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, 99 insertions, 29 deletions

diff --git a/transport-helper.c b/transport-helper.c
index a46afcb..1738c81 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -719,13 +719,61 @@ static int fetch(struct transport *transport,
 	return -1;
 }
 
+struct push_update_ref_state {
+	struct ref *hint;
+	struct ref_push_report *report;
+	int new_report;
+};
+
 static int push_update_ref_status(struct strbuf *buf,
-				   struct ref **ref,
+				   struct push_update_ref_state *state,
 				   struct ref *remote_refs)
 {
 	char *refname, *msg;
 	int status, forced = 0;
 
+	if (starts_with(buf->buf, "option ")) {
+		struct object_id old_oid, new_oid;
+		const char *key, *val;
+		char *p;
+
+		if (!state->hint || !(state->report || state->new_report))
+			die(_("'option' without a matching 'ok/error' directive"));
+		if (state->new_report) {
+			if (!state->hint->report) {
+				state->hint->report = xcalloc(1, sizeof(struct ref_push_report));
+				state->report = state->hint->report;
+			} else {
+				state->report = state->hint->report;
+				while (state->report->next)
+					state->report = state->report->next;
+				state->report->next = xcalloc(1, sizeof(struct ref_push_report));
+				state->report = state->report->next;
+			}
+			state->new_report = 0;
+		}
+		key = buf->buf + 7;
+		p = strchr(key, ' ');
+		if (p)
+			*p++ = '\0';
+		val = p;
+		if (!strcmp(key, "refname"))
+			state->report->ref_name = xstrdup_or_null(val);
+		else if (!strcmp(key, "old-oid") && val &&
+			 !parse_oid_hex(val, &old_oid, &val))
+			state->report->old_oid = oiddup(&old_oid);
+		else if (!strcmp(key, "new-oid") && val &&
+			 !parse_oid_hex(val, &new_oid, &val))
+			state->report->new_oid = oiddup(&new_oid);
+		else if (!strcmp(key, "forced-update"))
+			state->report->forced_update = 1;
+		/* Not update remote namespace again. */
+		return 1;
+	}
+
+	state->report = NULL;
+	state->new_report = 0;
+
 	if (starts_with(buf->buf, "ok ")) {
 		status = REF_STATUS_OK;
 		refname = buf->buf + 3;
@@ -781,16 +829,16 @@ static int push_update_ref_status(struct strbuf *buf,
 		}
 	}
 
-	if (*ref)
-		*ref = find_ref_by_name(*ref, refname);
-	if (!*ref)
-		*ref = find_ref_by_name(remote_refs, refname);
-	if (!*ref) {
+	if (state->hint)
+		state->hint = find_ref_by_name(state->hint, refname);
+	if (!state->hint)
+		state->hint = find_ref_by_name(remote_refs, refname);
+	if (!state->hint) {
 		warning(_("helper reported unexpected status of %s"), refname);
 		return 1;
 	}
 
-	if ((*ref)->status != REF_STATUS_NONE) {
+	if (state->hint->status != REF_STATUS_NONE) {
 		/*
 		 * Earlier, the ref was marked not to be pushed, so ignore the ref
 		 * status reported by the remote helper if the latter is 'no match'.
@@ -799,9 +847,11 @@ static int push_update_ref_status(struct strbuf *buf,
 			return 1;
 	}
 
-	(*ref)->status = status;
-	(*ref)->forced_update |= forced;
-	(*ref)->remote_status = msg;
+	if (status == REF_STATUS_OK)
+		state->new_report = 1;
+	state->hint->status = status;
+	state->hint->forced_update |= forced;
+	state->hint->remote_status = msg;
 	return !(status == REF_STATUS_OK);
 }
 
@@ -809,37 +859,57 @@ static int push_update_refs_status(struct helper_data *data,
 				    struct ref *remote_refs,
 				    int flags)
 {
+	struct ref *ref;
+	struct ref_push_report *report;
 	struct strbuf buf = STRBUF_INIT;
-	struct ref *ref = remote_refs;
-	int ret = 0;
+	struct push_update_ref_state state = { remote_refs, NULL, 0 };
 
 	for (;;) {
-		char *private;
-
 		if (recvline(data, &buf)) {
-			ret = 1;
-			break;
+			strbuf_release(&buf);
+			return 1;
 		}
-
 		if (!buf.len)
 			break;
+		push_update_ref_status(&buf, &state, remote_refs);
+	}
+	strbuf_release(&buf);
 
-		if (push_update_ref_status(&buf, &ref, remote_refs))
-			continue;
+	if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
+		return 0;
 
-		if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
-			continue;
+	/* propagate back the update to the remote namespace */
+	for (ref = remote_refs; ref; ref = ref->next) {
+		char *private;
 
-		/* propagate back the update to the remote namespace */
-		private = apply_refspecs(&data->rs, ref->name);
-		if (!private)
+		if (ref->status != REF_STATUS_OK)
 			continue;
-		update_ref("update by helper", private, &ref->new_oid, NULL,
-			   0, 0);
-		free(private);
+
+		if (!ref->report) {
+			private = apply_refspecs(&data->rs, ref->name);
+			if (!private)
+				continue;
+			update_ref("update by helper", private, &(ref->new_oid),
+				   NULL, 0, 0);
+			free(private);
+		} else {
+			for (report = ref->report; report; report = report->next) {
+				private = apply_refspecs(&data->rs,
+							 report->ref_name
+							 ? report->ref_name
+							 : ref->name);
+				if (!private)
+					continue;
+				update_ref("update by helper", private,
+					   report->new_oid
+					   ? report->new_oid
+					   : &(ref->new_oid),
+					   NULL, 0, 0);
+				free(private);
+			}
+		}
 	}
-	strbuf_release(&buf);
-	return ret;
+	return 0;
 }
 
 static void set_common_push_options(struct transport *transport,