Re: [PATCH 00/11] Complete merge-ort implementation...almost

On Fri, Mar 05 2021, Elijah Newren via GitGitGadget wrote:

In order to help Ævar test his tree-walk changes against merge-ort[1], this
series completes the merge-ort implementation and cleans up testsuite
failures...EXCEPT for some t6423 failures. It also leaves out a lot of
performance work, which incidentally will fix the t6423 failures and is
being reviewed independently[2].

For those testing this in combination with their work, the expected
failures are these specific tests:

    ./t6423-merge-rename-directories.sh (Wstat: 256 Tests: 68 Failed: 4)
      Failed tests:  7, 53, 55, 59

Perhaps I'm missing something but why not have [1] below on top of this
series? It makes that test pass in both modes, and means we could
e.g. follow-up by running CI with "ort".

That CI step seems worth doing sooner than later, even if it needs some
GIT_TEST_SKIP for now...

This 11-patch series could be submitted as 7 independent series, 1-4 patches
in length each, but it's probably easier for Ævar if we can merge just one
more thing and it's only 11 total patches. This series sub-divides as
follows:

 * Patch 1: Fix bug in already-merged portion of merge-ort affecting
   rename/rename conflicts on platforms where qsort isn't stable. (Could be
   considered for merging before 2.31 since it is a new bug in the 2.31
   cycle that I just learned of last night, but not sure it matters since
   merge-ort wasn't complete anyway and we're not even mentioning merge-ort
   in the release notes.)
 * Patches 2-5: Add support for renormalization
 * Patch 6: Add support for subtree shifting
 * Patch 7-8: Add test and support for conflicts affecting sparse-checkout
   entries
 * Patch 9: Update submodule related merge tests to note the ones that
   merge-ort fixes relative to merge-recursive
 * Patch 10: New feature -- allow "git diff AUTO_MERGE" during conflict
   resolution to let user review changes they made since
   merge/rebase/cherry-pick/revert stopped and informed them of conflicts
 * Patch 11: Add comments noting various bugs in merge-recursive

The last two patches aren't needed by Ævar, so they could be left out and
submitted later. I just figured that it was only two more patches and they
were part of "completing the merge-ort implementation" in my view.

This whole thing was a pleasant read, and helped me catch a subtle
regression in my WIP "mode" work (which I'm now about to submit).

Reviewing this series suffered from the problem you have with writing
code that's clearly good enough: Mostly all I had were minor nits,
suggestions to re-arrange code differently etc.

That being said I'm not all that familiar with the guts of the merge
logic, so I may have missed other issues...

[1] https://lore.kernel.org/git/877dmmkhnt.fsf@evledraar.gmail.com/ (local) [2] See
https://lore.kernel.org/git/pull.845.git.1614484707.gitgitgadget@gmail.com/ (local);
there are five more waiting after that -- viewable by the curious at
https://github.com/gitgitgadget/git/pulls?q=is%3Apr+author%3Anewren+Optimization+batch

Elijah Newren (11):
  merge-ort: use STABLE_QSORT instead of QSORT where required
  merge-ort: add a special minimal index just for renormalization
  merge-ort: add a function for initializing our special attr_index
  merge-ort: have ll_merge() calls use the attr_index for
    renormalization
  merge-ort: let renormalization change modify/delete into clean delete
  merge-ort: support subtree shifting
  t6428: new test for SKIP_WORKTREE handling and conflicts
  merge-ort: implement CE_SKIP_WORKTREE handling with conflicted entries
  t: mark several submodule merging tests as fixed under merge-ort
  merge-ort: write $GIT_DIR/AUTO_MERGE whenever we hit a conflict
  merge-recursive: add a bunch of FIXME comments documenting known bugs

 branch.c                                      |   1 +
 builtin/rebase.c                              |   1 +
 merge-ort.c                                   | 230 ++++++++++++++++--
 merge-recursive.c                             |  37 +++
 path.c                                        |   1 +
 path.h                                        |   2 +
 sequencer.c                                   |   5 +
 t/t3512-cherry-pick-submodule.sh              |   9 +-
 t/t3513-revert-submodule.sh                   |   7 +-
 t/t5572-pull-submodule.sh                     |   9 +-
 t/t6428-merge-conflicts-sparse.sh             | 158 ++++++++++++
 t/t6437-submodule-merge.sh                    |   5 +-
 t/t6438-submodule-directory-file-conflicts.sh |   9 +-
 13 files changed, 449 insertions(+), 25 deletions(-)
 create mode 100755 t/t6428-merge-conflicts-sparse.sh


base-commit: f01623b2c9d14207e497b21ebc6b3ec4afaf4b46
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-973%2Fnewren%2Fort-remainder-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-973/newren/ort-remainder-v1
Pull-Request: https://github.com/git/git/pull/973

1.:

diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index 5d3b711fe68..4f6ead11e51 100755
--- a/t/t6423-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh

@@ -507,7 +507,7 @@ test_setup_2a () {
 	)
 }
 
-test_expect_success '2a: Directory split into two on one side, with equal numbers of paths' '
+test_expect_merge_algorithm success failure '2a: Directory split into two on one side, with equal numbers of paths' '
 	test_setup_2a &&
 	(
 		cd 2a &&

@@ -3060,7 +3060,7 @@ test_setup_9g () {
 	)
 }
 
-test_expect_failure '9g: Renamed directory that only contained immediate subdirs, immediate subdirs renamed' '
+test_expect_merge_algorithm failure failure '9g: Renamed directory that only contained immediate subdirs, immediate subdirs renamed' '
 	test_setup_9g &&
 	(
 		cd 9g &&

@@ -4267,7 +4267,7 @@ test_setup_12b1 () {
 	)
 }
 
-test_expect_merge_algorithm failure success '12b1: Moving two directory hierarchies into each other' '
+test_expect_merge_algorithm failure failure '12b1: Moving two directory hierarchies into each other' '
 	test_setup_12b1 &&
 	(
 		cd 12b1 &&

@@ -4435,7 +4435,7 @@ test_setup_12c1 () {
 	)
 }
 
-test_expect_merge_algorithm failure success '12c1: Moving one directory hierarchy into another w/ content merge' '
+test_expect_merge_algorithm failure failure '12c1: Moving one directory hierarchy into another w/ content merge' '
 	test_setup_12c1 &&
 	(
 		cd 12c1 &&

@@ -4797,7 +4797,7 @@ test_setup_12f () {
 	)
 }
 
-test_expect_merge_algorithm failure success '12f: Trivial directory resolve, caching, all kinds of fun' '
+test_expect_merge_algorithm failure failure '12f: Trivial directory resolve, caching, all kinds of fun' '
 	test_setup_12f &&
 	(
 		cd 12f &&