[TYPO3-core] RFC #6415: Bug: preg_replace error on php5.2 sometimes resulting in empty pages.

[Francois Suter]

REMINDER #2

> Hi,
> 
> REMINDER #1
> 
> I've reviewed this bug report again during the October Bug Day. New 
> remarks have been added recently to the bugtracker entry, but they point 
> to other problems. I think we should get this patch committed and the 
> other problems can be solved with another patch.
> 
> Cheers
> 
>> This is an SVN patch request.
>>
>> Type: Bugfix
>>
>> Bugtracker references:
>> http://bugs.typo3.org/view.php?id=6415
>>
>>
>> Branches:
>> Trunk
>>
>> Problem:
>> The function prefixLocalAnchorsWithScript in class.tslib_fe.php runs
>> preg_replace directly on $this->content. In php 5.2 all calls to 
>> preg_* functions will return an empty string (or
>> false) if it encounters an error (This is new in PHP 5.2). thus is a 
>> pages
>> consists of a lot of content with many anchor links, the
>> pcre.backtrack_limit or pcre.recursiion_limit will be reached, and the
>> result is a completely blank output in the frontend.
>>
>> The error only occurs if the TypoScript option: 
>> config.prefixLocalAnchors is
>> set to all.
>>
>> The original trigger for this bug, was that the regular expression:
>> '/(<(a|area).*?href=")(#[^"]*")/i' resulted in recursion_limit being 
>> reached
>> on one of my sites. The regular expression is not correct, and should 
>> in my
>> opinion be '/(<(a|area).+href=")(#[^"]*")/i'
>>
>> Solution:
>> 1: Change the regular expression to a non-faulty one
>> 2: Introduce some error checking. Since php 5.2 a call to preg_last_error
>> will give some insight into the result of the last call to preg_ 
>> functions.
>> The patch here checks if there was an error, and if yes, then return the
>> unsubstitued content (in order to avoid empty pages) and  write an 
>> entry to
>> the syslog.
>> Notes:
>> The patch requires php 5.2 to run.
>>
>> Regards
>> Jan-Erik Revsbech
>> MOC Systems
> 
> 
> 



-- 

Francois Suter
Cobweb Development Sarl - http://www.cobweb.ch