Re: [RFD] Long term plan with submodule refs?

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 9, 2017, 05:47 UTC
Message-ID: <xmqq7ev0j95t.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20171108172945.33c42a0e91b4ac494217b788@google.com>

Jonathan Tan <jonathantanmy@google.com> writes:

Show 7 quoted lines

> What if, in the submodule, we have a new ref backend that mirrors the
> superproject? When initializing the submodule, its original refs are not
> cloned at all, but instead virtual refs are used.
> ...
> These rules seem straightforward to me (although I have been working
> with Git for a while, so perhaps I'm not the best judge), and I think
> leads to a good workflow, as discussed below.

Indeed this is intriguing.

Show 7 quoted lines

> The above rules allow the following workflow:
>  - "checkout --recurse-submodules" the branch you want on the
>    superproject
>  - make whatever changes you want in each submodule
>  - commit each individual submodule (which updates the index of the
>    superproject), then commit the superproject (we can introduce a
>    commit --recurse-submodules to make this more convenient)

The "recurse" option would also give users an extra atomicity, and would not be merely for convenience; when a user wants to treat a superproject and its two submodules as if the combined whole were a single repository, there shouldn't be two separate commits in the history of the superproject only because two submodules made one commit each to work on a single theme that spans all of them.