Version control systems

[Max Bolingbroke]

2008/8/15 Ian Lynagh <igloo at earth.li>:
>> You can explicitly tell Git about nested Git repos using
>> http://www.kernel.org/pub/software/scm/git/docs/git-submodule.html.
>> This essentially associates a particular version of each subrepo with
>> every version of the repo that contains them, so e.g. checking out GHC
>> from 2 weeks ago could check out the libraries from the same point in
>> time.
>
> We were talking about this last night on #ghc, and AIUI this doesn't
> play well with the in-tree branching style that is advocated, e.g. if
> you want to branch ghc and base then as you change between ghc branch X
> and Y, git won't automatically change base between branches X' and Y'.

If you change the submodules in branch X to point to the X' commit in
base, and do the corresponding thing for Y and Y', I believe you
/would/ get this behaviour (though you might have to remember to do
"git submodule update" when switching.. this can probably be
automated).

Provisio: I'm also not a Git expert, but this is my understanding of
how it works.

Cheers,
Max