Re: [PATCH 5/8] rebase: introduce the --recreate-merges option

From: Sergey Organov <sorganov@gmail.com>
Date: Feb 7, 2018, 09:47 UTC
Message-ID: <876079qggl.fsf@javad.com>
In-Reply-To: <CA+P7+xqs=cEC+9LJ9VB4XZU-oS7CX6eQSNSGfPeg-whRCwU1Lg@mail.gmail.com>

Jacob Keller <jacob.keller@gmail.com> writes:

Show 24 quoted lines

> On Tue, Feb 6, 2018 at 10:16 PM, Sergey Organov <sorganov@gmail.com> wrote:
>> Johannes Schindelin <johannes.schindelin@gmx.de> writes:
>>
>> [...]
>>
>>> +--recreate-merges::
>>> +     Recreate merge commits instead of flattening the history by replaying
>>> +     merges. Merge conflict resolutions or manual amendments to merge
>>> +     commits are not preserved.
>>
>> I wonder why you guys still hold on replaying "merge-the-operation"
>> instead of replaying "merge-the-result"? The latter, the merge commit
>> itself, no matter how exactly it was created in the first place, is the
>> most valuable thing git keeps about the merge, and you silently drop it
>> entirely! OTOH, git keeps almost no information about
>> "merge-the-operation", so it's virtually impossible to reliably replay
>> the operation automatically, and yet you try to.
>>
>
> I'm not sure I follow what you mean here?
>
> You mean that you'd want this to actually attempt to re-create the
> original merge including conflict resolutions by taking the contents
> of the result?

I mean just cherry-pick the merge the same way all other commits are essentially cherry-picked during rebase. That's what Johannes Sixt did in his patch I was reffering to.

> How do you handle if that result has conflicts? What UX do you present
> to the user to handle such conflicts? I don't think the normal 3-way
> conflicts would even be possible in this case?

No problem here. It goes exactly the same way as for non-merge commits that are being rebased. You can try it right now using

$ git cherry-pick -m1 <merge_commit>

that will induce conflicts.

The (somewhat tricky) functional difference is only in recording correct additional parents to the final commit, but that part is hidden from the user.

-- Sergey