Re: [PATCH] grep: avoid setting UTF mode when not needed

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Tue, Nov 16 2021, Hamza Mahfooz wrote:

> Does anyone know if René's patch causes older PCRE versions to break?
> If it doesn't I think René's patch plus Ævar's fix is the way to go.

I haven't tested, but I think a very good thing to do/test (hint hint!)
is to add a CI job where we build/test git in combination with various
PCRE versions.

PCRE2 used to be in SVN, but nowadays it's in a git repository on
github: https://github.com/PhilipHazel/pcre2

It should be a small matter of copying the existing template to set up a
"matrix" where we test various known older pcre versions, they're
available as tags in the git repository.

"--enable-jit" and "--disable-jit" should be part of that matrix too,
and "--enable-utf" and "--disable-utf".

See the "microsoft/vcpkg" and "regular:" parts of
.github/workflows/main.git for relevant examples, i.e. this would
e.g. clone pcre2.git into compat/pcre2-repo, check out a given version
from the matrix. Then:

    cd compat/pcre2-repo &&
    ./autogen.sh &&
    ./configure --prefix="$PWD/inst" &&
    make install

Then at the top-level:

    make USE_LIBPCRE=Y CFLAGS=-O3 LIBPCREDIR="$PWD/compat/pcre2-repo/inst"

Then run "make test", for saving some CPU & speeding up the runs it
should be more than sufficient to only run those tests that match
*{grep,log,pickaxe}*