Edit report at http://bugs.php.net/bug.php?id=54614&edit=1
ID: 54614 User updated by: php at richardneill dot org Reported by: php at richardneill dot org Summary: Trivial RE failure: /([^b]*a*)*$/ -Status: Feedback +Status: Open Type: Bug Package: *Regular Expressions Operating System: Linux PHP Version: 5.3.6 Block user comment: N Private report: N New Comment: Sorry, my bad (sort of). There is a genuine bug that affected longer regexps even with backtrack.limit set to 32M, which I saw on 5.3.2, but is now solved on 5.3.6. Unfortunately, the test-case which I simplified for the bug-report didn't remember to set backtrack.limit (I thought I'd done it in php.ini, but had actually done it explicitly with ini.set in my original script). So the test case: - works for backtrack.limit = 1M (on both 5.3.2 and 5.3.6) - fails for the default 100k on both. Either way, it's still something that, imho, should work on a default install. May I make a few suggestions: * backtrack.limit should be raised by default, to at least 10M. * backtrack.limit should default to 100M for the CLI version of PHP. * validating bug reports is painful, partly because I had to spend some extra time tracking down the latest version of PHP and building it. This is error- prone. How about providing a sandboxed VM on bugs.php.net where we can paste our own code to check it? This would make it far easier to file correct bug reports. (it would take the reporter 3 minutes, rather than an hour). Previous Comments: ------------------------------------------------------------------------ [2011-04-27 21:54:07] ras...@php.net With pcre.backtrack_limit = 1000000 this works fine for me on 5.3.6. Are you sure you increased the limit in the right place? ------------------------------------------------------------------------ [2011-04-27 21:15:34] php at richardneill dot org A slightly simpler test case is: $contents = "aaaaaaaab"; $search = '/(a*a*)*$/'; ------------------------------------------------------------------------ [2011-04-27 18:43:02] php at richardneill dot org Description: ------------ If I search in the string : 'aaaaaaaab' with the RE: '/([^b]*a*)*$/' then preg_replace fails with a backtrack-limit error. (error 2) I have backtrack.limit configured to 32MB, so something is very wrong. The example fails on several different PHP versions, CPU architectures and Linux Distros. However, using Perl for the same RE works fine. Test script: --------------- $contents = "aaaaaaaab"; $search = '/([^b]*a*)*$/'; $result = preg_replace($search,"x",$contents); if ($result === NULL){ echo "preg failed, error is ".preg_last_error()."\n"; }else{ echo "success\n"; } Expected result: ---------------- preg_replace shouldn't fail. Actual result: -------------- preg_replace returns NULL, and preg_last_error returns 2. ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/bug.php?id=54614&edit=1