Re: Avery Pennarun's git-subtree?

From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Jul 21, 2010, 20:36 UTC
Message-ID: <AANLkTikl2zKcie3YGhBHrGbYbX3yB9QCtuJTKjsAfK07@mail.gmail.com>
In-Reply-To: <AANLkTinl1SB1x1bEObLIo-LWjvxM-Yf1PfdUp4DNJda3@mail.gmail.com>

On Wed, Jul 21, 2010 at 19:56, Avery Pennarun <apenwarr@gmail.com> wrote:

Show 5 quoted lines

> No amount of bugfixing in git submodule can fix this workflow, because
> it's not a result of bugs.  (The bugs, particularly the
> disconnected-by-default HEADs on submodule checkouts, do make it a bit
> worse :( )  It would require a fundamental redesign to make this work
> nicely with submodules.

I think most of those can be fixed, actually. The only requirement that the git plumbing imposes on git-submodules is that a "commit" entry exist in your tree, the rest is just (ugly plumbing).

Thus, we could:

   * Hack git-submodule (or its replacement) to check import the tree
     that contains that "commit" into one central .git

   * Fix git status / git commit so that you could commit into
     submodules, i.e.:

     for each submodule in this-commit:
         chdir $submodule && commit
     done && cd $root && commit -m"bumping sumbodules"

   * Make git-push push the submodule contents and the
     superprojects. You'd just need to have commit access to the url
     listed in .gitmodules.

What's missing from that (which would be nice) is the ability to check out a subdirectory from another repository. That could (I think) be done by just adding a normal "tree" entry, and then specifying that that tree can be found in git://... instead of the main tree.

> If we can get some kind of consensus in principle that git-subtree is
> a good idea to merge into git core, I can prepare some patches and we
> can talk about the details.

From having looked at it briefly it looks very nice. But it looks to me as if the main differences between git-submodule and git-subtree are in the porcelain, not the plumbing.

It would be a lot less confusing to users of Git in the long term if we would at least try to unify these two approaches instead of having two mutually incompatible ways of doing essentially the same thing.