#45816 [NEW]: serialize() modifies objects

From:             gmtfn at yahoo dot com
Operating system: Linux
PHP version:      5.2.6
PHP Bug Type:     Session related
Bug description:  serialize() modifies objects

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

-- 
Edit bug report at http://bugs.php.net/?id=45816&edit=1
-- 
Try a CVS snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=45816&r=trysnapshot52
Try a CVS snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=45816&r=trysnapshot53
Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=45816&r=trysnapshot60
Fixed in CVS:                 http://bugs.php.net/fix.php?id=45816&r=fixedcvs
Fixed in release:             http://bugs.php.net/fix.php?id=45816&r=alreadyfixed
Need backtrace:               http://bugs.php.net/fix.php?id=45816&r=needtrace
Need Reproduce Script:        http://bugs.php.net/fix.php?id=45816&r=needscript
Try newer version:            http://bugs.php.net/fix.php?id=45816&r=oldversion
Not developer issue:          http://bugs.php.net/fix.php?id=45816&r=support
Expected behavior:            http://bugs.php.net/fix.php?id=45816&r=notwrong
Not enough info:              http://bugs.php.net/fix.php?id=45816&r=notenoughinfo
Submitted twice:              http://bugs.php.net/fix.php?id=45816&r=submittedtwice
register_globals:             http://bugs.php.net/fix.php?id=45816&r=globals
PHP 4 support discontinued:   http://bugs.php.net/fix.php?id=45816&r=php4
Daylight Savings:             http://bugs.php.net/fix.php?id=45816&r=dst
IIS Stability:                http://bugs.php.net/fix.php?id=45816&r=isapi
Install GNU Sed:              http://bugs.php.net/fix.php?id=45816&r=gnused
Floating point limitations:   http://bugs.php.net/fix.php?id=45816&r=float
No Zend Extensions:           http://bugs.php.net/fix.php?id=45816&r=nozend
MySQL Configuration Error:    http://bugs.php.net/fix.php?id=45816&r=mysqlcfg