Re: git aliases and GIT_PREFIX

Sorry for the late reply.

On Tue, Nov 02, 2021 at 03:26:05PM +0100, Johannes Schindelin wrote:

Hi Federico,

On Thu, 28 Oct 2021, Federico Kircheis wrote:

quoted

today I reported what I believed to be a bug on

 https://github.com/git-for-windows/git/issues/3496

and learned about GIT_DIR when working with aliases and git worktree.

It's annoying that GIT_DIR it is defined only if (as far as I've understood)
working from a worktrees or submodule, as it does not seem to be related to
those type of repositories.

To clarify: `GIT_DIR` is set when executing an alias in a worktree other
than the primary one (and probably also in submodules), but not when
executing in a primary worktree.

quoted

This is also irritating because apparently working aliases breaks when being
executed from those repositories.

To clarify: an alias that wants to switch to a different repository and
execute Git commands there works well in a primary worktree. But when you
switch to a different repository while executing an alias from a secondary
worktree, it will fail because of `GIT_DIR` having been set.

quoted

I believe it would be better if GIT_DIR it's either always set or never
(could someone enlighten me why the variable is needed in first place?).

Yes, sorry if I was not clear, your clarification are what I meant to say.

The fact that `GIT_DIR` is not set when calling an alias in a primary
worktree suggests that the behavior in secondary worktrees is not by
design. We should therefore be able to stop setting it there.

The question is: what code is responsible for setting it only in some
circumstances but not others?

Federico, do you have any experience in debugging C code? If so, it would
be good if you could take a crack at investigating this.

Ciao,
Johannes

Yes, I have some experience, but never looked at the git codebase.

On GitHub (https://github.com/git-for-windows/git/issues/3496) there is already an hint where those variables are set:

  https://github.com/git/git/blob/v2.33.1/git.c#L354

Or do you mean if I could investigate the test cases Ævar Arnfjörð Bjarmason mentioned?