Re: [RFC] Submodules in GIT

[Josef Weidendorfer <Josef.Weidendorfer@gmx.de>]

On Friday 01 December 2006 23:12, Martin Waitz wrote:
> hoi :)
> 
> On Fri, Dec 01, 2006 at 11:06:40PM +0100, Josef Weidendorfer wrote:
> > > Well, I would actually argue that you may often want to have a
> > > supermodule and then at least have the _option_ to decide to not
> > > fetch all the submodules.
> > 
> > If you want to allow this, you have to be able to cut off fetching the
> > objects of the supermodule at borders to given submodules, the ones you
> > do not want to track. With "border" I mean the submodule commit in some
> > tree of the supermodule.
> 
> I don't think this is something special to submodules.  There has been
> interest in checking out only a part of the tree even before talking
> about submodules and I really think this feature should be independent
> to submodules.

After some thinking, a submodule namespace even is important for checking
out only parts of a supermodule, exactly because the root of a submodule
potentially can change at every commit.

When checking out some arbitrary supermodule commit, how do you check that
at some submodule border, the user did not want to check out the submodule
at all? You need a way to check the DAG identity you are diving
into at this border: lets say by going to the root commit of this DAG (!).
And via this identity, you have to check whether the user had
specified that he wants the submodule to be check out.
Without any further meta information (indexed by a submodule name!), this
information is only available from the checkout the user switched from,
as there would be no file in the working tree from this submodule?

Quite a pain.