Re: [PATCH/RFC] init, clone: support --real-git-dir for .git file

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 4, 2011, 00:08 UTC
Message-ID: <7v8vwv927a.fsf@alter.siamese.dyndns.org>
In-Reply-To: <1299156201-12149-1-git-send-email-pclouds@gmail.com>

Nguyễn Thái Ngọc Duy  <pclouds@gmail.com> writes:

> Instead of creating the repository at $GIT_DIR, --real-git-dir will
> tell git to put the repository there, then make $GIT_DIR a .git file
> that points to --real-git-dir.

Just like you, I am also bad at naming things, so I cannot offhand suggest a better name, even though I _know_ --real-git-dir sounds horrible.

The naming aside, the feature is what we have wanted to have for a long time and is way overdue. Thanks for showing how small-impact the necessary changes are.

"submodule init subpro" should be able to use this to clone a submodule with:

	git clone --xxx=.git/modules/subpro.git subpro

When we need to switch to a revision without that submodule, after making sure that there is no precious file in subpro/ directory, we would:

	rm -rf subpro/

Now, what do we need to switch back to a revision with that submodule? It would involve something like this:

	... after checking if we already have .git/modules/subpro.git
        ... and seeing that we do ...

	mkdir subpro
	commit=$(git rev-parse :subpro)
        echo 'gitdir: ../.git/modules/subpro.git' >subpro/.git
	cd subpro && git checkout $commit^0

The above four lines packaged for "git submodule" script would be a useful thing to have, especially because then nobody has to write the "echo" part.

>  I intend to make 'git init --real-git-dir' move current repo to
>  somewhere else if called on existing repo.

I don't know if that is useful in real life. Do you have a concrete use case (like the one I showed an example above) in mind?