Re: [PATCH] rebase: Allow merge strategies to be used when rebasing

[Junio C Hamano <junkio@cox.net>]

Eric Wong <normalperson@yhbt.net> writes:

> Junio C Hamano <junkio@cox.net> wrote:
>
>>  - You kept the original "format-patch piped to am" workflow
>>    optionally working.
>
> I left it as the default, too.  I figured that it's best not
> to change the default (and most likely faster) behavior of
> something people rely on.

I should have said: "You kept ... working, which is good".

>> I think the three-way merge you would want here is not between B
>> and G using E as the pivot, but between B and G using A as the
>> pivot.  That's how cherry-pick and revert works.  I would
>> leverage the interface that is one level lower for this -- the
>> strategy modules themselves.
>> 
>> 	git-merge-$strategy $cmt^ -- HEAD $cmt
>
> Changing the 'git-merge $strategy_args "rebase-merge: $cmt" HEAD "$cmt"'
> line in call_merge() to this seems to have broken more tests.

Oh, that is to be expected if you changed git-merge -s recursive
with git-merge-recursive without other changes.  The former
makes a commit (which your original patch later used to create a
separate commit chain and discarded); the latter does not make a
commit but expects the caller to create a commit out of the
resulting index file.

> I'm not an expert at merging strategies by any measure, I've just
> trusted merge-recursive to Do The Right Thing(TM) more often than not,
> and use rerere to avoid repeating work.

I was originally hoping that rebasing would just be a matter of
listing sequence of commits to be ported onto a new base and
running "git-cherry-pick" on each of them in sequence.  Now
cherry-pick does not use merge machinery (hence does not use
git-merge-recursive), but if we change that then updating rebase
would be pretty much straightforward.  It just needs a UI layer
to guide the user through recovery process when the merge does
not resolve cleanly in the middle, no?