Re: [PATCH 0/5] Fix 'url.*.insteadOf' for submodule URLs

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 4, 2008, 02:06 UTC
Message-ID: <7vwsix5y9w.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <200808040147.16797.johan@herland.net>

Johan Herland <johan@herland.net> writes:

> 1. Consistency: Other git commands in the supermodule does _not_ require the 
> URL rewriting rule to reside in the global config. Why should 'git 
> submodule' be different.

When it comes to "submodules", I do not think such consistency argument makes much sense. "git submodule" command crosses module boundary, normal commands don't. They are naturally different and they should be.

Your kind of consistency means breaking the separation between module boundary, doesn't it?

Having said that...

> 2. I believe there are valid use cases for adding URL rewriting rules to the 
> repo config instead of the global config. You may want to check out Fred's 
> version of project X (including submodules), without making your other 
> clones of project X start cloning/fetching from Fred.

I think you are referring to the example given in an earlier thread to peek what your neighbor did between you two, without affecting other people.

Personally I think it is partly showing the shortcoming of the current "git submodule" that minimally supports the workflow to follow what the canonical repository does, and partly showing that it is an abuse of that interface to rewrite config file to temporarily switch to peek somewhere else in such a workflow.

Let's step back and think what we would do if there is no submodule involved. That is, you usually follow origin, but you temporarily want to peek at what Fred did. How would you do this?

	$ git fetch $fred $branch_fred_wants_you_to_review
        $ git checkout FETCH_HEAD ;# this detaches HEAD.

And you take a look around. Perhaps you like the change and decide to merge that to your branch. Perhaps you create your own branch on top of that state, build a few fix-up commits, and give the result back to Fred.

Shouldn't peeking what Fred did in the whole submodule hierarchy be essentially the same thing? That is,

	$ git submodule for-each-submodule sh -c '
                git fetch "$fred/$1" $branch_fred_wants_you_to_review &&
                git checkout FETCH_HEAD
	' -

where "for-each-submodule" would iterate over the submodules in the current superproject that you are interested in (that is, you actually have corresponding repositories there), and runs any given command with the path to the submodule in that directory.

Hmm?