I'm trying out using global loot modifiers to modify the loot tables of some vanilla entities for my mod.  At first I thought I had it working fine: my custom item dropped for entities in the specified tag and didn't drop for entities outside of it.  Great.  The next day, though, while doing some testing in survival mode, I broke an oak log... and my custom item dropped for that too.  And then again for stone, granite, and coal ore.  Not great.

Can anyone tell me what I'm doing wrong?  Why my loot modifier, with conditions that seem to imply that it should only drop for certain entity types, is also triggering for every block under the sun?  I haven't found anything that derives from ILootCondition with a name that suggests it differentiates between blocks and entities, so I'm feeling stuck.

Here's the code for the loot modifier object:

package com.verdantartifice.primalmagic.common.loot.modifiers;

import java.util.ArrayList;
import java.util.List;

import com.google.gson.JsonObject;
import com.verdantartifice.primalmagic.common.items.ItemsPM;
import com.verdantartifice.primalmagic.common.util.ItemUtils;

import net.minecraft.item.ItemStack;
import net.minecraft.loot.ConstantRange;
import net.minecraft.loot.ItemLootEntry;
import net.minecraft.loot.LootContext;
import net.minecraft.loot.LootPool;
import net.minecraft.loot.LootTable;
import net.minecraft.loot.RandomValueRange;
import net.minecraft.loot.conditions.ILootCondition;
import net.minecraft.loot.functions.LootingEnchantBonus;
import net.minecraft.loot.functions.SetCount;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
import net.minecraftforge.common.loot.LootModifier;

/**
 * Global loot modifier that allows mobs in the conditioned tag to drop Bloody Flesh when killed.
 * 
 * @author Daedalus4096
 */
public class BloodyFleshModifier extends LootModifier {
    public BloodyFleshModifier(ILootCondition[] conditionsIn) {
        super(conditionsIn);
    }

    @SuppressWarnings("deprecation")
    @Override
    protected List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
        LootTable table = LootTable.builder().addLootPool(LootPool.builder().rolls(ConstantRange.of(1)).addEntry(ItemLootEntry.builder(ItemsPM.BLOODY_FLESH.get()).acceptFunction(SetCount.builder(RandomValueRange.of(0.0F, 1.0F))).acceptFunction(LootingEnchantBonus.builder(RandomValueRange.of(0.0F, 1.0F))))).build();
        List<ItemStack> lootList = new ArrayList<>();
        table.generate(context, lootList::add); // Use deprecated version to avoid calling modifyLoot and prevent infinite recursion
        return ItemUtils.mergeItemStackLists(generatedLoot, lootList);
    }

    public static class Serializer extends GlobalLootModifierSerializer<BloodyFleshModifier> {
        @Override
        public BloodyFleshModifier read(ResourceLocation location, JsonObject object, ILootCondition[] ailootcondition) {
            return new BloodyFleshModifier(ailootcondition);
        }

        @Override
        public JsonObject write(BloodyFleshModifier instance) {
            return this.makeConditions(instance.conditions);
        }
    }
}

And here's the JSON file for the modifier:

{
  "conditions": [
    {
      "condition": "minecraft:entity_properties",
      "predicate": {
        "type": "#primalmagic:drops_bloody_flesh"
      },
      "entity": "this"
    }
  ],
  "type": "primalmagic:bloody_flesh"
}

The GitHub repository can be found here if you need to look at anything else.  Thank you for your time.

3 hours ago, Daedalus4096 said:

Can anyone tell me what I'm doing wrong?

When you are breaking a block, the "this" entity in the condition is the player, and since the primalmagic:drops_bloody_flesh tag contains the player, the condition is met. You would have to add another condition that checks that an entity was actually killed.

Also why are you building a new loot table every time?

Either:

a) build the loot table once and store it in a field
b) don't use a loot table at all and just go "derp, I can ask for a random integer from 0 to 1 and if 1 add a new item stack to the generated loot list." Because the loot table you're building is overkill for what you need.
c) put that loot table stuff in the loot table json file and deserialize the details so datapacks can override it

Edited June 3, 20214 yr by Draco18s

Thank you for the advice, both of you.  I'll make the necessary fixes!