstract
class firstChildren extends motherClass {}
class 
secondChildren extends motherClass {}
class 
thirdChildren extends motherClass {}

new 
firstChildren();
new 
secondChildren();
new 
thirdChildren();

//Not a single : new motherClass()
?>


See also Class Abstraction, Abstract classes and methods

Continue Is For Loop

[Since 1.3.9] - [ -P Structures/ContinueIsForLoop ] - [ Online docs ]

break and continue are very similar in PHP : they both break out of loop or switch. Yet, continue should be reserved for loops.

Since PHP 7.3, the execution will emit a warning when finding a continue inside a switch inside a loop : '"continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"?'

<?php 
while ($foo) {
    switch (
$bar) {
        case 
'baz':
            continue; 
// In PHP: Behaves like 'break;'
                      // In C:   Behaves like 'continue 2;'
    
}
}
?>



See also Deprecate and remove continue targeting switch

Trailing Comma In Calls

[Since 1.4.0] - [ -P Php/TrailingComma ] - [ Online docs ]

The last argument may be left empty.

This feature was introduced in PHP 7.3.

<?php 
// VCS friendly call
// PHP 7.3 and more recent
foo(1,
    
2,
    
3,
   );

// backward compatible call
// All PHP versions
foo(1,
    
2,
    
3
   
);
?>



See also PHP RFC: Allow a trailing comma in function calls

Must Call Parent Constructor

[Since 1.4.1] - [ -P Php/MustCallParentConstructor ] - [ Online docs ]

Some PHP native classes require a call to parent::__construct() to be stable.

As of PHP 7.3, two classes currently need that call : SplTempFileObject and SplFileObject.

The error is only emitted if the class is instantiated, and a parent class is called.

<?php 
class mySplFileObject extends \SplFileObject {
    public function 
__construct()    { 
        
// Forgottent call to parent::__construct()
    
}
}

(new 
mySplFileObject())->`passthru() <https://www.php.net/passthru>`_;
?>



See also Why, php? WHY???

Undefined Variable

[Since 1.4.2] - [ -P Variables/UndefinedVariable ] - [ Online docs ]

Variable that is used before any initialisation.

It is recommended to use a default value for every variable used. When not specified, the default value is set to NULL by PHP.

<?php 
// Adapted from the PHP manual
$var 'Bob';
$Var 'Joe';
// The following line may emit a warning : Undefined variable: $undefined
echo $var$Var$undefined;      // outputs Bob, Joe,
?>


Variable may be created in various ways : assignation, arguments, foreach blind variables, static and global variables.

This analysis doesn't handle dynamic variables, such as $$x . It also doesn't handle variables outside a method or function.


See also Variable basics

Undefined Insteadof

[Since 1.4.2] - [ -P Traits/UndefinedInsteadof ] - [ Online docs ]

Insteadof tries to replace a method with another, but it doesn't exists. This happens when the replacing class is refactored, and some of its definition are dropped.

Insteadof may replace a non-existing method with an existing one, but not the contrary.

<?php 
trait {
    function 
(){}
}

trait 
{
    function 
(){}
}

class 
Talker {
    use 
A{
        
B::insteadof A;
        
B::insteadof A;
    }
}

new 
Talker();
?>


This error is not linted : it only appears at execution time.


See also Traits

Method Collision Traits

[Since 1.4.2] - [ -P Traits/MethodCollisionTraits ] - [ Online docs ]

Two or more traits are included in the same class, and they have methods collisions.

Those collisions should be solved with a use expression. When they are not, PHP stops execution with a fatal error : Trait method M has not been applied, because there are collisions with other trait methods on C .

<?php 
trait {
    public function 
A() {}
    public function 
M() {}
}

trait 
{
    public function 
B() {}
    public function 
M() {}
}

class 
{
    use  
AB;
}

class 
{
    use  
AB{
        
B::insteadof A;
    };
}
?>


The code above lints, but doesn't execute.


See also Traits

Class Could Be Final

[Since 1.4.3] - [ -P Classes/CouldBeFinal ] - [ Online docs ]

Any class that has no extension should be final by default.

As stated by Matthias Noback : If a class is not marked final, it has at least one subclass .

Prevent your classes from being subclassed by making them final . Sometimes, classes are not meant or thought to be derivable.

<?php 
class {}            // This class is extended
class extends {}  // This class is extended
class extends {}  // This class is not extended

final class z2 extends {}  // This class is not extended
?>


See also Negative architecture, and assumptions about code, When to declare methods final

Inconsistent Elseif

[Since 1.4.3] - [ -P Structures/InconsistentElseif ] - [ Online docs ]

Chaining if/elseif requires a consistent string of conditions. The conditions are executed one after the other, and the conditions shouldn't overlap.

This analysis reports chains of elseif that don't share a common variable (or array, or property, etc.. ). As such, testing different conditions are consistent.

<?php 
// $a is always common, so situations are mutually exclusive
if ($a === 1) {
    
doSomething();
} else if (
$a 1) {
    
doSomethingElse();
} else {
    
doSomethingDefault();
}

// $a is always common, so situations are mutually exclusive
// although, it may be worth checking the consistency here
if ($a->=== 1) {
    
doSomething();
} else if (
$a->1) {
    
doSomethingElse();
} else {
    
doSomethingDefault();
}

// if $a === 1, then $c doesn't matter? 
// This happens, but then logic doesn't appear in the code.
if ($a === 1) {
    
doSomething();
} else if (
$c 1) {
    
doSomethingElse();
} else {
    
doSomethingDefault();
}
?>


Can't Disable Class

[Since 0.8.4] - [ -P Security/CantDisableClass ] - [ Online docs ]

This is the list of potentially dangerous PHP class being used in the code, such as \Phar.

<?php 
// This script uses ftp_connect(), therefore, this function shouldn't be disabled. 
$phar = new Phar();
?>


This analysis is the base for suggesting values for the disable_classes directive.

ext/seaslog

[Since 1.4.4] - [ -P Extensions/Extseaslog ] - [ Online docs ]

Extension Seaslog.

An effective,fast,stable log extension for PHP.

<?php 
$basePath_1 SeasLog::getBasePath();

SeasLog::setBasePath('/log/base_test');
$basePath_2 SeasLog::getBasePath();

var_dump($basePath_1,$basePath_2);

/*
string(19) /log/seaslog-ciogao
string(14) /log/base_test
*/

$lastLogger_1 SeasLog::getLastLogger();

SeasLog::setLogger('testModule/app1');
$lastLogger_2 SeasLog::getLastLogger();

var_dump($lastLogger_1,$lastLogger_2);
/*
string(7) default
string(15) testModule/app1
*/
?>


See also ext/SeasLog on Github, and
SeasLog.

Only Variable For Reference

[Since 1.4.6] - [ -P Functions/OnlyVariableForReference ] - [ Online docs ]

When a method is requesting an argument to be a reference, it cannot be called with a literal value.

The call must be made with a variable, or any assimilated data container : array, property or static property.

<?php 
// This is not possible
foo(1,2);

// This is working
foo($a$b);

function 
foo($a, &$b) {}
?>


Note that PHP may detect this error at linting time, if the method is defined after being called : at that point, PHP will only check the problem during execution. This is definitely the case for methods, compared to functions or static methods.


See also Passing arguments by reference

Wrong Access Style to Property

[Since 1.4.9] - [ -P Classes/UndeclaredStaticProperty ] - [ Online docs ]

Use the right syntax when reaching for a property. Static properties use the :: operator, and non-static properties use -> .

Mistaking one of the other raise two different reactions from PHP : Access to undeclared static property is a fatal error, while PHP Notice: Accessing static property aa::$a as non static is a notice.

<?php 
class 
    static public 
$a 1;
    
    function 
foo() {
        echo 
self::$a// right
        
echo $this->a// WRONG
    
}
}

class 

    public 
$b 1;

    function 
foo() {
        echo 
$this->$b;  // right
        
echo b::$b;      // WRONG
    
}
}
?>


This analysis reports both static properties with a `->` access, and non-static properties with a `::` access.


See also Static Keyword

Invalid Pack Format

[Since 1.4.9] - [ -P Structures/InvalidPackFormat ] - [ Online docs ]

Some characters are invalid in a pack() format string.

pack() and unpack() accept the following format specifiers : aAhHcCsSnviIlLNVqQJPfgGdeExXZ .

unpack() also accepts a name after the format specifier and an optional quantifier.

All other situations is not a valid, and produces a warning : pack() `_: Type t: unknown format code

<?php 
$binarydata pack(nvc*, 0x12340x56786566);
    
    
// the first unsigned short is stored as 'first'. The next matches are names with numbers.
    
$res unpack('nfirst/vc*'$binarydata);
?>


Check pack() documentation for format specifiers that were introduced in various PHP version, namely 7.0, 7.1 and 7.2.


See also pack, unpack

Repeated Interface

[Since 1.4.9] - [ -P Interfaces/RepeatedInterface ] - [ Online docs ]

A class should implements only once an interface. An interface can only extends once another interface. In both cases, parent classes or interfaces must be checked.

PHP accepts multiple times the same interface in the implements clause. In fact, it doesn't do anything beyond the first implement.

<?php 
use as j;

interface 
{}

// Multiple ways to reference an interface
class foo implements i\i{}

// This applies to interfaces too
interface bar extends i\i{}
?>


This code may compile, but won't execute.


See also Object Interfaces, The Basics

Don't Read And Write In One Expression

[Since 1.4.9] - [ -P Structures/DontReadAndWriteInOneExpression ] - [ Online docs ]

Avoid giving value and using it at the same time, in one expression. This is an undefined behavior of PHP, and may change without warning.

One of those changes happens between PHP 7.2 and 7.3 :

<?php 
$arr = [1];
$ref =& $arr[0];
var_dump($arr[0] + ($arr[0] = 2));
// PHP 7.2: int(4)
// PHP 7.3: int(3)
?>



See also UPGRADING 7.3

Pack Format Inventory

[Since 1.5.0] - [ -P Type/Pack ] - [ Online docs ]

All format used in the code with pack() and unpack().

<?php 
$binarydata "\x04\x00\xa0\x00";
$array unpack("cn"$binarydata);
$initial pack("cn", ...$array);
?>



See also `pack() `_

Printf Format Inventory

[Since 1.5.0] - [ -P Type/Printf ] - [ Online docs ]

All format used in the code with printf(), vprintf(), sprintf(), scanf() and fscanf().

<?php 
// Display a number with 2 digits
echo printf("%'.2d\n"123);
?>


idn_to_ascii() New Default

[Since 2.2.3] - [ -P Php/IdnUts46 ] - [ Online docs ]

The default parameter value of idn_to_ascii() and idn_to_utf8() is now `INTL_IDNA_VARIANT_UTS46` instead of the deprecated `INTL_IDNA_VARIANT_2003`.

<?php 
echo idn_to_ascii('täst.de');
?>



See also idn_to_ascii, idn_to_utf8, Unicode IDNA Compatibility Processing

ext/decimal

[Since 1.5.2] - [ -P Extensions/Extdecimal ] - [ Online docs ]

Extension php-decimal, by Rudi Theunissen .

This library provides a PHP extension that adds support for correctly-rounded, arbitrary-precision decimal floating point arithmetic. Applications that rely on accurate numbers (ie. money, measurements, or mathematics) can use Decimal instead of float or string to represent numerical values.

<?php 
use Decimal\Decimal;

$op1 = new Decimal(0.14);
$op2 0.123456789;

print_r($op1 $op2);


use 
Decimal\Decimal;

/**
 * @param int $n The factorial to calculate, ie. $n!
 * @param int $p The precision to calculate the factorial to.
 *
 * @return Decimal
 */
function factorial(int $nint $p Decimal::DEFAULT_PRECISION): Decimal
{
    return 
$n ? new Decimal($n$p) : $n factorial($n 1$p);
}

echo 
factorial(1000032);
?>



See also PHP Decimal, libmpdec

ext/psr

[Since 1.5.2] - [ -P Extensions/Extpsr ] - [ Online docs ]

Extension PSR : PHP Standards Recommendations.

This PHP extension provides the interfaces from the PSR standards as established by the PHP-FIG group. You can use interfaces provided by this extension in another extension easily - see this example.

Currently supported PSR :



<?php 
// Example from the tests, for Cache (PSR-6)
use Psr\Cache\CacheException;
class 
MyCacheException extends Exception implements CacheException {}
$ex = new MyCacheException('test');
var_dump($ex instanceof CacheException);
var_dump($ex instanceof Exception);
try {
    throw 
$ex;
} catch( 
CacheException $e ) {
    
var_dump($e->getMessage());
}
?>


See also php-psr, PHP-FIG

Should Yield With Key

[Since 1.5.2] - [ -P Functions/ShouldYieldWithKey ] - [ Online docs ]

iterator_to_array() will overwrite generated values with the same key.

PHP generators are based on the yield keyword. They also delegate some generating to other methods, with yield from .

When delegating, yield from uses the keys that are generated with yield , and otherwise, it uses auto-generated index, starting with 0.

The trap is that each yield from reset the index generation and start again with 0. Coupled with iterator_to_array(), this means that the final generated array may lack some values, while a foreach() loop would yield all of them.

<?php 
function g1() : Generator {
    for ( 
$i 0$i 4$i++ ) { yield $i; }
}

function 
g2() : Generator {
    for ( 
$i 5$i 10$i++ ) { yield $i; }
}

function 
aggregator() : Generator {
    yield from 
g1();
    yield from 
g2();
}

print_r(`iterator_to_array() <https://www.php.net/iterator_to_array>`_);

/*
Array
(
    [0] => 6
    [1] => 7
    [2] => 8
    [3] => 9
    [4] => 4  // Note that 4 and 5 still appears
    [5] => 5  // They are not overwritten by the second yield
)
*/


foreach ( aggregator() as $i ) {
    print 
$i.PHP_EOL;
}

/*
0  // Foreach has no overlap and yield it all.
1
2
3
4
5
6
7
8
9
*/
?>


Thanks to Holger Woltersdorf for pointing this.


See also Generator syntax, Yielding values with keys

Useless Method Alias

[Since 1.5.6] - [ -P Traits/UselessAlias ] - [ Online docs ]

It is not possible to declare an alias of a method with the same name.

PHP reports that Trait method f has not been applied, because there are collisions with other trait methods on x , which is a way to say that the alias will be in conflict with the method name.

When the method is the only one bearing a name, and being imported, there is no need to alias it. When the method is imported in several traits, the keyword insteadof is available to solve the conflict.

<?php 
trait {
    function 
h() {}
}

class 
{
    use 

        
// This is possible
        
t::as g

        
// This is not possible, as the alias is in conflict with itself
        // alias are case insensitive
        
t::as f
    }
}
?>



This code lints but doesn't execute.


See also Conflict resolution

ext/sdl

[Since 1.5.6] - [ -P Extensions/Extsdl ] - [ Online docs ]

Extensions ext/sdl.

Simple DirectMedia Layer (SDL) is a cross-platform software development library designed to provide a hardware abstraction layer for computer multimedia hardware components.

<?php 
/**
 * Example of how to change screen properties such as title, icon or state using the PHP-SDL extension.
 *
 * @author Santiago Lizardo <santiagolizardo@php.net>
 */
require 'common.php';
SDL_InitSDL_INIT_VIDEO );
$screen SDL_SetVideoMode64048016SDL_HWSURFACE );
if( 
null == $screen )
{
    
fprintfSTDERR'Error: %s' PHP_EOLSDL_GetError() );
}
for( 
$i 3$i 0$i-- )
{
    
SDL_WM_SetCaptionSwitching to fullscreen mode in $i seconds..., null );
    
SDL_Delay1000 );
}
SDL_WM_ToggleFullscreen$screen );
SDL_Delay3000 );
SDL_WM_ToggleFullscreen$screen );
SDL_WM_SetCaptionBack from fullscreen modeQuitting in 2 seconds..., null );
SDL_Delay2000 );
SDL_FreeSurface$screen );
SDL_Quit();
?>


See also phpsdl,
Simple DirectMedia Layer and
About SDL.

ext/async

[Since 1.5.6] - [ -P Extensions/Extasync ] - [ Online docs ]

Concurrent Task Extension for PHP.

This extension provides concurrent Zend VM executions using native C fibers in PHP.

<?php 
namespace Concurrent;
register_shutdown_function(function () {
    echo 
"===> Shutdown function(s) execute here.\n";
});
$work = function (string $title): void {
    
var_dump($title);
};
Task::await(Task::async(function () use ($work) {
    
$defer = new Deferred();
    
    
Task::await(Task::async($work'A'));
    
Task::await(Task::async($work'B'));
    
    
Task::async(function () {
        
$defer = new Deferred();
        
        
Task::async(function () use ($defer) {
            (new 
Timer(1000))->awaitTimeout();
            
            
$defer->resolve('H :)');
        });
        
        
var_dump(Task::await($defer->awaitable()));
    });
    
    
Task::async(function () use ($defer) {
        
var_dump(Task::await($defer->awaitable()));
    });
    
    
$timer = new Timer(500);
    
    
Task::async(function () use ($timer$defer$work) {
        
$timer->awaitTimeout();
        
        
$defer->resolve('F');
        
        
Task::async($work'G');
    });
    
    
var_dump('ROOT TASK DONE');
}));
Task::async($work'C');
Task::async(function () use ($work) {
    (new 
Timer(0))->awaitTimeout();
    
    
Task::async($work'E');
});
Task::async(function ($v) {
    
var_dump(Task::await($v));
}, 
Deferred::value('D'));
var_dump('=> END OF MAIN SCRIPT');
?>



See also ext-async repository

ext/wasm

[Since 1.5.7] - [ -P Extensions/Extwasm ] - [ Online docs ]

Extension WASM.

The goal of the project is to be able to run WebAssembly binaries from PHP directly. So much fun coming!

From the php-ext-wasm documentation :

<?php 
//There is a toy program in examples/simple.rs, written in Rust (or any other language that compiles to WASM):
// Stored in file __DIR__ . '/simple.wasm'
/*
#[no_mangle]
pub extern C fn sum(x: i32, y: i32) -> i32 {
    x + y
}
*/

$instance = new WASM\Instance(__DIR__ '/simple.wasm');

var_dump(
    
$instance->sum(537// 42!
);
?>


See also php-ext-wasm.

Method Could Be Static

[Since 1.5.7] - [ -P Classes/CouldBeStatic ] - [ Online docs ]

A method that doesn't make any usage of $this could be turned into a static method.

While static methods are usually harder to handle, recognizing the static status is a first step before turning the method into a standalone function.

<?php 
class foo {
    static 
$property 1;
    
    
// legit static method
    
static function staticMethod() {
        return 
self::$property;
    }

    
// This is not using $this, and could be static
    
function nonStaticMethod() {
        return 
self::$property;
    }

    
// This is not using $this nor self, could be a standalone function
    
function nonStaticMethod() {
        return 
self::$property;
    }
}
?>


Path lists

[Since 1.5.8] - [ -P Type/Path ] - [ Online docs ]

List of all paths that were found in the code.

Path are identified with this regex : ^(.*/)([^/]*)\.\w+$ . In particular, the directory delimiter is / : Windows delimiter \ are not detected.

<?php 
// the first argument is recognized as an URL
fopen('/tmp/my/file.txt''r+');

// the string argument  is recognized as an URL
$source 'https://www.other-example.com/';
?>


URL are ignored when the protocol is present in the literal : http://www.example.com is not mistaken with a file.


See also Dir predefined constants, Supported Protocols and Wrappers

Possible Missing Subpattern

[Since 1.6.1] - [ -P Php/MissingSubpattern ] - [ Online docs ]

When capturing subpatterns are the last ones in a regex, PHP doesn't fill their spot in the resulting array. This leads to a possible missing index in the result array.

<?php 
// displays a partial array, from 0 to 1
preg_match('/(a)(b)?/''adc'$r);
print_r($r);
/*
Array
(
    [0] => a
    [1] => a
)
*/

// displays a full array, from 0 to 2
preg_match('/(a)(b)?/''abc'$r);
print_r($r);

/*
Array
(
    [0] => ab
    [1] => a
    [2] => b
)
*/

// double 'b' when it is found
print preg_replace(',^a(b)?,''./$1$1''abc'); // prints ./abbc
print preg_replace(',^a(b)?,''./$1$1''adc'); // prints ./dc
?>


The same applies to preg_replace() : the pattern may match the string, but no value is available is the corresponding sub-pattern.

In PHP 7.4, a new option was added : PREG_UNMATCHED_AS_NULL, which always provides a value for the subpatterns.


See also Bug #73948 Preg_match_all should return NULLs on trailing optional capture groups., Bug #50887 preg_match , last optional sub-patterns ignored when empty

Assign And Compare

[Since 1.6.3] - [ -P Structures/AssigneAndCompare ] - [ Online docs ]

Assignation has a lower precedence than comparison. As such, the assignation always happens after the comparison. This leads to the comparison being stored in the variable, and not the value being compared.

<?php 
if ($id strpos($string$needle) !== false) { 
    
// $id now contains a boolean (true or false), but not the position of the $needle.
}

// probably valid comparison, as $found will end up being a boolean
if ($found strpos($string$needle) === false) { 
    
doSomething();
}

// always valid comparison, with parenthesis
if (($id strpos($string$needle)) !== false) { 
    
// $id now contains a boolean (true or false), but not the position of the $needle.
}

// Being a lone instruction, this is always valid : there is no double usage with if condition
$isFound strpos($string$needle) !== false;
?>



See also Operator Precedence

Typed Property Usage

[Since 1.6.2] - [ -P Php/TypedPropertyUsage ] - [ Online docs ]

PHP properties may be typed. Since PHP 7.4, it is possible to type properties, just like arguments and return values.

<?php 
class User {
    public 
int $id;
    public 
string $name;
 
    public function 
__construct(int $idstring $name) {
        
$this->id $id;
        
$this->name $name;
    }
}
?>



See also Typed Properties 2.0, Typed Properties in PHP 7.4

Variable Is Not A Condition

[Since 1.6.5] - [ -P Structures/NoVariableIsACondition ] - [ Online docs ]

Avoid using a lone variable as a condition. It is recommended to use a comparative value, or one of the filtering function, such as isset(), empty().

Using the raw variable as a condition blurs the difference between an undefined variable and an empty value. By using an explicit comparison or validation function, it is easier to understand what the variable stands for.

<?php 
if (isset($error)) {
    echo 
'Found one error : '.$error!;
}

//
if ($errors) {
    print 
count($errors).' errors found : '.join(''$errors).PHP_EOL;
    echo 
'Not found';
}
?>


Thanks to the PMB team for the inspiration.

ext/weakref

[Since 1.6.5] - [ -P Extensions/Extweakref ] - [ Online docs ]

Weak References for PHP.

Weak references provide a non-intrusive gateway to ephemeral objects. Unlike normal (strong) references, weak references do not prevent the garbage collector from freeing that object. For this reason, an object may be destroyed even though a weak reference to that object still exists. In such conditions, the weak reference seamlessly becomes invalid.

<?php 
class MyClass {
    public function 
__destruct() {
        echo 
Destroying object!\n;
    }
}

$o1 = new MyClass;

$r1 = new WeakRef($o1);

if (
$r1->valid()) {
    echo 
Object still exists!\n;
    
var_dump($r1->get());
} else {
    echo 
Object is dead!\n;
}

unset(
$o1);

if (
$r1->valid()) {
    echo 
Object still exists!\n;
    
var_dump($r1->get());
} else {
    echo 
Object is dead!\n;
}
?>


See also Weak references and
PECL extension that implements weak references and weak maps in PHP.

ext/pcov

[Since 1.6.5] - [ -P Extensions/Extpcov ] - [ Online docs ]

CodeCoverage compatible driver for PHP.

A self contained CodeCoverage compatible driver for PHP7

<?php 
\pcov\start();
$d = [];
for (
$i 0$i 10$i++) {
    
$d[] = $i 42;
}
\pcov\stop();
var_dump(\pcov\collect());
?>



See also PCOV

Insufficient Typehint

[Since 1.6.6] - [ -P Functions/InsufficientTypehint ] - [ Online docs ]

An argument is typehinted, but it actually calls methods that are not listed in the interface.

Classes may be implementing more methods than the one that are listed in the interface they also implements. This means that filtering objects with a typehint, but calling other methods will be solved at execution time : if the method is available, it will be used; if it is not, a fatal error is reported.

<?php 
class implements {
    function 
methodI() {}
    function 
notInI() {}
}

interface 
{
    function 
methodI();
}

function 
foo(i $x) {
    
$x->methodI(); // this call is valid
    
$x->notInI();  // this call is not garanteed
}
?>


Inspired by discussion with Brandon Savage.

Constant Dynamic Creation

[Since 1.6.7] - [ -P Constants/DynamicCreation ] - [ Online docs ]

Registering constant with dynamic values. Dynamic values include values read in external sources (files, databases, remote API, ... ), random sources (time, rand(), ...)

Dynamic constants are not possible with the const keyword, though static constant expression allows for a good range of combinations, including conditions.

<?php 
$a range(04);
foreach(
$array as $i) {
    
define(A$i$i);
    
define(N$itrue);
}

define(C5);
?>




See also PHP Constants

PHP 8.0 Removed Functions

[Since 1.6.8] - [ -P Php/Php80RemovedFunctions ] - [ Online docs ]

The following PHP native functions were deprecated in PHP 8.0, and will be removed in PHP 9.0.



See also Backward Incompatible Changes

PHP 8.0 Removed Constants

[Since 1.6.8] - [ -P Php/Php80RemovedConstant ] - [ Online docs ]

The following PHP native constants were removed in PHP 8.0.


An OOP Factory

[Since 1.6.7] - [ -P Patterns/Factory ] - [ Online docs ]

A method or function that implements a factory. A factory is a class that handles the creation of an object, based on parameters. The factory hides the logic that leads to the creation of the object.

<?php 
class AutomobileFactory {
        public static function 
create($make$model) {
            
$className = \\Automaker\\Brand\\$make;
            return new 
$className($model);
        }
    }
    
    
// The factory is able to build any car, based on their 
    
$fuego AutomobileFactory::create('Renault''Fuego');
    
    
print_r($fuego->getMakeAndModel()); // outputs Renault Fuego
?>


See also Factory (object-oriented programming) and
Factory.

Typehint Must Be Returned

[Since 1.6.9] - [ -P Functions/TypehintMustBeReturned ] - [ Online docs ]

When using a typehint for a method, it is compulsory to use a at least one return in the method's body. This is true for nullable typehint too : return alone won't be sufficient.

When the method contains a return expression, PHP will not lint unless the return expression has a value. Any value will do, and it will actually checked at execution time.

When the method contains no return expression, PHP will only check this at execution time.

There is no need for a return expression when the method throws an expression, triggers an error or triggers an assertion. Even in case of inheritance or implementation, the return type may be replaced by `never`.

<?php 
// The function returns a value (here, correct object)
function foo() : Bar { return new Bar(); }

// The function should at least, return a value
function foo() : Bar { }

// The function should at least, return a value : Null or an object. Void, here, is not acceptable.
function foo() : ?Bar { return; }
?>



See also Return Type Declaration, Type hint in PHP function parameters and return values

Clone With Non-Object

[Since 1.7.0] - [ -P Classes/CloneWithNonObject ] - [ Online docs ]

The clone keyword must be used on variables, properties or results from a function or method call.

clone cannot be used with constants or literals.

<?php 
class { }
$x = new x();

// Valid clone
$y = clone $x;

// Invalid clone
$y = clone x;
?>


Cloning a non-object lint but won't execute.


See also Object cloning

Check On __Call Usage

[Since 1.7.2] - [ -P Classes/CheckOnCallUsage ] - [ Online docs ]

When using the magic methods __call() and __staticcall(), make sure the method exists before calling it.

If the method doesn't exists, then the same method will be called again, leading to the same failure. Finally, it will crash PHP.

<?php 
class safeCall {
    function 
__class($name$args) {
        
// unsafe call, no checks
        
if (method_exists($this$name)) {
            
$this->$name(...$args);
        }
    }
}

class 
unsafeCall {
    function 
__class($name$args) {
        
// unsafe call, no checks
        
$this->$name(...$args);
    }
}
?>



See also Method overloading, Magical PHP: __call

PHP Overridden Function

[Since 1.7.6] - [ -P Php/OveriddenFunction ] - [ Online docs ]

It is possible to declare and use a function with the same name as a PHP native, in a namespace.

Within the declaration namespace, it is easy to confuse the local version and the global version, unless the function has been prefixed with \ .

<?php 
namespace {
    use function 
A\dirname as split;
    
    function 
dirname($a$b) { return __FUNCTION__; }
    
    echo 
dirname('/a/b/c');
    echo 
split('a''b');
    
    echo 
\dirname('/a/b/c');
}
?>


When a piece of code use overridden function, any newcomer may be confused by the usage of classic PHP native function in surprising situations.

It is recommended to avoid redeclare PHP native function in namespaces.

ext/svm

[Since 1.7.8] - [ -P Extensions/Extsvm ] - [ Online docs ]

Extension SVM .

SVM is in interface with the libsvm , from . libsvm is a library for Support Vector Machines, a classification tool for machine learning.

<?php 
$data = array(
       array(-
1=> 0.43=> 0.129284 => 0.2),
       array(
1=> 0.22=> 0.0194 => 0.11),
   );
   
   
$svm = new SVM();
   
$model $svm->train($data);
   
   
$data = array(=> 0.43=> 0.129284 => 0.2);
   
$result $model->predict($data);
   
var_dump($result);
   
$model->save('model.svm');
?>



See also SVM, LIBSVM -- A Library for Support Vector Machines, ext/svm , ianbarber/php-svm

Avoid option arrays in constructors

[Since 1.7.9] - [ -P Classes/AvoidOptionArrays ] - [ Online docs ]

Avoid option arrays in constructors. Use one parameter per injected element.

<?php 
class Foo {
    
// Distinct arguments, all typehinted if possible
    
function __constructor(A $aB $bC $cD $d) {
        
$this->$a;
        
$this->$b;
        
$this->$c;
        
$this->$d;
    }
}

class 
Bar {
    
// One argument, spread over several properties
    
function __constructor(array $options) {
        
$this->$options['a'];
        
$this->$options['b'];
        
$this->$options['c'];
        
$this->$options['d'];
    }
}
?>



See also Avoid option arrays in constructors, PHP RFC: Named Arguments (Type-safe and documented options)

ext/ffi

[Since 1.7.9] - [ -P Extensions/Extffi ] - [ Online docs ]

Extension FFI : Foreign Function Interface .

This extension allows the loading of shared libraries (.DLL or .so), calling of C functions and accessing of C data structures in pure PHP, without having to have deep knowledge of the Zend extension API, and without having to learn a third “intermediate” language. The public API is implemented as a single class FFI with several static methods (some of them may be called dynamically), and overloaded object methods, which perform the actual interaction with C data.

<?php 
//Example : Calling a function from shared library
// create FFI object, loading libc and exporting function `printf() <https://www.php.net/printf>`_
$ffi FFI::cdef(
    
"int printf(const char *format, ...);"// this is a regular C declaration
    
"libc.so.6");
// call C's `printf() <https://www.php.net/printf>`_
$ffi->printf("Hello %s!\n""world");
?>


See also ext/ffi, A PHP Compiler, aka The FFI Rabbit Hole

ext/password

[Since 0.8.4] - [ -P Extensions/Extpassword ] - [ Online docs ]

Extension password.

The password hashing API provides an easy to use wrapper around crypt() and some other password hashing algorithms, to make it easy to create and manage passwords in a secure manner.

<?php 
// See the `password_hash() <https://www.php.net/password_hash>`_ example to see where this came from.
$hash '$2y$07$BCryptRequires22Chrcte/VlQH0piJtjXl.0t1XkA8pw9dMXTpOq';

if (
password_verify('rasmuslerdorf'$hash)) {
    echo 
'Password is valid!';
} else {
    echo 
'Invalid password.';
}
?>


See also Password Hashing and
crypt man page.

ext/zend_monitor

[Since 1.7.9] - [ -P Extensions/Extzendmonitor ] - [ Online docs ]

Extension zend_monitor .


See also Zend Monitor - PHP API

ext/uuid

[Since 1.7.9] - [ -P Extensions/Extuuid ] - [ Online docs ]

Extension UUID . A universally unique identifier (UUID) is a 128-bit number used to identify information in computer systems.

An interface to the libuuid system library. The libuuid library is used to generate unique identifiers for objects that may be accessible beyond the local system. The Linux implementation was created to uniquely identify ext2 filesystems created by a machine. This library generates UUIDs compatible with those created by the Open Software Foundation (OSF) Distributed Computing Environment (DCE) utility uuidgen.

<?php 
// example from the test suitee of the extension.
    
    // check basic format of generated UUIDs
    
$uuid uuid_create();
    if (
preg_match("/[[:xdigit:]]{8}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{4}-[[:xdigit:]]{12}/"$uuid)) {
            echo 
"basic format ok\n";
    } else {
            echo 
"basic UUID format check failed, generated UUID was $uuid\n";
    }
?>



See also libuuid, ext/uuid

Already Parents Trait

[Since 1.8.0] - [ -P Traits/AlreadyParentsTrait ] - [ Online docs ]

Trait is already used a parent's class or trait. There is no use to include it a second time.

<?php 
trait ta {
    use 
tb;
}

trait 
t1 {
    use 
ta;
    use 
tb// also used by ta
}

class 
{
    use 
t1// also required by class c
    
use ta// also required by trait t1
}

class 
extends {
    use 
t1;
}
?>



See also Traits

Trait Not Found

[Since 1.7.9] - [ -P Traits/TraitNotFound ] - [ Online docs ]

A unknown trait is mentioned in the use expression.

The used traits all exist, but in the configuration block, some unmentioned trait is called.

Be aware that the traits used in any configuration block may originate in any use expression. PHP will check the configuration block at instantiation only, and after compiling : at that moment, it will know all the used traits across the class.

<?php 
class x  
    
// c is not a used trait
    
use ac::insteadof e;}

    
// e is a used trait, even if is not in the use above.
    
use e;
}
?>



See also Traits

Casting Ternary

[Since 1.8.0] - [ -P Structures/CastingTernary ] - [ Online docs ]

Type casting has a precedence over ternary operator, and is applied first. When this happens, the condition is cast, although it is often useless as PHP will do it if needed.

This applies to the ternary operator, the coalesce operator ?: and the null-coalesce operator ??.

<?php 
$a = (string) $b 4;
    
$a = (string) $b ?: 4;
    
$a = (string) $b ?? 4;
?>


The last example generates first an error `Undefined variable: b`, since $b is first cast to a string. The result is then an empty string, which leads to an empty string to be stored into $a. Multiple errors cascade.


See also Operators Precedence

Concat Empty String

[Since 1.8.0] - [ -P Structures/ConcatEmpty ] - [ Online docs ]

Using a concatenation to make a value a string should be replaced with a type cast.

Type cast to a string is done with (string) operator. There is also the function strval(), although it is less recommended.

<?php 
$a 3;

// explicite way to cast a value
$b = (string) $a// $b is a string with the content 3

// Wrong way to cast a value
$c $a ''// $c is a string with the content 3
$c '' $a// $c is a string with the content 3
$a .= '';     // $a is a string with the content 3

// Wrong way to cast a value
$c $a '' $b// This is not reported. The empty string is useless, but not meant to type cast
?>


See also Type Casting and
PHP Type Casting.

Concat And Addition

[Since 1.8.0] - [ -P Php/ConcatAndAddition ] - [ Online docs ]

Precedence between addition and concatenation has changed. In PHP 7.4, addition has precedence, and before, addition and concatenation had the same precedence.

From the RFC : Currently the precedence of '.', '+' and '-' operators are equal. Any combination of these operators are simply evaluated left-to-right .

This is counter-intuitive though: you rarely want to add or subtract concatenated strings which in general are not numbers. However, given PHP's capability of seamlessly converting an integer to a string, concatenation of these values is desired.

<?php 
// Extracted from the RFC
echo sum: . $a $b;
 
// current behavior: evaluated left-to-right
echo (sum: . $a) + $b;
 
// desired behavior: addition and subtraction have a higher precendence
echo sum : . ($a $b);
?>


This analysis reports any addition and concatenation that are mixed, without parenthesis. Addition also means substraction here, aka using `+` or `-`.

The same applies to bitshift operations, << and >>``. There is no RFC for this change.


See also Change the precedence of the concatenation operator

New Functions In PHP 7.4

[Since 1.8.0] - [ -P Php/Php74NewFunctions ] - [ Online docs ]

New functions are added to new PHP version.

The following functions are now native functions in PHP 7.4. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.


No Append On Source

[Since 1.8.2] - [ -P Structures/NoAppendOnSource ] - [ Online docs ]

Do not append new elements to an array in a foreach loop. Since PHP 7.0, the array is still used as a source, and will be augmented, and used again.

<?php 
// Relying on the initial copy
$a = [1];
$initial $a;
foreach(
$initial as $v) {
    
$a[] = $v 1;
}

// Keep new results aside
$a = [1];
$tmp = [];
foreach(
$a as $v) {
    
$tmp[] = $v 1;
}
$a array_merge($a$tmp);
unset(
$tmp);

// Example, courtesy of Frederic Bouchery
// This is an infinite loop
$a = [1];
foreach(
$a as $v) {
    
$a[] = $v 1;
}
?>


Thanks to Frederic Bouchery for the reminder.

See also foreach and
What will this code return? #PHP.

Memoize MagicCall

[Since 1.8.3] - [ -P Performances/MemoizeMagicCall ] - [ Online docs ]

Cache calls to magic methods in local variable. Local cache is faster than calling again the magic method as soon as the second call, provided that the value hasn't changed.

__get is slower, as it turns a simple member access into a full method call.

<?php 
class {
    private 
$values = array();
    
    function 
__get($name) {
        return 
$this->values[$name];
    }
    
// more code to set values to this class
}

function 
foo(x $b) {
    
$a $b->a
    
$c $b->c;
    
    
$d $c;     // using local cache, no new access to $b->__get($name)
    
$e $b->a;  // Second access to $b->a, through __get
}

function 
bar(x $b) {
    
$a $b->a
    
$c $b->c;
    
    
$b->bar2(); // this changes $b->a and $b->c, but we don't see it
    
    
$d $b->c
    
$e $b->a;  // Second access to $b->a, through __get
}
?>


The caching is not possible if the processing of the object changes the value of the property.


See also __get performance questions with PHP, Classes/MakeMagicConcrete, Benchmarking magic

curl_version() Has No Argument

[Since 1.8.4] - [ -P Structures/CurlVersionNow ] - [ Online docs ]

curl_version() used to accept CURLVERSION_NOW as argument. Since PHP 7.4, it is a function without arguments.

<?php 
// Compatible syntax
$details curl_version(CURLVERSION_NOW);

// New PHP 7.4 syntax
$details curl_version();
?>


See also curl_version.

Php 7.4 New Class

[Since 1.0.4] - [ -P Php/Php74NewClasses ] - [ Online docs ]

New classes, introduced in PHP 7.4. If classes where created with the same name, in current code, they have to be moved in a namespace, or removed from code to migrate safely to PHP 7.4.

The new classes are :

+ ReflectionReference
+ WeakReference

<?php 
namespace {
    
// Global namespace
    
class WeakReference {
        
// Move to a namespace
        // or, remove this class
    
}
}

namespace 
{
    class 
WeakReference {
        
// This is OK : in a namespace
    
}
}
?>


New Constants In PHP 7.4

[Since 1.8.4] - [ -P Php/Php74NewConstants ] - [ Online docs ]

The following constants are now native in PHP 7.4. It is advised to avoid using such names for constant before moving to this new version.

  • MB_ONIGURUMA_VERSION
  • SO_LABEL
  • SO_PEERLABEL
  • SO_LISTENQLIMIT
  • SO_LISTENQLEN
  • SO_USER_COOKIE
  • PHP_WINDOWS_EVENT_CTRL_C
  • PHP_WINDOWS_EVENT_CTRL_BREAK
  • TIDY_TAG_ARTICLE
  • TIDY_TAG_ASIDE
  • TIDY_TAG_AUDIO
  • TIDY_TAG_BDI
  • TIDY_TAG_CANVAS
  • TIDY_TAG_COMMAND
  • TIDY_TAG_DATALIST
  • TIDY_TAG_DETAILS
  • TIDY_TAG_DIALOG
  • TIDY_TAG_FIGCAPTION
  • TIDY_TAG_FIGURE
  • TIDY_TAG_FOOTER
  • TIDY_TAG_HEADER
  • TIDY_TAG_HGROUP
  • TIDY_TAG_MAIN
  • TIDY_TAG_MARK
  • TIDY_TAG_MENUITEM
  • TIDY_TAG_METER
  • TIDY_TAG_NAV
  • TIDY_TAG_OUTPUT
  • TIDY_TAG_PROGRESS
  • TIDY_TAG_SECTION
  • TIDY_TAG_SOURCE
  • TIDY_TAG_SUMMARY
  • TIDY_TAG_TEMPLATE
  • TIDY_TAG_TIME
  • TIDY_TAG_TRACK
  • TIDY_TAG_VIDEO
  • STREAM_CRYPTO_METHOD_TLSv1_3_CLIENT
  • STREAM_CRYPTO_METHOD_TLSv1_3_SERVER
  • STREAM_CRYPTO_PROTO_TLSv1_3
  • T_COALESCE_EQUAL
  • T_FN


See also New global constants in 7.4

Unused Class Constant

[Since 1.8.4] - [ -P Classes/UnusedConstant ] - [ Online docs ]

The class constant is unused. Consider removing it or using it.

Class constants may be used in expressions, in static expressions, when building other constants, or in default values.

<?php 
class foo {
    public const 
UNUSED 1// No mention in the code
    
    
private const USED 2;  // used constant
    
    
function bar() {
        echo 
self::USED;
    }
}
?>


Infinite Recursion

[Since 1.8.6] - [ -P Structures/InfiniteRecursion ] - [ Online docs ]

A method is calling itself, with unchanged arguments. This will probably repeat indefinitely.

This applies to recursive functions without any condition. This also applies to function which inject the incoming arguments, without modifications.

<?php 
function foo($a$b) {
    if (
$a 10) {
        return;
    }
    
foo($a$b);
}

function 
foo2($a$b) {
    ++
$a;   // $a is modified
    
if ($a 10) {
        return;
    }
    
foo2($a$b);
}
?>

Null Or Boolean Arrays

[Since 1.8.6] - [ -P Arrays/NullBoolean ] - [ Online docs ]

Null and booleans are valid PHP array base. Yet, they only produces null values. They also did not emits any warning until PHP 7.4.

This analysis has been upgraded to cover int and float types too.

<?php 
// outputs NULL
var_dump(null[0]);

const 
MY_CONSTANT true;
// outputs NULL
var_dump(MY_CONSTANT[10]);
?>



See also Null and True

Dependant Abstract Classes

[Since 1.8.6] - [ -P Classes/DependantAbstractClass ] - [ Online docs ]

Abstract classes should be autonomous. It is recommended to avoid depending on methods, constant or properties that should be made available in inheriting classes, without explicitly abstracting them.

The following abstract classes make usage of constant, methods and properties, static or not, that are not defined in the class. This means the inheriting classes must provide those constants, methods and properties, but there is no way to enforce this.

This may also lead to dead code : when the abstract class is removed, the host class have unused properties and methods.

<?php 
// autonomous abstract class : all it needs is within the class
abstract class {
    private 
$p 0;
    
    function 
foo() {
        return ++
$this->p;
    }
}

// dependant abstract class : the inheriting classes needs to provide some properties or methods
abstract class c2 {
    function 
foo() {
        
// $p must be provided by the extending class
        
return ++$this->p;
    }
}

class 
c3 extends c2 {
    private 
$p 0;
}
?>



See also Traits/DependantTrait

Wrong Type Returned

[Since 1.8.7] - [ -P Functions/WrongReturnedType ] - [ Online docs ]

The returned value is not compatible with the specified return type.

<?php 
// classic error
function bar() : int {
    return 
'A';
}

// classic static error
const 2;
function 
bar() : string {
    return 
B;
}

// undecideable error
function bar($c) : string {
    return 
$c;
}

// PHP lint this, but won't execute it
function foo() : void {
    
// No return at all 
}
?>



See also Returning values, Void Return Type, Functions/MismatchTypeAndDefault, Classes/WrongTypedPropertyInit

Overwritten Source And Value

[Since 1.8.9] - [ -P Structures/ForeachSourceValue ] - [ Online docs ]

In a foreach(), it is best to keep source and values distinct. Otherwise, they overwrite each other.

Since PHP 7.0, PHP makes a copy of the original source, then works on it. This makes possible to use the same name for the source and the values.

<?php 
// displays 0-1-2-3-3
$array range(03);
foreach(
$array as $array) {
    print 
$array '-';
}
print_r($array);


/* displays 0-1-2-3-Array
(
    [0] => 0
    [1] => 1
    [2] => 2
    [3] => 3
)
*/
$array range(03);
foreach(
$array as $v) {
    print 
$v '-';
}
print_r($array);
?>


When the source is used as the value, the elements in the array are successively assigned to itself. After the loop, the original array has been replaced by its last element.

The same applies to the index, or to any variable in a list() structure, used in a foreach().

Avoid mb_dectect_encoding()

[Since 1.8.9] - [ -P Php/AvoidMbDectectEncoding ] - [ Online docs ]

mb_dectect_encoding() is bad at guessing encoding.

For example, UTF-8 and ISO-8859-1 share some common characters : when a string is build with them it is impossible to differentiate the actual encoding.

<?php 
$encoding mb_encoding_detect($_GET['name']);
?>



See also mb_encoding_detect, PHP vs. The Developer: Encoding Character Sets, DPC2019: Of representation and interpretation: A unified theory - Arnout Boks

PHP 7.4 Removed Functions

[Since 1.9.0] - [ -P Php/Php74RemovedFunctions ] - [ Online docs ]

The following PHP native functions were deprecated in PHP 7.4.


This analysis skips redefined PHP functions : when a replacement for a removed PHP function was created, with condition on the PHP version, then its usage is considered valid.

See also PHP 7.4 Removed Functions and
PHP 7.4 Deprecations : Introduction.

mb_strrpos() Third Argument

[Since 1.8.9] - [ -P Php/Php74mbstrrpos3rdArg ] - [ Online docs ]

Passing the encoding as 3rd parameter to mb_strrpos() is deprecated. Instead pass a 0 offset, and encoding as 4th parameter.

<?php 
// Finds the position of the last occurrence of of a string in a string, starting at position 10
$extract mb_strrpos($haystack$needle10'utf8');

// This is the old behavior. Here, the offset will be 0, by default
$extract mb_strrpos($haystack$needle'utf8');
?>


See also mb_strrpos().

array_key_exists() Works On Arrays

[Since 1.9.0] - [ -P Php/ArrayKeyExistsWithObjects ] - [ Online docs ]

array_key_exists() requires arrays as second argument. Until PHP 7.4, objects were also allowed, yet it is now deprecated.

<?php 
// Valid way to check for key
$array = ['a' => 1];
var_dump(array_key_exists('a'$array))


// Deprecated since PHP 7.4
$object = new Stdclass();
$object->1;
var_dump(array_key_exists('a'$object))
?>


See also `array_key_exists() with objects _, `array_key_exists

Reflection Export() Is Deprecated

[Since 1.9.0] - [ -P Php/ReflectionExportIsDeprecated ] - [ Online docs ]

export() method in Reflection classes is now deprecated. It is obsolete since PHP 7.4 and will disappear in PHP 8.0.

The Reflector interface, which is implemented by all reflection classes, specifies two methods: __toString() and export().

<?php 
ReflectionFunction::export('foo');
// same as
echo new ReflectionFunction('foo'), \n;
 
$str ReflectionFunction::export('foo'true);
// same as
$str = (string) new ReflectionFunction('foo');
?>


See also Reflection export() methods and
Reflection.

Unbinding Closures

[Since 1.9.0] - [ -P Functions/UnbindingClosures ] - [ Online docs ]

Never drop $this , once a closure was created in a non-static method.

From the PHP wiki : Currently it is possible to unbind the $this variable from a closure that originally had one by using $closure->bindTo(null) . Due to the removal of static calls to non-static methods in PHP 8, we now have a guarantee that $this always exists inside non-static methods. We would like to have a similar guarantee that $this always exists for non-static closures declared inside non-static methods. Otherwise, we will end up imposing an unnecessary performance penalty either on $this accesses in general, or $this accesses inside such closures.

<?php 
class {
    private 
$a 3;
    
    function 
foo() {
        return function () { echo 
$this->a; };
    }
}

$closure = (new x)->foo();

// $this was expected, and it is not anymore
$closure->bindTo(null);

$closure->bindTo(new x);
?>


Calling bindTo() with a valid object is still valid.


See also Unbinding $this from non-static closures

Numeric Literal Separator

[Since 1.9.0] - [ -P Php/IntegerSeparatorUsage ] - [ Online docs ]

Integer and floats may be written with internal underscores. This way, it is possible to separate large number into smaller groups, and make them more readable.

Numeric Literal Separators were introduced in PHP 7.4 and are not backward compatible.

<?php 
$a 1_000_000_000;   // A billion
$a 1000000000;      // A billion too...

$b 107_925_284.88;‬ // 6 light minute to kilometers = 107925284.88 kilometers
$b 107925284.88;‬   // Same as above
?>



See also PHP RFC: Numeric Literal Separator

Class Without Parent

[Since 1.9.0] - [ -P Classes/NoParent ] - [ Online docs ]

Classes should not refer to parent when it is not extending another class.

In PHP 7.4, it is a Deprecated warning. In PHP 7.3, it was a Fatal error, when the code was eventually executed. In PHP 8.0, PHP detects this error at compile time, except for parent keyword in a closure.

<?php 
class {
    function 
foo() {
        
parent::foo();
    }
}
?>


Scalar Are Not Arrays

[Since 1.9.0] - [ -P Php/ScalarAreNotArrays ] - [ Online docs ]

It is wrong to use a scalar as an array, a Warning is emitted. PHP 7.4 emits a Warning in such situations.

<?php 
// Here, $x may be null, and in that case, the echo will fail.
function foo(?A $x) { 
    echo 
$x[2]; 
}
?>


Typehinted argument with a scalar are reported by this analysis. Also, nullable arguments, both with typehint and return type hint.


See also E_WARNING for invalid container read array-access

PHP 7.4 Reserved Keyword

[Since 1.9.2] - [ -P Php/Php74ReservedKeyword ] - [ Online docs ]

fn is a new PHP keyword. In PHP 7.4, it is used to build the arrow functions. When used at an illegal position, fn generates a Fatal error at compile time.

As a key word, fn is not allowed as constant name, function name, class name or inside namespaces.

<?php 
// PHP 7.4 usage of fn
function array_values_from_keys($arr$keys) {
    return 
array_map(fn($x) => $arr[$x], $keys);
}

// PHP 7.3 usage of fn
const fn = 1;

function fn() {}

class 
{
    
// This is valid in PHP 7.3 and 7.4
    
function fn() {}
}
?>


fn is fine for method names. It may also be used for constants with define(), and constant() but it is not recommended.


See also PHP RFC: Arrow Functions

No More Curly Arrays

[Since 1.9.2] - [ -P Php/NoMoreCurlyArrays ] - [ Online docs ]

Only use square brackets to access array elements. The usage of curly brackets for array access is deprecated since PHP 7.4.

<?php 
$array = [1,2,3];

// always valid
echo $array[1];

// deprecated in PHP 7.4
echo $array{1};
?>



See also Deprecate curly brace syntax, Deprecate curly brace syntax for accessing array elements and string offsets

array_merge() And Variadic

[Since 1.9.2] - [ -P Structures/ArrayMergeAndVariadic ] - [ Online docs ]

Always check value in variadic before using it with array_merge() and array_merge_recursive().

Before PHP 7.4, array_merge() and array_merge_recursive() would complain when no argument was provided. As such, using the spread operator `...` on an empty array() would yield no argument, and an error.

<?php 
$b array_merge(...$x);
?>


PHP 7.4 Constant Deprecation

[Since 1.9.3] - [ -P Php/Php74Deprecation ] - [ Online docs ]

One constant is deprecated in PHP 7.4.

  • CURLPIPE_HTTP1

See also Deprecations for PHP 7.2.

Implode() Arguments Order

[Since 1.9.2] - [ -P Structures/ImplodeArgsOrder ] - [ Online docs ]

implode() accepted two signatures, but is only recommending one. Both types orders of string then array, and array then string have been possible until PHP 7.4.

In PHP 7.4, the order array then string is deprecated, and emits a warning. It will be removed in PHP 8.0.

<?php 
$glue ',';
$pieces range(04);

// documented argument order
$s implode($glue$pieces);

// Pre 7.4 argument order
$s implode($pieces$glue);

// both produces 0,1,2,3,4
?>



See also implode()

PHP 7.4 Removed Directives

[Since 1.9.3] - [ -P Php/Php74RemovedDirective ] - [ Online docs ]

List of directives that are removed in PHP 7.4.

+ allow_url_include


See also Deprecation allow_url_include

Hash Algorithms Incompatible With PHP 7.4-

[Since 1.3.4] - [ -P Php/HashAlgos74 ] - [ Online docs ]

List of hash algorithms incompatible with PHP 7.3 and older recent. At the moment of writing, this is compatible up to 7.4s.

The hash algorithms were introduced in PHP 7.4s.

<?php 
// Compatible only with 7.1 and more recent
echo hash('crc32cs''The quick brown fox jumped over the lazy dog.');

// Always compatible
echo hash('ripemd320''The quick brown fox jumped over the lazy dog.');
?>



See also hash_algos

openssl_random_pseudo_byte() Second Argument

[Since 1.9.3] - [ -P Structures/OpensslRandomPseudoByteSecondArg ] - [ Online docs ]

openssl_random_pseudo_byte() uses exceptions to signal an error. Since PHP 7.4, there is no need to use the second argument.

On the other hand, it is important to catch the exception that openssl_random_pseudo_byte() may emit.

<?php 
// PHP 7.4 way to check on random number generation
    
try {
        
$bytes openssl_random_pseudo_bytes($i);
    } catch(
\Exception $e) {
        die(
Error while loading random number);
    }

    
// Old way to check on random number generation
    
$bytes openssl_random_pseudo_bytes($i$cstrong);
    if (
$cstrong === false) {
        die(
Error while loading random number);
    }
?>


See also openssl_random_pseudo_byte and
PHP RFC: Improve openssl_random_pseudo_bytes().

strip_tags() Skips Closed Tag

[Since 1.9.3] - [ -P Structures/StripTagsSkipsClosedTag ] - [ Online docs ]

strip_tags() skips non-self closing tags. This means that tags such as
will be ignored from the second argument of the function.

<?php 
$input 'a<br />';

// Displays 'a' and clean the tag
echo strip_tags($input'<br>');

// Displays 'a<br />' and skips the allowed tag
echo strip_tags($input'<br/>');
?>


See also strip_tags

No Spread For Hash

[Since 1.9.3] - [ -P Arrays/NoSpreadForHash ] - [ Online docs ]

The spread operator ... only works on integer-indexed arrays.

<?php 
// This is valid, as  -33  is cast to integer by PHP automagically
var_dump(...[1,-33 => 23]);

// This is not valid
var_dump(...[1,=> 23]);
?>



See also Variable-length argument lists

Use Covariance

[Since 1.9.3] - [ -P Php/UseCovariance ] - [ Online docs ]

Covariance is compatible return typehint. A child class may return an object of a child class of the return type of its parent's method.

Since a children class may return a children class of the return type, the evolution is in the same order.

Covariance is a PHP 7.4 feature. Covariance is distinct from argument contravariance.

<?php 
class {
  function 
m(Y $z): {}
}

// m is overwriting the parent's method. 
// The return type is different.
// The return type is compatible, as Y is also a sub-class of X.
class extends {
  function 
m(X $z): {}
}
?>



See also Covariant Returns and Contravariant Parameters, `Php/UseContravariance`_

Use Contravariance

[Since 1.9.3] - [ -P Php/UseContravariance ] - [ Online docs ]

Contravariance is compatible argument typehint. A child class may accept an object of a parent class of the argument type of its parent's method.

Since a children class may accept a parent class of the argynebt type, the evolution is in opposite order.

Contravariance is a PHP 7.4 feature. Contravariance is distinct from return type covariance.

<?php 
class {
  function 
m(Y $z): {}
}

// m is overwriting the parent's method. 
// The return type is different.
// The return type is compatible, as Y is also a sub-class of X.
class extends {
  function 
m(X $z): {}
}
?>


See also Covariant Returns and Contravariant Parameters, `Php/UseCovariance`

Use Arrow Functions

[Since 1.9.4] - [ -P Functions/UseArrowFunctions ] - [ Online docs ]

Arrow functions are closures that require less code to write.

Arrow functions were introduced in PHP 7.4. They added the reserved keyword fn . s

<?php 
array_map(fn(A $b): int => $b->c$array);

function 
array_values_from_keys($arr$keys) {
    return 
array_map(fn($x) => $arr[$x], $keys);
}
?>


See also RFC : Arrow functions, Arrow functions in PHP

Max Level Of Nesting

[Since 1.9.3] - [ -P Structures/MaxLevelOfIdentation ] - [ Online docs ]

Avoid nesting structures too deep, as it hurts readability.

Nesting structures are : if/then, switch, for, foreach, while, do...while. Ternary operator, try/catch are not considered a nesting structures.

Closures, and more generally, functions definitions are counted separatedly.

This analysis checks for 4 levels of nesting, by default. This may be changed by configuration.

<?php 
// 5 levels of indentation
function foo() {
    if (
1) {
        if (
2) {
            if (
3) {
                if (
4) {
                    if (
5) {
                        
51;
                    } else {
                        
5;
                    }
                } else {
                    
4;
                }
            } else {
                
3;
            }
        } else {
            
2;
        }
    } else {
        
1;
    }
}

// 2 levels of indentation
function foo() {
    if (
1) {
        if (
2) {
            
// 3 levels of indentation
            
return function () {
                if (
3) {
                    if (
4) {
                        if (
5) {
                            
51;
                        } else {
                            
5;
                        }
                    } else {
                        
4;
                    }
                } else {
                    
3;
                }
            }
        } else {
            
2;
        }
    } else {
        
1;
    }
}
?>

Spread Operator For Array

[Since 1.9.4] - [ -P Php/SpreadOperatorForArray ] - [ Online docs ]

The variadic operator may be used with arrays. This has been introduced in PHP 7.4.

list() is not allowed to use this operator, as list() expected variables, not values.

<?php 
$array = [123];
$extended_array = [...$array456];

// invalid syntax
[...$a] = [1,2,3];
?>


See also Spread Operator in Array Expression

Nested Ternary Without Parenthesis

[Since 1.9.4] - [ -P Php/NestedTernaryWithoutParenthesis ] - [ Online docs ]

It is not allowed to nest ternary operator within itself, without parenthesis. This has been implemented in PHP 7.4.

The reason behind this feature is to keep the code expressive. See the Warning message for more explanations

<?php 
$a : ($b 3);

// Still valid, as not ambiguous 
$a $b 3;

// Produces a warning
//Unparenthesized `a ? b : c ? d : e` is deprecated. Use either `(a ? b : c) ? d : e` or `a ? b : (c ? d : e)`
$a $b 3;
?>



See also PHP RFC: Deprecate left-associative ternary operator

Should Use Explode Args

[Since 1.9.4] - [ -P Structures/ShouldUseExplodeArgs ] - [ Online docs ]

explode() has a third argument, which limits the amount of exploded elements. With it, it is possible to collect only the first elements, or drop the last ones.

<?php 
$exploded explode(DELIMITER$string);

// use explode(DELIMITER, $string, -1);
array_pop($exploded);

// use explode(DELIMITER, $string, -2);
$c array_slice($exploded0, -2);

// with `explode() <https://www.php.net/explode>`_'s third argument : 
list($a$b) = explode(DELIMITER$string2);

// with list() omitted arguments
list($a$b, ) = explode(DELIMITER$string);
?>



See also explode

Use array_slice()

[Since 1.9.5] - [ -P Performances/UseArraySlice ] - [ Online docs ]

Array_slice() is de equivalent of substr() for arrays.

array_splice() is also available, to remove a portion of array inside the array, not at the ends. This has no simple equivalent for strings.

<?php 
$array range(09);

// Extract the 5 first elements
print_r(array_slice($array05));

// Extract the 4 last elements
print_r(array_slice($array, -4));

// Extract the 2 central elements : 4 and 5
print_r(array_splice($array42));

// slow way to remove the last elementst of an array
for($i 0$i 4) {
    
array_pop($array);
}
?>



See also array_slice, array_splice

Too Many Array Dimensions

[Since 1.9.4] - [ -P Arrays/TooManyDimensions ] - [ Online docs ]

When arrays a getting to many nesting.

<?php 
$a          = array();   // level 1;
$a[1]       = array();   // level 2
$a[1][2]    = array();   // level 3 : still valid by default
$a[1][2][3] = array();   // level 4
?>


PHP has no limit, and accepts any number of nesting levels. Yet, this is usually very memory hungry.

Coalesce And Concat

[Since 1.9.4] - [ -P Structures/CoalesceAndConcat ] - [ Online docs ]

The concatenation operator dot has precedence over the coalesce operator ??.

<?php 
// Parenthesis are the right solution when in doubt
echo . ($b ?? 'd') . $e;

// 'a' . $b is evaluated first, leading ot a useless ?? operator
'a' $b ?? $c;

// 'd' . 'e' is evaluated first, leading to $b OR 'de'. 
echo $b ?? 'd' 'e';
?>


Comparison Is Always True

[Since 1.9.4] - [ -P Structures/AlwaysFalse ] - [ Online docs ]

Based on the incoming type of arguments, the comparison always yield the same value.

<?php 
function foo(array $a) {
    
// This will always fail
    
if ($a === 1) {
        
    } elseif (
is_int($a)) {
    
    }

    
// This will always succeed
    
if ($a !== null) {
        
    } elseif (
is_null($a)) {
        
    }
}
?>


Incompatible Signature Methods With Covariance

[Since 1.3.3] - [ -P Classes/IncompatibleSignature74 ] - [ Online docs ]

Methods should have the compatible signature when being overwritten.

The same signatures means the children class must have :

+ the same name
+ the same visibility or less restrictive
+ the same contravariant typehint or removed
+ the same covariant return typehint or removed
+ the same default value or removed
+ a reference like its parent

This problem emits a fatal error, for abstract methods, or a warning error, for normal methods. Yet, it is difficult to lint, because classes are often stored in different files. As such, PHP do lint each file independently, as unknown parent classes are not checked if not present. Yet, when executing the code, PHP lint the actual code and may encounter a fatal error.

<?php 
class {
    public function 
foo($a 1) {}
}

class 
ab extends {
    
// foo is overloaded and now includes a default value for $a
    
public function foo($a) {}
}
?>



See also Object Inheritance, PHP RFC: Covariant Returns and Contravariant Parameters, Classes/IncompatibleSignature

Interfaces Is Not Implemented

[Since 1.9.5] - [ -P Interfaces/IsNotImplemented ] - [ Online docs ]

Classes that implements interfaces, must implements each of the interface's methods. Otherwise, the class shall be marked as abstract .

<?php 
class implements {
    
// This method implements the foo method from the i interface
    
function foo() {}

    
// The method bar is missing, yet is requested by interface i
    
function foo() {}
}

interface 
{
    function 
foo();
    function 
bar(); 
}
?>


This problem tends to occur in code that splits interfaces and classes by file. This means that PHP's linting will skip the definitions and not find the problem. At execution time, the definitions will be checked, and a Fatal error will occur.

This situation usually detects code that was forgotten during a refactorisation of the interface or the class and its siblings.


See also Interfaces

No Literal For Reference

[Since 1.9.5] - [ -P Functions/NoLiteralForReference ] - [ Online docs ]

Method arguments and return values may be by reference. Then, they need to be a valid variable.

Objects are always passed by reference, so there is no need to explicitly declare it.

Expressions, including ternary operator, produce value, and can't be used by reference directly. This is also the case for expression that include one or more reference.

<?php 
// variables, properties, static properties, array items are all possible
$a 1;
foo($a);

//This is not possible, as a literal can't be a reference
foo(1);

function 
foo(&$int) { return $int; }


// This is not a valid reference
function &bar() { return 2; }
function &
bar2() { return $r; }
?>


Wrongly passing a value as a reference leads to a PHP Notice.


See also References

Interfaces Don't Ensure Properties

[Since 1.9.5] - [ -P Interfaces/NoGaranteeForPropertyConstant ] - [ Online docs ]

When using an interface as a typehint, properties are not enforced, nor available.

An interface is a template for a class, which specify the minimum amount of methods and constants. Properties are never defined in an interface, and should not be relied upon.

<?php 
interface {
    function 
() ;
}

class 
implements {
    public 
$p 1;
    
    function 
m() {
        return 
$this->p;
    }
}

function 
foo(i $ix $x) {
    
// this is invalid, as $p is not defined in i, so it may be not available
    
echo $i->p;
    
    
// this is valid, as $p is defined in $x
    
echo $x->p;
}
?>



See also Interface And Abstract Class

Non Nullable Getters

[Since 1.9.6] - [ -P Classes/NonNullableSetters ] - [ Online docs ]

A getter needs to be nullable when a property is injected.

In particular, if the injection happens with a separate method, there is a time where the object is not consistent, and the property holds a default non-object value.

<?php 
class Consistent {
    private 
$db null;
    
    function 
__construct(Db $db) { 
        
$this->db $db;
        
// Object is immediately consistent 
    
}
    
    
// Db might be null
    
function getDb() {
        return 
$this->db;
    }
}

class 
Inconsistent {
    private 
$db null;
    
    function 
__construct() { 
        
// No initialisation
    
}

    
// This might be called on time, or not
    // This typehint cannot be nullable, nor use null as default 
    
function setDb(DB $db) {
        return 
$this->db;
    }

    
// Db might be null
    
function getDb() {
        return 
$this->db;
    }
}
?>


Too Many Dereferencing

[Since 1.9.7] - [ -P Classes/TooManyDereferencing ] - [ Online docs ]

Linking too many properties and methods, one to the other.

This analysis counts both static calls and normal call; methods, properties and constants. It also takes into account arrays along the way.

The default limit of chaining methods and properties is set to 7 by default.

<?php 
// 9 chained calls.
$main->getA()->getB()->getC()->getD()->getE()->getF()->getG()->getH()->getI()->property;
?>


Too many chained methods is harder to read.

Can't Implement Traversable

[Since 1.9.8] - [ -P Interfaces/CantImplementTraversable ] - [ Online docs ]

It is not possible to implement the Traversable interface. The alternative is to implement Iterator or IteratorAggregate , which also implements Traversable .

Traversable may be useful when used with instanceof .

<?php 
// This lints, but doesn't run
class implements Traversable {

}

if( 
$argument instanceof Traversable ) {
    
// doSomething
}
?>



See also Traversable, Iterator, IteratorAggregate

Is_A() With String

[Since 1.9.9] - [ -P Php/IsAWithString ] - [ Online docs ]

When using is_a() with a string as first argument, the third argument is compulsory.

<?php 
// `is_a() <https://www.php.net/is_a>`_ works with string as first argument, when the third argument is 'true'
if (is_s('A''B'true)) {}

// `is_a() <https://www.php.net/is_a>`_ works with object as first argument
if (is_s(new A'A')) {}
?>



See also is_a

Mbstring Unknown Encoding

[Since 1.9.9] - [ -P Structures/MbstringUnknownEncoding ] - [ Online docs ]

The encoding used is not known to the ext/mbstring extension.

This analysis takes in charge all mbstring encoding and aliases. The full list of supported mbstring encoding is available with mb_list_encodings(). Each encoding alias is available with mb_encoding_aliases().

<?php 
// Invalid encoding
$str mb_strtolower($str'utf_8');

// Valid encoding
$str mb_strtolower($str'utf8');
$str mb_strtolower($str'UTF8');
$str mb_strtolower($str'UTF-8');
?>



See also ext/mbstring

Filter To add_slashes()

[Since 1.9.9] - [ -P Php/FilterToAddSlashes ] - [ Online docs ]

FILTER_SANITIZE_MAGIC_QUOTES is deprecated. In PHP 7.4, it should be replaced with addslashes()

According to the migration RDFC : 'Magic quotes were deprecated all the way back in PHP 5.3 and later removed in PHP 5.4. The filter extension implements a sanitization filter that mimics this behavior of magic_quotes by calling addslashes() on the input in question.'

<?php 
// Deprecated way to filter input
$var filter_input($inputFILTER_SANITIZE_MAGIC_QUOTES);

// Alternative way to filter input
$var addslashes($input);
?>


addslashes() used to filter data while building SQL queries, to prevent injections. Nowadays, prepared queries are a better option.


See also Deprecations for PHP 7.4

Mbstring Third Arg

[Since 1.9.9] - [ -P Structures/MbstringThirdArg ] - [ Online docs ]

Some mbstring functions use the third argument for offset, not for encoding.

Those are the following functions :


<?php 
// Display BC
echo mb_substr('ABC'2'UTF8');

// Yields Warning: `mb_substr() <https://www.php.net/mb_substr>`_ expects parameter 3 to be int, string given
// Display 0 (aka, substring from 0, for length (int) 'UTF8' => 0)
echo mb_substr('ABC','UTF8');
?>


See also mb_substr() manual pages.

Typo 3 usage

[Since 1.9.9] - [ -P Vendors/Typo3 ] - [ Online docs ]

This analysis reports usage of the Typo 3 CMS.

The current supported version is 11.4

<?php 
declare(strict_types=1);

namespace 
MyVendor\SjrOffers\Controller;

use 
TYPO3\CMS\Extbase\Mvc\Controller\ActionController;

class 
OfferController extends ActionController
{
   
// action methods will be following here
}
?>



See also Typo3

Concrete5 usage

[Since 1.9.9] - [ -P Vendors/Concrete5 ] - [ Online docs ]

This analysis reports usage of the Concrete 5 framework.

<?php 
namespace Application\Controller\PageType;

use 
Concrete\Core\Page\Controller\PageTypeController;

class 
BlogEntry extends PageTypeController
{

    public function 
view()
    {
    }
}
?>



See also Concrete 5

Immutable Signature

[Since 1.9.9] - [ -P Classes/ImmutableSignature ] - [ Online docs ]

Overwrites makes refactoring a method signature difficult. PHP enforces compatible signature, by checking if arguments have the same type, reference and default values.

In PHP 7.3, typehint had to be the same, or dropped. In PHP 7.4, typehint may be contravariant (arguments), or covariant (returntype).

This analysis may be configured with maxOverwrite . By default, a minimum of 8 overwritten methods is considered difficult to update.

<?php 
// Changing any of the four foo() method signature will trigger a PHP warning
class {
    function 
foo($a) {}
}

class 
ab1 extends {
    
// four foo() methods have to be refactored at the same time!
    
function foo($ab1) {}
}

class 
ab2 extends {
    function 
foo($ab2) {}
}

class 
ab3 extends ab1 {
    function 
foo($abc1) {}
}
?>


When refactoring a method, all the related methodcall may have to be updated too. Adding a type, a default value, or a new argument with default value won't affect the calls, but only the definitions. Otherwise, calls will also have to be updated.

IDE may help with signature refactoring, such as Refactoring code.


See also Covariance and contravariance (computer science), extends

Merge If Then

[Since 1.9.9] - [ -P Structures/MergeIfThen ] - [ Online docs ]

Two successive if/then into one, by merging the two conditions.

<?php 
// two merge conditions
if ($a == && $b == 2) {
    
// doSomething()
}

// two distinct conditions
// two nesting
if ($a == 1) {
    if (
$b == 2) {
        
// doSomething()
    
}
}
?>


Wrong Type With Call

[Since 1.9.9] - [ -P Functions/WrongTypeWithCall ] - [ Online docs ]

This analysis checks that a call to a method uses the right literal values' types.

Currently, this analysis doesn't take into account strict_types = 1 .

This analysis is compatible with Union types and with Intersection types.

<?php 
function foo(string $a) {

}

// wrong type used
foo(1);

// wrong type used
foo("1");
?>


Shell commands

[Since 1.9.9] - [ -P Type/Shellcommands ] - [ Online docs ]

Shell commands, called from PHP.

Shell commands are detected with the italic quotes, and using shell_exec(), system(), exec() and proc_open().

<?php 
// Shell command in a `shell_exec() <https://www.php.net/shell_exec>`_ call
shell_exec('ls -1');

// Shell command with backtick operator
`ls -1 $path`;
?>



See also Execution operator, shell_exec, exec

Links Between Parameter And Argument

[Since 2.0.6] - [ -P Dump/ParameterArgumentsLinks ] - [ Online docs ]

Collect various stats about arguments and parameter usage.

A parameter is one slot in the method definition. An argument is a slot in the method call. Both are linked by the method and their respective position in the argument list.

+ Total number of argument usage, linked to a parameter : this excludes arguments from external libraries and native PHP functions. For reference.
+ Number of identical parameter : cases where argument and parameter have the same name.
+ Number of different parameter : cases where argument and parameter have the different name.
+ Number of expression argument : cases where argument is an expression
+ Number of constant argument : cases where the argument is a constant

<?php 
function foo($a$b) {
    
// some code
}

// $a is the same as the parameter
// $c is different from the paramter $b
foo($a$c);

const 
1;

// Foo is called with a constant (1rst argument)
// Foo is called with a expression (2nd argument)
foo(C1+3);
?>


Not Equal Is Not !==

[Since 2.0.6] - [ -P Structures/NotEqual ] - [ Online docs ]

Not and Equal operators, used separately, don't amount to the different operator !== .

!$a == $b first turns $a into the opposite boolean, then compares this boolean value to $b . On the other hand, $a !== $b compares the two variables for type and value, and returns a boolean.

<?php 
if ($string != 'abc') {
    
// doSomething()
}

// Here, string will be an boolean, leading 
if (!$string == 'abc') {
    
// doSomething()
}

// operator priority may be confusing
if (!$object instanceof OneClass) {
    
// doSomething()
}
?>


Note that the instanceof operator may be use with this syntax, due to operator precedence.


See also Operator Precedence

Php 8.0 Variable Syntax Tweaks

[Since 2.0.8] - [ -P Php/Php80VariableSyntax ] - [ Online docs ]

Several variable syntaxes are added in version 8.0. They extends the PHP 7.0 syntax updates, and fix a number of edges cases.

In particular, new and instanceof now support a way to inline the expression, rather than use a temporary variable.

Magic constants are now accessible with array notation, just like another constant. It is also possible to use method calls : although this is Syntacticly correct for PHP, this won't be executed, as the left operand is a string, and not an object.

<?php 
// array name is dynamically build
 
echo foo$bar[0];
 
// static method
 
foo$bar::baz();
 
// static property 
 
foo$bar::$baz;
 
 
// Syntactly correct, but not executable
 
foo$bar->baz();
 
 
// expressions with instanceof and new
    
$object = new (class_.$name);
    
$x instanceof (class_$name);

    
// PHP 7.0 style
    
$className class_.$name;
    
$object = new $className;
?>


See also PHP RFC: Variable Syntax Tweaks, scalar_objects in PHP

New Functions In PHP 8.0

[Since 2.0.8] - [ -P Php/Php80NewFunctions ] - [ Online docs ]

New functions are added to new PHP version.

The following functions are now native functions in PHP 8.0. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.

  • str_contains()
  • fdiv()
  • preg_last_error_msg()

Dont Collect Void

[Since 2.0.9] - [ -P Functions/DontUseVoid ] - [ Online docs ]

When a method returns void, there is no need to collect the result. The collected value will actually be null .

With a void return type, the method is intented to be without return value. This analysis also include methods which are not returning anything, and could be completed with a void returntype.

<?php 
function foo() : void {
    
// doSomething()
}

// This is useless
$result foo(); 

// This is useless. It looks like this is a left over from code refactoring
echo foo();
?>


Php 8.0 Only TypeHints

[Since 2.0.9] - [ -P Php/Php80OnlyTypeHints ] - [ Online docs ]

Three scalar typehints are introduced in version 8.0. They are mixed , false and null .

false represents a false boolean, and nothing else. It is more restrictive than a boolean, which accepts true too.
null is an alternative syntax to ? : it allows the type to be null .
mixed is an special typehint which explicitly means any type.

An interface stringable was also introduced to identify objects that may be turned into a string.

Both the above typehints are to be used in conjunction with other types : they can't be used alone.

<?php 
// function accepts an A object, or null. 
function foo(A|null $x) {}

// same as above
function foo2(A|null $x) {}

// returns an object of class B, or false
function bar($x) : false|{}
?>


In PHP 7.0, both those values could not be used as a class or interface name, to avoid confusion with the actual booleans, nor null value.


See also PHP RFC: Union Types 2.0

Union Typehint

[Since 2.0.9] - [ -P Php/Php80UnionTypehint ] - [ Online docs ]

Union typehints allows the specification of several typehint for the same argument or return value.

Several typehints are specified at the same place as a single one. The different values are separated by a pipe character | , like for exceptions

<?php 
// Example from the RFC https://wiki.php.net/rfc/union_types_v2
class Number {
    private 
int|float $number;
 
    public function 
setNumber(int|float $number): void {
        
$this->number $number;
    }
 
    public function 
getNumber(): int|float {
        return 
$this->number;
    }
}
?>


Nullable is reported as union type. Mixed and iterable are not reported as a union type.

Union types are a PHP 8.0 new feature. They are not compatible with PHP 7.4 and older.

See also PHP RFC: Union Types 2.0, PHP 8 Union types, Type declarations

Wrong Typed Property Default

[Since 2.0.9] - [ -P Classes/WrongTypedPropertyInit ] - [ Online docs ]

Property is typed, yet receives an incompatible value at constructor time.

Initialized type might be a new instance, the return of a method call or an interface compatible object.

<?php 
class {
    private 
A $property;
    private 
B $incompatible;
    
    function 
__construct() {
        
// This is compatible
        
$this->property = new A();
        
        
// This is incompatible : new B() expected
        
$this->incompatible = new C();
        
    }
}
?>


PHP compiles such code, but won't execute it, as it detects the incompatibility at execution time.


See also Functions/WrongReturnedType, Functions/MismatchTypeAndDefault

Signature Trailing Comma

[Since 2.1.0] - [ -P Php/SignatureTrailingComma ] - [ Online docs ]

Trailing comma in method signature. This feature was added in PHP 8.0.

Allowing the trailing comma makes it possible to reduce the size of VCS's diff, when adding , removing a parameter.

<?php 
// Example from the RFC
class Uri {
    private function 
__construct(
        ?
string $scheme,
        ?
string $user,
        ?
string $pass,
        ?
string $host,
        ?
int $port,
        
string $path,
        ?
string $query,
        ?
string $fragment // <-- ARGH!
    
) {
        ...
    }
}
?>



See also PHP RFC: Allow trailing comma in parameter list

Hidden Nullable Typehint

[Since 2.1.0] - [ -P Classes/HiddenNullable ] - [ Online docs ]

Argument with default value of null are nullable. It works both with the null typehint (PHP 8.0), or the ? operator are not used, setting the default value to null is allowed, and makes the argument nullable.

This works with single types, both classes and scalars; it works with union types but not with intersection types.

This doesn't happen with properties : they must be defined with the nullable type to accept a null value as default value.

This doesn't happen with constant, which can't be typehinted.

<?php 
// explicit nullable parameter $s
function bar(?string $s null) {

// implicit nullable parameter $s
function foo(string $s null) {
    echo 
$s ?? 'NULL-value';
}

// both display NULL-value
foo(); 
foo(null);
?>



See also Nullable types, Type declaration, Deprecate implicit nullable parameters #3535

Fn Argument Variable Confusion

[Since 2.1.0] - [ -P Functions/FnArgumentVariableConfusion ] - [ Online docs ]

Avoid using local variables as arrow function arguments.

When a local variable name is used as an argument's name in an arrow function, the local variable from the original scope is not imported. They are now two distinct variables.

When the local variable is not listed as argument, it is then imported in the arrow function.

<?php 
function foo() {
    
$locale 1;

    
// Actually ignores the argument, and returns the local variable  $locale .
    
$fn2 = fn ($argument) => $locale;

    
// Seems similar to above, but returns the incoming argument    
    
$fn2 = fn ($locale) => $locale;
}
?>



See also Arrow functions

Missing Abstract Method

[Since 2.1.0] - [ -P Classes/MissingAbstractMethod ] - [ Online docs ]

Abstract methods must have a non-abstract version for the class to be complete. A class that is missing one abstract definition cannot be instantiated.

<?php 
// This is a valid definition
class extends {
    function 
foo() {}
    function 
bar() {}
}

// This compiles, but will emit a fatal error if instantiated
class extends {
    function 
bar() {}
}

// This illustration lint but doesn't run.
// moving this class at the beginning of the code will make lint fail
abstract class {
    abstract function 
foo() ;
}
?>


See also Classes Abstraction.

Throw Was An Expression

[Since 2.1.1] - [ -P Php/ThrowWasAnExpression ] - [ Online docs ]

Throw used to be an expression. In PHP 7.0, there were some location where one couldn't use a throw : this was the case for arrow functions, which expect one expression as function's body.

Using throw as an instruction makes the code incompatible with PHP 7 version and older.

<?php 
// Valid in PHP 8.0 and more recent
$fn = fn($a) => throw new Exception($a);
?>


See also Throw Expression, Exceptions

Undefined Constant Name

[Since 2.1.1] - [ -P Variables/UndefinedConstantName ] - [ Online docs ]

When using the syntax for variable, the name used must be a defined constant. It is not a simple string, like 'x', it is an actual constant name.

Interestingly, it is possible to use a qualified name within
, full or partial. PHP will lint such code, and will collect the value of the constant immediately. Since there is no fallback mechanism for fully qualified names, this ends with a Fatal error.

<?php 
const a;
$a Hello;

// Display 'Hello'  -> $a -> Hello
echo ;

// Yield a PHP Warning 
// Use of undefined constant y - assumed 'y' (this will throw an Error in a future version of PHP)
echo ;

// Yield a PHP Fatal error as PHP first checks that the constant exists 
//Undefined constant 'y'
echo ;
?>


Using Deprecated Method

[Since 2.1.2] - [ -P Functions/UsingDeprecated ] - [ Online docs ]

A call to a deprecated method has been spotted. A method is deprecated when it bears a @deprecated parameter in its typehint definition.

Deprecated methods which are not called are not reported.

<?php 
// not deprecated method
not_deprecated();

// deprecated methods
deprecated();
$object = new X();
$object->deprecatedToo();

/**
 * @deprecated since version 2.0.0
 */
function deprecated() {}

// PHP 8.0 attribute for deprecation
class {
    #[ 
Deprecated]
    function 
deprecatedToo() {}
}

function 
not_deprecated() {}
?>


See also @deprecated.

Protocol lists

[Since 2.1.3] - [ -P Type/Protocols ] - [ Online docs ]

List of all protocols that were found in the code.

From the manual : PHP comes with many built-in wrappers for various URL-style protocols for use with the filesystem functions such as fopen(), copy(), file_exists() and filesize().

<?php 
// Example from the PHP manual, with the glob:// wrapper

// Loop over all *.php files in ext/spl/examples/ directory
// and print the filename and its size
$it = new DirectoryIterator(glob://ext/spl/examples/*.php);
foreach($it as $f) {
    
printf(%s: %.1FK\n$f->getFilename(), $f->getSize()/1024);
}
?>


See also Supported Protocols and Wrappers.

Cyclic References

[Since 2.1.3] - [ -P Classes/CyclicReferences ] - [ Online docs ]

Avoid cyclic references.

Cyclic references happen when an object points to another object, which reciprocate. This is particularly possible with classes, when the child class has to keep a reference to the parent class.

<?php 
class {
    private 
$p null;
    
    function 
foo() {
        
$this->= new b();
        
// the current class is stored in the child class
        
$this->p->m($this);
    }
}

class 
{
    private 
$pb null;
    
    function 
n($a) {
        
// the current class keeps a link to its parent
        
$this->pb $a;
    }
}
?>


Cyclic references, or circular references, are memory intensive : only the garbage collector can understand when they may be flushed from memory, which is a costly operation. On the other hand, in an acyclic reference code, the reference counter will know immediately know that an object is free or not.

See also About circular references in PHP, A Journey to find a memory leak

Double Object Assignation

[Since 2.1.2] - [ -P Structures/DoubleObjectAssignation ] - [ Online docs ]

Make sure that assigning the same object to two variables is the intended purpose.

<?php 
// $x and $y are the same object, as they both hold a reference to the same object.
// This means that changing $x, also changes $y.
$x $y = new Z();

// $a and $b are distinct values, by default
$a $b 1;
?>



See also class

Wrong Argument Type

[Since 2.1.3] - [ -P Functions/WrongArgumentType ] - [ Online docs ]

Checks that the type of the argument is consistent with the type of the called method.

<?php 
function foo(int $a) { }

//valid call, with an integer
foo(1);

//invalid call, with a string
foo('asd');
?>


This analysis is valid with PHP 8.0.

Uses PHP 8 Match()

[Since 2.1.4] - [ -P Php/UseMatch ] - [ Online docs ]

Use the match() syntax.

<?php 
$A = match($a) {
    
'a' => 'A',
    
'b' => 'B',
    default => 
'd',
};
?>



See also match, Match expression

Mismatch Properties Typehints

[Since 2.1.4] - [ -P Classes/MismatchProperties ] - [ Online docs ]

Properties must match within the same family.

When a property is declared both in a parent class, and a child class, they must have the same type. The same type includes a possible null value.

This doesn't apply to private properties, which are only visible locally.

<?php 
// property $p is declared as an object of type a
class 
    protected 
A $p
}

// property $p is declared again, this time without a type
class extends 
    protected 
$p
}
?>


This code will lint, but not execute.

No Need For Triple Equal

[Since 2.1.4] - [ -P Structures/NoNeedForTriple ] - [ Online docs ]

There is no need for the identity comparison when the methods returns the proper type.

<?php 
// foo() returns a string. 
if ('a' === foo()) {
    
// doSomething()
}


function 
foo() : string 
    return 
'a';
}
?>


Array_merge Needs Array Of Arrays

[Since 2.1.4] - [ -P Structures/ArrayMergeArrayArray ] - [ Online docs ]

When collecting data to feed array_merge(), use an array of array as default value. array(array()) is the neutral value for array_merge();

This analysis also reports when the used types are not an array : array_merge() does not accept scalar values, but only arrays.

<?php 
// safe default value
$a = array(array());

// when $list is empty, it is 
foreach($list as $l) {
    
$a[] = $l;
}
$b array_merge($a);
?>


Since PHP 7.4, it is possible to call array_merge() without an argument : this means the default value may an empty array. This array shall not contain scalar values.


See also array_merge

Wrong Type For Native PHP Function

[Since 2.1.5] - [ -P Php/WrongTypeForNativeFunction ] - [ Online docs ]

This analysis reports calls to a PHP native function with a wrongly typed value.

<?php 
// valid calls
echo exp(1);
echo 
exp(2.5);

// invalid calls
echo exp(1);
echo 
exp(array(2.5));

// valid call, but invalid math
// -1 is not a valid value for `log() <https://www.php.net/log>`_, but -1 is a valid type (int) : it is not reported by this analysis.
echo log(-1);
?>



See also PHP 7.1 no longer converts string to arrays the first time a value is assigned with square bracket notation

Catch Undefined Variable

[Since 2.1.5] - [ -P Exceptions/CatchUndefinedVariable ] - [ Online docs ]

Always initialize variable before the try block, when they are used in a catch block. If the exception is raised before the variable is defined, the catch block may have to handle an undefined variable, leading to more chaos.

<?php 
$a 1;
try {
    
mayThrowAnException();
    
$b 2;
} catch (
\Exception $e) {
    
// $a is already defined, as it was done before the try block
    // $b may not be defined, as it was initialized after the exception-throwing expression
    
echo $a $b;
}
?>



See also catch, Non-capturing exception catches in PHP 8

Swapped Arguments

[Since 2.1.5] - [ -P Classes/SwappedArguments ] - [ Online docs ]

Overwritten methods must be compatible, but argument names is not part of that compatibility.

Methods with the same name, in two classes of the same hierarchy, must be compatible for typehint, default value, reference. The name of the argument is not taken into account when checking such compatibility, at least until PHP 7.4.

<?php 
class {
    function 
foo($a$b) {}
    
    function 
bar($a$b) {}
}

class 
extends {
    
// foo is compatible (identical) with the above class
    
function foo($a$b) {}
    
    
// bar is compatible with the above class, yet, the argument might not receive what they expect.
    
function bar($b$a) {}
}
?>


This analysis reports argument lists that differs in ordering. This analysis doesn't report argument lists that also differs in argument names.

Different Argument Counts

[Since 2.1.6] - [ -P Classes/DifferentArgumentCounts ] - [ Online docs ]

Two methods with the same name shall have the same number of compulsory argument. PHP accepts different number of arguments between two methods, if the extra arguments have default values. Basically, they shall be called interchangeably with the same number of arguments.

The number of compulsory arguments is often mistaken for the same number of arguments. When this is the case, it leads to confusion between the two signatures. It will also create more difficulties when refactoring the signature.

While this code is legit, it is recommended to check if the two signatures could be synchronized, and reduce future surprises.

<?php 
class {
    function 
foo($a ) {}
}

class 
extends {
    
// This method is compatible with the above, its signature is different
    
function foo($a$b 1) {}
}
?>


Use PHP Attributes

[Since 2.1.6] - [ -P Php/UseAttributes ] - [ Online docs ]

PHP 8.0 attributes in use.

<?php 
#[foo(4)]
class 
{

}
?>



See also PHP RFC: Shorter Attribute Syntax, Attributes Amendements, Shorter Attribute Syntax Change

Use NullSafe Operator

[Since 2.1.6] - [ -P Php/UseNullSafeOperator ] - [ Online docs ]

The nullsafe operator ?-> is an alternative to the object operator -> . It silently fails the whole expression if a null is used for object.

<?php 
$o null;

// PHP 8.0 Failsafe : $r = null;
$r $o->method();

// PHP 7.4- : Call to a member function method() on null
$r $o->method();
?>



See also PHP RFC: Nullsafe operator

Use Closure Trailing Comma

[Since 2.1.6] - [ -P Php/UseTrailingUseComma ] - [ Online docs ]

Use a trailing comma in the closure's use list. This feature was added in PHP 8.0.

<?php 
// PHP 8.0 valid syntax
$f = function foo() use ($a, ) { };

// always valid syntax for closure
$f = function foo() use ($a ) { };
?>



See also Trailing Comma In Closure Use List

Unknown Parameter Name

[Since 2.1.6] - [ -P Functions/UnknownParameterName ] - [ Online docs ]

The name of the parameter doesn't belong to the method signature. Named arguments were introduced in PHP 8.0.

Named arguments errors will also arise when spreading a hash array with arbitrary number of arguments. For example, with array_merge(), the array should not use named keys.

<?php 
// All good
foo(a:1b:2c:3);
foo(...['a':1'b':2'c':3]);

// A is not a parameter name, it should be a : names are case sensitive
foo(A:1b:2c:3);
foo(...['A':1'b':2'c':3]);

function 
foo($a$b$c) {}

array_merge(['a' => [1], 'b' => [2]]);
?>



See also Named Arguments

Missing Some Returntype

[Since 2.1.7] - [ -P Typehints/MissingReturntype ] - [ Online docs ]

The specified typehints are not compatible with the returned values.

The code of the method may return other types, which are not specified and will lead to a PHP fatal error. It is the case for insufficient typehints, when a typehint is missing, or inconsistent typehints, when the method returns varied types.

<?php 
// correct return typehint
function fooSN() : ?string  {
    return 
shell_exec('ls -hla');
}

// insufficient return typehint
// `shell_exec() <https://www.php.net/shell_exec>`_ may return null or string. Here, only string in specified for fooS, and that may lead to a Fatal error
function fooS() : string  {
    return 
shell_exec('ls -hla');
}

// inconsistent return typehint
function bar() : int {
    return 
rand(010) ? b;
}
?>


The analysis reports a method when it finds other return types than the one expected. In the case of multiple typehints, as for the last example, the PHP code may require an upgrade to PHP 8.0.

Don't Pollute Global Space

[Since 2.1.7] - [ -P Php/DontPolluteGlobalSpace ] - [ Online docs ]

Avoid creating definitions in the global name space.

The global namespace is the default namespace, where all functions, classes, constants, traits and interfaces live. The global namespace is also known as the root namespace.

In particular, PHP native classes usually live in that namespace. By creating functions in that namespace, the code may encounter naming conflict, when the PHP group decides to use a name that the code also uses. This already happened in PHP version 5.1.1, where a Date native class was introduced, and had to be disabled in the following minor version.

Nowadays, conflicts appear between components, which claim the same name.


See also Using namespaces: fallback to global function/constant

Cast Unset Usage

[Since 2.1.8] - [ -P Php/CastUnsetUsage ] - [ Online docs ]

Usage of the `(unset)` cast operator. It is removed in PHP 8.0, and was deprecated since PHP 7.2.0.

<?php 
$a 1;
(unset) 
$a;

// functioncall is OK
unset($a);
?>


See also Unset casting

$php_errormsg Usage

[Since 2.1.8] - [ -P Php/PhpErrorMsgUsage ] - [ Online docs ]

$php_errormsg is removed since PHP 8.0. $php_errormsg tracks the last error message, with the directive track_errors`. All was removed in PHP 8.0, and shall be replaced with `error_get_last().

<?php 
function foo() {
    global 
$php_errormsg;
    
    echo 
'Last error: '.$php_errormsg;
    
    echo 
'Also, last error: '.`error_get_last() <https://www.php.net/error_get_last>`_;
}
?>

Mismatch Parameter Name

[Since 2.1.8] - [ -P Functions/MismatchParameterName ] - [ Online docs ]

Parameter name change in overwritten method. This may lead to errors when using PHP 8.0 named arguments.

PHP use the name of the parameter in the method whose code is executed. When the name change between the method and the overwritten method, the consistency is broken.

<?php 
class {
    function 
getValue($name) {}
}

class 
extends {
    
// consistent with the method above
    
function getValue($name) {}
}

class 
extends {
    
// inconsistent with the method above
    
function getValue($label) {}
}
?>


Here is another example, in early PHP 8.0 (courtesy of Carnage).

<?php 
interface Pager 
{
    public function 
fetch($page 0, ...$categories);
}
 
class 
DbPager implements Pager
{
    public function 
fetch($seite 0, ...$kategorien)
    {
        
var_dump($kategorien);
    }
}
 
$dbPager = new DbPager();
$dbPager->fetch(page1categories2);
?>


Multiple Declaration Of Strict_types

[Since 2.1.8] - [ -P Php/MultipleDeclareStrict ] - [ Online docs ]

At least two declare() commands are declaring `strict_types` in one file. Only one is sufficient, and should be the first expression in the file.

Indeed, any `strict_types` set to 1 will have the final word. Setting `strict_types` to 0 will not revert the configuration, wherever is this call made.

<?php 
declare(strict_types=1);
declare(
strict_types=1);

// rest of the code
?>



See also Declare

Array_Fill() With Objects

[Since 2.1.9] - [ -P Structures/ArrayFillWithObjects ] - [ Online docs ]

array_fill() fills an array with identical objects, not copies nor clones. This means that all the filled objects are a reference to the same object. Changing one of them will change any of them.

Make sure this is the intended effect in the code.

<?php 
$x = new StdClass();
$array array_fill(010$x);

$array[3]->Set in object #3;

// displays Set in object #3;
echo $array[5]->y;
?>


This applies to array_pad() too. It doesn't apply to array_fill_keys(), as objects will be cast to a string before usage in this case.

Modified Typed Parameter

[Since 2.1.9] - [ -P Functions/ModifyTypedParameter ] - [ Online docs ]

Reports modified parameters, which have a non-scalar typehint. Such variables should not be changed within the body of the method. Unlike typed properties, which always hold the expected type, typed parameters are only guaranteed type at the beginning of the method block.

<?php 
class {

    function 
foo(Y $y) {
        
// $y is type Y

        // A cast version of $y is stored into $yAsString. $y is untouched.
        
$yAsString = (string) $y;

        
// $y is of type 'int', now.
        
$y 1;

        
// Some more code

        // display the string version.
        
echo $yAsString
        
// so, Y $y is now raising an error
        
echo $y->name
    }
}
?>


This problem doesn't apply to scalar types : by default, PHP pass scalar parameters by value, not by reference. Class types are always passed by reference.

This problem is similar to Classes/DontUnsetProperties : the static specification of the property may be unset, leading to confusing 'undefined property', while the class hold the property definition.

Assumptions

[Since 2.1.9] - [ -P Php/Assumptions ] - [ Online docs ]

Assumptions in the code, that leads to possible bugs.

Some conditions may be very weak, and lead to errors. For example, the code below checks that the variable `$a` is not null, then uses it as an array. There is no relationship between 'not null' and 'being an array', so this is an assumption.

<?php 
// Assumption : if $a is not null, then it is an array. This is not always the case. 
function foo($a) {
    if (
$a !== null) {
        echo 
$a['name'];
    }
}

// Assumption : if $a is not null, then it is an array. Here, the typehint will ensure that it is the case. 
// Although, a more readable test is `is_array() <https://www.php.net/is_array>`_
function foo(?array $a) {
    if (
$a !== null) {
        echo 
$a['name'];
    }
}
?>



See also From assumptions to assertions

PHP 8.0 Removed Directives

[Since 2.1.9] - [ -P Php/Php80RemovedDirective ] - [ Online docs ]

List of directives that are removed in PHP 8.0.

In PHP 8.0, `track_errors` was removed.

You can detect valid directives with ini_get(). This native function will return false, when the directive doesn't exist, while actual directive values will be returned as a string.

See `Deprecation track_errors

Unsupported Types With Operators

[Since 2.1.9] - [ -P Structures/UnsupportedTypesWithOperators ] - [ Online docs ]

Arrays, resources and objects are generally not accepted with unary and binary operators.

The operators are `+`, `-`, `*`, `/`, `**`, `%`, `<<`, `>>`, `&`, `|`, `^`, `~`, `++` and `--`.

<?php 
var_dump([] % [42]);
// int(0) in PHP 7.x
// TypeError in PHP 8.0 + 

// Also impossible usage : index are string or int
$a = [];
$b $c[$a];
?>


In PHP 8.0, the rules have been made stricter and more consistent.

The only valid operator is `+`, combined with arrays in both operands. Other situations throw TypeError .


See also Stricter type checks for arithmetic/bitwise operators, TypeError

Negative Start Index In Array

[Since 2.1.9] - [ -P Arrays/NegativeStart ] - [ Online docs ]

Negative starting index in arrays changed in PHP 8.0. Until then, they were ignored, and automatic index started always at 0. Since PHP 8.0, the next index is calculated.

The behavior will break code that relies on automatic index in arrays, when a negative index is used for a starter.

<?php 
$x = [-=> 2];
$x[] = 3;

print_r($x);

/*
PHP 7.4 and older 
Array
(
    [-5] => 2
    [0] => 3
)
*/

/*
PHP 8.0 and more recent
Array
(
    [-5] => 2
    [-4] => 3
)
*/
?>


See also PHP RFC: Arrays starting with a negative index

Nullable With Constant

[Since 2.1.9] - [ -P Functions/NullableWithConstant ] - [ Online docs ]

Arguments are automatically nullable with a literal null. They used to also be nullable with a constant null, before PHP 8.0.

<?php 
// Extracted from https://github.com/php/php-src/blob/master/UPGRADING

// Replace
function test(int $arg CONST_RESOLVING_TO_NULL) {}
// With
function test(?int $arg CONST_RESOLVING_TO_NULL) {}
// Or
function test(int $arg null) {}
?>

PHP 8.0 Resources Turned Into Objects

[Since 2.2.0] - [ -P Php/Php80RemovesResources ] - [ Online docs ]

Multiple PHP native functions now return objects, not resources. Any check on those values with is_resource() is now going to fail.

The affected functions are the following :

+ curl_init()
+ curl_multi_init()
+ curl_share_init()
+ deflate_init()
+ enchant_broker_init()
+ enchant_broker_request_dict()
+ enchant_broker_request_pwl_dict()
+ inflate_init()
+ msg_get_queue()
+ openssl_csr_new()
+ openssl_csr_sign()
+ openssl_pkey_new()
+ openssl_x509_read()
+ sem_get()
+ shm_attach()
+ shmop_open()
+ socket_accept()
+ socket_addrinfo_bind()
+ socket_addrinfo_connect()
+ socket_create_listen()
+ socket_create()
+ socket_import_stream()
+ socket_wsaprotocol_info_import()
+ xml_parser_create_ns()
+ xml_parser_create()


See also Resource to object migration

PHP 80 Named Parameter Variadic

[Since 2.2.0] - [ -P Php/Php80NamedParameterVariadic ] - [ Online docs ]

Named parameter with variadic have been renamed from 0 to 'parameter name' in PHP 8.0.

<?php 
function foo($a, ...$b) {
    
print_r($b);
}

foo(34);
foo(3b4);              // PHP 8 only 
foo(...[2b=> [34]]); // PHP 8 only
?>


In PHP 7.0, with positional argument only, the content of $b is in an array, index 0. This is also true with PHP 8.0.

In PHP 8.0, with named arguments, the content of $b is in an array, index 'b';

Since the behavior of the variadic depends on the calling syntax (with or without named parameter), the receiving must ensure the correct reception, and handle both cases.

Wrong Attribute Configuration

[Since 2.2.0] - [ -P Php/WrongAttributeConfiguration ] - [ Online docs ]

A class is attributed to the wrong PHP structure.

<?php 
#[Attribute(Attribute::TARGET_CLASS)]
class 
ClassAttribute { }

// Wrong
#[ClassAttribute]
function 
foo () {}

// OK
#[ClassAttribute]
class 
y  {}
?>


See also Declaring Attribute Classes

Cancelled Parameter

[Since 2.2.0] - [ -P Functions/CancelledParameter ] - [ Online docs ]

A parameter is cancelled, when its value is hardcoded, and cannot be changed by the calling expression. The argument is in the signature, but it is later hardcoded to a literal value : thus, it is not usable, from the caller point of view.

Reference argument are omitted in this rule, as their value changes, however hardcoded, may have an impact on the calling code.

<?php 
function foo($a$b) {
    
// $b is cancelled, and cannot be changed.
    
$b 3;

    
// $a is the only parameter here
    
return $a $b;
}

function 
bar($a$b) {
    
// $b is actually processed
    
$c $b;
    
$c process($c);
    
    
$b $c;

    
// $a is the only parameter here
    
return $a $b;
}
?>


Constant Typo Looks Like A Variable

[Since 2.2.0] - [ -P Variables/ConstantTypo ] - [ Online docs ]

A constant bears the same name as a variable. This might be a typo.

When the constant doesn't exist, PHP 8.0 yields a Fatal Error and stops execution. PHP 7.4 turns the undefined constant into its string equivalent.

<?php 
// Get an object or null
$object foo(); 

// PHP 8.0 stops here, with a Fatal Error
// PHP 7.4 makes this a string, and the condition is always true
if (!empty(object)) {
    
// In PHP 7.4, this is not protected by the condition, and may yield an error.
    
$object->doSomething();
}
?>


This analysis is case sensitive.

Final Private Methods

[Since 2.2.0] - [ -P Classes/FinalPrivate ] - [ Online docs ]

PHP's private methods cannot be overwritten, as they are dedicated to the current class. That way, the final keyword is useless.

PHP 8.0 warns when it finds such a method.

<?php 
class foo {
    
// Final and private both prevent child classes to overwrite the method
    
final private function bar() {}

    
// Final and protected (or public) keep this method available, but not overwritable
    
final protected function bar() {}
}
?>



See also Final Keyword

Array_Map() Passes By Value

[Since 2.2.0] - [ -P Structures/ArrayMapPassesByValue ] - [ Online docs ]

array_map() requires the callback to receive elements by value. Unlike array_walk(), which accepts by value or by reference, depending on the action taken.

PHP 8.0 and more recent emits a Warning

<?php 
// Example, courtery of Juliette Reinders Folmer
function trimNewlines(&$line$key) {
    
$line str_replace(array(\n\r), ''$line);
}

$original = [
    
text\n\n,
    
text\n\r
];

$array $original;
array_walk($array'trimNewlines');

var_dump($array);

array_map('trimNewlines'$original, [01]);
?>



See also array_map

Missing __isset() Method

[Since 2.2.0] - [ -P Php/MissingMagicIsset ] - [ Online docs ]

When using empty() on magic properties, the magic method __isset() must be implemented.

<?php 
class foo {
    function 
__get($name) { return 'foo'; }
    
// No __isset method
}

// Return TRUE, until __isset() exists
var_dump(
   empty((new 
foo)->bar);
);
?>



See also When empty is not empty

Modify Immutable

[Since 2.2.0] - [ -P Attributes/ModifyImmutable ] - [ Online docs ]

A class, marked as immutable, is being modified.

This attribute is supported as a PHPdoc comment, `@immutable, and as a PHP 8.0 attribute.

<?php 
/** @Immutable */
#[Immutable]
class 
{
    public 
$x 1$y$z;
}

$x = new X;
// $x->x is modified, while it should not
$x->$x->z;

// $x->z is read only, as expected
?>



See also phpstorm-stubs/meta/attributes/Immutable.php, PhpStorm 2020.3 EAP \#4: Custom PHP 8 Attributes

Reserved Match Keyword

[Since 2.2.1] - [ -P Php/ReservedMatchKeyword ] - [ Online docs ]

Match is a new instruction in PHP 8.0. For that, it becomes a reserved keyword, and cannot be used in various situations.

<?php 
// Match as a standalone keyword
use as Match;

// No more use as a typehint
function foo(match $a ) : match {}
$a instanceof match; 

// No use as method name or function name
matCH(a4) ;
$method->MAtch();
$static::MATch();

// Match in a Fully qualified name is OK
b\match ;

// Match a property name or a class constant is OK
$match->maTCH;
C::MATCH;
?>



See also Match expression V2

Avoid get_object_vars()

[Since 2.2.1] - [ -P Php/AvoidGetobjectVars ] - [ Online docs ]

get_object_vars() changes behavior between PHP 7.3 and 7.4. It also behaves different within and outside a class.

<?php 
// Illustration courtesy of Doug Bierer
$obj = new ArrayObject(['A' => 1,'B' => 2,'C' => 3]);
var_dump($obj->getArrayCopy());
var_dump(get_object_vars($obj));
?>



See also get_object_vars script on 3V4L, The Strange Case of ArrayObject

Only Container For Reference

[Since 2.2.0] - [ -P Php/OnlyVariableForReference ] - [ Online docs ]

When a PHP function requires an argument to be a reference, it cannot be called with a literal value.

The call must be made with a variable, or any assimilated data container : array, property or static property.

<?php 
// This is not possible
preg_match('/a/'$string, []);

// This is working
preg_match('/a/'$string$r);
?>



See also Passing arguments by reference

Cannot Use Static For Closure

[Since 2.2.2] - [ -P Functions/CannotUseStaticForClosure ] - [ Online docs ]

The reported closures and arrow functions cannot use the static keyword.

Closures that makes use of the $this pseudo-variable cannot use the static keyword, at it prevents the import of the $this context in the closure. It will fail at execution.

Closures that makes use of the bindTo() method, to change the context of execution, also cannot use the static keyword. Even if $this is not used in the closure, the static keyword prevents the call to bindTo().

<?php 
class {
    function 
foo() {
        
// Not possible, $this is now undefined in the body of the closure
        
static function () { return $this->a;};
    }

    function 
foo2() {
        
// Not possible, $this is now undefined in the body of the arrow function
        
static fn () => $this->a;
    }
    
    function 
foo3() {
        
// Not possible, the closure gets a new context before being called.
        
$a = static fn () => $ba;
        
$this->foo4($a);
    }
    
    function 
foo4($c) {
        
$c->bindTo($this);
        
$c();
    }
    
}
?>



See also Static anonymous functions

Only First Byte

[Since 2.2.2] - [ -P Structures/OnlyFirstByte ] - [ Online docs ]

When assigning a char to a string with an array notation, only the first byte is used.

<?php 
$str 'xy';  

    
// first letter is now a
    
$str[0] = 'a';

    
// second letter is now b, c is ignored
    
$str[1] = 'bc';
?>



See also String access and modification by character

Restrict Global Usage

[Since 2.2.2] - [ -P Php/RestrictGlobalUsage ] - [ Online docs ]

$GLOBALS access, as whole, is forbidden. In PHP 8.1, it is not possible to this as a variable, but only access its individual values.

<?php 
// Example extracted from the RFC (see link below)
// Continues to work:
foreach ($GLOBALS as $var => $value) {
    echo 
$var ' => ' $value PHP_EOL;
}

// Generates compile-time error:
$GLOBALS = [];
$GLOBALS += [];
$GLOBALS =& $x;
$x =& $GLOBALS;
unset(
$GLOBALS);
?>




See also Restrict $GLOBALS usage

Inherited Property Type Must Match

[Since 2.2.2] - [ -P Classes/InheritedPropertyMustMatch ] - [ Online docs ]

Properties that are inherited between classes must match.

This affect public and protected properties. Private properties are immune to this rule, as they actually are distinct properties.

<?php 
class {
    private 
A $a;
    protected array 
$b;
    public 
$c;
}

class 
extends {
    private 
A $a;       // OK, as it is private
    
protected int $b;   // type must match with the previous definition
    
public $c;          // no type behaves just like a type : it must match too.
}
?>



See also Properties

No Object As Index

[Since 2.2.2] - [ -P Structures/NoObjectAsIndex ] - [ Online docs ]

PHP accepts objects as index, though it will report various error messages when this happens.

<?php 
$s 'Hello';
$o = new stdClass();

try {
    
$s[$o] = 'A';
} catch (
\Throwable $e) {
    echo 
$e->getMessage(), \n;
    
//Cannot access offset of type stdClass on string
}
?>


Thanks to George Peter Banyard for the inspiration.


See also Use an object as an offet

Class Overreach

[Since 2.2.2] - [ -P Classes/ClassOverreach ] - [ Online docs ]

An object of class A may reach any private or protected properties, constants or methods in another object of the same class. This is a PHP feature, though seldom known.

This feature is also called class invasion.

<?php 
class {
    private 
$p 1;
    
    public function 
foo(A $a) {
        return 
$a->1;
    }
}

echo (new 
A)->foo(new A);
?>



See also Visibility from other objects, spatie/invade

Inherited Static Variable

[Since 2.2.2] - [ -P Variables/InheritedStaticVariable ] - [ Online docs ]

Static variables are distinct when used in an inherited static method. In PHP 8.1, the static variable will also be inherited, and shared between the two methods, like a static property.

<?php 
// Code extracted from the RFC
class {
    public static function 
counter() {
        static 
$i 0;
        return ++
$i;
    }
}
class 
extends {}
 
var_dump(A::counter()); // int(1)
var_dump(A::counter()); // int(2)
var_dump(B::counter()); // int(1)
var_dump(B::counter()); // int(2)
?>



See also PHP RFC: Static variables in inherited methods

Enum Usage

[Since 2.2.2] - [ -P Php/EnumUsage ] - [ Online docs ]

PHP's enumeration. Introduced in PHP 8.1.

<?php 
enum {
    case 
A;
    case 
B;
}
?>




See also Enumerations in PHP

PHP 8.1 Removed Directives

[Since 2.2.3] - [ -P Php/Php81RemovedDirective ] - [ Online docs ]

List of directives that are removed in PHP 8.1.

In PHP 8.1, the following directives were removed :

  • `mysqlnd.fetch_data_copy`
  • `filter.default`
  • `filter.default_options`
  • `auto_detect_line_endings`
  • `oci8.old_oci_close_semantics`

You can detect valid directives with ini_get(). This native function will return false, when the directive doesn't exist, while actual directive values will be returned as a string.

See PHP RFC: Deprecations for PHP 8.1.

Htmlentities Using Default Flag

[Since 2.2.3] - [ -P Structures/HtmlentitiescallDefaultFlag ] - [ Online docs ]

htmlspecialchars(), htmlentities(), htmlspecialchars_decode(), html_entity_decode() and get_html_translation_table(), are used to prevent injecting special characters in HTML code. As a bare minimum, they take a string and encode it for HTML.

The second argument of the functions is the type of protection. The protection may apply to quotes or not, to HTML 4 or 5, etc. It is highly recommended to set it explicitly.

In PHP 8.1, the default value of this parameter has changed. It used to be ENT_COMPAT and is now ENT_QUOTES | ENT_SUBSTITUTE . The main difference between the different configuration is that the single quote, which was left intact so far, is now protected HTML style.

<?php 
$str 'A quote in <b>bold</b> : \' and ';

// PHP 8.0 outputs, without depending on the php.ini: A quote in &lt;b&gt;bold&lt;/b&gt; : ' and &quot;
echo htmlentities($str);

// PHP 8.1 outputs, while depending on the php.ini: A quote in &lt;b&gt;bold&lt;/b&gt; : &#039; and &quot;
echo htmlentities($str);
?>



See also htmlentities and htmlspecialchars

Openssl Encrypt Default Algorithm Change

[Since 2.2.3] - [ -P Php/OpensslEncryptAlgoChange ] - [ Online docs ]

openssl_pkcs7_encrypt() and openssl_cms_encrypt() will now default to using AES-128-CBC rather than RC2-40. The RC2-40 cipher is considered insecure and not enabled by default in OpenSSL 3.

This means that the default argument of OPENSSL_CIPHER_RC2_40 is replaced by OPENSSL_CIPHER_AES_128_CBC.

<?php 
// extracted from the PHP documentation
// encrypt it
if (openssl_pkcs7_encrypt(msg.txtenc.txt$key,
    array(
To => nighthawk@example.com// keyed syntax
          
FromHQ <hq@example.com>, // indexed syntax
          
Subject => Eyes only))) {
    
// message encrypted - send it!
    
exec(ini_get(sendmail_path) . < enc.txt);
}
?>


PHP 8.1 Removed Constants

[Since 1.6.8] - [ -P Php/Php81RemovedConstant ] - [ Online docs ]

The following PHP native constants were disabled in PHP 8.1. They are not removed, but they have no more effect.

  • MYSQLI_STMT_ATTR_UPDATE_MAX_LENGTH
  • MYSQLI_STORE_RESULT_COPY_DATA
  • FILE_BINARY
  • FILE_TEXT
  • FILTER_SANITIZE_STRING


See also PHP RFC: Deprecations for PHP 8.1

Wrong Argument Name With PHP Function

[Since 2.2.3] - [ -P Functions/WrongArgumentNameWithPhpFunction ] - [ Online docs ]

The name of the argument provided is not a valid parameter name for that PHP function. Named arguments also works with PHP native function.

<?php 
// those are the valid names
strcmp(string1'a'string2'b');

// those are not the valid names
strcmp(string'a'stringToo'b');
?>

Duplicate Named Parameter

[Since 2.2.3] - [ -P Functions/DuplicateNamedParameter ] - [ Online docs ]

Two parameters have the same name in a method call. This will yield a Fatal error at execution time.

<?php 
function foo($a$b) {}

// parameters are all distinct
foo(a:1b:2);

// parameter a is double
foo(a:1a:1);
?>



See also Function arguments

PHP Native Class Type Compatibility

[Since 2.2.4] - [ -P Php/NativeClassTypeCompatibility ] - [ Online docs ]

PHP eventually enforces the method compatibility with native classes and interfaces.

This means that classes that extends those native PHP classes or interfaces must declare compatible types. They can't skip the type like it was the case before.

<?php 
class extends RecursiveFilterIterator 

    
// fully declared method
    
function hasChildren(): bool {
        return 
true;
    }

    
// `key() <https://www.php.net/key>`_ returns mixed. Omitting the type used to be quiet
    
function `key() <https://www.php.net/key>`{}
    
    
//    #[\ReturnTypeWillChange] is taken into account 

}
?>


This is needed for compatibility with PHP 8.1. This is probably good for older versions too, although invisible.

The attribute ReturnTypeWillChange is taken into account. Note that it is not detected when auditing with PHP < 8.0, so it won't have effect until this version. The attribute was declared in PHP 8.1, though it is also taken into account when auditing with PHP 8.0.


See also method-compatibility

Missing Attribute Attribute

[Since 2.2.4] - [ -P Attributes/MissingAttributeAttribute ] - [ Online docs ]

While not strictly required it is recommended to create an actual class for every attribute.

<?php 
namespace Example;

use 
Attribute;

#[
Attribute]
class 
MyAttribute
{
}

#Missing the above attribute
class MyOtherAttribute
{
}
?>



See also Declaring Attribute Classes

$FILES full_path

[Since 2.2.4] - [ -P Php/FilesFullPath ] - [ Online docs ]

A new index 'full_path' was added to the $_FILES to handle directory uploads. This was added in PHP 8.1, and is not available before.

<?php 
// list uploaded files in a directory
print_r($_FILES['full_path']);
?>



See also PHP 8.1: $_FILES: New full_path value for directory-uploads

No Null For Native PHP Functions

[Since 2.2.5] - [ -P Php/NoNullForNative ] - [ Online docs ]

Null is not acceptable anymore as an argument, for PHP native functions that require a non-nullable argument.

Until PHP 8.1, it was magically turned into an empty string.

<?php 
$haystack 'abc';
// $needle was omitted...
echo strpos($haystack$needle);
?>



See also PHP RFC: Deprecate passing null to non-nullable arguments of internal functions

Calling Static Trait Method

[Since 2.2.5] - [ -P Php/CallingStaticTraitMethod ] - [ Online docs ]

Calling directly a static method, defined in a trait is deprecated. It emits a deprecation notice in PHP 8.1.

<?php 
trait {
    public static function 
t() {
        
//
    
}
}

T::t();
?>


Calling the same method, from the class point of view is valid.


See also PHP RFC: Deprecations for PHP 8.1

No Referenced Void

[Since 2.2.4] - [ -P Functions/NoReferencedVoid ] - [ Online docs ]

There is no point returning a reference with a void type. This is now reported as deprecated in PHP 8.1.

<?php 
function &test(): void {}
?>



See also PHP RFC: Deprecations for PHP 8.1

PHP Native Interfaces and Return Type

[Since 2.3.0] - [ -P Php/JsonSerializeReturnType ] - [ Online docs ]

Native PHP interface which define a type, expect the derived methods to use the same time. In particular, a mixed return type was added to the jsonSerialize() of the JsonSerialize PHP interface.

In PHP 8.1, the mixed return type is now enforced, and a deprecated notice is displayed.

One solution is to add the good return type, or to use the `#[ReturnTypeWillChange]` attribute.

<?php 
class MyJsonSerialize implements jsonserialize 
        function 
json`serialize() <https://www.php.net/serialize>`int {}
    }
?>


This rule covers the following interfaces :

+ ArrayAccess
+ Countable
+ Exception
+ FilterIterator
+ Iterator
+ JsonSerializable
+ php_user_filter
+ SessionHandlerInterface


See also JsonSerializable::jsonSerialize

Final Constant

[Since 2.3.0] - [ -P Php/FinalConstant ] - [ Online docs ]

Final modifier for class constants.

<?php 
class MyClass {
    final const 
1// This constant cannot be redefined
    
    
const 2// This constant might be redefined in a child
    
    
private const 3// This private, and can't be made final, because it is not available anyway
}
?>


See also https://www.php.net/manual/en/language.oop5.final.php, https://php.watch/versions/8.1/final-class-const

Never Typehint Usage

[Since 2.3.0] - [ -P Php/NeverTypehintUsage ] - [ Online docs ]

Never is a typehint, which characterize methods that never return a value. It will either terminate the execution or throw an exception.

<?php 
function redirect(string $url): never {
    
header('Location: ' $url);
    exit();
}
?>



See also The “never” Return Type for PHP

PHP 8.1 Typehints

[Since 2.3.0] - [ -P Php/PHP81scalartypehints ] - [ Online docs ]

A new scalar typehint was introduced : never.

It can't be used before PHP 8.1, and will be confused with classes or interfaces.

<?php 
function test() : never
{
    exit();
}
?>



See also PHP RFC: noreturn type

PHP 8.0 Typehints

[Since 2.3.0] - [ -P Php/PHP80scalartypehints ] - [ Online docs ]

New scalar typehints were introduced : mixed and false.

They can't be used before PHP 8.0, and will be confused with classes or interfaces, or generate a parse error.

<?php 
function test(mixed $a) : false|other
{
    
//....
}
?>



See also PHP RFC: noreturn type

Named Parameter Usage

[Since 2.3.0] - [ -P Php/NamedParameterUsage ] - [ Online docs ]

Named parameters is a way to call a method, by specifying the name of the argument, instead of their position order.

Named parameters works for both custom methods and PHP native functions.

<?php 
// named parameters
foo(12);
foo(21);

// positional parameters
foo(12);

function 
foo($a$b) { }
?>


First Class Callable

[Since 2.3.0] - [ -P Php/FirstClassCallable ] - [ Online docs ]

A syntax using ellipsis was introduced to make it easy to make a method into a callable.

<?php 
// Using ellipsis as the only argument
$a $object->method(...);

// Old style equivalent
$a = array($object'method');

// calling the closure.
$a();
?>



See also PHP RFC: First-class callable syntax

New Functions In PHP 8.1

[Since 2.3.0] - [ -P Php/Php81NewFunctions ] - [ Online docs ]

New functions are added to new PHP version.

The following functions are now native functions in PHP 8.1. It is compulsory to rename any custom function that was created in older versions. One alternative is to move the function to a custom namespace, and update the use list at the beginning of the script.



PHP 8.1 Removed Functions

[Since 2.3.0] - [ -P Php/Php81RemovedFunctions ] - [ Online docs ]

The following PHP native functions were deprecated in PHP 8.1, and will be removed in PHP 9.0.


Never Keyword

[Since 2.3.0] - [ -P Php/NeverKeyword ] - [ Online docs ]

Never becomes a PHP keyword. It is used for typing functions which never returns anything (either dies or throw an exception).

It should be avoided in namespaces, classes, traits and interfaces. Methods, constants and functions are OK.

<?php 
// This is OK
function never() { } 

// This is no OK
class never {  }
?>



See also never, PHP RFC: noreturn type

Mixed Keyword

[Since 2.3.0] - [ -P Php/MixedKeyword ] - [ Online docs ]

Never becomes a PHP keyword. It is used for typing functions which never returns anything (either dies or throw an exception).

It should be avoided in classes, traits and interfaces. Methods, anonymous classes (sic), namespaces and functions are OK.

Setting a `never` class in a namespaces doesn't make it legit.

<?php 
// This is OK
function never() { } 

// This is no OK
class never {  }
?>



See also mixed

Mixed Typehint Usage

[Since 2.3.0] - [ -P Php/MixedUsage ] - [ Online docs ]

Usage of the mixed typehint.

<?php 
function foo() : mixed {
    switch(
rand(03)) {
        case 
0:
            return 
false;
            
        case 
1
            return 
'a';
            
        case 
2:
            return [];
            
        default:
            return 
null;
    }
}
?>


See also Type declarations.

False To Array Conversion

[Since 2.3.0] - [ -P Php/FalseToArray ] - [ Online docs ]

The auto vivification of false is deprecated. This feature is the automagical conversion of a boolean into an array, if needed.

<?php 
$a false;

//valid in PHP
$a[3] = 1;
?>


Until PHP 8.1, this was possible. This feature is deprecated in PHP 8.1, and will be removed in PHP 9.0.


See also Autovivification from false

Float Conversion As Index

[Since 2.3.1] - [ -P Arrays/FloatConversionAsIndex ] - [ Online docs ]

Only integers and strings are possible types when used for array index. Until PHP 8.1, floats were converted to integer by truncation. Since PHP 8.1, a deprecated message is emitted.

The implicit conversion of float to int which leads to a loss in precision is now deprecated. This affects array keys, int type declarations in coercive mode, and operators working on integers.

<?php 
$a = [];
$a[15.5]; // deprecated, as key value loses the 0.5 component
$a[15.0]; // ok, as 15.0 == 15
?>



See also Implicit incompatible float to int conversions

Cannot Call Static Trait Method Directly

[Since 2.3.1] - [ -P Traits/CannotCallTraitMethod ] - [ Online docs ]

From the migration docs : Calling a static method, or accessing a static property directly on a trait is deprecated. Static methods and properties should only be accessed on a class using the trait.

<?php 
trait { static public function t() {}}
 
a::t();
// OK
 
t::t();
 
//Calling static trait method t::t is deprecated, it should only be called on a class using the trait
 
 
class {
    use 
t;
 }
?>



See also Calling a static element on a trait

Nested Attributes

[Since 2.3.1] - [ -P Attributes/NestedAttributes ] - [ Online docs ]

Nested attribute are attribute in attributes.

<?php 
// Extracted from PHP 8.1 addendum (https://www.php.net/releases/8.1/en.php#new_in_initializers)
class User
{
    #[
\Assert\All(
        new 
\Assert\NotNull,
        new 
\Assert\Length(min6))
    ]
    public 
string $name '';
}
?>


Nested attributes are not available in PHP 8.0 and older. It is reported as an invalid constant expression.


See also PHP RFC: New in initializers, `New initializers`

New Initializers

[Since 2.3.1] - [ -P Php/NewInitializers ] - [ Online docs ]

Parameters, static variables and global constants may be initialized with an object.

<?php 
function foo$a = new A) {
    static 
$static = new B;

}

const 
= new C;
?>


This feature is available in PHP 8.1 and more recent. It is reported as an invalid constant expression in older PHP versions.


See also PHP RFC: New in initializers, `Nested Attributes`_

Promoted Properties

[Since 2.3.1] - [ -P Classes/PromotedProperties ] - [ Online docs ]

Promoted properties is a way to declare the properties within the constructor, and have them assigned to the constructing value at instantiation.

<?php 
class CustomerDTO
    
{
        public function 
__construct(
            public 
string $name
            public 
string $email
            public 
DateTimeImmutable $birth_date,
        ) {}
    }
?>



See also Constructor Promotion, PHP 8: Constructor property promotion

Overwritten Foreach Var

[Since 2.3.2] - [ -P Structures/OverwrittenForeachVar ] - [ Online docs ]

When using standard blind variable names, nested foreach may lead to overwriting the variables.

Careful coding may take advantage of that feature. Though, it tends to be error prone, and will generate bugs if the code is refactored.

<?php 
foreach($array as $key => $value) {
    foreach(
$array as $key2 => $value) {
        
// $value is now the one of the 2nd foreach, not the first.
        
    
}
}
?>


Cant Overload Constants

[Since 2.3.2] - [ -P Interfaces/CantOverloadConstants ] - [ Online docs ]

It was not possible to overload class constants within a class, when the constant was defined in an interface.

<?php 
interface 
    const 
1;
}

//This lints, but doesn't executin in PHP 8.0 and older.
class implements 
    const 
1;
}
?>



See also `interface constants `

Intersection Typehint

[Since 2.3.3] - [ -P Php/Php81IntersectionTypehint ] - [ Online docs ]

Intersection typehints allows the combination of several typehint for the same argument or return value.

Several typehints are specified at the same place as a single one. The different values are separated by a ampersand character & .

<?php 
class Number {
    private 
A&B $object;
}
?>


Intersection types are a PHP 8.1 new feature.

See also PHP RFC: Pure intersection types, Type declarations, How the New Intersection Types in PHP 8.1 Give You More Flexibility

Recycled Variables

[Since 2.3.3] - [ -P Variables/RecycledVariables ] - [ Online docs ]

A recycled variable is used for two distinct missions in a method. There is usually a first

<?php 
function foo() {
    
$variable initial;        // first initialisation
    
$variable goo($variable);   // processing the variable
    
hoo($variable);               // sending the variable to a final destination
    
    
$variable second ;        // second initialisation
    
hoo2($variable);              // sending the variable to a different final destination
}
?>


See also Please Don’t Recycle Local Variables

Check Division By Zero

[Since 2.3.3] - [ -P Structures/CheckDivision ] - [ Online docs ]

Always check before dividing by a value. If that value is cast to 0, PHP might stop the processing with an exception, or keep processing it with 0 as a result. Both will raise problems.

The best practise is to check the incoming value before attempting the division. On possible alternative is to catch the DivisionByZero exception, that PHP 8.0 and more recent will raise.

<?php 
// Check the value before usage
function foo($a 1) {
    if (
$a !== 0) {
        return 
42 $a;
    } else {
        
// process an error
    
}
}

// Check the value after usage (worse than the above)
function foo($a 1) {
    try {
        return 
42 $a;
    } catch (
DivisionByZero) {
        
// fix the situation now
    
}
}

// This might fails with a division by 0
function foo($a 1) {
    return 
42 $a;
}
?>


See also DivisionByZeroError

Readonly Usage

[Since 2.3.5] - [ -P Classes/ReadonlyUsage ] - [ Online docs ]

Usage of the readonly option on class properties.

<?php 
?>


See also Readonly properties

Dont Reuse Foreach Source

[Since 2.3.5] - [ -P Structures/DontReuseForeachSource ] - [ Online docs ]

It is dangerous to reuse the same variable inside a loop that use it as a source.

PHP actually takes a copy of the source, so the foreach() loop is not affected by the modification. On the other hand, the source of the loop is modified after the loop (and actually, also during), which may come as a surprise to a later coder.

<?php 
$properties = [];
foreach (
$values as $i => $vars) {

    
// $values is used again here, now as a blind variable
    
foreach ($vars as $class => $values) {
        foreach (
$values as $name => $v) {
            
$properties[$class][$name][$i] = $v;
        }
    }
}
?>


Unreachable Method

[Since 2.3.6] - [ -P Classes/UnreachableMethod ] - [ Online docs ]

A method that is never called from the code.

The method has the following characteristics :
+ not private, aka public or protected
+ The direct class is never instantiated
+ All children classes overwrite this method
+ parent:: is never used to reach it

Then, this class is actually dead code.

<?php 
class {
    protected function 
foox() {}
}

class 
xx extends {
    protected function 
foox() {}
}
?>


Unfinished Object

[Since 2.3.6] - [ -P Classes/UnfinishedObject ] - [ Online docs ]

Some of the properties are not assigned a value before or at constructor time. Then, they might be called when one of the other public method is called, and yield a fatal error.

<?php 
class {
    private 
$p;
    private 
$p2;
    
    function 
__construct($p) {
        
$this->$p;
        
// $p2 is not assigned
    
}
    
    function 
foo() {
        
$this->p->goo();
        
// This is not valid
        
$this->p2->goo();
    }
}
?>



See also Compulsory parameters should be required in your constructor

Use class_alias()

[Since 2.3.6] - [ -P Php/UseClassAlias ] - [ Online docs ]

class_alias() is a PHP features, that allows the creation of class alias, at execution time.

Those class aliases are application wide, as they are valid everywhere, yet they have a lower precedence over the use expression. This means that even when a class_alias() was called, the local use expression will have right of execution.

<?php 
// static type of aliasing
use as c;

class 
{}
class_alias('a''b');

new 
b;
?>



See also class_alias

Undefined Enumcase

[Since 2.3.6] - [ -P Enums/UndefinedEnumcase ] - [ Online docs ]

The enumeration case does not exists. It may also be a constant.

<?php 
enum theEnum {
    case 
A// an enum case
    
    // a constant
    
const 1;
}

function 
foo(theEnum $a) {}

foo(theEnum::A);
foo(theEnum::C);
?>

Dont Add Seconds

[Since 2.3.9] - [ -P Structures/DontAddSeconds ] - [ Online docs ]

Avoid adding seconds to a date, and use DateTime::modify to add an intervalle.

This method will handle situations like daylight savings, leap seconds and even leap days.

<?php 
// Tomorrow, same time 
$tomorrow = new DateTime('now')->modify('+1 day');

// Tomorrow, but may be not at the same hour
$tomorrow date('now') + 86400;
?>



See also DateTime::modify, datetime

Use Constants As Returns

[Since 2.3.9] - [ -P Functions/UseConstantsAsReturns ] - [ Online docs ]

When a native PHP function returns only constants, it is recommended to use those constants to identify the returned values.

<?php 
if (preg_last_error() != PREG_NO_ERROR ) {
    
// An error occured with the last Regex call
}

// Who will guess PREG_JIT_STACKLIMIT_ERROR ? 
if (preg_last_error() == ) {
    
// An error occured with the last Regex call
}
?>


Identical Variables In Foreach

[Since 2.3.9] - [ -P Structures/IdenticalVariablesInForeach ] - [ Online docs ]

Do not use the same name for foreach() source and one of its blind variable.

Foreach() makes a copy of the original data while working on it : this prevents any interference. Yet, when the source and the blind variable is the same, the source will have changed after the loop.

<?php 
// classic way to use a foreach loop
foreach($array as $key => $value) {
    
// doSomething with $key and $value
}

// unusual way to end up with a name conflict
foreach($a as $a => [$b$c$a]) {
    
// doSomething with $a and $a, $b, $c
}


// classic way to use a foreach loop
foreach($a as $a => $b) {
    
// doSomething with $a and $a
}
// Now, after the loop, $a is an integer or a string!
?>


Cant Overwrite Final Constant

[Since 2.3.9] - [ -P Classes/CantOverwriteFinalConstant ] - [ Online docs ]

A constant may be final, and can't be overwritten in a child class.

<?php 
class extends 
    const 
1;
    const 
2;
}

class 

    final const 
3;
    private const 
PRI 5// Private can't be final
    
const 4;
}
?>

String Int Comparison

[Since 2.3.9] - [ -P Php/StringIntComparison ] - [ Online docs ]

While PHP allows direct comparison of integer and strings, with some type conversion, the rules of conversion changed in PHP 8.0. This lead to a change in behavior for comparison.

In particular, strings that are equal to 0, or empty strings, have changed.

This doesn't affect identity comparison, since the type is initially checked.

<?php 
PHP 7   PHP 8
var_dump
(== 0);      true     true
var_dump
(== 0.0);     true     true
var_dump
(== foo);   false   false

var_dump
('');       false   true
var_dump
('');       false   false
var_dump
(>= '');      true    true
var_dump
(<= '');      true    false?>



See also String to Number Comparison

ext/protobuf

[Since 0.8.4] - [ -P Extensions/Extprotobuf ] - [ Online docs ]

Extension Protobuf.

Protocol Buffers (a.k.a., protobuf) are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data.

<?php 
// Example extracted from https://developers.google.com/protocol-buffers/docs/reference/php-generated

// given a simple message 
//message Foo {}

/*
The protocol buffer compiler generates a PHP class called Foo. This class inherits from a common base class, Google\Protobuf\Internal\Message, which provides methods for encoding and decoding your message types, as shown in the following example:
*/

$from = new Foo();
$from->setInt32(1);
$from->setString('a');
$from->getRepeatedInt32()[] = 1;
$from->getMapInt32Int32()[1] = 1;
$data $from->serializeToString();
try {
  
$to->mergeFromString($data);
} catch (
Exception $e) {
  
// Handle parsing error from invalid data.
  
...
}
?>



See also Protocol Buffers, PHP Protocol Buffers, protobuf-php on packagist

Unsupported Operand Types

[Since 1.7.2] - [ -P Structures/UnsupportedOperandTypes ] - [ Online docs ]

This error is raised when trying to combine an array and a scalar value.

Always checks that the types are compatible with the planned operations.

<?php 
const MY_ARRAY 'error';

// This leads to the infamous Unsupported operand types error
$b MY_ARRAY + array(3,4);
?>


PHP detects this error at linting time, when using literal values. When static expression are involved, this error will appear at execution time.


See also PHP - Fatal error: Unsupported operand types [duplicate]

version_compare Operator

[Since 2.3.1] - [ -P Php/VersionCompareOperator ] - [ Online docs ]

version_compare()'s third argument is checked for value. The third argument specifies the operator, which may be only one of the following : `<`, `lt`, `<=`, `le`, `>`, `gt`, `>=`, `ge`, `==`, `=`, `eq`, `!=`, `<>`, `ne`. The operator is case sensitive.

Until PHP 8.1, it was silently reverted to the default value. It is a deprecated warning in PHP 8.1 and will be finalized in PHP 9.0. It is recommended to fix this parameter in any PHP version.

<?php 
// return true
var_dump(version_compare('2.0''2.1''<'));

// returns false
var_dump(version_compare('2.0''2.1''>'));

// returns NULL and might be interpreted as false
var_dump(version_compare('2.0''2.1''as'));
?>


PHP 8.1 Resources Turned Into Objects

[Since 2.2.0] - [ -P Php/Php81RemovesResources ] - [ Online docs ]

Multiple PHP native functions now return objects, not resources. Any check on those values with is_resource() is now going to fail.

The affected functions are the following :

+ finfo_open()
+ ftp_connect()
+ imap_open()
+ ldap_connect()
+ ldap_list()
+ ldap_search()
+ ldap_first_entry()
+ ldap_next_entry ()
+ ldap_read()
+ pg_connect()
+ pg_pconnect()
+ pg_query()
+ pg_execute ()
+ pg_lo_create()
+ pspell_config_create()
+ pspell_new()
+ pspell_new_personal()
+ pspell_new_config()


See also UPGRADING PHP 8.1

Do Not Cast To Int

[Since 0.10.6] - [ -P Php/NoCastToInt ] - [ Online docs ]

Do not cast floats values to int. Uses conversion functions like intval(), round(), floor() or ceil() to convert the value to integer, with known behavior.

Use functions like floor(), round() or ceil() : they use an explicit method for rounding, that helps keeping the side effects under control.

<?php 
// echoes 7!
    
echo (int) ( (0.1 0.7) * 10 );
?>



See also Integers

Constant Scalar Expression

[Since 0.8.4] - [ -P Php/ConstantScalarExpression ] - [ Online docs ]

Since PHP 5.6, it is possible to use expression with Constants and default values. One may only use simple operators.

<?php 
const THREE 2;
const ARRAY = array(
1,2,3);

// dynamic version
define('ARRAY', array(1,2,3));

// constant scalar expression are available for default values
function foo($a M_PI) {

}
?>


See also New features.

Could Be Spaceship

[Since 2.4.0] - [ -P Structures/CouldBeSpaceship ] - [ Online docs ]

The spaceship operator compares values and returns 0 for equality, 1 for superior and -1 for inferior.

It is the same as below, and prevents lots of code.

<?php 
if ($a) {
    return 
1;
} elseif (
$b) {
    return 
0;
} else {
    return -
1;
}
?>



See also spaceship operator, Remembering what spaceship operator do on comparison in PHP

Sylius usage

[Since 2.4.0] - [ -P Vendors/Sylius ] - [ Online docs ]

This analysis reports usage of the Sylius framework.

Sylius is an Open Source Headless eCommerce Platform for mid-market and enterprise brands that need custom solutions.

<?php 
declare(strict_types=1);

namespace 
App\Controller;

use 
Sylius\Bundle\ResourceBundle\Controller\ResourceController;
use 
Sylius\Component\Resource\ResourceActions;
use 
Symfony\Component\HttpFoundation\Request;
use 
Symfony\Component\HttpFoundation\Response;

class 
ProductController extends ResourceController
{
    public function 
showAction(Request $request): Response
    
{
        
$configuration $this->requestConfigurationFactory->create($this->metadata$request);

        
$this->isGrantedOr403($configurationResourceActions::SHOW);
        
$product $this->findOr404($configuration);

        
// some custom provider service to retrieve recommended products
        
$recommendationService $this->get('app.provider.product');

        
$recommendedProducts $recommendationService->getRecommendedProducts($product);

        
$this->eventDispatcher->dispatch(ResourceActions::SHOW$configuration$product);

        if (
$configuration->isHtmlRequest()) {
            return 
$this->render($configuration->getTemplate(ResourceActions::SHOW '.html'), [
                
'configuration' => $configuration,
                
'metadata' => $this->metadata,
                
'resource' => $product,
                
'recommendedProducts' => $recommendedProducts,
                
$this->metadata->getName() => $product,
            ]);
        }

        return 
$this->createRestView($configuration$product);
    }
}
?>


See also sylius

Unused Enumeration Case

[Since 2.4.0] - [ -P Enums/UnusedEnumCase ] - [ Online docs ]

Those are enumeration cases which are defined, yet not used.

<?php 
enum {
    case 
A;
    case 
C;
    
    const 
1;
}

function 
foo(x $a) {}

foo(x::A);
?>


The error message when the case is missing mentions the class constant : this is because enumeration cases and class constants use the same configuration. They are only distinguished by their definition, which, here, does not exists.

Useless Null Coalesce

[Since 2.4.0] - [ -P Structures/UselessNullCoalesce ] - [ Online docs ]

When the type system ensure the condition is never null, the operator becomes useless.

This is particularly true for properties (static or not) and returntype of methods and functions. And, to a lesser extend, to variables and parameters.

<?php 
function foo(A $a, ?B $b) {
    
// $a is never null, so this is OK
    
$a ?? 'a';
    
    
// $b might be null, so this is OK
    
$b ?? 'b';
}
?>



See also Null coalescing operator

Throw Raw Exceptions

[Since 2.4.0] - [ -P Exceptions/ThrowRawExceptions ] - [ Online docs ]

Avoid throwing raw exceptions : always refine the exception with an adapted name.

<?php 
// Throwing a raw exception
throw new exception('This is an error!');

class 
myException extends Exception {}

throw new 
myException('This is a distinguished error!');
?>


Thanks to Atif Shahab Qureshi for the inspiration.


See also Stop using regular exceptions in PHP!

Extensions yar

[Since 2.4.1] - [ -P Extensions/Extyar ] - [ Online docs ]

yar : Yet Another RPC framework.

<?php 
/* assume this page can be accessed by http://example.com/operator.php */

class Operator {

    
/**
     * Add two operands
     * @param interge 
     * @return interge
     */
    
public function add($a$b) {
        return 
$this->_add($a$b);
    }

    
/**
     * Sub 
     */
    
public function sub($a$b) {
        return 
$a $b;
    }

    
/**
     * Mul
     */
    
public function mul($a$b) {
        return 
$a $b;
    }

    
/**
     * Protected methods will not be exposed
     * @param interge 
     * @return interge
     */
    
protected function _add($a$b) {
        return 
$a $b;
    }
}

$server = new Yar_Server(new Operator());
$server->handle();
?>

Implicit Conversion To Int

[Since 2.4.2] - [ -P Structures/ImplicitConversionToInt ] - [ Online docs ]

PHP warns when a value is implicitely converted from float to int. This usually leads to a loss of precision and unexpected values.

The conversion happens in various situations in PHP lifecycle (extracted from the wiki article):

+ Bitwise OR operator |
+ Bitwise AND operator &
+ Bitwise XOR operator ^
+ Shift right and left operators
+ Modulo operator
+ The combined assignment operators of the above operators
+ Assignment to a typed property of type int in coercive typing mode
+ Argument for a parameter of type int for both internal and userland functions in coercive typing mode
+ Returning such a value for userland functions declared with a return type of int in coercive typing mode
+ Bitwise NOT operator ~
+ As an array key

<?php 
function foo(int $i) {}

//Implicit conversion from float 1.2 to int loses precision
foo(1.2);
?>


This features is applied to PHP 8.1 and later, yet it is also applicable to older versions of PHP.


See also PHP RFC: Deprecate implicit non-integer-compatible float to int conversions

Excimer

[Since 2.4.2] - [ -P Extensions/Extexcimer ] - [ Online docs ]

Excimer is a PHP 7.1+ extension that provides an interrupting timer and a low-overhead sampling profiler.

<?php 
$timer = new ExcimerTimer;
$timer->setInterval10 /* seconds */ );
$timer->setCallback( function () {
    throw new 
ExceptionThe allowed time has been exceeded );
} );
$timer->start();
do_expensive_thing();
?>


See also Excimer

Use Same Types For Comparisons

[Since 2.4.2] - [ -P Structures/UseSameTypesForComparisons ] - [ Online docs ]

Beware when using inequality operators that the type of the values are the same on both sites of the operators.

Different types may lead to PHP type juggling, where the values are first cast to one of the used types. Other comparisons are always failing, leading to unexpected behavior.

This applies to all inequality operators, as well as the spaceship operator.

<?php 
// Both are wrong, while one should be true (depending on when you read this)
var_dump('1995-06-08' < new DateTimeImmutable());
var_dump('1995-06-08' > new DateTimeImmutable());

enum 
int {
    case 
1;
    case 
2;
}

// Both are false as objects are compared, not their integer value
var_dump(x::x::B);
var_dump(x::x::B);

var_dump(x::A->value x::b->value);
var_dump(x::A->value x::b->value);
?>


This analysis skips comparisons between integers, floats and strings, as those are usually expected.

Thanks to Jordi Boggiano and Filippo Tessarotto.

Wrong Locale

[Since 2.4.2] - [ -P Structures/WrongLocale ] - [ Online docs ]

Checks the locale used in the code against a library.

<?php 
// what language ? 
setLocale(LC_ALL'hx');

// utf8 actually needs a - : utf-8
setLocale(LC_ALL'utf8');
?>


ext/pkcs11

[Since 2.4.2] - [ -P Extensions/Extpkcs11 ] - [ Online docs ]

In cryptography, PKCS #11 is one of the Public-Key Cryptography Standards. This extensions provides methods to create, read and check those keys.

<?php 
$key $session->generateKey(new Pkcs11\Mechanism(Pkcs11\CKM_AES_KEY_GEN), [
  
Pkcs11\CKA_CLASS => Pkcs11\CKO_SECRET_KEY,
  
Pkcs11\CKA_SENSITIVE => true,
  
Pkcs11\CKA_ENCRYPT => true,
  
Pkcs11\CKA_DECRYPT => true,
  
Pkcs11\CKA_VALUE_LEN => 32,
  
Pkcs11\CKA_KEY_TYPE => Pkcs11\CKK_AES,
  
Pkcs11\CKA_LABEL => Test AES,
  
Pkcs11\CKA_PRIVATE => true,
]);
?>

ext/spx

[Since 2.4.2] - [ -P Extensions/Extspx ] - [ Online docs ]

SPX, which stands for Simple Profiling eXtension, is just another profiling extension for PHP.

<?php 
while ($task get_next_ready_task()) {
  
spx_profiler_start();
  try {
    
$task->process();
  } finally {
    
spx_profiler_stop();
  }
}
?>



See also ``_

Parent Is Not Static

[Since 2.4.3] - [ -P Classes/ParentIsNotStatic ] - [ Online docs ]

The `parent` keyword behaves like `self`, not like `static`. It links to the parent of the defining expression, not to the one being called.

This may skip the parent of the calling class, and create a `Undefined method` call, or yield the wrong `::class` value. It may also skip a local version of the method.

<?php 
class {
}

class 
extends {
    function 
foo() {
        
parent::method();
    }

    
// method() is in the parent of Y, but not in the one of X.
    
function method() {
        print 
__METHOD__;
    }
}

class 
extends {}

(new 
y)->foo(); 
// print W::method
(new y)->method(); 
// print x::method
?>

No Magic Method For Enum

[Since 2.4.2] - [ -P Enums/NoMagicMethod ] - [ Online docs ]

Enumeration cannot have a magic method, nor a constructor.

<?php 
enum {
    function 
__construct($a) {}
}
?>


See also Enumeration Methods

No Readonly Assignation In Global

[Since 2.4.2] - [ -P Classes/NoReadonlyAssignationInGlobal ] - [ Online docs ]

When a property is marked readonly, it may only be assigned within the class of definition.

It cannot be assigned outside this class, in the global scope. It is also immune to class invasion.

<?php 
class {
    public readonly 
int $p;
    
    function 
foo() {
        
$this->-= 1// OK
        
        
$x = new x;
        
$x->1;     // Not OK, even if $x is of type x
    
}
}

$x = new x;
$x->1;     // Not OK
?>

Stomp

[Since 2.4.2] - [ -P Extensions/Extstomp ] - [ Online docs ]

This extension allows php applications to communicate with any Stomp compliant Message Brokers through easy object-oriented and procedural interfaces.

<?php 
$queue  '/queue/foo';
$msg    'bar';

/* connection */
try {
    
$stomp = new Stomp('tcp://localhost:61613');
} catch(
StompException $e) {
    die(
'Connection failed: ' $e->getMessage());
}

/* send a message to the queue 'foo' */
$stomp->send($queue$msg);

/* subscribe to messages from the queue 'foo' */
$stomp->subscribe($queue);

/* read a frame */
$frame $stomp->readFrame();

if (
$frame->body === $msg) {
    
var_dump($frame);

    
/* acknowledge that the frame was received */
    
$stomp->ack($frame);
}

/* close connection */
unset($stomp);
?>


See also Stomp

ext/CSV

[Since 2.4.2] - [ -P Extensions/Extcsv ] - [ Online docs ]

A small PHP extension to add/improve the handling of CSV strings.

<?php 
$fields = [
    
'Hello',
    
'World',
];

$output Hello,World;

var_dump($output === CSV::arrayToRow($fields));
var_dump(CSV::rowToArray($output));
?>


See also PHP csv extension

Overload Existing Names

[Since 2.4.2] - [ -P Namespaces/OverloadExistingNames ] - [ Online docs ]

Imported alias have precedence over existing ones, and as such, may replace existing features with unexpected ones.

This example shows how to replace strtolower() with strtoupper() while keeping the main code intact. This might be very confusing code.

<?php 
// Replacing a PHP classic with another one
use function strtoupper as strtolower;

echo 
strtolower('pHp'); 
// displays PHP
?>


This behavior is important for backward compatibility, and also to avoid naming conflicts when the coding has been done with a PHP installation which do not have some specific declaration. For example, a source may define an 'Event' class, which will be in conflict when the ext/event library is installed.

This feature is also useful to mock some native PHP structures, during tests.

This rule relies on the PDFF configuration to check for external existing structures.

Array Addition

[Since 2.4.2] - [ -P Structures/ArrayAddition ] - [ Online docs ]

Addition where one of the operands are arrays.

<?php 
$a = [1] + [,3];
?>


See also Combining arrays using + versus array_merge in PHP, Array operators

Retyped Reference

[Since 2.4.3] - [ -P Functions/RetypedReference ] - [ Online docs ]

A parameter with a reference may be typed differently, at the end of a method call.

It is possible for a referenced and typed parameter to be retyped during a method call. As such, the type of the used variable might both be checked and changed.

Using such syntax will lead to confusion in the code.

<?php 
$a = [1];
foo($a);
echo 
$a// Now, $a is a string

function foo(array &$a) {
    
$a NowI am a string;
}
?>


This works on all types, scalars or objects.

This rule will detect variables which are defined with a placeholder value, or even undefined, and are filled during the method call.

Wrong Type With Default

[Since 2.4.4] - [ -P Typehints/WrongTypeWithDefault ] - [ Online docs ]

The default value is not of the declared type.

For properties, this will generate an error as soon as the default value is used : this is before constructor call for properties, and when the argument is omitted for promoted properties.

For parameters, the error happens when the argument is omitted, and the default value is fetched. Otherwise, it won't happen.

<?php 
const 1;

class 
{
    private 
string $c A;
}

new 
B;
//Cannot assign string to property B::$c of type string
?>


This error is immediately detected when a literal value is used. It only happens when the default is a constant (class or global) or an expression, as those are only solved at execution time.


See also When does PHP check for Fatal error

Ice framework

[Since 2.4.4] - [ -P Extensions/Extice ] - [ Online docs ]

Ice - simple, fast and open-source PHP framework frozen in C-extension.

See also ice framework, ice framework : Hello world tutorial

Extensions/Exttaint

[Since 2.4.4] - [ -P Extensions/Exttaint ] - [ Online docs ]

Taint is a extension used to detect and track tainted string. It follows each assignation of the code and keeps track of its taint. And also can be used to spot sql injection vulnerabilities, shell inject, etc.

<?php 
$a trim($_GET['a']);

$file_name '/tmp' .  $a;
$output    "Welcome, {$a} !!!";

//Warning: main() [function.echo]: Attempt to echo a string that might be tainted
?>




See also taint, taint on github

Sprintf Format Compilation

[Since 2.4.5] - [ -P Structures/SprintfFormatCompilation ] - [ Online docs ]

The sprintf() format used yields an error.

This applies to printf(), sprintf(), vprintf(), vfprintf(), vsprintf(), sscanf(), fscanf()

<?php 
printf('%we3e'123); 
    
//Unknown format specifier
?>



See also sprintf

Invalid Date Scanning Format

[Since 2.4.5] - [ -P Structures/InvalidDateScanningFormat ] - [ Online docs ]

The format string used with Datetime::createFromFormat() method (or similar) contains unknown characters.

This won't raise an error, though the resulting values should be checked.

<?php 
// format is valid
$date datetimeimmutable::createFromFormat('d/m/Y'$a);
// When wrong, $date is false
// The errors are in datetimeimmutable::getLastErrors();

// X is not a valid character for 
$date datetimeimmutable::createFromFormat('d/X/Y'$a);
?>


Same Name For Property And Method

[Since 2.4.5] - [ -P Classes/PropertyMethodSameName ] - [ Online docs ]

A property and a method have the same name. While it is a valid naming scheme with PHP, it may lead to confusion while codeing.

Such naming collision may appear with words that are the same as a verb (for method) and as a noun (for property). For example, in English : query, work, debug, run, process, rain, polish, paint, etc,.

It may also happen during the life cycle of the class, as it is extended with new methods and properties, and little care is give to semantic meaning of the names, beyond the task at hand.

<?php 
class {
    public 
$foo;
    function 
foo() {}
}

$x = new X:
$x->$x->foo();
?>


It is recommended to avoid those collisions, and keep properties and methods named distinctly.

That problem do not happen to constants, which are mostly written uppercase. This rule is case-insensitive.


See also Words That Are Both Nouns And Verbs

No Private Abstract Method In Trait

[Since 2.4.5] - [ -P Traits/NoPrivateAbstract ] - [ Online docs ]

Method could not be both abstract and private in traits. This was changed in PHP 8.0 : the class might overwrite the trait's method, since it has precedence of it. And when the class doesn't overwrite it, then the class has an abstract method, and can't be instantiated.

<?php 
trait { abstract private function foo() ;}

 class 
{
    use 
t;
    
    
// valid
    
private function foo() {}
}

// This is a hidden abstract class
class {
    use 
t;
}
?>


This might be important for backward incompatibility, although it doesn't lint in previous versions.

See also Abstract Trait Members

Clone Constant

[Since 2.4.7] - [ -P Php/CloneConstant ] - [ Online docs ]

Cloning constant is only possible since PHP 8.1. Until that version, constants could not be an object, and as such, could not be cloned.

This is also valid with default values, however they are assigned to a variable, which falls back to the classic clone usage.

Backward compatibility is OK, since PHP compile such code, and only checks at execution time that the constant is an object.

<?php 
// new is available in constant definition, since PHP 8.2
const = new B();
$c = clone A;
?>



See also New in initializers

Ip

[Since 2.4.7] - [ -P Type/Ip ] - [ Online docs ]

List of IP in hardcode in the source.


<?php 
$ip '123.34.56.227';
$a '3627734755';
$a '000000000330.0000000072.00000000326.0343';
?>



See also IP converter