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<?php interface EntityInterface { } class EntityDecorator implements EntityInterface { public $subject; public function __construct(EntityInterface $subject) { $this->subject = $subject instanceof static ? $subject->getEntity() : $subject; } public function getEntity() { return $this->subject; } } class Entity implements EntityInterface {} class DecoratorA extends EntityDecorator {} class DecoratorB extends EntityDecorator {} $entity = new Entity(); var_dump($entity); $a = new DecoratorA($entity); var_dump($a); $b = new DecoratorB($a); var_dump($b); $b2 = new DecoratorB($b); var_dump($b2); $a2 = new DecoratorA($b2); var_dump($a2);
Output for 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
object(Entity)#1 (0) { } object(DecoratorA)#2 (1) { ["subject"]=> object(Entity)#1 (0) { } } object(DecoratorB)#3 (1) { ["subject"]=> object(DecoratorA)#2 (1) { ["subject"]=> object(Entity)#1 (0) { } } } object(DecoratorB)#4 (1) { ["subject"]=> object(DecoratorA)#2 (1) { ["subject"]=> object(Entity)#1 (0) { } } } object(DecoratorA)#5 (1) { ["subject"]=> object(DecoratorB)#4 (1) { ["subject"]=> object(DecoratorA)#2 (1) { ["subject"]=> object(Entity)#1 (0) { } } } }

preferences:
182.48 ms | 410 KiB | 5 Q