Description:
------------
When references between more objects, and on of objects is extended from domDocument, has reference to it caller object and use its property in vsprinf, reference to orignal object is destroyed or wrongly managed by garbageCollector... Really confusing -> could be workarounded by calling method of domDocument extended object from outside of referenced object...


Reproduce code:
---------------
<?php
class a {
  public $a = array(1,2,3);
  function aa($b){ $b->bb(); }
}
class b extends domDocument {
  public $a = NULL;
  function bb(){ $x = vsprintf('www %s www %s www %s www', $this->a->a) ; }
}
class x {
  public $a = null; public $b = null;
  function __construct() {
    $this->a = new a(); $this->b = new b();
    $this->b->a = $this->a;
    var_dump('Object a',$this->a, 'Object b',$this->b);
    $this->a->aa($this->b);
    var_dump('Object a',$this->a, 'Object b',$this->b);
  }
}
$x = new x();
?>

Expected result:
----------------
string(8) "Object a"
object(a)#2 (1) {
  ["a"]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
}
string(8) "Object b"
object(b)#3 (1) {
  ["a"]=>
  object(a)#2 (1) {
    ["a"]=>
    array(3) {
      [0]=>
      int(1)
      [1]=>
      int(2)
      [2]=>
      int(3)
    }
  }
}
string(8) "Object a"    <<< RIGHT
object(a)#2 (1) {
  ["a"]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
}
string(8) "Object b"
object(b)#3 (1) {
  ["a"]=>
  object(a)#2 (1) {
    ["a"]=>
    array(3) {
      [0]=>
      int(1)
      [1]=>
      int(2)
      [2]=>
      int(3)
    }
  }
}


Actual result:
--------------
string(8) "Object a"
object(a)#2 (1) {
  ["a"]=>
  array(3) {
    [0]=>
    int(1)
    [1]=>
    int(2)
    [2]=>
    int(3)
  }
}
string(8) "Object b"
object(b)#3 (1) {
  ["a"]=>
  object(a)#2 (1) {
    ["a"]=>
    array(3) {
      [0]=>
      int(1)
      [1]=>
      int(2)
      [2]=>
      int(3)
    }
  }
}
string(8) "Object a"
string(8) "Object a"  <<<  WRONG
string(8) "Object b"
object(b)#3 (1) {
  ["a"]=>
  string(8) "Object a"
}