Re: [RFC/PATCHv2] git submodule split

[Lars Hjemli <hjemli@gmail.com>]

[* sorry for the late reply *]

On Tue, Feb 17, 2009 at 11:17, Nanako Shiraishi <nanako3@lavabit.com> wrote:
> Quoting Lars Hjemli <hjemli@gmail.com>:
>
>> I didn't look at the patch, but if the submodule uses a single
>> module-name while moving around, the re-cloning problem would by
>> solved if the submodule git-dir was stored inside the git-dir of the
>> containing repository  (by using the git-file mechanism). Maybe I
>> should try to finally implement this...
>
> Is it similar to what was discussed earlier in the thread
> http://thread.gmane.org/gmane.comp.version-control.git/47466/focus=47621
> (I asked gmane for "submodule relocate")?

Well, kind of. We ended up with a scheme similar to what Junio
described in the linked mail: every submodule in a repository is given
a canonical name by the .gitmodules file and this name is then linked
with a url in .git/config. The .gitmodules file also states at which
path(s) this submodule is located. So we can keep track of which
submodules we're interested in (and what urls to use for fetching
objects to those submodules) irrespective of the path used to check
out the submodules.

But when we're switching between branches in which a submodule is
checked out at different paths, we currently loose track of both the
old worktree and its gitdir. My gitfile proposal would salvage the
gitdir but, as Dscho mentioned, uncommited+untracked data in the
worktree would not be handled.

So I currently think it's better to make `git submodule init` update
.git/config with information about the current submodule path (again,
as Dscho mentioned). Then, after switching branches, `git submodule
<some-verb>` could notice that the current path is different from the
one in .git/config and simply `mv oldpath newpath` before updating
.git/config with the new path.

Btw. this wouldn't work smoothly if a single submodule was checked out
at multiple paths in the same revision, but I don't see why anyone
would want to do something like that...

--
larsh