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] [email protected]

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


------------------------------------------------------------------------



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