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

[Stephane Chazelas]

2016-11-18 17:06:36 +0000, Stephane Chazelas:
[...]
> That might have been the case a long time ago, as I remember
> some discussion about it as it explained some wrong information
> in the documentation, but as far as I and gdb can tell, grep
> 2.26 at least call pcre_exec for every line of the input with
> grep -P.
> 
> If it didn't
> 
> echo test | grep -P '\n$'
> 
> would match.
> 
> I'll try and dig up the old discussions.
[...]

I can't find the discussions, and they should have been a
follow-up on https://debbugs.gnu.org/cgi/bugreport.cgi?bug=16871
but looking at the code, that changed in commit
a14685c2833f7c28a427fecfaf146e0a861d94ba in 2010 for
https://savannah.gnu.org/bugs/?27460

And shortly after, -Pz was supported (as that was made
straightforward to do  after the change I guess).

Note that we should also be able to support grep -Pe pat1 -e
pat2 now as well.

And PCRE_MULTILINE now can only improve performance.

-- 
Stephane