Re: Bug: Git sees branch as valid commit ref and works; should fail

[Matt Thompson <fortran@gmail.com>]

Well, I tried the "for-each-ref" command and:

$ git for-each-ref | grep /bugfix/mathomp4/trivial-ci-commit-gcc14
$ echo $?
1

Indeed, if I try a few other greps, there are no "trivial" or "gcc14":

$ git for-each-ref | grep -i gcc14
$ echo $?
1
$ git for-each-ref | grep -i trivial
$ echo $?
1

But, I did some experimenting and I found that "ci-gcc14" does
trigger...something:

$ git for-each-ref | grep -i ci-gcc14
mathomp4@gslwl2023080107 ~/GitBugReport/fvdycore geos/main
$ echo $?
0

But I'm confused as to how the grep returned a status of 0 but didn't
print anything? So it said "Yes I see this string" but it actually
didn't? And it can switch to it:

$ git switch ci-gcc14
fatal: a branch is expected, got commit 'ci-gcc14'
hint: If you want to detach HEAD at the commit, try again with the
--detach option.
mathomp4@gslwl2023080107 ~/GitBugReport/fvdycore geos/main
$ git switch --detach ci-gcc14
HEAD is now at cc14d30 removed an unused module use in fv_sg


On Mon, Aug 5, 2024 at 12:35 PM Junio C Hamano <gitster@pobox.com> wrote:
>
> Matt Thompson <fortran@gmail.com> writes:
>
> > Thank you for filling out a Git bug report!
> > Please answer the following questions to help us understand your issue.
> >
> > What did you do before the bug happened? (Steps to reproduce your issue)
> >
> > $ git clone https://github.com/GEOS-ESM/GFDL_atmos_cubed_sphere.git fvdycore
> > $ cd fvdycore
> > $ git checkout bugfix/mathomp4/trivial-ci-commit-gcc14
> >
> > What did you expect to happen? (Expected behavior)
> >
> > I expected a failure as there is no branch named
> > 'bugfix/mathomp4/trivial-ci-commit-gcc14' in the repository.
>
> If you run
>
>   $ git for-each-ref | grep /bugfix/mathomp4/trivial-ci-commit-gcc14
>
> I suspect you have a remote-tracking branch that matches the
> pattern.  In such a case, "bugfix/mathomp4/trivial-ci-commit-gcc14"
> is a very valid way to refer to a commit to any Git command.  It is
> handy to say "git show bugfix/mathomp4/trivial-ci-commit-gcc14", for
> example.
>
> And when "git checkout" is given a commit that is not a local
> branch, what it did below (by the way, thanks for giving a very
> accurate "Actual behavior" description in your report) is very much
> expected behaviour, including the part that it gave a message to
> advise how to work on a detached HEAD.
>
> > What happened instead? (Actual behavior)
> >
> > $ git checkout bugfix/mathomp4/trivial-ci-commit-gcc14
> > Note: switching to 'bugfix/mathomp4/trivial-ci-commit-gcc14'.
> > ...
>


-- 
Matt Thompson
   “The fact is, this is about us identifying what we do best and
   finding more ways of doing less of it better” -- Director of Better
Anna Rampton