[darcs-devel] Re: A darcs that can pull from git

[David Roundy]

On Tue, Apr 26, 2005 at 02:34:45PM +0200, Petr Baudis wrote:
> Dear diary, on Tue, Apr 26, 2005 at 01:06:17PM CEST, I got a letter
> where David Roundy <droundy at abridgegame.org> told me that...
> > Do the git have any suggestions about how to avoid excess downloads or
> > excess copies of a git repository? It seems to me like it would make sense
> > to always download sha1s to ~/.gitcache/, and then hardlink them to the
> > current git repository, so you wouldn't end up ever downloading the same
> > sha1 twice.  Or we should use $GITCACHE/, to give the user some
> > flexibility.  But perhaps this is an already-solved problem, and I've just
> > not noticed...
> 
> I'm not sure about the problem you are actually trying to solve, and I
> didn't manage to guess it quickly just from the mails themselves;
> cg-init /local/path now hardlinks the sha1 objects to the local
> .git/objects directory, so you get no space waste. If you are talking
> about downloading stuff from remote repositories, http-pull might help.

Yeah, what I was wondering about was the scenario where a user does (and
pardon any errors, I haven't actually used cogito) something like

cd foo
cg-init http://remote_repository
cd ../bar
cg-init ../foo

(so far we've only got hard links and everything is great)

http-pull http://remote_repository (downloads a few more commits to bar)
cd ../foo
http-pull http://remote_repository

Does this last pull download the same commits as the previous one? Ideally
it wouldn't.  The whole point of the sha1-named files is that you don't
have to worry about where you got it from.  Ideally the second pull would
get the actual files from ../bar, where they've already been downloaded.

Or perhaps (and this was what I was *really* hoping) all the cogito remote
operations would store a hardlink of their results in a common cache
directory, so that one could actually do

cd foo
cg-init http://remote_repository
cd ../bar
cg-init http://remote_repository

without either downloading anything twice, or wasting any disk space.  In
practice what's more likely in practice is that you'll want to

cd foo
cg-init http://linus_remote_repository
cd ../bar
cg-init http://gregkh_remote_repository

and would like to avoid downloading redundant info.
-- 
David Roundy
http://www.darcs.net