Re: t5607 fail with GIT_TEST_FAIL_PREREQS enabled

On Wed, Aug 11, 2021 at 03:02:52PM +0200, Son Luong Ngoc wrote:

    git/t% GIT_TEST_FAIL_PREREQS=1 ./t5607-clone-bundle.sh
[...]
    #               if ! test_have_prereq SHA1
    #               then
    #                       echo "@object-format=sha256"
    #               fi >expect &&

The problem is presumably here. If test_have_prereq lies and say "no, we
are using sha256" then we cannot expect what the built binary does to
match that lie.

Perhaps that is a sign that test_have_prereq is not the right tool to
check "which hash format are we using", but I don't think we have
another convenient mechanism to do so currently.

I also think that the FAIL_PREREQS system may be mis-designed a bit. We
had a similar problem a few months ago, and I think Junio's response
here points in a good direction:

  https://lore.kernel.org/git/xmqqblbgrwkg.fsf@gitster.g/ (local)

-Peff