Re: [boost] torvalds on branching/merging (was Boost Development Environment proposal)

From: troy d straszheim (troy_at_[hidden])
Date: 2007-06-08 09:34:54

On Thu, Jun 07, 2007 at 04:49:01PM +0200, Julio M. Merino Vidal wrote:
> I am a big fan of DVCS systems, so I felt the need to chime in.  See  
> below.
> 

Hey Julio,

Thanks a lot for chiming in.  I found your comments very interesting
(will comment directly in a minute though I don't have much to add).

I do have some questions about the talk...  I'm going back it and came
across a section at ~45:00 where Linus mentions 'superprojects'.  I'm
trying to determine if this parallels the way I have been using
subversion+externals.

He is talking about performance and points out that, if your
repository is very large, initial clone operations will be slow, since
you have to download the entire history of this repository.  He goes
on to say that if you have a multiple components, you should put them
in separate repositories.  You then have a 'superproject' that
contains 'pointers' to other projects.  You keep separate projects
separate.  If you have a library, for instance, that is used by
several components, you would put this in a separate repository.  He
mentions that the UI is still rough in this area.

If you know about this stuff, could you discuss it a bit?
Specificially, I'm wondering:

- what does the syntax look like (just for the sake of concreteness)?  

- If I branch my superproject, what happens to my subprojects?
  anything?

- If I was working on a superproject and discovered that I needed to
  branch four components simultaneously (e.g. they were somehow
  interdependent and i wanted to detangle them), how would I do it?

- How widespread is the use of superprojects in the kernel....  how
  many projects does the toplevel superproject contain?

Thanks in advance,

-t