Re: [PATCH 0/2] A new merge algorithm, take 3

From: Fredrik Kuivinen <freku045@student.liu.se>
Date: Sep 8, 2005, 06:06 UTC
Message-ID: <20050908060651.GA22734@c165.ib.student.liu.se>
In-Reply-To: <Pine.LNX.4.63.0509071409470.23242@iabervon.org>

On Wed, Sep 07, 2005 at 02:33:42PM -0400, Daniel Barkalow wrote:

Show 20 quoted lines

> On Wed, 7 Sep 2005, Fredrik Kuivinen wrote:
> 
> > Of the 500 merge commits that currently exists in the kernel
> > repository 19 produces non-clean merges with git-merge-script. The
> > four merge cases listed in
> > <20050827014009.GB18880@c165.ib.student.liu.se> are cleanly merged by
> > git-merge-script. Every merge commit which is cleanly merged by
> > git-resolve-script is also cleanly merged by git-merge-script,
> > furthermore the results are identical. There are currently two merges
> > in the kernel repository which are not cleanly merged by
> > git-resolve-script but are cleanly merged by git-merge-script.
> 
> If you use my read-tree and change git-resolve-script to pass all of the 
> ancestors to it, how does it do? I expect you'll still be slightly ahead, 
> because we don't (yet) have content merge with multiple ancestors. You 
> should also check the merge that Tony Luck reported, which undid a revert, 
> as well as the one that Len Brown reported around the same time which had 
> similar problems. I think maintainer trees are a much better test for a 
> merge algorithm, because the kernel repository is relatively linear, while 
> maintainers tend more to merge things back and forth.

Junio tested some of the multiple common ancestor cases with your version of read-tree and reported his results in <7virxeycod.fsf@assigned-by-dhcp.cox.net>.

The two cases my algorithm merges cleanly and git-resolve-script do not merge cleanly are 0e396ee43e445cb7c215a98da4e76d0ce354d9d7 and 0c168775709faa74c1b87f1e61046e0c51ade7f3. Both of them have two common ancestors. The second one have, as far as I know, not been tested with your read-tree.

The merge cases reported by Tony Luck and Len Brown are both cleanly merged by my code.

You are probably right about the maintainer trees. I should have a look at some of them. Do you know any specific repositories with interesting merge cases?

- Fredrik