[Paper 1.20.4] Disable invalid items from creative inventory with ProtocolLib

NoInvalidItem.kt

import com.comphenix.protocol.PacketType
import com.comphenix.protocol.events.ListenerPriority
import com.comphenix.protocol.events.PacketAdapter
import com.comphenix.protocol.events.PacketEvent
import net.kyori.adventure.text.Component
import org.bukkit.Material
import org.bukkit.craftbukkit.v1_20_R3.entity.CraftItem
import org.bukkit.craftbukkit.v1_20_R3.inventory.CraftItemStack
import org.bukkit.inventory.ItemStack

object NoInvalidItem {

    fun init() {
        protocolManager.addPacketListener(object : PacketAdapter(
            plugin,
            ListenerPriority.NORMAL,
            PacketType.Play.Client.SET_CREATIVE_SLOT
        ) {
            override fun onPacketReceiving(event: PacketEvent) {
                val packet = event.packet
                val slot = packet.integers.read(0)
                val item = packet.itemModifier.read(0)

                val craftItem = (item as CraftItemStack)

                if ((craftItem.handle != null && craftItem.handle.hasTag())) {
                    //println("cancel")
                    event.isCancelled = true
                }
            }
        })
    }

}