@matheusbsbs / matheus-bagliano / commits / 0acbaf9000

merge: use repo_in_merge_bases for octopus up-to-date check

The octopus merge path checks whether each remote head is already an ancestor of HEAD by computing all merge-bases via repo_get_merge_bases() and comparing the first result's OID to the remote head. This is more expensive than necessary: repo_get_merge_bases() calls paint_down_to_common() with min_generation=0, performs the full STALE drain, and may run remove_redundant(), when all we need is a yes/no reachability answer. Replace this with repo_in_merge_bases(), which answers the is-ancestor question directly. When generation numbers are available, repo_in_merge_bases() uses can_all_from_reach() -- a DFS bounded by generation number that stops as soon as the target is found or ruled out, without entering paint_down_to_common() at all. Without generation numbers, it still benefits from a tighter min_generation floor. Signed-off-by: Kristofer Karlsson <krka@spotify.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Kristofer Karlsson committed May 12, 2026 at 06:11 UTC 0acbaf9000bd50bfbec24e5c40ab96bbd5e79281

2 files changed +14 -14

builtin/merge.c

+4 -14

index 2cbce56f8d..862107cf41 100644 --- a/builtin/merge.c +++ b/builtin/merge.c @@ -1735,21 +1735,11 @@ int cmd_merge(int argc, struct commit_list *j; for (j = remoteheads; j; j = j->next) { - struct commit_list *common_one = NULL; - struct commit *common_item; - - /* - * Here we *have* to calculate the individual - * merge_bases again, otherwise "git merge HEAD^ - * HEAD^^" would be missed. - */ - if (repo_get_merge_bases(the_repository, head_commit, - j->item, &common_one) < 0) + int ret = repo_in_merge_bases(the_repository, + j->item, head_commit); + if (ret < 0) exit(128); - - common_item = common_one->item; - commit_list_free(common_one); - if (!oideq(&common_item->object.oid, &j->item->object.oid)) { + if (!ret) { up_to_date = 0; break; }

t/t6408-merge-up-to-date.sh

+10

index 7763c1ba98..be0840efb6 100755 --- a/t/t6408-merge-up-to-date.sh +++ b/t/t6408-merge-up-to-date.sh @@ -89,4 +89,14 @@ test_expect_success 'merge fast-forward octopus' ' test "$expect" = "$current" ' +test_expect_success 'merge octopus already up to date' ' + + git reset --hard c2 && + test_tick && + git merge c0 c1 && + expect=$(git rev-parse c2) && + current=$(git rev-parse HEAD) && + test "$expect" = "$current" +' + test_done