Re: Retrospectively add alternates to a repository?

From: Steve Folly <steve@spfweb.co.uk>
Date: Feb 27, 2010, 11:43 UTC
Message-ID: <loom.20100227T123539-643@post.gmane.org>
In-Reply-To: <20100227083418.GC27191@coredump.intra.peff.net>

Jeff King <peff <at> peff.net> writes:

Show 40 quoted lines

> 
> On Sat, Feb 27, 2010 at 10:37:25AM +0800, Tay Ray Chuan wrote:
> 
> > yes, just make sure the objects/info/alternates file points to the
> > location of that cloned repo's object directory; for example:
> > 
> >   $ echo /path/to/cloned/repo/.git/objects > .git/objects/info/alternates
> 
> You will probably want to then get rid of anything in the child that is
> now available in the alternates repository.
> 
> I would have thought "git repack -adl" works, but I think there is
> something a little funny in the logic. It reports "nothing new to pack",
> but does not delete the loose objects. But packing first then worked:
> 
>   $ git clone large-parent child
>   $ echo $PWD/large-parent/.git/objects >child/.git/objects/info/alternates
>   $ cd child
> 
>   $ du -sh .git/objects
>   51M     .git/objects
> 
>   $ git repack -adl && du -sh .git/objects
>   Nothing new to pack.
>   51M     .git/objects
> 
>   $ git repack -ad && du -sh .git/objects
>   Counting objects: 3, done.
>   Delta compression using up to 2 threads.
>   Compressing objects: 100% (2/2), done.
>   Writing objects: 100% (3/3), done.
>   Total 3 (delta 0), reused 0 (delta 0)
>   51M     .git/objects
> 
>   $ git repack -adl && du -sh .git/objects
>   Nothing new to pack.
>   20K     .git/objects
> 
> -Peff
>

Excellent, this is exactly what I need. Thanks very much Tay
 and Jeff.

I now have a plan to write a script to attach and detach repositories to and from local mirrors on demand:

attach = 
    echo "/path/to/mirror" > .git/objects/info/alternates && 
    git repack -adl && 
    git repack -ad && 
    git repack -adl

detach = 
    git repack -a && 
    rm .git/objects/info/alternates

Cheers, Steve