Re: A rebase regression in Git 2.18.0

[Elijah Newren <newren@gmail.com>]

On Tue, Aug 28, 2018 at 9:58 AM Junio C Hamano <gitster@pobox.com> wrote:
>
> Elijah Newren <newren@gmail.com> writes:
>
> >   - Add a flag to turn off directory rename detection, and set the
> > flag for every call from am.c in order to avoid problems like this.
>
> I'd say this is the only practical solution, before you deprecate
> the "pipe format-patch output to am -3" style of "git rebase" (and
> optionally replace with something else).

I posted a patch a while back to add an --am flag to "git rebase",
make "--am" be implied by options which are still am-specific
(--whitespace, --committer-date-is-author-date, and -C), and change
--merge to be the default.

I'll post it as an RFC again after the various rebase-rewrite series
have settled and merged down...along with my other rebase cleanups
that I was waiting on to avoid conflicts with GSoC stuff.

> The whole point of "am -3" is to do _better_ than just "patch" with
> minimum amount of information available on the pre- and post- image
> blobs, without knowing the remainder of the tree that the patch did
> not touch.  It is not surprising that the heuristics that look at
> the unchanging part of the tree to infer renames that may or may not
> exist guesses incorrectly, either with false positive or negative.
> In the context of "rebase", we always have all the trees that are
> involved.  We should be able to do better than "am -3".