Re: [PATCH 1/3] fsck: verify commit graph when implicitly enabled

From: Eric Sunshine <sunshine@sunshineco.com>
Date: Sep 13, 2021, 23:32 UTC
Message-ID: <CAPig+cS2E6c9YYKTThPSVpyBkouoL+nK2rgpsZxNODPmTr2hzQ@mail.gmail.com>
In-Reply-To: <YT/bfZu5mnMMqq0z@chooglen-macbookpro.roam.corp.google.com>

On Mon, Sep 13, 2021 at 7:19 PM Glen Choo <chooglen@google.com> wrote:

Show 21 quoted lines

> On Mon, Sep 13, 2021 at 03:29:25PM -0400, Taylor Blau wrote:
> > > +        git config --unset core.commitGraph &&
> >
> > But I'm not aware of a way to temporarily unset a configuration variable
> > for the duration of a test, so here I would probably write:
> >
> >     test_must_fail git -c core.commitGraph= fsck
> >
> > which Git interprets as "pretend this variable is unset in-core".
>
> From my testing, I suspect that git does not pretend the variable is
> unset, but rather, it pretends that the variable is set to the empty
> string. It seems that git behaves as if the variable is set to "false".
> This is called out in Documentation/git.txt:
>
>   Including the equals but with an empty value (like `git -c
>   foo.bar= ...`) sets `foo.bar` to the empty string which `git config
>   --type=bool` will convert to `false`.
>
> If the variable really is set to false, how might we proceed here? Shall
> we stick with test_when_finished?

That's probably reasonable, however, for robustness, you should probably use test_unconfig() rather than raw `git config --unset` to clear the variable.

Aside: This certainly makes one wonder if we should have a new
function in t/test-lib-functions.sh which unsets a variable for the
duration of a test only. However, that's outside the scope of this
submission.