[RFC PATCH v2 0/9] Improve merge recursive performance

[Elijah Newren <newren@gmail.com>]

You probably want to wait to review this series until my rename detection
series lands so that I can clean up any more conflicts, but I'm posting
this new series in case anyone wants to take an early look.  It includes
fixes identified by the reviews of my other patch series, and has been
rebased on top of newer versions with conflicts resolved.

For the adventerous, though...

This patch series improves merge recursive performance, particularly when
one side of history only makes a small number of changes, and the other has
lots of renames (or lots of adds and deletes); I saw a speedup factor of
over 30 on one particular real world repository.

Still RFC for the same reasons that the first series was (see
https://public-inbox.org/git/20171110222156.23221-1-newren@gmail.com/), I
haven't yet had time to push this further other than rebasing and cleaning
up issues shared with my other series.

If you just want to test it out, it's available as the
'big-repo-small-cherry-pick' branch of https://github.com/newren/git .

Elijah Newren (9):
  diffcore-rename: no point trying to find a match better than exact
  merge-recursive: avoid unnecessary string list lookups
  merge-recursive: new function for better colliding conflict
    resolutions
  Add testcases for improved file collision conflict handling
  merge-recursive: fix rename/add conflict handling
  merge-recursive: improve handling for rename/rename(2to1) conflicts
  merge-recursive: improve handling for add/add conflicts
  merge-recursive: accelerate rename detection
  diffcore-rename: filter rename_src list when possible

 diff.c                               |   1 +
 diff.h                               |   7 +
 diffcore-rename.c                    |  85 ++++++-
 merge-recursive.c                    | 452 ++++++++++++++++++++++++-----------
 t/t2023-checkout-m.sh                |   2 +-
 t/t3418-rebase-continue.sh           |  27 ++-
 t/t3504-cherry-pick-rerere.sh        |  19 +-
 t/t4200-rerere.sh                    |  12 +-
 t/t6020-merge-df.sh                  |   4 +-
 t/t6024-recursive-merge.sh           |  35 +--
 t/t6025-merge-symlinks.sh            |   9 +-
 t/t6031-merge-filemode.sh            |   4 +-
 t/t6036-recursive-corner-cases.sh    |  19 +-
 t/t6042-merge-rename-corner-cases.sh | 212 +++++++++++++++-
 t/t6043-merge-rename-directories.sh  |  15 +-
 t/t7060-wtstatus.sh                  |   1 +
 t/t7064-wtstatus-pv2.sh              |   4 +-
 t/t7506-status-submodule.sh          |  11 +-
 t/t7610-mergetool.sh                 |  28 +--
 19 files changed, 723 insertions(+), 224 deletions(-)

-- 
2.15.0.323.g31fe956618