[PATCH v10 4/8] replay: support empty commit ranges

From: Patrick Steinhardt <ps@pks.im>
Date: Jan 12, 2026, 14:15 UTC
Message-ID: <20260112-b4-pks-history-builtin-v10-4-e3c6aa5b4cec@pks.im>
In-Reply-To: <20260112-b4-pks-history-builtin-v10-0-e3c6aa5b4cec@pks.im>

In a subsequent commit we're about to introduce a new user of the replay subsystem. With that new user, the range of commits that we'll want to replay will be identified implicitly via "HEAD". With such implicit ranges it becomes likely that the range of revisions that we're asked to replay becomes empty. This case does not make sense with git-replay(1), but with the new command it will.

This case is not currently supported by `replay_revisions()` though because we zero-initialize `struct merge_result`. This includes its `.clean` member, which indicates whether the merge ran into a conflict or not. But given that we don't have any revision to replay, we won't ever perform any merge at all, and consequently that member will never be set to `1`. We thus later think that there's been a merge conflict and return an error from `replay_commits()`.

Address this issue by initializing the `.clean` member to `1`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
---
 replay.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/replay.c b/replay.c
index 1e660171d2..a8e6d5b30b 100644
--- a/replay.c
+++ b/replay.c
@@ -266,7 +266,9 @@ int replay_revisions(struct rev_info *revs,
 	struct commit *commit;
 	struct commit *onto = NULL;
 	struct merge_options merge_opt;
-	struct merge_result result;
+	struct merge_result result = {
+		.clean = 1,
+	};
 	char *advance;
 	int ret;
 
@@ -282,7 +284,6 @@ int replay_revisions(struct rev_info *revs,
 	}
 
 	init_basic_merge_options(&merge_opt, revs->repo);
-	memset(&result, 0, sizeof(result));
 	merge_opt.show_rename_progress = 0;
 	last_commit = onto;
 	replayed_commits = kh_init_oid_map();

-- 
2.52.0.590.g1f87b77810.dirty