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

[Taylor Blau <me@ttaylorr.com>]

On Mon, Sep 13, 2021 at 04:15:09PM -0700, Glen Choo wrote:
> > > +	cd "$TRASH_DIRECTORY/full" &&
> > > +	git fsck &&
> > > +	corrupt_graph_and_verify $GRAPH_BYTE_FOOTER "\00" \
> > > +		"incorrect checksum" &&
> > > +        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?

Hmm, I thought that we did support `git -c foo.bar=` as shorthand to
unset the key `foo.bar`, but I must have been mistaken, because the
documentation there is quite clear.

In that case, I think your original approach to use test_when_finished
makes sense and is good. Thanks for double checking!

Thanks,
Taylor