[PATCH 0/3] Turn off directory rename detection in am -3

From: Elijah Newren <newren@gmail.com>
Date: Aug 29, 2018, 07:06 UTC
Message-ID: <20180829070613.11793-1-newren@gmail.com>
In-Reply-To: <xmqqh8jeh1id.fsf@gitster-ct.c.googlers.com>

On Tue, Aug 28, 2018 at 9:58 AM Junio C Hamano <gitster@pobox.com> wrote:

Show 17 quoted lines

> 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).
>
> 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".

Here are patches to do so; they are built on the top of en/rebase-consistency, since I wanted to re-use some test code and the testfile introduced in that series, and to keep similar tests together.

Elijah Newren (3):
  t3401: add another directory rename testcase for rebase and am
  merge-recursive: add ability to turn off directory rename detection
  am: avoid directory rename detection when calling recursive merge
    machinery

 builtin/am.c                    |   1 +
 merge-recursive.c               |  18 ++++--
 merge-recursive.h               |   1 +
 t/t3401-rebase-and-am-rename.sh | 110 +++++++++++++++++++++++++++++++-
 4 files changed, 124 insertions(+), 6 deletions(-)

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2.18.0.12.g97a29da30a