A simple example of memory leak in PHP

memory.php

<?php
class A {
	public $b;
	function __destruct() {
		//echo 'Уничтожается ', __CLASS__, PHP_EOL;

		// Looks like no difference between "unset" and "null" method
		//$this->b = null;
		unset($this->b);
	}
}

class B {
	public $a;

	function __destruct() {
		//echo 'Уничтожается ', __CLASS__, PHP_EOL;

		// Looks like no difference between "unset" and "null" method
		//$this->a = null;
		unset($this->a);
	}
}


for( $i = 0; $i < 1000; $i++ ) {
	$a = new A();
	$b = new B();

	$a->b = $b;
	$b->a = $a;

	// Delete objects "pointers"
	unset($a, $b);
	// But looks like they are exists.

	// With this method memory freeing correctly
	/*$a->b = null;
	$b->a = null;*/
}

echo memory_get_usage() / 1024, ' Kbytes used.', PHP_EOL;
die();