[PATCH v5 13/30] commit.c: use ref transactions for updates

[Ronnie Sahlberg <sahlberg@google.com>]

Change commit.c to use ref transactions for all ref updates.
Make sure we pass a NULL pointer to ref_transaction_update if have_old
is false.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 builtin/commit.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index d9550c5..a56f47a 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1541,11 +1541,12 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	const char *index_file, *reflog_msg;
 	char *nl;
 	unsigned char sha1[20];
-	struct ref_lock *ref_lock;
 	struct commit_list *parents = NULL, **pptr = &parents;
 	struct stat statbuf;
 	struct commit *current_head = NULL;
 	struct commit_extra_header *extra = NULL;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_commit_usage, builtin_commit_options);
@@ -1667,12 +1668,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_release(&author_ident);
 	free_commit_extra_headers(extra);
 
-	ref_lock = lock_any_ref_for_update("HEAD",
-					   !current_head
-					   ? NULL
-					   : current_head->object.sha1,
-					   0, NULL);
-
 	nl = strchr(sb.buf, '\n');
 	if (nl)
 		strbuf_setlen(&sb, nl + 1 - sb.buf);
@@ -1681,13 +1676,15 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
 	strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
 
-	if (!ref_lock) {
-		rollback_index_files();
-		die(_("cannot lock HEAD ref"));
-	}
-	if (write_ref_sha1(ref_lock, sha1, sb.buf) < 0) {
+	transaction = ref_transaction_begin();
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD", sha1,
+				   current_head ?
+				   current_head->object.sha1 : NULL,
+				   0, !!current_head) ||
+	    ref_transaction_commit(transaction, sb.buf, &err)) {
 		rollback_index_files();
-		die(_("cannot update HEAD ref"));
+		die(_("HEAD: cannot update ref: %s"), err.buf);
 	}
 
 	unlink(git_path("CHERRY_PICK_HEAD"));
-- 
1.9.1.532.gf8485a6