Re: Strange merge conflicts against earlier merge.

From: Junio C Hamano <junkio@cox.net>
Date: Nov 11, 2005, 17:29 UTC
Message-ID: <7v64qzozyx.fsf@assigned-by-dhcp.cox.net>
In-Reply-To: <20051111114511.GQ30496@pasky.or.cz>

Petr Baudis <pasky@suse.cz> writes:

> Does core GIT have support for multibase merges, except for the
> recursive merge strategy? How do you do it?

There were lengthy discussion on this and a lot of work that went into the resolution. We do three things.

 - The first implementation does a trial read-tree 3-way using
   each of the base candidates without smudging the working
   tree, and counts paths that need file-level merges, to guess
   the best base, and uses that base.  This is in the 'stupid'
   stratagy.

 - The above turned out to have a risky corner case, especially
   when one side reverted a patch and the other one did not.  To
   address this, read-tree was rewritten and 3-way form of
   read-tree can take more than three trees these days, letting
   you feed it all the merge base candidates.  This code is used
   in 'resolve' strategy.

 - The 'recursive' strategy tries to come up with a merge of the
   candidate bases and uses it as the base of the final merge.