From: Johannes Sixt <j6t@kdbg.org>
Date: Mon, 11 Jan 2010 21:05:54 GMT
Subject: Re: [PATCH 9/9] rerere forget path: forget recorded resolution
Message-ID: <201001112205.54404.j6t@kdbg.org>
In-Reply-To: <7v3a2cif04.fsf@alter.siamese.dyndns.org>

On Montag, 11. Januar 2010, Junio C Hamano wrote:
> Actually it is _very_ easy to fool rerere to do something totally
> unexpected, and I have been thinking about using the similarity comparison
> algorithm on the region outside the conflicted area between preimage and
> thisimage and reject use of rerere.
>
> Try this in an empty directory.
>[snip]
> Now, immediately after this sequence, rerere will give you an disaster.

Indeed. The problem here is that two entirely different resolutions are 
recorded for the same conflict hash *in one run of rerere*. The damage can be 
avoided if conflict hashes are not reused in do_plain_rerere (in the first 
loop). (Though, I'm currently not in the mood to look into this in more 
depth.)

Of course, this does not mean that *both* conflicts can be resolved 
automatically when the merge is repeated. In my use-case this would have been 
desirable (and even your example would suggest it is, but that is not 
generally true).

-- Hannes