#34358 [Asn]: Fatal error: Cannot re-assign $this

ID: 34358 User updated by: pacha dot shevaev at gmail dot com Reported By: pacha dot shevaev at gmail dot com Status: Assigned Bug Type: Scripting Engine problem Operating System: * PHP Version: 5.* Assigned To: dmitry New Comment: Guys your notes about possible misuse($ref =& $this;$ref = 'foo') are totally valid but is soooooo much difficult to spot this situation _when_it_actually_happens_? I'm by no means going to use this ref improperly but simply want BC with PHP4... Previous Comments: ------------------------------------------------------------------------ [2005-10-03 12:42:48] derick@php.net I'm reopening this so that we can discuss it. I don't think we should be silently ignoring references as that's something vague. See mail to internals@ in a bit. ------------------------------------------------------------------------ [2005-10-03 12:14:59] rasmus@php.net So for the curious who are wondering what "fixed" means. The & is simply ignored in this case now. ------------------------------------------------------------------------ [2005-10-03 10:22:47] dmitry@php.net Fixed in CVS HEAD and PHP_5_1. ------------------------------------------------------------------------ [2005-10-03 09:40:14] rasmus@php.net It has everything to do with the new object model. Take this code: $x = &$this; $x = 'foo'; For performance reasons we need to catch such references when they happen in order to prevent the object being overwritten inside itself. It would be a bit less confusing if the error happened on the actual assignment, but in this new object model there $x = &$this; is just as wrong as $this = &$x since the only purpose one could have for making a reference to $this itself is if you wanted to change it directly. In all valid cases this should be $x = $this. I suppose an option would be to ignore the reference in this case and continue on. That seems to be happening with that last indirect case you posted, but it would cost us a lookup. ------------------------------------------------------------------------ [2005-09-15 15:32:13] pacha dot shevaev at gmail dot com And why does the following code work then??? <?php class Foo { function Foo() { $this->ref =& $this; $this->ref->test(); } function test() { echo 'test'; } } $foo = new Foo(); ?> ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/34358 -- Edit this bug report at http://bugs.php.net/?id=34358&edit=1