Merge branch 'jt/clone-server-option'

"git clone" learned a new --server-option option when talking over
the protocol version 2.

* jt/clone-server-option:
  clone: send server options when using protocol v2
  transport: die if server options are unsupported

Documentation/fetch-options.txt

@@ -216,7 +216,8 @@ endif::git-pull[]
 --server-option=<option>::
 	Transmit the given string to the server when communicating using
 	protocol version 2.  The given string must not contain a NUL or LF
-	character.
+	character.  The server's handling of server options, including
+	unknown ones, is server-specific.
 	When multiple `--server-option=<option>` are given, they are all
 	sent to the other side in the order listed on the command line.
 

Documentation/git-clone.txt

@@ -131,6 +131,14 @@ objects from the source repository into a pack in the cloned repository.
 	is specified. This flag forces progress status even if the
 	standard error stream is not directed to a terminal.
 
+--server-option=<option>::
+	Transmit the given string to the server when communicating using
+	protocol version 2.  The given string must not contain a NUL or LF
+	character.  The server's handling of server options, including
+	unknown ones, is server-specific.
+	When multiple `--server-option=<option>` are given, they are all
+	sent to the other side in the order listed on the command line.
+
 --no-checkout::
 -n::
 	No checkout of HEAD is performed after the clone is complete.

builtin/clone.c

@@ -66,6 +66,7 @@ static int option_dissociate;
 static int max_jobs = -1;
 static struct string_list option_recurse_submodules = STRING_LIST_INIT_NODUP;
 static struct list_objects_filter_options filter_options;
+static struct string_list server_options = STRING_LIST_INIT_NODUP;
 
 static int recurse_submodules_cb(const struct option *opt,
 				 const char *arg, int unset)
@@ -137,6 +138,8 @@ static struct option builtin_clone_options[] = {
 		   N_("separate git dir from working tree")),
 	OPT_STRING_LIST('c', "config", &option_config, N_("key=value"),
 			N_("set config inside the new repository")),
+	OPT_STRING_LIST(0, "server-option", &server_options,
+			N_("server-specific"), N_("option to transmit")),
 	OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
 			TRANSPORT_FAMILY_IPV4),
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
@@ -1136,6 +1139,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK,
 				     option_upload_pack);
 
+	if (server_options.nr)
+		transport->server_options = &server_options;
+
 	if (filter_options.choice) {
 		struct strbuf expanded_filter_spec = STRBUF_INIT;
 		expand_list_objects_filter_spec(&filter_options,

t/t5702-protocol-v2.sh

@@ -182,6 +182,13 @@ test_expect_success 'server-options are sent when using ls-remote' '
 	grep "server-option=world" log
 '
 
+test_expect_success 'warn if using server-option with ls-remote with legacy protocol' '
+	test_must_fail env GIT_TEST_PROTOCOL_VERSION=0 git -c protocol.version=0 \
+		ls-remote -o hello -o world "file://$(pwd)/file_parent" master 2>err &&
+
+	test_i18ngrep "see protocol.version in" err &&
+	test_i18ngrep "server options require protocol version 2 or later" err
+'
 
 test_expect_success 'clone with file:// using protocol v2' '
 	test_when_finished "rm -f log" &&
@@ -251,6 +258,40 @@ test_expect_success 'server-options are sent when fetching' '
 	grep "server-option=world" log
 '
 
+test_expect_success 'warn if using server-option with fetch with legacy protocol' '
+	test_when_finished "rm -rf temp_child" &&
+
+	git init temp_child &&
+
+	test_must_fail env GIT_TEST_PROTOCOL_VERSION=0 git -C temp_child -c protocol.version=0 \
+		fetch -o hello -o world "file://$(pwd)/file_parent" master 2>err &&
+
+	test_i18ngrep "see protocol.version in" err &&
+	test_i18ngrep "server options require protocol version 2 or later" err
+'
+
+test_expect_success 'server-options are sent when cloning' '
+	test_when_finished "rm -rf log myclone" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		clone --server-option=hello --server-option=world \
+		"file://$(pwd)/file_parent" myclone &&
+
+	grep "server-option=hello" log &&
+	grep "server-option=world" log
+'
+
+test_expect_success 'warn if using server-option with clone with legacy protocol' '
+	test_when_finished "rm -rf myclone" &&
+
+	test_must_fail env GIT_TEST_PROTOCOL_VERSION=0 git -c protocol.version=0 \
+		clone --server-option=hello --server-option=world \
+		"file://$(pwd)/file_parent" myclone 2>err &&
+
+	test_i18ngrep "see protocol.version in" err &&
+	test_i18ngrep "server options require protocol version 2 or later" err
+'
+
 test_expect_success 'upload-pack respects config using protocol v2' '
 	git init server &&
 	write_script server/.git/hook <<-\EOF &&

transport.c

@@ -252,6 +252,14 @@ static int connect_setup(struct transport *transport, int for_push)
 	return 0;
 }
 
+static void die_if_server_options(struct transport *transport)
+{
+	if (!transport->server_options || !transport->server_options->nr)
+		return;
+	advise(_("see protocol.version in 'git help config' for more details"));
+	die(_("server options require protocol version 2 or later"));
+}
+
 /*
  * Obtains the protocol version from the transport and writes it to
  * transport->data->version, first connecting if not already connected.
@@ -286,6 +294,7 @@ static struct ref *handshake(struct transport *transport, int for_push,
 		break;
 	case protocol_v1:
 	case protocol_v0:
+		die_if_server_options(transport);
 		get_remote_heads(&reader, &refs,
 				 for_push ? REF_NORMAL : 0,
 				 &data->extra_have,
@@ -362,6 +371,7 @@ static int fetch_refs_via_pack(struct transport *transport,
 		break;
 	case protocol_v1:
 	case protocol_v0:
+		die_if_server_options(transport);
 		refs = fetch_pack(&args, data->fd,
 				  refs_tmp ? refs_tmp : transport->remote_refs,
 				  to_fetch, nr_heads, &data->shallow,