My bug
When using /vanish, my vanish plugin sends an Entity Destroy packet. I've used an integer array with the Entity ID in it, but ProtocolLib can't find the field. Propably a bug in ProtocolLib. I'm using Paper 1.18.1.

Console Error
[21:54:02 ERROR]: null org.bukkit.command.CommandException: Unhandled exception executing command 'v' in plugin UltraVanish v1.0-SNAPSHOT at org.bukkit.command.PluginCommand.execute(PluginCommand.java:47) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?] at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:159) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?] at org.bukkit.craftbukkit.v1_18_R1.CraftServer.dispatchCommand(CraftServer.java:897) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.server.network.ServerGamePacketListenerImpl.handleCommand(ServerGamePacketListenerImpl.java:2268) ~[?:?] at net.minecraft.server.network.ServerGamePacketListenerImpl.handleChat(ServerGamePacketListenerImpl.java:2079) ~[?:?] at net.minecraft.server.network.ServerGamePacketListenerImpl.handleChat(ServerGamePacketListenerImpl.java:2060) ~[?:?] at net.minecraft.network.protocol.game.ServerboundChatPacket.handle(ServerboundChatPacket.java:46) ~[?:?] at net.minecraft.network.protocol.game.ServerboundChatPacket.a(ServerboundChatPacket.java:6) ~[?:?] at net.minecraft.network.protocol.PacketUtils.lambda$ensureRunningOnSameThread$1(PacketUtils.java:56) ~[?:?] at net.minecraft.server.TickTask.run(TickTask.java:18) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:149) ~[?:?] at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:23) ~[?:?] at net.minecraft.server.MinecraftServer.doRunTask(MinecraftServer.java:1413) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.server.MinecraftServer.c(MinecraftServer.java:189) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:122) ~[?:?] at net.minecraft.server.MinecraftServer.pollTaskInternal(MinecraftServer.java:1391) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.server.MinecraftServer.pollTask(MinecraftServer.java:1384) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.util.thread.BlockableEventLoop.runAllTasks(BlockableEventLoop.java:110) ~[?:?] at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1518) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1264) ~[paper-1.18.1.jar:git-Paper-97] at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:317) ~[paper-1.18.1.jar:git-Paper-97] at java.lang.Thread.run(Thread.java:833) ~[?:?] Caused by: com.comphenix.protocol.reflect.FieldAccessException: No field with type [I exists in class PacketPlayOutEntityDestroy. at com.comphenix.protocol.reflect.StructureModifier.writeInternal(StructureModifier.java:365) ~[ProtocolLib.jar:?] at com.comphenix.protocol.reflect.StructureModifier.write(StructureModifier.java:345) ~[ProtocolLib.jar:?] at me.thianfrietpan.ultravanish.spigot.SpigotAPI.sendEntityDestroyPacket(SpigotAPI.java:212) ~[UltraVanish.jar:?] at me.thianfrietpan.ultravanish.spigot.SpigotAPI.hidePlayer(SpigotAPI.java:140) ~[UltraVanish.jar:?] at me.thianfrietpan.ultravanish.spigot.commands.VanishCommand.lambda$new$0(VanishCommand.java:33) ~[UltraVanish.jar:?] at me.thianfrietpan.panapi.CommandLibV4.CustomCommand.lambda$register$0(CustomCommand.java:123) ~[PanCore 1.17.jar:?] at org.bukkit.command.PluginCommand.execute(PluginCommand.java:45) ~[paper-api-1.18.1-R0.1-SNAPSHOT.jar:?] ... 21 more

My Code
private void sendEntityDestroyPacket(final Player receiver, final Player vanishedPlayer) { <<-- line 206 in class SpigotAPI
if (!ProtocolLibrary.getProtocolManager().getEntityTrackers(vanishedPlayer).contains(receiver)) {
return;
}
final PacketContainer packetContainer = new PacketContainer(PacketType.Play.Server.ENTITY_DESTROY);
int[] ids = { vanishedPlayer.getEntityId() };
packetContainer.getIntegerArrays().write(0, ids); <<-- line 212
try {
ProtocolLibrary.getProtocolManager().sendServerPacket(receiver, packetContainer);
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}

I hope you are able to fix it or send me the mistake that I'm making.

Kind regards,

ThianFrietpan

Use getIntLists instead of getIntArrays. The field type changed in 1.18 (again) :)

I'll try that. Thank you for your response!