1 files changed, 47 insertions, 2 deletions

diff --git a/send-pack.c b/send-pack.c
index 4974825923..266f37f060 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -282,6 +282,29 @@ free_return:
 	return update_seen;
 }
 
+
+static int atomic_push_failure(struct send_pack_args *args,
+			       struct ref *remote_refs,
+			       struct ref *failing_ref)
+{
+	struct ref *ref;
+	/* Mark other refs as failed */
+	for (ref = remote_refs; ref; ref = ref->next) {
+		if (!ref->peer_ref && !args->send_mirror)
+			continue;
+
+		switch (ref->status) {
+		case REF_STATUS_EXPECTING_REPORT:
+			ref->status = REF_STATUS_ATOMIC_PUSH_FAILED;
+			continue;
+		default:
+			break; /* do nothing */
+		}
+	}
+	return error("atomic push failed for ref %s. status: %d\n",
+		     failing_ref->name, failing_ref->status);
+}
+
 int send_pack(struct send_pack_args *args,
 	      int fd[], struct child_process *conn,
 	      struct ref *remote_refs,
@@ -298,6 +321,8 @@ int send_pack(struct send_pack_args *args,
 	int use_sideband = 0;
 	int quiet_supported = 0;
 	int agent_supported = 0;
+	int use_atomic = 0;
+	int atomic_supported = 0;
 	unsigned cmds_sent = 0;
 	int ret;
 	struct async demux;
@@ -318,6 +343,8 @@ int send_pack(struct send_pack_args *args,
 		agent_supported = 1;
 	if (server_supports("no-thin"))
 		args->use_thin_pack = 0;
+	if (server_supports("atomic"))
+		atomic_supported = 1;
 	if (args->push_cert) {
 		int len;
 
@@ -332,6 +359,10 @@ int send_pack(struct send_pack_args *args,
 			"Perhaps you should specify a branch such as 'master'.\n");
 		return 0;
 	}
+	if (args->atomic && !atomic_supported)
+		die(_("server does not support --atomic push"));
+
+	use_atomic = atomic_supported && args->atomic;
 
 	if (status_report)
 		strbuf_addstr(&cap_buf, " report-status");
@@ -339,6 +370,8 @@ int send_pack(struct send_pack_args *args,
 		strbuf_addstr(&cap_buf, " side-band-64k");
 	if (quiet_supported && (args->quiet || !args->progress))
 		strbuf_addstr(&cap_buf, " quiet");
+	if (use_atomic)
+		strbuf_addstr(&cap_buf, " atomic");
 	if (agent_supported)
 		strbuf_addf(&cap_buf, " agent=%s", git_user_agent_sanitized());
 
@@ -363,9 +396,21 @@ int send_pack(struct send_pack_args *args,
 	 * the pack data.
 	 */
 	for (ref = remote_refs; ref; ref = ref->next) {
-		if (check_to_send_update(ref, args) < 0)
+		switch (check_to_send_update(ref, args)) {
+		case 0: /* no error */
+			break;
+		case CHECK_REF_STATUS_REJECTED:
+			/*
+			 * When we know the server would reject a ref update if
+			 * we were to send it and we're trying to send the refs
+			 * atomically, abort the whole operation.
+			 */
+			if (use_atomic)
+				return atomic_push_failure(args, remote_refs, ref);
+			/* Fallthrough for non atomic case. */
+		default:
 			continue;
-
+		}
 		if (!ref->deletion)
 			need_pack_data = 1;