AvoidCircularReference.php

<?php
class A{
    public $obj;
    public function __destruct() {
        unset($this->obj);
    }
}
class B{
    public $obj;
    public function __destruct() {
        unset($this->obj);
    }
}

function getRecursiveReferenceObj(){
    $a = new A;
    $b = new B;
    $a->obj = $b;
    $b->obj = $a;
    return $a;
}

foreach (range(1, 100) as $i){
    $a = getRecursiveReferenceObj();
//    unset($a); // BAD: unset doesn't call __destruct
//    $a->__destruct(); // GOOD
    var_dump(memory_get_usage());
}