[PATCH 3/3] rename_ref: replace empty deletion message in HEAD's log

[Kyle Meyer <kyle@kyleam.com>]

When the current branch is renamed, the deletion of the old ref is
recorded in HEAD's log with an empty message.  Now that delete_refs()
accepts a reflog message, provide a more descriptive message.  This
message will not be included in the reflog of the renamed branch, but
its log already covers the renaming event with a message of "Branch:
renamed ...".

Signed-off-by: Kyle Meyer <kyle@kyleam.com>
---
 refs/files-backend.c | 8 +++++++-
 t/t3200-branch.sh    | 4 ++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/refs/files-backend.c b/refs/files-backend.c
index ffa75d816..bb5df7ee6 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2598,6 +2598,7 @@ static int files_rename_ref(struct ref_store *ref_store,
 	struct stat loginfo;
 	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
 	struct strbuf err = STRBUF_INIT;
+	struct strbuf logmsg_del = STRBUF_INIT;
 
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
@@ -2616,10 +2617,15 @@ static int files_rename_ref(struct ref_store *ref_store,
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
 
-	if (delete_ref(oldrefname, orig_sha1, REF_NODEREF, NULL)) {
+	strbuf_addf(&logmsg_del, "Deleted %s", oldrefname);
+
+	if (delete_ref(oldrefname, orig_sha1, REF_NODEREF, logmsg_del.buf)) {
 		error("unable to delete old %s", oldrefname);
+		strbuf_release(&logmsg_del);
 		goto rollback;
 	}
+	strbuf_release(&logmsg_del);
+
 
 	/*
 	 * Since we are doing a shallow lookup, sha1 is not the
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 8a833f354..4af7cd2b7 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -139,6 +139,10 @@ test_expect_success 'git branch -M baz bam should succeed when baz is checked ou
 	test $(git rev-parse --abbrev-ref HEAD) = bam
 '
 
+test_expect_success 'git branch -M baz bam should add entry to .git/logs/HEAD' '
+	grep "Deleted refs/heads/baz$" .git/logs/HEAD >/dev/null
+'
+
 test_expect_success 'git branch -M baz bam should succeed when baz is checked out as linked working tree' '
 	git checkout master &&
 	git worktree add -b baz bazdir &&
-- 
2.11.1