Re: bogus merges

From: Linus Torvalds <torvalds@osdl.org>
Date: Sep 5, 2005, 16:01 UTC
Message-ID: <Pine.LNX.4.58.0509050853080.3568@evo.osdl.org>
In-Reply-To: <59a6e58305090507387d412b3d@mail.gmail.com>

On Mon, 5 Sep 2005, Wayne Scott wrote:

>
> A recent commit in linux-2.6 looks like this:

It hopefully shouldn't happen any more with the improved and fixed git-merge-base.

> Author: Russell King <rmk@dyn-67.arm.linux.org.uk>
> Date:   Wed Aug 31 10:12:14 2005 +0100

I suspect rmk is using cogito-0.13, and that it still has the older git-merge-base that can get confused by the date-ordering problem. And when git-merge-base gives the wrong result (not either of the commit objects it was given as an argument), then "git resolve" will do the wrong thing.

I just checked, and the _current_ git-merge-base definitely gives the right result:

	linux$ git-merge-base -a \
		6b39374a27eb4be7e9d82145ae270ba02ea90dc8 \
		194d0710e1a7fe92dcf860ddd31fded8c3103b7a

results in

	194d0710e1a7fe92dcf860ddd31fded8c3103b7a

ie it correctly notices that the second commit is the parent of the first one.

> Really 'git commit' should detect problems like this automatically and
> prevent them from getting in the tree.

Well, that would depend on having the fixed git-merge-base in the first place, which in turn would mean that such a commit wouldn't happen at all, so it's kind of circular. It's not worth fixing anywhere else, since once you fix it in git-merge-base, it just becomes a non-issue.

Hopefully we'll have a new cogito release soon, and this particular bug will be a thing of the past.

		Linus