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Date: Mon, 4 Oct 2004 09:39:16 -0500
To: internals@lists.php.net
Message-ID: <20041004143916.GA19506@romulus.a-s-i.com>
Mail-Followup-To: Bob Glamm <glamm@a-s-i.com>, internals@lists.php.net
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Subject: Odd reference => global bug?
From: glamm@a-s-i.com (Bob Glamm)

I saw this behavior this morning and was curious if I'd tripped a bug
in PHP (running version 4.3.7 at the moment).  I scanned through the
bug list for this particular bug but didn't find it.  I'm running it
by you all because I'm not intimately familiar with the reference
system to really be sure that it's a bug and not just my misunderstanding.

A demonstration script is included below:
globals $x and $v are set to NULL.  q() is called
and references globals $x and $v.  $x is set to the new class X;
$v is set to a reference to a new class Y (by means of a factory
function in X, a common structure in PEAR).

My version of PHP prints NULL at the var_dump() statement immediately
following the call to q(); I would expect it to dump an instance of
class Y.  So: am I misunderstanding references (and if so, why is the
behavior what it is), is this a duplicate
of another known bug, is this bug fixed in a newer version of PHP,
or should I file a new bug?

-Bob

<?php

class Y		// class created by factory in X, below
{
  function Y($t) { $this->a = $t; }
}

class X
{
  function X() { }

  function &getY($t)	// factory method to create Y and return a ref to it
  {
    $k = new Y($t);
    return($k);
  }
}

$x = null;
$v = null;

function q()
{
  global $x, $v;

  $x = new X();		// get an X simply to acquire a Y
  $v =& $x->getY("here");	// use the factory in X to assign a ref
  				// to Y to the global $v
}

q();			// initialize the globals with X and &Y
var_dump($v);		// should dump a Y, instead prints NULL ?

?>