From: Jeff King <peff@peff.net>
Date: Sat, 31 Jan 2009 07:12:38 GMT
Subject: Re: 'git clone' doesn't use alternates automatically?
Message-ID: <20090131071238.GC3033@coredump.intra.peff.net>
In-Reply-To: <885649360901301412jd5c6b0dne1eff1ff00dd043e@mail.gmail.com>

On Fri, Jan 30, 2009 at 03:12:42PM -0700, James Pickens wrote:

> I have a central, shared Git repository on an NFS drive at path
> $central.  I have added "$central/objects" to
> $central/objects/info/alternates.  I see that when I clone this
> repository with Git 1.6.1, the alternates file is automatically copied
> to the clone, but so are all the pack files and loose objects.  If I
> then cd to the clone and run 'git gc', it removes the redundant local
> objects.

Yes, we don't set up alternates to an origin by default. If it's a local
clone, we do hardlink by default:

  $ ls -i git/.git/objects/pack
  7639155 pack-0651ae7e35ffde1921db158a3292e1c81153be1a.idx
  7638782 pack-0651ae7e35ffde1921db158a3292e1c81153be1a.pack
  $ git clone git foo
  ...
  $ ls -i foo/.git/objects/pack
  7639155 pack-0651ae7e35ffde1921db158a3292e1c81153be1a.idx
  7638782 pack-0651ae7e35ffde1921db158a3292e1c81153be1a.pack

but presumably in your example the second clone is _not_ on the NFS
mount, and therefore can't hardlink.

So you can try "git clone -s" to specify that you definitely want
alternates.

> I thought I tested this setup a few months back, and 'git clone'
> automatically used the alternates file to avoid copying the redundant
> objects into the clone.  Has this behavior changed, or is my memory
> bad?

I don't recall clone ever being that clever, but I could be wrong (it is
not an area of the code that I am too familiar with).

Can you try a test with a few different versions to see if it ever
behaved as you expected (and if it does, bisect to find the breakage)?

-Peff