Hello!
I'm trying to set up a GUI with buttons, and to communicate button changes, I'm using a SimpleChannel. This works flawlessly on client, however, on server, I experience a crash on the server related to missing classes. I assume this is due to referencing a class only present in Client, however I do not know where I do this.

 

Class for handling packets.

https://github.com/HaydenBelanger/assembly_line_machines/blob/development/src/main/java/me/haydenb/assemblylinemachines/packets/HashPacketImpl.java

 

Method for sending the packet to the channel.
https://github.com/HaydenBelanger/assembly_line_machines/blob/development/src/main/java/me/haydenb/assemblylinemachines/block/energy/BlockBasicBatteryCell.java#L327-L341

 

Registering the channels.
https://github.com/HaydenBelanger/assembly_line_machines/blob/development/src/main/java/me/haydenb/assemblylinemachines/registry/Registry.java#L290-L294

 

java.lang.NoSuchMethodError: net.minecraft.network.PacketBuffer.readString()Ljava/lang/String;
	at me.haydenb.assemblylinemachines.packets.HashPacketImpl$DecoderConsumer.apply(HashPacketImpl.java:83) ~[main/:?] {re:classloading}
	at me.haydenb.assemblylinemachines.packets.HashPacketImpl$DecoderConsumer.apply(HashPacketImpl.java:1) ~[main/:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.lambda$tryDecode$0(IndexedMessageCodec.java:116) ~[forge-1.15.2-31.1.0_mapped_snapshot_20200514-1.15.1-recomp.jar:?] {re:classloading}
	at java.util.Optional.map(Optional.java:215) ~[?:1.8.0_181] {}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.tryDecode(IndexedMessageCodec.java:116) ~[forge-1.15.2-31.1.0_mapped_snapshot_20200514-1.15.1-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.consume(IndexedMessageCodec.java:157) ~[forge-1.15.2-31.1.0_mapped_snapshot_20200514-1.15.1-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.SimpleChannel.networkEventListener(SimpleChannel.java:79) ~[forge-1.15.2-31.1.0_mapped_snapshot_20200514-1.15.1-recomp.jar:?] {re:classloading}
	at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:212) ~[eventbus-2.0.0-milestone.1-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:204) ~[eventbus-2.0.0-milestone.1-service.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-2.0.0-milestone.1-service.jar:?] {}
	at net.minecraftforge.fml.network.NetworkInstance.dispatch(NetworkInstance.java:84) ~[?:?] {re:classloading}
	at net.minecraftforge.fml.network.NetworkHooks.lambda$onCustomPayload$0(NetworkHooks.java:74) ~[?:?] {re:classloading}
	at java.util.Optional.map(Optional.java:215) ~[?:1.8.0_181] {}
	at net.minecraftforge.fml.network.NetworkHooks.onCustomPayload(NetworkHooks.java:74) ~[?:?] {re:classloading}
	at net.minecraft.network.play.ServerPlayNetHandler.processCustomPayload(ServerPlayNetHandler.java:1366) ~[?:?] {re:classloading}
	at net.minecraft.network.play.client.CCustomPayloadPacket.processPacket(CCustomPayloadPacket.java:51) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.network.play.client.CCustomPayloadPacket.processPacket(CCustomPayloadPacket.java:12) ~[?:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.network.PacketThreadUtil.lambda$checkThreadAndEnqueue$0(PacketThreadUtil.java:19) ~[?:?] {re:classloading}
	at net.minecraft.util.concurrent.TickDelayedTask.run(TickDelayedTask.java:20) ~[?:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.run(ThreadTaskExecutor.java:140) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.util.concurrent.RecursiveEventLoop.run(RecursiveEventLoop.java:22) ~[?:?] {re:classloading}
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:757) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:141) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.driveOne(ThreadTaskExecutor.java:110) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.server.MinecraftServer.driveOneInternal(MinecraftServer.java:740) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.server.MinecraftServer.driveOne(MinecraftServer.java:734) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.driveUntil(ThreadTaskExecutor.java:123) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.server.MinecraftServer.runScheduledTasks(MinecraftServer.java:720) ~[?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:664) [?:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}

I would love a point in the right direction as I don't see what could be the problem with this.

Quote

readString()

 is client only method marked as @OnlyIn(Dist.CLIENT). use

readString(int maxLength)

readString(int maxLength)

instead

3 minutes ago, poopoodice said:

 is client only method marked as @OnlyIn(Dist.CLIENT). use

readString(int maxLength)

readString(int maxLength)

instead

So is maxLength the length of the String being packet-ified?

1 minute ago, Haydenman2 said:

So is maxLength the length of the String being packet-ified?

It says maxLength means the string read from the packet can not be longer than it, readString() passed in 32767.

   /**
    * Reads a string from this buffer. Expected parameter is maximum allowed string length. Will throw IOException if
    * string length exceeds this value!
    */

Quote from the comment 

1 minute ago, poopoodice said:

It says maxLength means the string read from the packet can not be longer than it, readString() passed in 32767.

   /**
    * Reads a string from this buffer. Expected parameter is maximum allowed string length. Will throw IOException if
    * string length exceeds this value!
    */

Quote from the comment 

Considering readString() legitimately passes to readString(32767), that is a very... peculiar sided restriction. Thank you very much for helping me figure it out!

On 6/7/2020 at 3:15 AM, diesieben07 said:

It's not peculiar if you understand how the dist-only methods come to be. They are most likely optimized away by Mojang's obfuscator (or some other step in their build process), not removed by hand.

If a method is not used on the server, it is not included.

That makes a lot of sense, actually.