Re: [IRC/patches] Failed octopus merge does not clean up

> Dnia wtorek 16. września 2008 02:20, Junio C Hamano napisał:
>> Junio C Hamano <gitster@pobox.com> writes:
>>> Thomas Rast <trast@student.ethz.ch> writes:
>>>
>>>> The merge says
>>>>
>>>>   Trying simple merge with 5b3e4bb1c2d88d6967fb575729fbfc86df5eaec9
>>>>   Simple merge did not work, trying automatic merge.
>>>>   Auto-merging foo
>>>>   ERROR: Merge conflict in foo
>>>>   fatal: merge program failed
>>>>   Automated merge did not work.
>>>>   Should not be doing an Octopus.
>>>>   Merge with strategy octopus failed.
>>> ...
>>> Read the second from the last line of what you were told by git.  Run "git
>>> reset --hard" after that, perhaps.
> 
> The problem, as far as I understand it, is not that octopus merge fails.
> The problem is that it fails halfway, and it leaves working are in
> inconsistent state: git-status output with its "unmerged" suggests that
> we are in the middle of the merge, but we are not.
> 
>> By the way, there are three failure modes in Octopus.
>>
>>  (0) your index (not work tree) is dirty; this is not limited to octopus
>>      merge but any merge will be refused;
> 
> IIRC the idea of stashing away changes, doing merge, and then unstashing
> was shot down as encouraging bad workflows, and more often than not
> leading only to mess in workdir and index.
> 
>>  (1) while it merges other heads one-by-one, it gets conflicts on an
>>      earlier one, before it even attempts to merge all of them.  Recording
>>      the heads that it so far attempted to merge in MERGE_HEAD is wrong
>>      (the result won't be an Octopus the end user wanted to carete), and
>>      recording all the heads the user gave in MERGE_HEAD is even more
>>      wrong (it hasn't even looked at the later heads yet, so there is no
>>      way for the index or work tree to contain anything from them).
>>
>>      The above is hitting this case.
> 
> IMVHO the correct solution would be to rollback changes to the state
> before attempting a merge. I'd rather 'octopus' did its thing as
> transaction; contrary to ordinary merges if merge fails it doesn't
> mean necessary that it is in the state of resolvable conflict, state
> we can stop at. Perhaps (if it is still a shell script, doing git-stash
> at beginning, and either dropping or popping the stash at the end;
> or just saving old index if it is built-in).
> 
> 
> BTW. does it mean that "git merge a b" might be not the same as
> "git merge b a"?
>