@matheusbsbs / matheus-bagliano / commits / 1e3497a24c

commit-reach: replace ref_newer logic

The ref_newer method is used by 'git push' to check if a force-push is required. This method does not use any kind of cutoff when walking, so in the case of a force-push will walk all reachable commits. The is_descendant_of method already uses paint_down_to_common along with cutoffs. By translating the ref_newer arguments into the commit and commit_list required by is_descendant_of, we can have one fewer commit walk and also improve our performance! For a copy of the Linux repository, 'test-tool reach ref_newer' presents the following improvements with the specified input. In the case that ref_newer returns 1, there is no improvement. The improvement is in the second case where ref_newer returns 0. Input: A:v4.9 B:v3.19 Before: 0.09 s After: 0.09 s To test the negative case, add a new commit with parent v3.19, regenerate the commit-graph, and then run with B pointing at that commit. Before: 0.43 s After: 0.09 s Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Derrick Stolee committed Jul 20, 2018 at 16:33 UTC 1e3497a24cf13fe907b247d1b93a997d6537cca1

1 file changed +3 -23

commit-reach.c

+3 -23

@@ -366,20 +366,11 @@ void reduce_heads_replace(struct commit_list **heads)

366 *heads = result;

367 }

368

369 -static void unmark_and_free(struct commit_list *list, unsigned int mark)

370 -{

371 - while (list) {

372 - struct commit *commit = pop_commit(&list);

373 - commit->object.flags &= ~mark;

374 - }

375 -}

376 -

369 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)

370 {

371 struct object *o;

372 struct commit *old_commit, *new_commit;

381 - struct commit_list *list, *used;

382 - int found = 0;

373 + struct commit_list *old_commit_list = NULL;

374

375 /*

376 * Both new_commit and old_commit must be commit-ish and new_commit is descendant of

@@ -400,19 +391,8 @@ int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)

391 if (parse_commit(new_commit) < 0)

392 return 0;

393

403 - used = list = NULL;

404 - commit_list_insert(new_commit, &list);

405 - while (list) {

406 - new_commit = pop_most_recent_commit(&list, TMP_MARK);

407 - commit_list_insert(new_commit, &used);

408 - if (new_commit == old_commit) {

409 - found = 1;

410 - break;

411 - }

412 - }

413 - unmark_and_free(list, TMP_MARK);

414 - unmark_and_free(used, TMP_MARK);

415 - return found;

394 + commit_list_insert(old_commit, &old_commit_list);

395 + return is_descendant_of(new_commit, old_commit_list);

396 }

397

398 /*