[PATCH v4 6/8] transport: add object-info fallback to fetch

[Calvin Wan <calvinwan@google.com>]

If a v2 server does not support object-info or if the client requests
information that isn't supported by object-info, fetch the objects as if
it were a standard v2 fetch (however without changing any refs).

---
 fetch-pack.c | 14 +++++++++++++-
 fetch-pack.h |  2 ++
 transport.c  | 18 +++++++++++++++---
 3 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/fetch-pack.c b/fetch-pack.c
index 506ca28e05..938d082b80 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1639,6 +1639,9 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	if (args->depth > 0 || args->deepen_since || args->deepen_not)
 		args->deepen = 1;
 
+	if (args->object_info)
+		state = FETCH_SEND_REQUEST;
+
 	while (state != FETCH_DONE) {
 		switch (state) {
 		case FETCH_CHECK_LOCAL:
@@ -1648,7 +1651,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 			/* Filter 'ref' by 'sought' and those that aren't local */
 			mark_complete_and_common_ref(negotiator, args, &ref);
 			filter_refs(args, &ref, sought, nr_sought);
-			if (!args->refetch && everything_local(args, &ref))
+			if (!args->refetch && !args->object_info && everything_local(args, &ref))
 				state = FETCH_DONE;
 			else
 				state = FETCH_SEND_REQUEST;
@@ -2035,6 +2038,15 @@ struct ref *fetch_pack(struct fetch_pack_args *args,
 		args->connectivity_checked = 1;
 	}
 
+	if (args->object_info) {
+		struct ref *ref_cpy_reader = ref_cpy;
+		int i = 0;
+		while (ref_cpy_reader) {
+			oid_object_info_extended(the_repository, &ref_cpy_reader->old_oid, &(*args->object_info_data)[i], OBJECT_INFO_LOOKUP_REPLACE);
+			ref_cpy_reader = ref_cpy_reader->next;
+			i++;
+		}
+	}
 	update_shallow(args, sought, nr_sought, &si);
 cleanup:
 	clear_shallow_info(&si);
diff --git a/fetch-pack.h b/fetch-pack.h
index c27018d48c..552fd7bde0 100644
--- a/fetch-pack.h
+++ b/fetch-pack.h
@@ -17,6 +17,7 @@ struct fetch_pack_args {
 	const struct string_list *deepen_not;
 	struct list_objects_filter_options filter_options;
 	const struct string_list *server_options;
+	struct object_info **object_info_data;
 
 	/*
 	 * If not NULL, during packfile negotiation, fetch-pack will send "have"
@@ -43,6 +44,7 @@ struct fetch_pack_args {
 	unsigned reject_shallow_remote:1;
 	unsigned deepen:1;
 	unsigned refetch:1;
+	unsigned object_info:1;
 
 	/*
 	 * Indicate that the remote of this request is a promisor remote. The
diff --git a/transport.c b/transport.c
index 08c505e1d0..b85e52d9a8 100644
--- a/transport.c
+++ b/transport.c
@@ -436,10 +436,12 @@ static int fetch_refs_via_pack(struct transport *transport,
 			       int nr_heads, struct ref **to_fetch)
 {
 	int ret = 0;
+	size_t i;
 	struct git_transport_data *data = transport->data;
 	struct ref *refs = NULL;
 	struct fetch_pack_args args;
 	struct ref *refs_tmp = NULL;
+	struct ref *wanted_refs = xcalloc(1, sizeof (struct ref));
 
 	memset(&args, 0, sizeof(args));
 	args.uploadpack = data->options.uploadpack;
@@ -468,10 +470,19 @@ static int fetch_refs_via_pack(struct transport *transport,
 	args.object_info = transport->smart_options->object_info;
 
 	if (transport->smart_options && transport->smart_options->object_info) {
+		struct ref *ref = wanted_refs;
+
 		if (!fetch_object_info(transport, data->options.object_info_data))
 			goto cleanup;
-		ret = -1;
-		goto cleanup;
+		args.object_info_data = data->options.object_info_data;
+		for (i = 0; i < transport->smart_options->object_info_oids->nr; i++) {
+			struct ref *temp_ref = xcalloc(1, sizeof (struct ref));
+			temp_ref->old_oid = *(transport->smart_options->object_info_oids->oid + i);
+			temp_ref->exact_oid = 1;
+			ref->next = temp_ref;
+			ref = ref->next;
+		}
+		transport->remote_refs = wanted_refs->next;
 	} else if (!data->got_remote_heads) {
 		int i;
 		int must_list_refs = 0;
@@ -489,7 +500,7 @@ static int fetch_refs_via_pack(struct transport *transport,
 	else if (data->version <= protocol_v1)
 		die_if_server_options(transport);
 
-	if (data->options.acked_commits) {
+	if (data->options.acked_commits && !transport->smart_options->object_info) {
 		if (data->version < protocol_v2) {
 			warning(_("--negotiate-only requires protocol v2"));
 			ret = -1;
@@ -532,6 +543,7 @@ static int fetch_refs_via_pack(struct transport *transport,
 
 	free_refs(refs_tmp);
 	free_refs(refs);
+	free_refs(wanted_refs);
 	return ret;
 }
 
-- 
2.36.0.rc2.10170.gb555eefa6f