Merge branch 'bc/clone-empty-repo-via-protocol-v0' into nextnext

* bc/clone-empty-repo-via-protocol-v0:
  upload-pack: advertise capabilities when cloning empty repos

3 files changed, 73 insertions, 7 deletions

diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index 0908534f25..21b7767cbd 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -611,6 +611,33 @@ test_expect_success 'client falls back from v2 to v0 to match server' '
 	grep symref=HEAD:refs/heads/ trace
 '
 
+test_expect_success 'create empty http-accessible SHA-256 repository' '
+	mkdir "$HTTPD_DOCUMENT_ROOT_PATH/sha256.git" &&
+	(cd "$HTTPD_DOCUMENT_ROOT_PATH/sha256.git" &&
+	 git --bare init --object-format=sha256
+	)
+'
+
+test_expect_success 'clone empty SHA-256 repository with protocol v2' '
+	rm -fr sha256 &&
+	echo sha256 >expected &&
+	git -c protocol.version=2 clone "$HTTPD_URL/smart/sha256.git" &&
+	git -C sha256 rev-parse --show-object-format >actual &&
+	test_cmp actual expected &&
+	git ls-remote "$HTTPD_URL/smart/sha256.git" >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'clone empty SHA-256 repository with protocol v0' '
+	rm -fr sha256 &&
+	echo sha256 >expected &&
+	GIT_TRACE=1 GIT_TRACE_PACKET=1 git -c protocol.version=0 clone "$HTTPD_URL/smart/sha256.git" &&
+	git -C sha256 rev-parse --show-object-format >actual &&
+	test_cmp actual expected &&
+	git ls-remote "$HTTPD_URL/smart/sha256.git" >actual &&
+	test_must_be_empty actual
+'
+
 test_expect_success 'passing hostname resolution information works' '
 	BOGUS_HOST=gitbogusexamplehost.invalid &&
 	BOGUS_HTTPD_URL=$HTTPD_PROTO://$BOGUS_HOST:$LIB_HTTPD_PORT &&
diff --git a/t/t5700-protocol-v1.sh b/t/t5700-protocol-v1.sh
index 6c8d4c6cf1..a73b4d4ff6 100755
--- a/t/t5700-protocol-v1.sh
+++ b/t/t5700-protocol-v1.sh
@@ -244,15 +244,28 @@ test_expect_success 'push with ssh:// using protocol v1' '
 	grep "push< version 1" log
 '
 
+test_expect_success 'clone propagates object-format from empty repo' '
+	test_when_finished "rm -fr src256 dst256" &&
+
+	echo sha256 >expect &&
+	git init --object-format=sha256 src256 &&
+	git clone --no-local src256 dst256 &&
+	git -C dst256 rev-parse --show-object-format >actual &&
+
+	test_cmp expect actual
+'
+
 # Test protocol v1 with 'http://' transport
 #
 . "$TEST_DIRECTORY"/lib-httpd.sh
 start_httpd
 
-test_expect_success 'create repo to be served by http:// transport' '
+test_expect_success 'create repos to be served by http:// transport' '
 	git init "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" &&
 	git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" config http.receivepack true &&
-	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" one
+	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" one &&
+	git init --object-format=sha256 "$HTTPD_DOCUMENT_ROOT_PATH/sha256" &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/sha256" config http.receivepack true
 '
 
 test_expect_success 'clone with http:// using protocol v1' '
@@ -269,6 +282,20 @@ test_expect_success 'clone with http:// using protocol v1' '
 	grep "git< version 1" log
 '
 
+test_expect_success 'clone with http:// using protocol v1 with empty SHA-256 repo' '
+	GIT_TRACE_PACKET=1 GIT_TRACE_CURL=1 git -c protocol.version=1 \
+		clone "$HTTPD_URL/smart/sha256" sha256 2>log &&
+
+	echo sha256 >expect &&
+	git -C sha256 rev-parse --show-object-format >actual &&
+	test_cmp expect actual &&
+
+	# Client requested to use protocol v1
+	grep "Git-Protocol: version=1" log &&
+	# Server responded using protocol v1
+	grep "git< version 1" log
+'
+
 test_expect_success 'fetch with http:// using protocol v1' '
 	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" two &&
 
diff --git a/upload-pack.c b/upload-pack.c
index 08633dc121..d3312006a3 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -120,6 +120,7 @@ struct upload_pack_data {
 	unsigned allow_ref_in_want : 1;				/* v2 only */
 	unsigned allow_sideband_all : 1;			/* v2 only */
 	unsigned advertise_sid : 1;
+	unsigned sent_capabilities : 1;
 };
 
 static void upload_pack_data_init(struct upload_pack_data *data)
@@ -1206,18 +1207,17 @@ static void format_session_id(struct strbuf *buf, struct upload_pack_data *d) {
 		strbuf_addf(buf, " session-id=%s", trace2_session_id());
 }
 
-static int send_ref(const char *refname, const struct object_id *oid,
-		    int flag UNUSED, void *cb_data)
+static void write_v0_ref(struct upload_pack_data *data,
+			const char *refname, const char *refname_nons,
+			const struct object_id *oid)
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow deepen-since deepen-not"
 		" deepen-relative no-progress include-tag multi_ack_detailed";
-	const char *refname_nons = strip_namespace(refname);
 	struct object_id peeled;
-	struct upload_pack_data *data = cb_data;
 
 	if (mark_our_ref(refname_nons, refname, oid, &data->hidden_refs))
-		return 0;
+		return;
 
 	if (capabilities) {
 		struct strbuf symref_info = STRBUF_INIT;
@@ -1240,12 +1240,20 @@ static int send_ref(const char *refname, const struct object_id *oid,
 			     git_user_agent_sanitized());
 		strbuf_release(&symref_info);
 		strbuf_release(&session_id);
+		data->sent_capabilities = 1;
 	} else {
 		packet_fwrite_fmt(stdout, "%s %s\n", oid_to_hex(oid), refname_nons);
 	}
 	capabilities = NULL;
 	if (!peel_iterated_oid(oid, &peeled))
 		packet_fwrite_fmt(stdout, "%s %s^{}\n", oid_to_hex(&peeled), refname_nons);
+	return;
+}
+
+static int send_ref(const char *refname, const struct object_id *oid,
+		    int flag UNUSED, void *cb_data)
+{
+	write_v0_ref(cb_data, refname, strip_namespace(refname), oid);
 	return 0;
 }
 
@@ -1379,6 +1387,10 @@ void upload_pack(const int advertise_refs, const int stateless_rpc,
 			data.no_done = 1;
 		head_ref_namespaced(send_ref, &data);
 		for_each_namespaced_ref(send_ref, &data);
+		if (!data.sent_capabilities) {
+			const char *refname = "capabilities^{}";
+			write_v0_ref(&data, refname, refname, null_oid());
+		}
 		/*
 		 * fflush stdout before calling advertise_shallow_grafts because send_ref
 		 * uses stdio.