Clean up error handling a bit in protocol.readMessage

lib/protocol/protocol.go

@@ -430,36 +430,20 @@ func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
 		}
 	}
 
-	// We check each returned error for the XDRError.IsEOF() method.
-	// IsEOF()==true here means that the message contained fewer fields than
-	// expected. It does not signify an EOF on the socket, because we've
-	// successfully read a size value and that many bytes already. New fields
-	// we expected but the other peer didn't send should be interpreted as
-	// zero/nil, and if that's not valid we'll verify it somewhere else.
-
 	switch hdr.msgType {
 	case messageTypeIndex, messageTypeIndexUpdate:
 		var idx IndexMessage
 		err = idx.UnmarshalXDR(msgBuf)
-		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
-			err = nil
-		}
 		msg = idx
 
 	case messageTypeRequest:
 		var req RequestMessage
 		err = req.UnmarshalXDR(msgBuf)
-		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
-			err = nil
-		}
 		msg = req
 
 	case messageTypeResponse:
 		var resp ResponseMessage
 		err = resp.UnmarshalXDR(msgBuf)
-		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
-			err = nil
-		}
 		msg = resp
 
 	case messageTypePing:
@@ -468,23 +452,28 @@ func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
 	case messageTypeClusterConfig:
 		var cc ClusterConfigMessage
 		err = cc.UnmarshalXDR(msgBuf)
-		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
-			err = nil
-		}
 		msg = cc
 
 	case messageTypeClose:
 		var cm CloseMessage
 		err = cm.UnmarshalXDR(msgBuf)
-		if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
-			err = nil
-		}
 		msg = cm
 
 	default:
 		err = fmt.Errorf("protocol error: %s: unknown message type %#x", c.id, hdr.msgType)
 	}
 
+	// We check the returned error for the XDRError.IsEOF() method.
+	// IsEOF()==true here means that the message contained fewer fields than
+	// expected. It does not signify an EOF on the socket, because we've
+	// successfully read a size value and then that many bytes from the wire.
+	// New fields we expected but the other peer didn't send should be
+	// interpreted as zero/nil, and if that's not valid we'll verify it
+	// somewhere else.
+	if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
+		err = nil
+	}
+
 	return
 }