Re: Opinions on changing add/add conflict resolution?

From: Elijah Newren <newren@gmail.com>
Date: Mar 13, 2018, 23:14 UTC
Message-ID: <CABPp-BE=D_TgjLZkhRh6-7k3UpnDDMfZB6vE=FMdwFT+mmp_tw@mail.gmail.com>
In-Reply-To: <20180313225639.GC147135@aiede.svl.corp.google.com>

On Tue, Mar 13, 2018 at 3:56 PM, Jonathan Nieder <jrnieder@gmail.com> wrote:

Show 11 quoted lines

> Elijah Newren wrote:
>
>> However, my question here about what to write to the working tree for
>> a rename/rename(2to1) conflict in one particular corner case still
>> remains.  Should a two-way merge be performed even if it may result in
>> nested sets of conflict markers, or is that a sufficiently bad outcome
>> for the user that it's the one case we do want to write colliding
>> files out to different temporary paths?
>
> Nested conflict markers only happen in the conflictstyle=diff3 case, I
> would think.

Currently, yes. To be clear, though, this change would make it possible even when there is no recursive merge being done and when conflictstyle=merge.

Show 6 quoted lines

> merge-recursive writes them already.  I've often wished that it would
> use a union merge strategy when building the common ancestor to avoid
> the nested conflicts that rerere doesn't understand.  But anyway,
> that's an orthogonal issue: in the rename/rename context, it should be
> fine to write nested conflict markers since that's consistent with
> what merge-recursive already does.

Cool, sounds like we're now all on the same page.

Someone in the future might hate us if they use conflictstyle=diff3, and have a recursive merge, and have a rename/rename(2to1) conflict in the virtual merge base with nested conflicts, and that resulting file is also involved in a separate rename/rename(2to1) conflict in the outer merge that has its own nested conflicts; we'd have up to four levels of nested conflicts. But for now, I'm going to write that off as a crazy thought (or dismiss it as nigh impossible to reason about regardless of what we did to help them) and just proceed ahead. :-)