FS#966 Error Searching: Wrong parameter count for preg_match()

Backend

• 

  2006-11-04 malmgren

  With the latest version of DokuWiki (dokuwiki-rc2006-10-19.tgz RC3) it looks like the search is broken.  I currently only have a couple of pages created and the search problem occurs on every search regardless of the length or type of search parameters.
  
  Here's the error:
  
  Warning: Wrong parameter count for preg_match() in <web-path>/wiki/inc/fulltext.php on line 197
  
  A quick google search on the below error message suggested an older version of my PHP < 4.3.2.  Mine is 4.3.4 running on Solaris w/ Apache.
  
• 

  2006-11-04 ChrisS

  That particular line uses five parameters for preg_match, the last two, flags and offset, require php 4.3.0 and 4.3.3 respectively.  I don't know if the use of those two parameters also requires an appropriate libprce.
• 

  2006-11-05 malmgren

  Hi Chris, is there any workaround or fix for this?  Any possible solutions that I could try to resolve this?  I'm not sure what a libprce is.  
• 

  2006-11-05 malmgren

  Well I got it to work, but not exactly sure if this seriously impacts anything.
  
  I changed this:
  
     for ($cnt=3; $cnt--;) {
       if (!preg_match('#'.$re.'#iu',$text,$match,PREG_OFFSET_CAPTURE,$offset)) break;
  
  to this:
  
     for ($cnt=3; $cnt--;) {
       if (!preg_match('#'.$re.'#iu',$text,$match,PREG_OFFSET_CAPTURE)) break;
  
  
  And search works just fine now.  But why is $offset and "PREG_OFFSET_CAPTURE" both needed?
  
  Looks like Andi wrote this - Any comments?
  
  
• 

  2006-11-05 ChrisS

  I wrote it ;)
  
  The offset allows you to start at the position of the previous match, otherwise you will match the same thing three times.  Its written that way as the previous method (using preg_match_all) could be very inefficient (slow).
  
  The correct replacement will be
  
  if (!preg_match('#'.$re.'#iu',utf8_substr($text,$offset),$match,PREG_OFFSET_CAPTURE)) break;
  
  
  libpcre is the regex library used by php to provide the pcre functions (preg_*).
  
  Can you update your php?  
  4.3.10 was a significant update fixing several critical security issues - http://uk.php.net/releases/4_3_10.php
  
  Andi, is it worth including version dependent code to get around this problem and keep DW's php requirement at 4.3.x?
• 

  2006-11-05 malmgren

  Oh sorry, the remarks for that section give credit to Andi. :)
  
  /**
  * Creates a snippet extract
  *
  * @author Andreas Gohr <andi@splitbrain.org>
  */
  function ft_snippet($id,$poswords){
  <snip>
  
  Anyway - Thanks, that worked.  I didn't notice any difference in output between your changes and by me simply removing the $offset value.
  
  As far as PHP - I can't do much about that.  Small fish - big pond type of thing. :)   I'll see about installing a local copy.
  
  Will your workaround have any side effects I should know of?
  
  Thanks!
  
  
• 

  2006-11-05 ChrisS

  Yes, Andi wrote the original function, I redid parts of it recently looking to save a few ms.
  
  There should not be any significant side effects excepting a slight performance penalty.
  
  After discussing the PHP requirement with Andi, it'll be set at 4.3.3+ which (at least according to http://www.php.net/manual/en/function.preg-match.php) will include the offset parameter.  The installer will be updated to report a PHP version check failure.