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

On Mon, Sep 13, 2021 at 04:15:09PM -0700, Glen Choo wrote:

quoted

quoted

+	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