Predefined Attributes
PHP Manual

The AllowDynamicProperties attribute

Introduction

This attribute is used to mark classes that allow dynamic properties.

Note: Although attributes themselves are not inherited, the effect of the AllowDynamicProperties attribute is inherited. Child classes of a class marked with this attribute will also allow dynamic properties, even if they do not explicitly declare the attribute.

Class synopsis

#[\Attribute] final AllowDynamicProperties
/* Methods */
public __construct()

Examples

Dynamic properties are deprecated as of PHP 8.2.0, thus using them without marking the class with this attribute will emit a deprecation notice.

Example #1 AllowDynamicProperties with non-existing property

<?php
class DefaultBehaviour { }

#[\AllowDynamicProperties]
class ClassAllowsDynamicProperties { }

$o1 = new DefaultBehaviour();
$o2 = new ClassAllowsDynamicProperties();

$o1->nonExistingProp = true;
$o2->nonExistingProp = true;
?>

Output of the above example in PHP 8.2:

Deprecated: Creation of dynamic property DefaultBehaviour::$nonExistingProp is deprecated in file on line 10

Example #2 AllowDynamicProperties with non-existing property in inherited class

<?php
class DefaultBehaviour { }

#[\AllowDynamicProperties]
class ClassAllowsDynamicProperties { }

class InheritedClassAllowsDynamicProperties extends ClassAllowsDynamicProperties { }

$o1 = new DefaultBehaviour();
$o2 = new InheritedClassAllowsDynamicProperties();

$o1->nonExistingProp = true;
$o2->nonExistingProp = true;
?>

Output of the above example in PHP 8.2:

Deprecated: Creation of dynamic property DefaultBehaviour::$nonExistingProp is deprecated in file on line 12
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