fix...

legacyver/proto/command.go

@@ -295,3 +295,20 @@ func (x *CommandOutputMessage) Marshal(r protocol.IO) {
 	r.Bool(&x.Success)
 	protocol.FuncSlice(r, &x.Parameters, r.String)
 }
+
+// ToLatest ...
+func (x *CommandOutputMessage) ToLatest() protocol.CommandOutputMessage {
+	return protocol.CommandOutputMessage{
+		Success:    x.Success,
+		Message:    x.Message,
+		Parameters: x.Parameters,
+	}
+}
+
+// FromLatest ...
+func (x *CommandOutputMessage) FromLatest(latest protocol.CommandOutputMessage) CommandOutputMessage {
+	x.Success = latest.Success
+	x.Message = latest.Message
+	x.Parameters = latest.Parameters
+	return *x
+}

legacyver/protocol.go

@@ -796,11 +796,15 @@ func (p *Protocol) downgradePackets(pks []packet.Packet, conn *minecraft.Conn) [
 				Constraints:             pk.Constraints,
 			}
 		case *packet.CommandOutput:
+			outputMessages := make([]proto.CommandOutputMessage, len(pk.OutputMessages))
+			for i, outputMessage := range pk.OutputMessages {
+				outputMessages[i] = (&proto.CommandOutputMessage{}).FromLatest(outputMessage)
+			}
 			pks[pkIndex] = &legacypacket.CommandOutput{
 				CommandOrigin:  pk.CommandOrigin,
 				OutputType:     pk.OutputType,
 				SuccessCount:   pk.SuccessCount,
-				OutputMessages: pk.OutputMessages,
+				OutputMessages: outputMessages,
 				DataSet:        pk.DataSet,
 			}
 		case *packet.CommandRequest:
@@ -1397,11 +1401,15 @@ func (p *Protocol) upgradePackets(pks []packet.Packet, conn *minecraft.Conn) []p
 				Constraints:             pk.Constraints,
 			}
 		case *legacypacket.CommandOutput:
+			outputMessages := make([]protocol.CommandOutputMessage, len(pk.OutputMessages))
+			for i, outputMessage := range pk.OutputMessages {
+				outputMessages[i] = outputMessage.ToLatest()
+			}
 			pks[pkIndex] = &packet.CommandOutput{
 				CommandOrigin:  pk.CommandOrigin,
 				OutputType:     pk.OutputType,
 				SuccessCount:   pk.SuccessCount,
-				OutputMessages: pk.OutputMessages,
+				OutputMessages: outputMessages,
 				DataSet:        pk.DataSet,
 			}
 		case *legacypacket.CommandRequest: