Subject: [PATCH v5 16/29] sequencer: add trailers to message before writing file

From: Li Chen <[email-masked]>
Date: Wed, 22 Oct 2025 13:39:36 +0800

Added trailer processing to the in-memory commit message
within do_pick_commit, ensuring fixup/squash commands
remain untouched before the message is written.

Signed-off-by: Li Chen <[email-masked]>
---
 sequencer.c | 19 ++++++++-----------
 trailer.c   |  4 ++--
 trailer.h   |  3 +++
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index 5103ae786c..552e629e4f 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -2444,6 +2444,14 @@ static int do_pick_commit(struct repository *r,
 	if (opts->signoff && !is_fixup(command))
 		append_signoff(&ctx->message, 0, 0);
 
+	if (opts->trailer_args.nr && !is_fixup(command)) {
+		if (amend_strbuf_with_trailers(&ctx->message,
+					       &opts->trailer_args)) {
+			res = error(_("unable to add trailers to commit message"));
+			goto leave;
+		}
+	}
+
 	if (is_rebase_i(opts) && write_author_script(msg.message) < 0)
 		res = -1;
 	else if (!opts->strategy ||
@@ -2519,17 +2527,6 @@ static int do_pick_commit(struct repository *r,
 			oid_to_hex(&commit->object.oid), msg.subject);
 	} /* else allow == 0 and there's nothing special to do */
 
-	if (!res && opts->trailer_args.nr && !drop_commit) {
-		const char *trailer_file =
-			msg_file ? msg_file : git_path_merge_msg(r);
-
-		if (amend_file_with_trailers(trailer_file,
-						&opts->trailer_args)) {
-			res = error(_("unable to add trailers to commit message"));
-			goto leave;
-		}
-	}
-
 	if (!opts->no_commit && !drop_commit) {
 		if (author || command == TODO_REVERT || (flags & AMEND_MSG))
 			res = do_commit(r, msg_file, author, reflog_action,
diff --git a/trailer.c b/trailer.c
index 85e42859ca..3e96d1624a 100644
--- a/trailer.c
+++ b/trailer.c
@@ -1250,8 +1250,8 @@ void trailer_iterator_release(struct trailer_iterator *iter)
 	strbuf_release(&iter->key);
 }
 
-static int amend_strbuf_with_trailers(struct strbuf *buf,
-									  const struct strvec *trailer_args)
+int amend_strbuf_with_trailers(struct strbuf *buf,
+			       const struct strvec *trailer_args)
 {
 	struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
 	LIST_HEAD(new_trailer_head);
diff --git a/trailer.h b/trailer.h
index 4654ff9c96..479bc137cd 100644
--- a/trailer.h
+++ b/trailer.h
@@ -197,6 +197,9 @@ int trailer_iterator_advance(struct trailer_iterator *iter);
  */
 void trailer_iterator_release(struct trailer_iterator *iter);
 
+int amend_strbuf_with_trailers(struct strbuf *buf,
+			       const struct strvec *trailer_args);
+
 /*
  * Augment a file to add trailers to it (similar to 'git interpret-trailers').
  * Returns 0 on success or a non-zero error code on failure.
-- 
2.51.0