Deprecation rules

This document details the rules available in the Deprecation category.

Rule	Code
Deprecated Cast	deprecated-cast
Deprecated Shell Execute String	deprecated-shell-execute-string
Deprecated Switch Semicolon	deprecated-switch-semicolon
Explicit Nullable Param	explicit-nullable-param
No Underscore Class	no-underscore-class
No Void Reference Return	no-void-reference-return
Optional Parameter Before Required	optional-param-order

deprecated-cast

Detect the usage of deprecated type casts in PHP code.

In PHP 8.5, the following type casts have been deprecated:

• (integer): The integer cast has been deprecated in favor of (int).
• (boolean): The boolean cast has been deprecated in favor of (bool).
• (double): The double cast has been deprecated in favor of (float).
• (binary): The binary cast has been deprecated in favor of (string).

Requirements

• PHP version: >= 8.5.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"error"

Examples

Correct code

<?php

(int) $value;

Incorrect code

<?php

(integer) $value;

deprecated-shell-execute-string

Detect the usage of deprecated shell execute strings in PHP code.

In PHP 8.5, the shell execute string syntax (enclosed in backticks, e.g., `ls -l`) has been deprecated.

This rule identifies instances of shell execute strings and provides guidance on how to replace them with safer alternatives, such as using the shell_exec() function or other appropriate methods for executing shell commands.

Requirements

• PHP version: >= 8.5.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"error"

Examples

Correct code

<?php

shell_exec('ls -l');

Incorrect code

<?php

`ls -l`;

deprecated-switch-semicolon

Detect the usage of semicolon as a switch case separator.

In PHP 8.5, the use of a semicolon (;) as a case separator in switch statements has been deprecated.

Instead, the colon (:) should be used to separate case statements.

Requirements

• PHP version: >= 8.5.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"error"

Examples

Correct code

<?php

switch ($value) {
    case 1:
        // code for case 1
        break;
    case 2:
        // code for case 2
        break;
    default:
        // default case
        break;
}

Incorrect code

<?php

switch ($value) {
    case 1;
        // code for case 1
        break;
    case 2;
        // code for case 2
        break;
    default;
        // default case
        break;
}

explicit-nullable-param

Detects parameters that are implicitly nullable and rely on a deprecated feature.

Such parameters are considered deprecated; an explicit nullable type hint is recommended.

Requirements

• PHP version: >= 8.4.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"warning"

Examples

Correct code

<?php

function foo(?string $param) {}

function bar(null|string $param) {}

function baz(null|object $param = null) {}

Incorrect code

<?php

function foo(string $param = null) {}

function bar(string $param = NULL) {}

function baz(object $param = null) {}

no-underscore-class

Detects class, interface, trait, or enum declarations named _.

Such names are considered deprecated; a more descriptive identifier is recommended.

Requirements

• PHP version: >= 8.4.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"warning"

Examples

Correct code

<?php

class MyService {}

Incorrect code

<?php

class _ {}

no-void-reference-return

Detects functions, methods, closures, arrow functions, and set property hooks that return by reference from a void function. Such functions are considered deprecated; returning by reference from a void function is deprecated since PHP 8.0.

Requirements

• PHP version: >= 8.2.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"warning"

Examples

Correct code

<?php

function &foo(): string {
    // ...
}

Incorrect code

<?php

function &foo(): void {
    // ...
}

optional-param-order

            Detects optional parameters defined before required parameters in function-like declarations.

Such parameter order is considered deprecated; required parameters should precede optional parameters.

Requirements

• PHP version: >= 8.0.0

Configuration

Option	Type	Default
enabled	boolean	true
level	string	"warning"

Examples

Correct code

<?php

function foo(string $required, ?string $optional = null): void {}

Incorrect code

<?php

function foo(?string $optional = null, string $required): void {}