Bug #62437 [Opn->Nab]: Strange behavior with global variables (objects) in ob_start() output callback

Edit report at https://bugs.php.net/bug.php?id=62437&edit=1 ID: 62437 Updated by: mike@php.net Reported by: tero dot tasanen at gmail dot com Summary: Strange behavior with global variables (objects) in ob_start() output callback -Status: Open +Status: Not a bug Type: Bug Package: Output Control Operating System: Linux 64bit PHP Version: 5.3.14 -Assigned To: +Assigned To: mike Block user comment: N Private report: N New Comment: Thank you for taking the time to write to us, but this is not a bug. Please double-check the documentation available at http://www.php.net/manual/ and the instructions on how to report a bug at http://bugs.php.net/how-to-report.php So something has to be shut down first, it's kind of a chicken and egg problem. Object destruction is performed in two stages, objects with e.g. circular references are destroyed at the very last (try $object->ref=$object to see the difference). Previous Comments: ------------------------------------------------------------------------ [2012-07-02 11:51:53] tero dot tasanen at gmail dot com Yes, I agree that there might be two bugs here. Here's another test script that shows that this only affects objects and not other data types. http://3v4l.org/Ip5Sn <?php function output($buffer) { global $object, $string, $int, $float, $array; $ret_val = array($string, $object->bar, $int, sprintf("%.2f", $float), $array[0]); return implode(" ", $ret_val); } ob_start('output'); $object = new stdClass(); $object->bar = "bar"; $string = "foo"; $int = 1; $float = 2.0; $array = array('array'); // $test = $object; ?> ------------------------------------------------------------------------ [2012-06-30 13:25:09] Sjon at hortensius dot net Contrary to what tony2001 says in #40604, this was actually working fine until it was broken in 5.2 http://3v4l.org/SUUkK The reason that http://3v4l.org/pZ2PP works might be explained to the second reference to the same object which could prevent destruction, but that would then actually be a bug too (since it indicates a memory-leak). ------------------------------------------------------------------------ [2012-06-28 11:56:12] tero dot tasanen at gmail dot com Description: ------------ Global variables in output buffering seem to work in very strange way. don't know actually if this has anything to do with output buffering callback but see the test case attached to reproduce this. And the strangest thing is that if you uncomment the last line the script works as expected! After some searching I found two similar bug reports (#40604, #44840) and the comments indicate that this is expected behavior?! Not just that it seem really strange that all objects get destroyed before the output callback is called, but why does the use of the $test variable in the end of the script change this behavior? This really does not make any sense! Test script: --------------- <? function output($buffer) { global $object; return $buffer . $object->bar; } ob_start('output'); $object = new stdClass(); $object->bar = "bar"; echo "foo "; // $test = $object; Expected result: ---------------- foo bar Actual result: -------------- PHP Notice: Trying to get property of non-object in /home/ttasanen/test.php on line 5 PHP Stack trace: PHP 1. output() /home/ttasanen/test.php:0 foo ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=62437&edit=1