Bug #63651 [Opn->Nab]: preg_replace() returns null for very long string

Edit report at https://bugs.php.net/bug.php?id=63651&edit=1 ID: 63651 Updated by: nikic@php.net Reported by: magog dot the dot ogre at gmail dot com Summary: preg_replace() returns null for very long string -Status: Open +Status: Not a bug Type: Bug Package: PCRE related Operating System: Windows, Unix PHP Version: 5.3.19 Block user comment: N Private report: N New Comment: In particular this part of the regex seems odd: \s*?)\s*\s* Three asterix-quantifier on the same thing in a row, that's something that can easily blow up a regular expression ;) Previous Comments: ------------------------------------------------------------------------ [2012-12-04 01:04:38] mail+php at requinix dot net You're hitting the backtrack limit defined as the pcre.backtrack_limit setting. If I up mine to 10000000 (10e6) I get a string(80) "Hello worldHello world..." Simply put, your regex is too inefficient to work on that $text. ------------------------------------------------------------------------ [2012-11-30 01:46:45] magog dot the dot ogre at gmail dot com Description: ------------ I have tested and gotten this error on the following two distros: *5.3.19 for Windows *5.3.8 for SunOS Run the code at the pastebin link I've provided. You will see that PHP is returning null in a preg_replace function! It occurs in both Windows and Unix. I do not know if this is a PHP problem, or a PCRE problem. Test script: --------------- http://pastebin.com/PBCDexXH Expected result: ---------------- A string should be outputted Actual result: -------------- Instead, a NULL result is outputted. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=63651&edit=1