Resolved Packet 63 crash (world particles)

Hello, I made a bukkit plugin which spawns particles using Packet 63 (0x3F). When I don't have the server connected to lilyPad, everything works fine, but if I use lilyPad, it shows errors and all clients who receive the packet time out.

Code (text):

[LilyPad] build 16 of AllInOne
io.netty.handler.codec.DecoderException: java.lang.NullPointerException
        at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:459)
        at io.netty.handler.codec.ByteToMessageDecoder.inboundBufferUpdated(ByteToMessageDecoder.java:69)
        at io.netty.channel.ChannelInboundByteHandlerAdapter.inboundBufferUpdated(ChannelInboundByteHandlerAdapter.java:51)
        at io.netty.channel.DefaultChannelHandlerContext.invokeInboundBufferUpdated(DefaultChannelHandlerContext.java:896)
        at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated0(DefaultChannelHandlerContext.java:864)
        at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated(DefaultChannelHandlerContext.java:843)
        at io.netty.handler.timeout.ReadTimeoutHandler.inboundBufferUpdated(ReadTimeoutHandler.java:149)
        at io.netty.channel.DefaultChannelHandlerContext.invokeInboundBufferUpdated(DefaultChannelHandlerContext.java:917)
        at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated0(DefaultChannelHandlerContext.java:864)
        at io.netty.channel.DefaultChannelHandlerContext.fireInboundBufferUpdated(DefaultChannelHandlerContext.java:843)
        at io.netty.channel.DefaultChannelPipeline.fireInboundBufferUpdated(DefaultChannelPipeline.java:1017)
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:115)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:460)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:424)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:360)
        at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:103)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
        at lilypad.server.proxy.packet.GenericPacketCodec.decode(GenericPacketCodec.java:24)
        at lilypad.server.proxy.packet.GenericPacketCodec.decode(GenericPacketCodec.java:14)
        at lilypad.server.proxy.packet.GenericPacketCodec.decode(GenericPacketCodec.java:7)
        at lilypad.packet.common.PacketDecoder.decode(PacketDecoder.java:16)
        at lilypad.packet.common.PacketDecoder.decode(PacketDecoder.java:7)
        at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:404)
        ... 16 more
io.netty.handler.codec.DecoderException: java.lang.NullPointerException
        at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:459)
        at io.netty.handler.codec.ReplayingDecoder.channelInactive(ReplayingDecoder.java:371)
        at io.netty.channel.DefaultChannelHandlerContext.invokeChannelInactive(DefaultChannelHandlerContext.java:752)
        at io.netty.channel.DefaultChannelHandlerContext.fireChannelInactive(DefaultChannelHandlerContext.java:738)
        at io.netty.channel.ChannelStateHandlerAdapter.channelInactive(ChannelStateHandlerAdapter.java:69)
        at io.netty.handler.timeout.ReadTimeoutHandler.channelInactive(ReadTimeoutHandler.java:143)
        at io.netty.channel.DefaultChannelHandlerContext.invokeChannelInactive(DefaultChannelHandlerContext.java:752)
        at io.netty.channel.DefaultChannelHandlerContext.access$1600(DefaultChannelHandlerContext.java:36)
        at io.netty.channel.DefaultChannelHandlerContext$6.run(DefaultChannelHandlerContext.java:743)
        at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:276)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:365)
        at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:103)
        at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.NullPointerException
        at lilypad.server.proxy.packet.GenericPacketCodec.decode(GenericPacketCodec.java:24)
        at lilypad.server.proxy.packet.GenericPacketCodec.decode(GenericPacketCodec.java:14)
        at lilypad.server.proxy.packet.GenericPacketCodec.decode(GenericPacketCodec.java:7)
        at lilypad.packet.common.PacketDecoder.decode(PacketDecoder.java:16)
        at lilypad.packet.common.PacketDecoder.decode(PacketDecoder.java:7)
        at io.netty.handler.codec.ReplayingDecoder.callDecode(ReplayingDecoder.java:404)
        ... 12 more
 

As you can see in the log, I use AllInOne server. I tried sending the packet using playerConnection.sendPacket(packet) and also ProtocolLib, both work perfectly without lilyPad on which made me believe it's an error in lilyPad. This is the code I use, in case you need it:

Code (text):

PacketContainer packet=protocol.createPacket(63);
            packet.getSpecificModifier(String.class).write(0,(String)effect.getEffect());
            packet.getSpecificModifier(float.class)
                .write(0,(float)player.getLocation().getX())
                .write(1,(float)player.getLocation().getY()+0.5F)
                .write(2,(float)player.getLocation().getZ())
                .write(3,effect.getOffset(rand))
                .write(4,0.5F)
                .write(5,effect.getOffset(rand))
                .write(6,effect==Effect.SMOKE?0.04F:0.25F);
            packet.getSpecificModifier(int.class).write(0,effect.getAmount());
            try{
                for(Entity e:player.getNearbyEntities(16D,16D,16D)){
                    if (e.getType()==EntityType.PLAYER)protocol.sendServerPacket((Player)e,packet);
                }
                protocol.sendServerPacket(player,packet);
            }catch(InvocationTargetException e){}

Thanks for help, hope you can quickly fix it

Well, the packet is handled by ProtocolLib so it should be okay - 1 string, 7 floats and 1 integer, no other data in the packet. I'm 100% sure that it's the 0x3F packet, I don't send any other packets and the crash happens for 'player' and players 16 blocks away from him, so I have no doubt it's causing the issue.

I don't create the byte array nor I have access to it, that should be handled by the server. ProtocolLib just uses the playerConnection.sendPacket(packet) field in CraftPlayer, is there a special way of sending packets, that's specific to LilyPad?

createPacket just creates a PacketContainer, which is an easy way of setting packet data and then send it without any reflection and craftbukkit references in the plugin file, it's the ProtocolLib API. It creates a regular vanilla packet and fills in the data I specified, then sends it. I checked packet.toString() and it was Packet63WorldParticles which is correct, so it looks like it does the job good.

I also tried it with my own code, where I created an instance of Packet63WorldParticles and used reflection to set the fields. Again, just like the ProtocolLib solution, it works until I use LilyPad.

I really have no idea what could be the problem, both solutions lead to the same result (sendPacket()). I do have Minecraft decompiled and there's no field in the packet that I could've missed. Does LilyPad change the sendPacket() method, or does it have a special way of sending packets I have to use instead of the craftbukkit's one?

Thank you