Description:
------------
Made a simple recrusion function, sorting id by parentid, unsetting sorted values to shorten time of next recrusions. Unsetting inside foreach with deep arrays does work(!), but with simple array unset somehow stops the recrusion (first cicle will never finish its loop, the last loop will be made by latest child).

Tested with PHP 5.2.6 on Debian-40r3-amd64 and Windows Vista 32


Reproduce code:
---------------
<?php
function recrusion($array, $return, $pid=0, $level=0){
	foreach($array as $id=>$parent){
		if( $parent===$pid ){
			$return[$id]= $level;
			unset($array[$id]); /* remove this to get correct results */
			recrusion(&$array, &$return, $id, $level+1);
		}
	}
}
$return= array();
$array= array(1=>0,2=>1,3=>2,4=>3,5=>2,6=>2,7=>6,8=>6,9=>0,10=>0);
recrusion($array, &$return);
var_dump( $return );
?>

Expected result:
----------------
array(10) { [1]=> int(0) [2]=> int(1) [3]=> int(2) [4]=> int(3) [5]=> int(2) [6]=> int(2) [7]=> int(3) [8]=> int(3) [9]=> int(0) [10]=> int(0) }

Actual result:
--------------
array(6) { [1]=> int(0) [2]=> int(1) [3]=> int(2) [4]=> int(3) [9]=> int(0) [10]=> int(0) }