(PHP 8 >= 8.2.0)
This attribute is used to mark classes that allow dynamic properties.
Note: Although attributes themselves are not inherited, the effect of the
AllowDynamicPropertiesattribute 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.
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