Re: [RFC 1/2] submodules: test for fetch of non-init subsub-repo

> Here is my proposal for a new commit message of the test case:
>
> ----8<----
> A regression has been introduced by 'a62387b (submodule.c: fetch in
> submodules git directory instead of in worktree, 2018-11-28)'.
>
> The scenario in which it triggers is when one has a remote repository
> with a subrepository inside a subrepository like this:
> superproject/middle_repo/inner_repo
>
> Person A and B have both a clone of it, while Person B is not working
> with the inner_repo and thus does not have it initialized in his working
> copy.
>
> Now person A introduces a change to the inner_repo and propagates it
> through the middle_repo and the superproject.
> Once person A pushed the changes and person B wants to fetch them
> using "git fetch" on superproject level, git

> will return with error saying:
>
> Could not access submodule 'inner_repo'
> Errors during submodule fetch:
>         middle_repo
>
> Expectation is that in this case the inner submodule will be
> recognized as uninitialized subrepository and skipped by the git fetch
> command.
>
> This used to work correctly before 'a62387b (submodule.c: fetch in
> submodules git directory instead of in worktree, 2018-11-28)'.
>
> Starting with a62387b the code wants to evaluate "is_empty_dir()"
> inside .git/modules for a directory only existing in the worktree,
> delivering then of course wrong return value.
> ---->8----