From: Jeff King <peff@peff.net>
Date: Mon, 08 Apr 2013 21:36:52 GMT
Subject: Re: [RFC/PATCH 0/7] Rework git core for native submodules
Message-ID: <20130408213652.GE9649@sigill.intra.peff.net>
In-Reply-To: <51632B95.3040103@web.de>

On Mon, Apr 08, 2013 at 10:41:57PM +0200, Jens Lehmann wrote:

> (While it is easier to merge the link object, a .gitmodules
> aware merge driver would work just as well)

I have not been following this thread that closely, so apologies if I
missed it, but one thing I have not seen mention of is how the extra
information inside the gitlink object will require extra merge effort.

Imagine I have two branches; one updates the submodule's commit pointer,
and the other updates some meta-information about the submodule (e.g.,
it points the URL to a new host). In the current system, one change goes
into .gitmodules, and the other goes into the gitlink path. In a new
combined object, there is a conflict and we must do content-level
merging on it (which presumably would be done with a specialized merge
driver).

So I think that in some cases .gitmodules creates more conflicts
(submodule A and submodule B are touched and have a textual conflict),
and sometimes the combined object would create more objects (you touch
two parts of the of the combined object). The solution in both cases is
a smarter merge driver that understands which parts semantically
conflict and which parts do not.

-Peff