Re: [BUG?] git submodule update --remote assumes 'origin' remote

> I think I've found a bit of an edge case in
> `git submodule update --remote` [1] that got easier to reproduce in
> 2.30+ under certain configurations.
> `git submodule--helper print-default-remote` defaults to 'origin' when
> run in a submodule in a detached HEAD state or on a branch with no
> remote tracking branch [1].  In git < 2.30, the only way for that
> default to be incorrect required a user to manually change remote names
> with something like `git -C ./some-sm remote rename origin foo`.
> `git rev-parse`ing that ref would naturally fail, but at least it's
> because the user took manual steps to break git's assumptions.
>
> Under git 2.30+ with clone.defaultRemoteName set however, submodules are
> created with that remote name instead of 'origin'.  The same behavior
> occurs, but this time without direct user action - only a simple
> `git submodule init && git submodule update --remote` is required.
>
> I'm terribly sorry about that regression - I've only just started
> working on a few projects that use submodules heavily and probably could
> have found this sooner.  I'm happy to fix it, but would *super*
> appreciate a little guidance.  It seems the intention is "use the remote
> that has the url found in the superproject's .submodules entry", that'd
> require `git submodule--helper print-default-remote` to be called from
> the superproject from what I can tell.  I've experimented with
> introducing fallbacks to `remote_for_branch` in `remote.c` [2] as an
> alternative:
>
> 1. use remote tracking branch; or
> 2. if there's only one remote, use that; or
> 3. if config.defaultRemoteName is set, use that; or
> 4. fall back to "origin"
>
> This seems to work (at the very least, no tests fail?), but leaves
> `cd ./some-sm; git remote add foo bar; git remote rename origin baz`
> open to the original behavior.
>
> Something tells me y'all will have a very simple solution that I'm
> missing :)
>
> Again, I'm so sorry for introducing a regression here!
> Sean Barag