#45816 [Com]: serialize() modifies objects

 ID:               45816
 Comment by:       gmtfn at yahoo dot com
 Reported By:      gmtfn at yahoo dot com
 Status:           Feedback
 Bug Type:         Session related
 Operating System: Linux
 PHP Version:      5.2.6
 Assigned To:      fb-req-jani
 New Comment:

register_globals is on on Linux servers and off on Vista. But whatever
its value is, getting a string representation of an object, which
serialization is, shouldn't change the object. It's completely
counterintuitive, and I can't imagine a valid reason for ruining a still
perfectly usable object. It's analogous to changing a variable's type
just because it's been typecasted to something else.


Previous Comments:
------------------------------------------------------------------------

[2008-08-14 17:42:38] [email protected]

Check your phpinfo() output that register_globals is Off.

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[2008-08-14 07:48:52] gmtfn at yahoo dot com

line 25, not 26

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[2008-08-14 07:37:54] gmtfn at yahoo dot com

Description:
------------
Calling serialize() on an object whose name is the same as the key
under which it's saved in $_SESSION makes the object unusable (its
methods can't be called.

If I store store a serialized version of the object under a key that's
different from the name of the variable that points to the object, then
everything works fine. If this is by design and must remain this way, I
want to tell you that this is VERY counterintuitive and must be
prominently documented.

I can reproduce this on a Linux server (with PHP 5.2.5 and 5.2.6) but
not on Windows Vista.

Reproduce code:
---------------
<?php
	session_start();
	ob_start();

	class GoodObject {
		private $count = 0;
		public function doSmth()
		{
			echo "$this->count <br>";
			$this->count++;
		}
	}

	if(!isset($_SESSION['myObj'])) {
		$myObj = new GoodObject();
	}
	else {
		$s = $_SESSION['myObj'];
		$myObj = unserialize($s);
	}
	
	$myObj->doSmth();
	$s = serialize($myObj);
	$_SESSION['myObj'] = $s;
	$myObj->doSmth(); // this fails on the second page load
?>

Expected result:
----------------
Converting an object to a string should not change the object, and the
last statement in this script should output the value of $count.

Actual result:
--------------
On the second load of the page, I get this:

Fatal error: Call to a member function doSmth() on a non-object in
[path to the file] on line 26


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Edit this bug report at http://bugs.php.net/?id=45816&edit=1