Re: [PATCH v2] Add --track option to git clone

From: Jeff King <peff@peff.net>
Date: Dec 2, 2009, 19:08 UTC
Message-ID: <20091202190807.GB30778@coredump.intra.peff.net>
In-Reply-To: <20091202192028.6117@nanako3.lavabit.com>

On Wed, Dec 02, 2009 at 07:20:28PM +0900, Nanako Shiraishi wrote:

Show 14 quoted lines

> Quoting David Soria Parra <sn_@gmx.net> writes:
> 
> > I'm aware that it's not possible to give more than one --track
> > option. Implementing the possibility to specify multiple --track option
> > would certainly a good improvment later, but would also require a lot
> > more work as far as I understand the clone code.
> 
> I'm sorry if I'm asking the obvious, but how can multiple --track 
> options be a useful future enhancement? If I understand your use 
> case correctly, it's useful when you want to work on only one 
> branch that isn't the default, and that is why you don't want to 
> get data necessary for other branches. What does it mean to give 
> two --track options? You will get one master branch that tracks
> both versions, and "git pull" will merge both branches you track?

I would find something like this useful for cloning git.git, where I explicitly fetch maint, master, next, and pu, but none of html, man, or todo. This makes "gitk --all" much nicer to view.

However, I don't think --track is the right term. There are really two things happening here:

  1. Setting the fetch refspec(s).

  2. Choosing an initial branch to checkout.

We can already do (2) with "-b". But there is no way to do (1) currently. If we are going to implement (1), I don't see a reason to be restrictive about it. We should really accept arbitrary refspecs, and then provide a syntax on top of that for doing both (1) and (2) together. I am thinking something like:

  # most general case
  git clone -f 'refs/heads/subset/*:refs/remotes/origin/*' remote.git

  # expands to refs/heads/subset/*:refs/remotes/origin/*
  git clone -f 'refs/heads/subset/*' remote.git

  # expands to refs/heads/subset/*, which then expands as above
  git clone -f 'subset/*' remote.git

  # multiple -f should add multiple refspec lines
  git clone -f maint -f master -f next -f pu git.git

  # choose your favorite branch
  git clone -f maint -f master -f next -f pu -b next git.git

And for convenience of the user, you would want a way to avoid repeating the name of the "I want to check this out" branch. So either:

  1. Add "--track foo" as a convenience wrapper for "-f foo -b foo".

  2. If no "-b" is given, the first "-f" is assumed as "-b". So "git
     clone -f foo" becomes equivalent to David's --track.

And of course the name "-f" (for --fetch, if you were wondering) is open to suggestion.

What do you think?

-Peff