[SOLVED][1.18] Loot Modifiers Require "type"... but using any known ones causes error

[izofar]

In 1.16, LootModifierManager#deserializeModifier read:

private IGlobalLootModifier deserializeModifier(ResourceLocation location, JsonElement element) {
        if (!element.isJsonObject()) return null;
        JsonObject object = element.getAsJsonObject();
        ILootCondition[] lootConditions = GSON_INSTANCE.fromJson(object.get("conditions"), ILootCondition[].class);

        // For backward compatibility with the initial implementation, fall back to using the location as the type.
        // TODO: Remove fallback in 1.16
        ResourceLocation serializer = location;
        if (object.has("type"))
        {
            serializer = new ResourceLocation(JSONUtils.getAsString(object, "type"));
        }

        return ForgeRegistries.LOOT_MODIFIER_SERIALIZERS.getValue(serializer).read(location, object, lootConditions);
    }

Note the if(object.has(type")){} block, which is lacking from the 1.18 version of the class:

private IGlobalLootModifier deserializeModifier(ResourceLocation location, JsonElement element) {
        if (!element.isJsonObject()) return null;
        JsonObject object = element.getAsJsonObject();
        LootItemCondition[] lootConditions = GSON_INSTANCE.fromJson(object.get("conditions"), LootItemCondition[].class);

        ResourceLocation serializer = new ResourceLocation(GsonHelper.getAsString(object, "type"));

        return ForgeRegistries.LOOT_MODIFIER_SERIALIZERS.getValue(serializer).read(location, object, lootConditions);
    }

So, the "value" tag is required now for loot modifiers... fine. I added this to my loot modifer json files when I kept getting NullPointerExceptions. But when I use a valid "value" tag I get:

[15:27:02] [Render thread/ERROR]: Couldn't parse loot modifier examplemod:add_structure_loot
java.lang.NullPointerException: Cannot invoke "net.minecraftforge.common.loot.GlobalLootModifierSerializer.read(net.minecraft.resources.ResourceLocation, com.google.gson.JsonObject, net.minecraft.world.level.storage.loot.predicates.LootItemCondition[])" because the return value of "net.minecraftforge.registries.IForgeRegistry.getValue(net.minecraft.resources.ResourceLocation)" is null
        at net.minecraftforge.common.loot.LootModifierManager.deserializeModifier(LootModifierManager.java:133) ~[forge-1.18-38.0.14_mapped_official_1.18-recomp.jar%2376%2382!:?]
        at net.minecraftforge.common.loot.LootModifierManager.lambda$apply$0(LootModifierManager.java:115) ~[forge-1.18-38.0.14_mapped_official_1.18-recomp.jar%2376%2382!:?]
        at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?]
        at net.minecraftforge.common.loot.LootModifierManager.apply(LootModifierManager.java:113) ~[forge-1.18-38.0.14_mapped_official_1.18-recomp.jar%2376%2382!:?]
        at net.minecraftforge.common.loot.LootModifierManager.apply(LootModifierManager.java:54) ~[forge-1.18-38.0.14_mapped_official_1.18-recomp.jar%2376%2382!:?]

My json file is:

{
  "type": "chest",
  "conditions": [
    {
      "condition": "forge:loot_table_id",
      "loot_table_id": "examplemod:chests/modstructure"
    }
  ]
}

I tried printing the contents of ForgeRegistries.LOOT_MODIFIER_SERIALIZERS to know which keys I can use, but got:

[15:26:13] [modloading-worker-0/INFO]: Printing LOOT_MODIFER_SERIALIZERS
[15:26:13] [modloading-worker-0/INFO]: Printed LOOT_MODIFER_SERIALIZERS

Is this a bug, given 1.18 is new, or am I not using these classes right?

Edited December 6, 2021 by izofar

[diesieben07]

"minecraft:chest" is not a valid loot modifier registry name.

[izofar]

1 minute ago, diesieben07 said:

"minecraft:chest" is not a valid loot modifier registry name.

I got this from the link above, which says:

Quote

Optional type of the loot table. Must be one of empty if the loot table does not generate any loot, entity for loot an entity drops, block for loot a block drops, chest for a treasure chest, fishing for a fishing loot table, gift for a cat or villager gift, advancement_reward if it's used as a reward for an advancement, barter for loot from bartering with piglins, command for /execute, selector for predicate= in selectors, advancement_entity for entity predicates in advancements or generic if none of the above apply.

If these are not the valid names, then what are?

[diesieben07]

That is for loot tables. You are making a loot modifier.

4 minutes ago, izofar said:

If these are not the valid names, then what are?

You registered your GlobalLootModifierSerializer to the registry with a registry name. The "type" field tells the game which serializer to use.

[izofar]

2 minutes ago, diesieben07 said:

That is for loot tables. You are making a loot modifier.

You registered your GlobalLootModifierSerializer to the registry with a registry name. The "type" field tells the game which serializer to use.

Just noticed the first part. As for the second, thanks lad!