Re: [PATCH v3 0/4] cache parent project's gitdir in submodules

[Derrick Stolee <stolee@gmail.com>]

On 8/19/2021 4:09 PM, Emily Shaffer wrote:
> Since v2, mostly documentation changes and a handful of small nits from
> Junio and Jonathan Tan. Thanks for the reviews, both.

Sorry to show up late with many questions (mostly because my understanding
of submodules is not as strong as yours), but I do have some concerns that
we have not covered all the cases that could lead to the relative path
needing an update, such as a 'git checkout' across commits in the super-
project which moves a submodule.

Leading more to my confusion is that I thought 'git submodule update'
was the way to move a submodule, but that does not appear to be the case.
I used 'git mv' to move a submodule and that correctly updated the
.gitmodules file, but did not run any 'git submodule' subcommands (based
on GIT_TRACE2_PERF=1).

You mention in an earlier cover letter that this config does not need to
exist, but it seems to me that if it exists it needs to be correct for us
to depend on it for future features. I'm not convinced that we can rely
on it as-written, but you might be able to convince me by pointing out
why these submodule movements are safe.

Thanks,
-Stolee