Fixed riding on entities.

src/main/java/us/myles/ViaVersion/PacketUtil.java

@@ -184,6 +184,13 @@ public class PacketUtil {
         }
     }
 
+    public static void writeVarIntArray(List<Integer> integers, ByteBuf output) {
+        writeVarInt(integers.size(),output);
+        for (Integer i  : integers){
+            writeVarInt(i,output);
+        }
+    }
+
     public static int readVarShort(ByteBuf buf) {
         int low = buf.readUnsignedShort();
         int high = 0;

src/main/java/us/myles/ViaVersion/transformers/IncomingTransformer.java

@@ -36,7 +36,7 @@ public class IncomingTransformer {
 //        if (packet != PacketType.PLAY_PLAYER_POSITION_LOOK_REQUEST && packet != PacketType.PLAY_KEEP_ALIVE_REQUEST && packet != PacketType.PLAY_PLAYER_POSITION_REQUEST && packet != PacketType.PLAY_PLAYER_LOOK_REQUEST) {
 //            System.out.println("Packet Type: " + packet + " New ID: " + packetID + " Original: " + original);
 //        }
-        if (packet == PacketType.PLAY_TP_CONFIRM) {
+        if (packet == PacketType.PLAY_TP_CONFIRM || packet == PacketType.PLAY_VEHICLE_MOVE_REQUEST) { //TODO handle client-sided horse riding
             throw new CancelException();
         }
         PacketUtil.writeVarInt(packetID, output);

src/main/java/us/myles/ViaVersion/transformers/OutgoingTransformer.java

@@ -25,8 +25,7 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.*;
 
-import static us.myles.ViaVersion.PacketUtil.readString;
-import static us.myles.ViaVersion.PacketUtil.writeString;
+import static us.myles.ViaVersion.PacketUtil.*;
 
 public class OutgoingTransformer {
     private static Gson gson = new Gson();
@@ -75,10 +74,18 @@ public class OutgoingTransformer {
             output.writeBytes(input);
         }
         if (packet == PacketType.PLAY_ATTACH_ENTITY) {
-            int id = input.readInt();
-            output.writeInt(id);
-            int target = input.readInt();
-            output.writeInt(target);
+            int passenger = input.readInt();
+            int vehicle = input.readInt();
+            boolean lead = input.readBoolean();
+            if (!lead){
+                output.clear();
+                writeVarInt(PacketType.PLAY_SET_PASSENGERS.getNewPacketID(),output);
+                writeVarInt(vehicle,output);
+                writeVarIntArray(Collections.singletonList(passenger),output);
+                return;
+            }
+            output.writeInt(passenger);
+            output.writeInt(vehicle);
             return;
         }
         if (packet == PacketType.PLAY_DISCONNECT){