Subject: [PATCH 1/2] sequencer.c: make commit_post_rewrite() take two object names

From: Junio C Hamano <[email-masked]>
Date: Thu, 11 Mar 2021 19:01:06 -0800

The helper function is to copy notes between two commits by taking
the original one and a new one that is supposed to be a rewrite of
the original one.  It somehow takes "struct commit *" for the former
but "struct object_id *" for the latter, but what it does does not
need access to the in-core commit object.

Change the function to take two "struct object_id *" instead.

As we require "struct object_id *" for the original commit now,
the comment on the old "struct commit *" that must be non-NULL
which made taking the address of its object.oid member safe no
longer is relevant to this function (it is the caller's concern
now), so remove it.  Two callers we have are of course safe, and
there is no reason to call this "as we rewrote A to B, please copy
notes on A to B, too" helper if the caller knows A is NULL, so
the comment would have very little value even if it were kept.

Signed-off-by: Junio C Hamano <[email-masked]>
---
 builtin/commit.c | 6 +++---
 sequencer.c      | 9 ++++-----
 sequencer.h      | 2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index 739110c5a7..f2fbef053e 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1702,9 +1702,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	repo_rerere(the_repository, 0);
 	run_auto_maintenance(quiet);
 	run_commit_hook(use_editor, get_index_file(), "post-commit", NULL);
-	if (amend && !no_post_rewrite) {
-		commit_post_rewrite(the_repository, current_head, &oid);
-	}
+	if (amend && !no_post_rewrite)
+		commit_post_rewrite(the_repository, &current_head->object.oid, &oid);
+
 	if (!quiet) {
 		unsigned int flags = 0;
 
diff --git a/sequencer.c b/sequencer.c
index d2332d3e17..92a4871997 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1175,18 +1175,17 @@ static int run_rewrite_hook(const struct object_id *oldoid,
 }
 
 void commit_post_rewrite(struct repository *r,
-			 const struct commit *old_head,
+			 const struct object_id *old_head,
 			 const struct object_id *new_head)
 {
 	struct notes_rewrite_cfg *cfg;
 
 	cfg = init_copy_notes_for_rewrite("amend");
 	if (cfg) {
-		/* we are amending, so old_head is not NULL */
-		copy_note_for_rewrite(cfg, &old_head->object.oid, new_head);
+		copy_note_for_rewrite(cfg, old_head, new_head);
 		finish_copy_notes_for_rewrite(r, cfg, "Notes added by 'git commit --amend'");
 	}
-	run_rewrite_hook(&old_head->object.oid, new_head);
+	run_rewrite_hook(old_head, new_head);
 }
 
 static int run_prepare_commit_msg_hook(struct repository *r,
@@ -1538,7 +1537,7 @@ static int try_to_commit(struct repository *r,
 
 	run_commit_hook(0, r->index_file, "post-commit", NULL);
 	if (flags & AMEND_MSG)
-		commit_post_rewrite(r, current_head, oid);
+		commit_post_rewrite(r, &current_head->object.oid, oid);
 
 out:
 	free_commit_extra_headers(extra);
diff --git a/sequencer.h b/sequencer.h
index f8b2e4ab85..79eed55c4b 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -192,7 +192,7 @@ int update_head_with_reflog(const struct commit *old_head,
 			    const char *action, const struct strbuf *msg,
 			    struct strbuf *err);
 void commit_post_rewrite(struct repository *r,
-			 const struct commit *current_head,
+			 const struct object_id *old_head,
 			 const struct object_id *new_head);
 
 void create_autostash(struct repository *r, const char *path,
-- 
2.31.0-rc2-175-g3820f1c72e