From:
Operating system: Win XP Pro
PHP version: 5.3.2
Package: PCRE related
Bug Type: Feature/Change Request
Bug description:preg_match: Capturing subpatterns that don't match get empty
string.
Description:
------------
Capturing subpatterns that don't match anything still show an empty string
in the match array.
Since empty string is a legitimate value, the match array should have null
or false instead.
The workaround to detect a capturing subpattern not matching anything is to
use PREG_OFFSET_CAPTURE and look for offset -1 for the particular
subpattern.
Test script:
---------------
<?php
preg_match('%(a)|(b)%','b',$m);
var_dump($m);
//$m[1] === "" as if the first capturing parentheses matched ""
//$m[1] === null would be more appropriate (javascript uses "undefined")
--
Edit bug report at http://bugs.php.net/bug.php?id=51881&edit=1
--
Try a snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=51881&r=trysnapshot52
Try a snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=51881&r=trysnapshot53
Try a snapshot (PHP 6.0):
http://bugs.php.net/fix.php?id=51881&r=trysnapshot60
Fixed in SVN:
http://bugs.php.net/fix.php?id=51881&r=fixed
Fixed in SVN and need be documented:
http://bugs.php.net/fix.php?id=51881&r=needdocs
Fixed in release:
http://bugs.php.net/fix.php?id=51881&r=alreadyfixed
Need backtrace:
http://bugs.php.net/fix.php?id=51881&r=needtrace
Need Reproduce Script:
http://bugs.php.net/fix.php?id=51881&r=needscript
Try newer version:
http://bugs.php.net/fix.php?id=51881&r=oldversion
Not developer issue:
http://bugs.php.net/fix.php?id=51881&r=support
Expected behavior:
http://bugs.php.net/fix.php?id=51881&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=51881&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=51881&r=submittedtwice
register_globals:
http://bugs.php.net/fix.php?id=51881&r=globals
PHP 4 support discontinued: http://bugs.php.net/fix.php?id=51881&r=php4
Daylight Savings: http://bugs.php.net/fix.php?id=51881&r=dst
IIS Stability:
http://bugs.php.net/fix.php?id=51881&r=isapi
Install GNU Sed:
http://bugs.php.net/fix.php?id=51881&r=gnused
Floating point limitations:
http://bugs.php.net/fix.php?id=51881&r=float
No Zend Extensions:
http://bugs.php.net/fix.php?id=51881&r=nozend
MySQL Configuration Error:
http://bugs.php.net/fix.php?id=51881&r=mysqlcfg
