Re: [RFC] Support projects including other projects

I think that the core of your idea of recording "required
version" of the depended project (core GIT) in the depending
project (Cogito) is a very sound one.  GNU Arch folks do
something similar in their "package-framework" stuff.  

I however do not think that belongs to the core GIT nor even to
Cogito for that matter.  To me, it feels like this is a pure
build infrastructure issue.

I think you could arrange something like that with today's core
GIT tools, like this:

 - Tweak Cogito Makefile so that pure Cogito and core GIT are
   housed in separate subdirectories;

 - Add "required-git-pb" file to Cogito source as a tracked
   source file, and record the required version of git-pb there;

 - Arrange Cogito Makefile to make sure the subtree that has the
   core GIT side meets "required-git-pb" constraints.  The
   constraints could be "at least contains this one", "exactly
   this one".  The policy would be differnt from a depending
   project to another.  What happens if the requirements are not
   met is also up to the policy of that depending project.