bug#60690: -P '\d' in GNU and git grep

[Junio C Hamano]

Paul Eggert <eggert@cs.ucla.edu> writes:

> This is an evolving area. Git master is fiddling with flags and
> options, and so is GNU grep master, and so is PCRE2, and there are
> bugs. If you're running bleeding-edge versions of this code you'll get
> different behavior than if you're running grep 3.8, pcregrep 8.45,
> Perl 5.36, and git 2.39.2 (which is what Fedora 37 has).
>
> What I'm fearing is that we may evolve into mutually incompatible
> interpretations of how Perl regular expressions deal with UTF-8
> text. That'd be a recipe for confusion down the road.

Nicely said.  My personal inclination is to let Perl folks decide
and follow them (even though I am skeptical about the wisdom of
letting '\d' match anything other than [0-9]), but even in Git
circle there would be different opinions, so I am glad that the
discussion is visible on the list to those who are intrested.