Bug #51663 [Fbk]: PHP preg_match doesn't match string which should match

Edit report at http://bugs.php.net/bug.php?id=51663&edit=1 ID: 51663 Updated by: pajoye@php.net Reported by: jordi dot salvat dot i dot alabart at gmail dot com Summary: PHP preg_match doesn't match string which should match Status: Feedback Type: Bug Package: PCRE related Operating System: Ubuntu PHP Version: 5.3.2 New Comment: Only to be sure: did you actually try using 5.3.2 and the bundled PCRE? You can test it without having to install PHP on your system. You only have to compile php. The same applies for php 5.2.13. Previous Comments: ------------------------------------------------------------------------ [2010-04-28 11:31:07] adconrad at ubuntu dot com Given that Ubuntu builds PHP against the system libpcre, and pcretest (by definition, but also a quick visual check with ldd) also uses the system libpcre, it seems unlikely this is a problem with libpcre itself, since pcretest works and PHP doesn't. ------------------------------------------------------------------------ [2010-04-26 12:18:53] johannes@php.net Are you using the bundled PCRE lib or your system's one? - Default is the bundled one. currently bundled is 8.02. i assume this is a PCRE and no PHP issue. ------------------------------------------------------------------------ [2010-04-26 00:52:55] jordi dot salvat dot i dot alabart at gmail dot com I've been able to simplify the example to: <?= preg_match("/(.+)+:/", "a:bbbbbbbbbbbbb") ? "pass" : "fail" ?> (I've checked this simplified form fails in PHP 5.2.10-2ubuntu6.4; checking it in 5.3.2 too is left as an exercise for the reader). ------------------------------------------------------------------------ [2010-04-26 00:37:02] jordi dot salvat dot i dot alabart at gmail dot com Description: ------------ This regular expression: /^(?:[^\[\]{}']+|'[^']*')+:(?:[^\[\]{}']+|'[^']*')+$/ matches this string: a:bbbbbbbbbbbbbbb in Perl (5.10.0-24ubuntu4): perl <<__END__ print 'a:bbbbbbbbbbbbb' =~ q/^(?:[^\[\]{}']+|'[^']*')+:(?:[^\[\]{}']+|'[^']*')+$/; print "\n"; __END__ 1 and pcretest (libpcre3 7.8-3): pcretest <<__END__ /^(?:[^\[\]{}']+|'[^']*')+:(?:[^\[\]{}']+|'[^']*')+$/ a:bbbbbbbbbbbbbbb __END__ PCRE version 7.8 2008-09-05 re> data> 0: a:bbbbbbbbbbbbbbb data> Not, however, in PHP (5.3.2): $ ./php --version PHP 5.3.2 (cli) (built: Apr 25 2010 23:58:33) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies $ ./php <<__END__ <?= preg_match("/^(?:[^\[\]{}']+|'[^']*')+:(?:[^\[\]{}']+|'[^']*')+$/", "a:bbbbbbbbbbbbb") ?> __END__ 0 The bug is pretty sensible to changes in the input. Removing a couple of "b"s makes it match. I don't know which aspects of the regexp cause it to fail. For confirmation that this is indeed a bug without having to decypher the regexp, here's proof: <?php $A='(?:[^\[\]{}\']+|\'[^\']*\')+'; $a= 'a'; $B=":$A"; $b= ':bbbbbbbbbbbbbbb'; print_r(preg_match("/^$A$/", "$a")); print_r(preg_match("/^$B$/", "$b")); print_r(preg_match("/^$A$B$/", "$a$b")); print_r("\n"); This outputs "110", which is impossible since if /^$A$/ matches "$a" and /^$B$/ matches "$b", /^$A$B$/ should definitely match "$a$b". Test script: --------------- <?= preg_match("/^(?:[^\[\]{}']+|'[^']*')+:(?:[^\[\]{}']+|'[^']*')+$/", "a:bbbbbbbbbbbbb") ? "pass" : "fail" ?> Expected result: ---------------- pass Actual result: -------------- fail ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/bug.php?id=51663&edit=1