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run code in 200+ php & hhvm versions
Bugs & Features
<?php class Super { public $child; function setChild(Child $child){ echo "setting child to super\n"; $this->child = $child; if($child->getSuper() !== $this) $child->setSuper($this); } function getChild(){ return $this->child; } } class Child { public $super; function setSuper(Super $super){ echo "setting super to child\n"; $this->super = $super; if($super->getChild() !== $this) $this->super->setChild($this); } function getSuper(){ return $this->super; } } $super = new Super; $child = new Child; $super->setChild($child); var_dump($super); $super = new Super; $child = new Child; $child->setSuper($super); var_dump($super);
based on MLhMW
Output for 5.3.19 - 7.2.6
setting child to super setting super to child object(Super)#1 (1) { ["child"]=> object(Child)#2 (1) { ["super"]=> *RECURSION* } } setting super to child setting child to super object(Super)#3 (1) { ["child"]=> object(Child)#4 (1) { ["super"]=> *RECURSION* } }