Re: [PATCH 6/6] Teach core object handling functions about gitlinks

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Apr 11, 2007, 22:36 UTC
Message-ID: <Pine.LNX.4.64.0704111532540.6730@woody.linux-foundation.org>
In-Reply-To: <20070411221930.GN21701@admingilde.org>

On Thu, 12 Apr 2007, Martin Waitz wrote:

> 
> But why does everybody want to detach the submodule HEAD, instead
> of creating one 'special' branch which holds the commit which is
> used by the supermodule?

I don't think "everybody" wants it.

But the point is, *regardless* of whether you want a "detached HEAD" or you want a "'special' branch", you should always use HEAD to look up the commit, and using HEAD *allows* both (ie just make HEAD a symref to the 'special' branch if you want that behaviour).

And if you *do* use a special branch, HEAD *must* match that special branch anyway, since when you commit in the supermodule, the only behaviour that makes sense is to commit the currently checked out state!

> I want to create the extra branch exactly _because_ there is
> independent work going on in the submodule (or the project it is
> based on).

And that is entirely appropriate.

But that still means that HEAD must point to that branch (when in the submodule), since that branch must be the one that is checked out. If it isn't the branch that is checked out, normal operations like "git diff" etc wouldn't make sense from the supermodule.

And that is why *regardless* of whether you use a special branch or not, HEAD is the right thing to look up.

		Linus