MixinBucketItem.java

package online.connlost.allstackable.mixin;

import online.connlost.allstackable.util.ItemsHelper;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.item.BucketItem;
import net.minecraft.item.ItemStack;
import net.minecraft.item.Items;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Inject;
import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;

@Mixin(BucketItem.class)
public class MixinBucketItem {

    @Inject(method = "getEmptiedStack", at = @At(value = "HEAD"), cancellable = true)
    private static void stackableBucket(ItemStack stack, PlayerEntity player, CallbackInfoReturnable<ItemStack> cir){
            if (ItemsHelper.isModified(stack) && stack.getCount() > 1 && !player.getAbilities().creativeMode){
                ItemsHelper.insertNewItem(player, new ItemStack(Items.BUCKET));
                stack.decrement(1);
                cir.setReturnValue(stack);
            }
    }

}