New capability "report-status-v2" for git-push

The new introduced "proc-receive" hook may handle a command for a
pseudo-reference with a zero-old as its old-oid, while the hook may
create or update a reference with different name, different new-oid,
and different old-oid (the reference may exist already with a non-zero
old-oid).  Current "report-status" protocol cannot report the status for
such reference rewrite.

Add new capability "report-status-v2" and new report protocol which is
not backward compatible for report of git-push.

If a user pushes to a pseudo-reference "refs/for/master/topic", and
"receive-pack" creates two new references "refs/changes/23/123/1" and
"refs/changes/24/124/1", for client without the knowledge of
"report-status-v2", "receive-pack" will only send "ok/ng" directives in
the report, such as:

    ok ref/for/master/topic

But for client which has the knowledge of "report-status-v2",
"receive-pack" will use "option" directives to report more attributes
for the reference given by the above "ok/ng" directive.

    ok refs/for/master/topic
    option refname refs/changes/23/123/1
    option new-oid <new-oid>
    ok refs/for/master/topic
    option refname refs/changes/24/124/1
    option new-oid <new-oid>

The client will report two new created references to the end user.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 52 insertions, 2 deletions

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 38f230248d..d6a216b2e3 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -56,6 +56,7 @@ static int advertise_push_options;
 static int unpack_limit = 100;
 static off_t max_input_size;
 static int report_status;
+static int report_status_v2;
 static int use_sideband;
 static int use_atomic;
 static int use_push_options;
@@ -239,7 +240,7 @@ static void show_ref(const char *path, const struct object_id *oid)
 		struct strbuf cap = STRBUF_INIT;
 
 		strbuf_addstr(&cap,
-			      "report-status delete-refs side-band-64k quiet");
+			      "report-status report-status-v2 delete-refs side-band-64k quiet");
 		if (advertise_atomic_push)
 			strbuf_addstr(&cap, " atomic");
 		if (prefer_ofs_delta)
@@ -1937,6 +1938,8 @@ static struct command *read_head_info(struct packet_reader *reader,
 			const char *feature_list = reader->line + linelen + 1;
 			if (parse_feature_request(feature_list, "report-status"))
 				report_status = 1;
+			if (parse_feature_request(feature_list, "report-status-v2"))
+				report_status_v2 = 1;
 			if (parse_feature_request(feature_list, "side-band-64k"))
 				use_sideband = LARGE_PACKET_MAX;
 			if (parse_feature_request(feature_list, "quiet"))
@@ -2248,6 +2251,51 @@ static void report(struct command *commands, const char *unpack_status)
 	strbuf_release(&buf);
 }
 
+static void report_v2(struct command *commands, const char *unpack_status)
+{
+	struct command *cmd;
+	struct strbuf buf = STRBUF_INIT;
+	struct ref_push_report *report;
+
+	packet_buf_write(&buf, "unpack %s\n",
+			 unpack_status ? unpack_status : "ok");
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		int count = 0;
+
+		if (cmd->error_string) {
+			packet_buf_write(&buf, "ng %s %s\n",
+					 cmd->ref_name,
+					 cmd->error_string);
+			continue;
+		}
+		packet_buf_write(&buf, "ok %s\n",
+				 cmd->ref_name);
+		for (report = cmd->report; report; report = report->next) {
+			if (count++ > 0)
+				packet_buf_write(&buf, "ok %s\n",
+						 cmd->ref_name);
+			if (report->ref_name)
+				packet_buf_write(&buf, "option refname %s\n",
+						 report->ref_name);
+			if (report->old_oid)
+				packet_buf_write(&buf, "option old-oid %s\n",
+						 oid_to_hex(report->old_oid));
+			if (report->new_oid)
+				packet_buf_write(&buf, "option new-oid %s\n",
+						 oid_to_hex(report->new_oid));
+			if (report->forced_update)
+				packet_buf_write(&buf, "option forced-update\n");
+		}
+	}
+	packet_buf_flush(&buf);
+
+	if (use_sideband)
+		send_sideband(1, 1, buf.buf, buf.len, use_sideband);
+	else
+		write_or_die(1, buf.buf, buf.len);
+	strbuf_release(&buf);
+}
+
 static int delete_only(struct command *commands)
 {
 	struct command *cmd;
@@ -2356,7 +2404,9 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 				 &push_options);
 		if (pack_lockfile)
 			unlink_or_warn(pack_lockfile);
-		if (report_status)
+		if (report_status_v2)
+			report_v2(commands, unpack_status);
+		else if (report_status)
 			report(commands, unpack_status);
 		run_receive_hook(commands, "post-receive", 1,
 				 &push_options);