Bug #51663 [Com]: 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 Comment by: adconrad at ubuntu dot com 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: 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. Previous Comments: ------------------------------------------------------------------------ [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