Hello!
I created a custom enchantment that is supposed to work like knockback, but it sends the victim in a random direction at a random velocity depending on the enchantment level. It all works perfectly in a single player environment, but upon hitting a mob with a "Glitch" sword with separate physical client and server, the server crashes with a noSuchMethodError exception. I'm  fairly new to modding so I don't fully understand how sides work. Any help would be appreciated.

 

here is the event that executes logic upon a mob being hit with a glitch weapon:

public class glitchevent {

    @SubscribeEvent
    public void onglitch(AttackEntityEvent e) {
        Entity target = e.getTarget();
        PlayerEntity attacker = e.getPlayer();

        int level = EnchantmentHelper.getEnchantmentLevel(ObjectHolderStorage.GLITCH, attacker.getHeldItemMainhand());

        Random r = new Random();

        int ins = r.nextInt(level + 2);
        double launchmultiplier = ins;
        double invertedlaunchmultiplier = ins - ins * ins;
        int test = r.nextInt(4);

        World world = e.getPlayer().world;

        if (!world.isRemote) {

            switch (test) {
                case 0:
                    target.setVelocity(launchmultiplier, 0.1D, launchmultiplier);
                    break;
                case 1:
                    target.setVelocity(invertedlaunchmultiplier, 0.1D, launchmultiplier);
                    break;
                case 2:
                    target.setVelocity(invertedlaunchmultiplier, 0.1D, invertedlaunchmultiplier);
                    break;
                case 3:
                    target.setVelocity(launchmultiplier, 0.1D, invertedlaunchmultiplier);
                    break;
            }
        }
    }
}

and here are the exceptions thrown on the server:

[12Aug2020 00:21:21.669] [Server thread/ERROR] [net.minecraftforge.eventbus.EventBus/EVENTBUS]: Exception caught during firing event: net.minecraft.entity.Entity.func_70016_h(DDD)V
	Index: 1
	Listeners:
		0: NORMAL
		1: ASM: mod.extraenchants.events.glitchevent@2c63f610 onglitch(Lnet/minecraftforge/event/entity/player/AttackEntityEvent;)V
java.lang.NoSuchMethodError: net.minecraft.entity.Entity.func_70016_h(DDD)V
	at mod.extraenchants.events.glitchevent.onglitch(glitchevent.java:36)
	at net.minecraftforge.eventbus.ASMEventHandler_2_glitchevent_onglitch_AttackEntityEvent.invoke(.dynamic)
	at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85)
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:297)
	at net.minecraftforge.common.ForgeHooks.onPlayerAttackTarget(ForgeHooks.java:719)
	at net.minecraft.entity.player.PlayerEntity.func_71059_n(PlayerEntity.java:1035)
	at net.minecraft.entity.player.ServerPlayerEntity.func_71059_n(ServerPlayerEntity.java:1280)
	at net.minecraft.network.play.ServerPlayNetHandler.func_147340_a(ServerPlayNetHandler.java:1127)
	at net.minecraft.network.play.client.CUseEntityPacket.func_148833_a(SourceFile:74)
	at net.minecraft.network.play.client.CUseEntityPacket.func_148833_a(SourceFile:13)
	at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21)
	at net.minecraft.util.concurrent.TickDelayedTask.run(SourceFile:18)
	at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144)
	at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23)
	at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:735)
	at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:157)
	at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118)
	at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:718)
	at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:712)
	at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103)
	at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:697)
	at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:647)
	at net.minecraft.server.MinecraftServer.lambda$func_240784_a_$0(MinecraftServer.java:230)
	at java.base/java.lang.Thread.run(Thread.java:834)

[12Aug2020 00:21:21.825] [Server thread/ERROR] [net.minecraft.server.MinecraftServer/]: Encountered an unexpected exception
java.lang.NoSuchMethodError: net.minecraft.entity.Entity.func_70016_h(DDD)V
	at mod.extraenchants.events.glitchevent.onglitch(glitchevent.java:36) ~[?:1.2]
	at net.minecraftforge.eventbus.ASMEventHandler_2_glitchevent_onglitch_AttackEntityEvent.invoke(.dynamic) ~[?:?]
	at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:85) ~[eventbus-3.0.3-service.jar:?]
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:297) ~[eventbus-3.0.3-service.jar:?]
	at net.minecraftforge.common.ForgeHooks.onPlayerAttackTarget(ForgeHooks.java:719) ~[?:?]
	at net.minecraft.entity.player.PlayerEntity.func_71059_n(PlayerEntity.java:1035) ~[?:?]
	at net.minecraft.entity.player.ServerPlayerEntity.func_71059_n(ServerPlayerEntity.java:1280) ~[?:?]
	at net.minecraft.network.play.ServerPlayNetHandler.func_147340_a(ServerPlayNetHandler.java:1127) ~[?:?]
	at net.minecraft.network.play.client.CUseEntityPacket.func_148833_a(SourceFile:74) ~[?:?]
	at net.minecraft.network.play.client.CUseEntityPacket.func_148833_a(SourceFile:13) ~[?:?]
	at net.minecraft.network.PacketThreadUtil.func_225383_a(SourceFile:21) ~[?:?]
	at net.minecraft.util.concurrent.TickDelayedTask.run(SourceFile:18) ~[?:?]
	at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213166_h(SourceFile:144) ~[?:?]
	at net.minecraft.util.concurrent.RecursiveEventLoop.func_213166_h(SourceFile:23) ~[?:?]
	at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:735) ~[?:?]
	at net.minecraft.server.MinecraftServer.func_213166_h(MinecraftServer.java:157) ~[?:?]
	at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213168_p(SourceFile:118) ~[?:?]
	at net.minecraft.server.MinecraftServer.func_213205_aW(MinecraftServer.java:718) ~[?:?]
	at net.minecraft.server.MinecraftServer.func_213168_p(MinecraftServer.java:712) ~[?:?]
	at net.minecraft.util.concurrent.ThreadTaskExecutor.func_213160_bf(SourceFile:103) ~[?:?]
	at net.minecraft.server.MinecraftServer.func_213202_o(MinecraftServer.java:697) ~[?:?]
	at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:647) ~[?:?]
	at net.minecraft.server.MinecraftServer.lambda$func_240784_a_$0(MinecraftServer.java:230) ~[?:?]
	at java.lang.Thread.run(Thread.java:834) [?:?]

 

My guess would be the 

if (!world.isRemote) {

Try removing the if statement, (obviously keeping the switch statement), and see how that goes. I haven't tested it yet myself.

 

I believe world.isRemote checks if the world is on a separate physical server, so by inverting it, you're making it so it only works on a client.

Edited August 12, 20205 yr by BlockyPenguin

Entity#setVelocity is only present on the client, use Entity#setMotion instead. What BlockyPenguin suggested will not work.

51 minutes ago, BlockyPenguin said:

so by inverting it, you're making it so it only works on a client.

That's a valid assumption, but it doesn't work like that, you cannot access client code from common code without packets.

1 hour ago, Novârch said:

What BlockyPenguin suggested will not work.

 

18 minutes ago, Novârch said:

That's a valid assumption, but it doesn't work like that, you cannot access client code from common code without packets.

 

Ah ok, thanks