Re: [RFC] Submodules in GIT

[sf <sf@b-i-t.de>]

Andreas Ericsson wrote:
...
> The only problem I'm seeing atm is that the supermodule somehow has to 
> mark whatever commits it's using from the submodule inside the submodule 
> repo so that they effectively become un-prunable, otherwise the 
> supermodule may some day find itself with a history that it can't restore.

That has nothing to do with submodules. What you state here is the 
problem of alternate repositories.

There are two solutions:

1. Do not use alternates.

2. Do not prune a repository that is used as an alternate repository by 
other repositories.

For the submodule discussion that would mean:

1. Only fetch and work on branches of submodules you are interested in. 
It does not matter that the origin repository contains (probably orders 
of magnitude) more data. You will never touch that.

2. You can never prune the main (the supermodule's) repository, at least 
not with what git provides today.

That is why the sanest approach to subprojects is to put commits into 
tree objects, define a way to name these commits and make git understand 
these new commit names. Done. Works.

Regards

Stephan