Re: [PATCH 9/9] rerere forget path: forget recorded resolution

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