#33468 [Asn]: preg_match on long strings fails

From: Date: Tue, 09 Aug 2005 08:36:29 +0000
Subject: #33468 [Asn]: preg_match on long strings fails
References: 1  Groups: php.bugs 
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 ID:               33468
 Updated by:       sniper@php.net
 Reported By:      mjsherman at chartermi dot net
 Status:           Assigned
 Bug Type:         PCRE related
 Operating System: *
-PHP Version:      5CVS, 4CVS (2005-06-26)
+PHP Version:      5CVS, 4CVS (2005-08-09)
 Assigned To:      andrei
 New Comment:

Happens also with the new PCRE 6.2 lib which was bundled in PHP CVS
today.


Previous Comments:
------------------------------------------------------------------------

[2005-06-24 19:30:06] tony2001@php.net

Andrei, could you check it plz.
As far as I understand, this is something not related to PHP, but just
another PCRE limitation.

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

[2005-06-24 19:21:22] mjsherman at chartermi dot net

Just tested with 5.1.0beta2
Same problem.

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

[2005-06-24 18:28:01] tony2001@php.net

Please try using this CVS snapshot:

  http://snaps.php.net/php5-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5-win32-latest.zip



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

[2005-06-24 18:24:34] mjsherman at chartermi dot net

Description:
------------
preg_match, if passed a long subject string, fails unexpectedly.

I have read through the PCRE limitations, and can't see that this is
one of them.  I have tried increasing memory limit (to increase the
stack) with the same results.

Cutoff and examples are below:

Reproduce code:
---------------
$subject = str_repeat('a',100);
$subject .= str_repeat('b', 4370);
$subject .= str_repeat('a', 100);
if (preg_match('/(.*).*?\1/',$subject)) {
  echo "OK\n";
}

Expected result:
----------------
"OK" to be printed after matching 100 "a"s.
If 4370 is changed to 4369, then "OK" is printed.

Actual result:
--------------
With 4370 'b's, nothing is printed (failed preg_match)
With 4369 'b's, "OK" is printed (worked).


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


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