Bug #73948 [Ana->Asn]: Preg_match_all should return NULLs on trailing optional capture groups.

From:	nikic@php.net	Date:	Tue, 19 Mar 2019 13:04:46 +0000
Subject:	Bug #73948 [Ana->Asn]: Preg_match_all should return NULLs on trailing optional capture groups.
References:	1	Groups:	php.bugs
Request:	Send a blank email to php-bugs+get-220072@lists.php.net to get a copy of this message

Edit report at https://bugs.php.net/bug.php?id=73948&edit=1

 ID:                 73948
 Updated by:         nikic@php.net
 Reported by:        tomasyorke at hotmail dot com
 Summary:            Preg_match_all should return NULLs on trailing
                     optional capture groups.
-Status:             Analyzed
+Status:             Assigned
 Type:               Bug
 Package:            PCRE related
 Operating System:   Windows 7
 PHP Version:        7.0.14
-Assigned To:        
+Assigned To:        nikic
 Block user comment: N
 Private report:     N

 New Comment:

PR for PHP 7.4: https://github.com/php/php-src/pull/3964


Previous Comments:
------------------------------------------------------------------------
[2018-06-09 22:51:16] php at tecnopolis dot ca

For those stuck on older PHP's, I'm wondering if the following is sufficient to work
around this bug?

$pattern.='(.??)';
preg_match($pattern,$haystack,$matches);
array_pop($matches);

I can't yet find any instance where the fairly innocuous (.??) could possibly cause a problem,
it should match in all cases, when there's chars left or not, and being non-greedy will not eat
earlier matches' chars.

------------------------------------------------------------------------
[2018-04-14 15:08:34] nikic@php.net

@requinix: That's impossible for BC reasons. I agree with @cmb that this should only be done
for PREG_UNMATCHED_AS_NULL.

------------------------------------------------------------------------
[2018-04-14 14:47:18] requinix@php.net

The filling should happen with or without PREG_UNMATCHED_AS_NULL. What it should control whether the
filler is NULLs or empty strings.

------------------------------------------------------------------------
[2018-04-14 14:42:46] cmb@php.net

Since we now have PREG_UNMATCHED_AS_NULL, the solution appears to
be straight forward: fill up NULL values at the end, only if
PREG_UNMATCHED_AS_NULL is used.  Since this option is only
available as of PHP 7.2.0, the resulting BC break seems to be
acceptable.

------------------------------------------------------------------------
[2018-04-14 14:39:07] cmb@php.net

Related To: Bug #76221

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


The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at

    https://bugs.php.net/bug.php?id=73948


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Edit this bug report at https://bugs.php.net/bug.php?id=73948&edit=1


   

Thread (19 messages)

• tomasyorke at hotmail dot comMon, 16 Jan 2017 14:24:56 +0000
  • requinix@php.netMon, 16 Jan 2017 14:38:09 +0000Bug #73948 [Opn->Dup]: Preg_match_all should return empty strings on optional capture groups.
  • nikic@php.netMon, 16 Jan 2017 14:40:42 +0000Bug #73948 [Dup]: Preg_match_all should return empty strings on optional capture groups.
  • requinix@php.netMon, 16 Jan 2017 14:57:14 +0000Bug #73948 [Dup->Fbk]: Preg_match_all should return empty strings on optional capture groups.
  • requinix@php.netMon, 16 Jan 2017 15:50:24 +0000Bug #73948 [Fbk->Opn]: Preg_match_all should return NULLs on trailing optional capture groups.
  • cmb@php.netTue, 17 Jan 2017 13:28:23 +0000Bug #73948 [Opn->Ana]: Preg_match_all should return NULLs on trailing optional capture groups.
  • tomasyorke at hotmail dot comMon, 23 Jan 2017 15:48:20 +0000Bug #73948 [Com]: Preg_match_all should return NULLs on trailing optional capture groups.
  • tomasyorke at hotmail dot comMon, 23 Jan 2017 15:59:31 +0000Bug #73948 [Com]: Preg_match_all should return NULLs on trailing optional capture groups.
  • cmb@php.netMon, 23 Jan 2017 17:17:21 +0000Bug #73948 [Ana]: Preg_match_all should return NULLs on trailing optional capture groups.
  • tomasyorke at hotmail dot comMon, 23 Jan 2017 17:43:40 +0000Bug #73948 [Com]: Preg_match_all should return NULLs on trailing optional capture groups.
  • tomasyorke at hotmail dot comMon, 23 Jan 2017 17:53:31 +0000Bug #73948 [Com]: Preg_match_all should return NULLs on trailing optional capture groups.
  • cmb@php.netMon, 23 Jan 2017 18:31:20 +0000Bug #73948 [Ana]: Preg_match_all should return NULLs on trailing optional capture groups.
  • cmb@php.netSat, 14 Apr 2018 14:42:48 +0000Bug #73948 [Ana]: Preg_match_all should return NULLs on trailing optional capture groups.
  • requinix@php.netSat, 14 Apr 2018 14:47:19 +0000Bug #73948 [Ana]: Preg_match_all should return NULLs on trailing optional capture groups.
  • nikic@php.netSat, 14 Apr 2018 15:08:35 +0000Bug #73948 [Ana]: Preg_match_all should return NULLs on trailing optional capture groups.
  • php at tecnopolis dot caSat, 09 Jun 2018 22:51:19 +0000Bug #73948 [Com]: Preg_match_all should return NULLs on trailing optional capture groups.
  • nikic@php.netTue, 19 Mar 2019 13:04:46 +0000Bug #73948 [Ana->Asn]: Preg_match_all should return NULLs on trailing optional capture groups.
  • nikic@php.netTue, 19 Mar 2019 14:39:02 +0000Bug #73948 [Asn]: Preg_match_all should return NULLs on trailing optional capture groups.
  • nikic@php.netThu, 21 Mar 2019 09:23:19 +0000Bug #73948 [Asn->Csd]: Preg_match_all should return NULLs on trailing optional capture groups.