On 2019-06-14 at 22:55:17, Ævar Arnfjörð Bjarmason wrote:
> It seems most packagers build with PCRE v2 now (CC:
> git-packagers@). I.e. we'd keep something like compile_fixed_regexp()
> (and as an aside just use PCRE's \Q...\E instead of our own escaping).
> 
> We'd have performance regression for platforms that use kwset() now but
> don't build pcre2, or where pcre2 jit doesn't work. Does anyone care?

I know that there are people shipping newer versions of Git using CentOS
6, which IIRC doesn't ship PCRE 2[0]. Since having to ship your own PCRE
is a security maintenance nightmare, it's probably best to leave this at
least compatible with non-PCRE 2 systems until November 2020. At that
point, I'm happy to drop support for it.

If it would work but just be slower with PCRE 1, I'm not too terribly
concerned. Let that be an incentive to users to upgrade.

Also, as Carlos pointed out, not all platforms will have the JIT support
functional, such as OpenBSD, NetBSD, and PaX Linux systems. That may be
more of a blocker than the CentOS issue, especially since people run PaX
kernels with standard distros.

[0] I'm not certain because CentOS 6 Docker images segfault on newer
kernels and I'm too lazy to download a live CD image for testing.
-- 
brian m. carlson: Houston, Texas, US
OpenPGP: https://keybase.io/bk2204