net/rpc: fix RegisterName rejects "." character.

Fixes #5617.

R=r, rsc
CC=gobot, golang-dev
https://golang.org/cl/10370043

src/pkg/net/rpc/server.go

@@ -560,20 +560,23 @@ func (server *Server) readRequestHeader(codec ServerCodec) (service *service, mt
 	// we can still recover and move on to the next request.
 	keepReading = true
 
-	serviceMethod := strings.Split(req.ServiceMethod, ".")
-	if len(serviceMethod) != 2 {
+	dot := strings.LastIndex(req.ServiceMethod, ".")
+	if dot < 0 {
 		err = errors.New("rpc: service/method request ill-formed: " + req.ServiceMethod)
 		return
 	}
+	serviceName := req.ServiceMethod[:dot]
+	methodName := req.ServiceMethod[dot+1:]
+
 	// Look up the request.
 	server.mu.RLock()
-	service = server.serviceMap[serviceMethod[0]]
+	service = server.serviceMap[serviceName]
 	server.mu.RUnlock()
 	if service == nil {
 		err = errors.New("rpc: can't find service " + req.ServiceMethod)
 		return
 	}
-	mtype = service.method[serviceMethod[1]]
+	mtype = service.method[methodName]
 	if mtype == nil {
 		err = errors.New("rpc: can't find method " + req.ServiceMethod)
 	}

src/pkg/net/rpc/server_test.go

@@ -84,6 +84,7 @@ func listenTCP() (net.Listener, string) {
 
 func startServer() {
 	Register(new(Arith))
+	RegisterName("net.rpc.Arith", new(Arith))
 
 	var l net.Listener
 	l, serverAddr = listenTCP()
@@ -97,6 +98,7 @@ func startServer() {
 func startNewServer() {
 	newServer = NewServer()
 	newServer.Register(new(Arith))
+	newServer.RegisterName("net.rpc.Arith", new(Arith))
 
 	var l net.Listener
 	l, newServerAddr = listenTCP()
@@ -234,6 +236,17 @@ func testRPC(t *testing.T, addr string) {
 	if reply.C != args.A*args.B {
 		t.Errorf("Mul: expected %d got %d", reply.C, args.A*args.B)
 	}
+
+	// ServiceName contain "." character
+	args = &Args{7, 8}
+	reply = new(Reply)
+	err = client.Call("net.rpc.Arith.Add", args, reply)
+	if err != nil {
+		t.Errorf("Add: expected no error but got string %q", err.Error())
+	}
+	if reply.C != args.A+args.B {
+		t.Errorf("Add: expected %d got %d", reply.C, args.A+args.B)
+	}
 }
 
 func TestHTTP(t *testing.T) {