grpc: Fix cardinality violations in non-client streaming RPCs.

stream.go

@@ -1589,7 +1589,7 @@ type serverStream struct {
 
 	sendCompressorName string
 
-	recvFirstMsg bool // recv frist msg from client
+	recvFirstMsg bool // set after the first message is received
 
 	maxReceiveMessageSize int
 	maxSendMessageSize    int
@@ -1820,7 +1820,7 @@ func (ss *serverStream) RecvMsg(m any) (err error) {
 	} else if err != nil {
 		return err
 	}
-	return status.Error(codes.Internal, "cardinality violation: expected <EOF> for non client-streaming RPCs, but received another message")
+	return status.Error(codes.Internal, "cardinality violation: received multiple request messages for non-server-streaming RPC")
 }
 
 // MethodFromServerStream returns the method string for the input stream.

test/end2end_test.go

@@ -3837,7 +3837,7 @@ func (s) TestUnaryRPC_ClientCallSendMsgTwice(t *testing.T) {
 }
 
 // Tests the behavior for server-side streaming RPC when client misbehaves as Bidi-streaming
-// and sends multiple nessages.
+// and sends multiple messages.
 func (s) TestServerStreaming_ClientSendsMultipleMessages(t *testing.T) {
 	// The initial call to recvMsg made by the generated code, will return the error.
 	ss := stubserver.StubServer{}
@@ -3880,8 +3880,8 @@ func (s) TestServerStreaming_ClientSendsMultipleMessages(t *testing.T) {
 	}
 }
 
-// Tests the behavior for server-side streaming RPC when client sends zero request message.
-func (s) TestServerStreaming_ClientSendsZeroRequest(t *testing.T) {
+// Tests the behavior for server-side streaming RPC when client sends zero request messages.
+func (s) TestServerStreaming_ClientSendsZeroRequests(t *testing.T) {
 	// The initial call to recvMsg made by the generated code, will return the error.
 	ss := stubserver.StubServer{}
 	if err := ss.Start(nil); err != nil {