Re: git cloning paths

From: Jeff King <peff@peff.net>
Date: Jul 13, 2012, 08:07 UTC
Message-ID: <20120713080731.GA32303@sigill.intra.peff.net>
In-Reply-To: <CANmEAK_jGdzR9R=0DexC+-_0U6mb_7o_v5zSKTuhgoaYCaSiFQ@mail.gmail.com>

On Thu, Jul 12, 2012 at 03:17:09PM -0700, Douglas Garstang wrote:

Show 10 quoted lines

> I'm a relative newcomer to git and I've just inherited a setup where
> all of the company's code is in a single git repository. Within this
> repository are multiple projects. It seems that git doesn't natively
> allow cloning/checking out of individual paths within the repo (ie
> projects), which would seem to make integrating git with a continuous
> build system rather difficult. That is, the build system has to clone
> the entire repo, and therefore a change to any project will result in
> the entire contents of the repo being built.
> 
> Correct....?

Yes. The feature you are looking for is either "sparse checkout" (only check out a subset of the files in the repository databse to the working tree) or "sparse clone" (only copy a subset of the files into the local repository database during clone). Git v1.7.0 and later has sparse checkout (see the "sparse checkout" section in "git help read-tree"). There is no implementation for sparse clone (and not likely to be one any time soon, as it introduces a lot of complexity into the object negotiation phase).

The usual advice is that you should break up your big repository into logical projects. You can do so with git-filter-branch, but beware that this involves rewriting history, which means a flag day for everybody switching to the new history (or dealing with migrating commits from the old history to the new history via rebase).

Finally, if you have a build system which is cloning repeatedly, you may want to keep a repository on the build server all the time and just fetch the updates into it. This is much more efficient even if you do end up paring down your repository.

-Peff