Re: [PATCH] fetch: ensure submodule objects fetched

> Currently when git-fetch is asked to recurse into submodules, it dispatches
> a plain "git-fetch -C <submodule-dir>" (with some submodule related options
> such as prefix and recusing strategy, but) without any information of the
> remote or the tip that should be fetched.
>
> But this default fetch is not sufficient, as a newly fetched commit in
> the superproject could point to a commit in the submodule that is not
> in the default refspec. This is common in workflows like Gerrit's.
> When fetching a Gerrit change under review (from refs/changes/??), the
> commits in that change likely point to submodule commits that have not
> been merged to a branch yet.
>
> Fetch a submodule object by id if the object that the superproject
> points to, cannot be found. For now this object is fetched from the
> 'origin' remote as we defer getting the default remote to a later patch.
>
> A list of new submodule commits are already generated in certain
> conditions (by check_for_new_submodule_commits()); this new feature
> invokes that function in more situations.
>
> The submodule checks were done only when a ref in the superproject
> changed, these checks were extended to also be performed when fetching
> into FETCH_HEAD for completeness, and add a test for that too.
>
> Signed-off-by: Stefan Beller <sbeller@google.com>
> ---
>
> Thanks Jonathan for the review!
> So it looks like only the last patch needs some improvements,
> which is why I'd only resend the last patch here.
> Also note the test with interious superproject commits.