bug#22655: grep -Pz '^' now fails!

[Zev Weiss]

On Sat, Nov 19, 2016 at 12:36:12AM -0800, Paul Eggert wrote:
> Stephane Chazelas wrote:
> > one can
> > use (?m) if he wants ^ to match the beginning of each line in
> > the NUL-delimited record instead of just the beginning of the
> > record.
>
> I think the intent is that ^ and $ should match only the 
> line-terminator specified by -z (or by -z's absence). So the sort of 
> usage you describe is unspecified and not supported. That being said, 
> it does make sense to match tricky regular expressions like that line 
> by line, even if this hurts performance. Otherwise, I suspect there 
> are even trickier regular expressions that could reject a buffer full 
> of lines even though it contains matching lines. When in doubt we 
> should avoid optimization so I installed the attached patch into the 
> master branch. Please give it a try.

> From 0e00fe0fc34184b1cdcea92a671eb9ffebb4899b Mon Sep 17 00:00:00 2001
> From: Paul Eggert <address@hidden>
> Date: Sat, 19 Nov 2016 00:25:46 -0800
> Subject: [PATCH] grep: -Pz no longer rejects ^, $
>
> Problem reported by Stephane Chazelas (Bug#22655).
> * NEWS: Document this.
> * doc/grep.texi (grep Programs): Warn about -Pz.
> * src/pcresearch.c (reflags): New static var.
> (multibyte_locale): Remove static var; now local to Pcompile.
> (Pcompile): Check for (? and (* too.  Set reflags instead of
> dying when problematic operators are found.
> (Pexecute): Use reflags to decide whether searches should
> be multiline.
> * tests/pcre: Test new behavior.

I'm a bit confused by this patch -- I see 'reflags' being tested in 
Pexecute(), but I don't see it getting set anywhere, just Pcompile()'s 
local 'flags'...I'm guessing 'flags' was supposed to be replaced by 
'reflags'?  (Not entirely certain though.)


Zev