Re: [PATCH] githooks: discuss Git operations in foreign repositories

[Eric Sunshine <sunshine@sunshineco.com>]

On Sun, Jan 8, 2023 at 11:58 PM Junio C Hamano <gitster@pobox.com> wrote:
> "Eric Sunshine via GitGitGadget" <gitgitgadget@gmail.com> writes:
> > +If your hook needs to invoke Git commands in a foreign repository or in a
> > +different working tree of the same repository, then it should clear local Git
> > +environment variables, such as `GIT_DIR`, `GIT_WORK_TREE`, etc., which could
> > +interfere with Git operations in the foreign repository since those variables
> > +will be referencing the local repository and working tree. For example:
> > +
> > +------------
> > +local_desc=$(git describe)
> > +foreign_desc=$(unset $(git rev-parse --local-env-vars); git -C ../foreign-repo describe)
> > +------------
>
> It is an excellent idea to add the above, but
>
>  * I think adding it one paragraph earlier may make it fit better.

That was my initial choice, as well, and is where I initially inserted
it, but moved it down a paragraph at the last moment. I'm happy to
move it back up again.

>  * The paragraph, after which the above gets inserted, can use a bit
>    of enhancement.
>
> That is, something like this?
>
>  repository. An exception are hooks triggered during a push ('pre-receive',
>  'update', 'post-receive', 'post-update', 'push-to-checkout') which are always
> -executed in $GIT_DIR.
> +executed in $GIT_DIR.  Environment variables like GIT_DIR and GIT_WORK_TREE
> +are exported so that the hook can easily learn which repository it is
> +working with.

Yes, good idea, although I might phrase it something like:

    Environment variables such as ... are exported so that Git
    commands run by the hook can correctly locate the repository.