[1.19.2] Loading loot modifier causes NullPointerException

[AvaLS]

Currently trying to edit the loot modifier for oak leaves. I'm fairly certain I have everything set up correctly and I checked for spelling errors in all the JSONs, but to no avail. Here is the error:

[22:32:19] [Render thread/ERROR] [ne.mi.co.lo.LootModifierManager/]: Couldn't parse loot modifier storange:oak_leaves_orange
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:119) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2387%2394!/:?] {re:classloading}
	at net.minecraftforge.common.loot.LootModifierManager.lambda$apply$0(LootModifierManager.java:101) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2387%2394!/:?] {re:classloading}
	at java.util.ArrayList.forEach(ArrayList.java:1511) ~[?:?] {}
	at net.minecraftforge.common.loot.LootModifierManager.apply(LootModifierManager.java:99) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2387%2394!/:?] {re:classloading}
	at net.minecraftforge.common.loot.LootModifierManager.apply(LootModifierManager.java:40) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2387%2394!/:?] {re:classloading}
	at net.minecraft.server.packs.resources.SimplePreparableReloadListener.lambda$reload$1(SimplePreparableReloadListener.java:12) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading}
	at java.util.concurrent.CompletableFuture$UniAccept.tryFire(CompletableFuture.java:718) ~[?:?] {}
	at java.util.concurrent.CompletableFuture$Completion.run(CompletableFuture.java:482) ~[?:?] {}
	at net.minecraft.server.packs.resources.SimpleReloadInstance.lambda$new$3(SimpleReloadInstance.java:65) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading}
	at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:143) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:22) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading}
	at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:116) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.thread.BlockableEventLoop.managedBlock(BlockableEventLoop.java:126) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.Minecraft.makeWorldStem(Minecraft.java:2082) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.doLoadLevel(Minecraft.java:1909) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.loadLevel(Minecraft.java:1873) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screens.worldselection.WorldSelectionList$WorldListEntry.loadWorld(WorldSelectionList.java:473) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screens.worldselection.WorldSelectionList$WorldListEntry.joinWorld(WorldSelectionList.java:330) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screens.worldselection.WorldSelectionList$WorldListEntry.mouseClicked(WorldSelectionList.java:257) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.components.AbstractSelectionList.mouseClicked(AbstractSelectionList.java:323) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.components.events.ContainerEventHandler.mouseClicked(ContainerEventHandler.java:28) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.MouseHandler.lambda$onPress$0(MouseHandler.java:88) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screens.Screen.wrapScreenError(Screen.java:528) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.MouseHandler.onPress(MouseHandler.java:85) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.MouseHandler.lambda$setup$4(MouseHandler.java:185) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.util.thread.BlockableEventLoop.execute(BlockableEventLoop.java:90) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.MouseHandler.lambda$setup$5(MouseHandler.java:184) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:36) ~[lwjgl-glfw-3.2.2.jar%2366!/:build 10] {}
	at org.lwjgl.system.JNI.invokeV(Native Method) ~[lwjgl-3.2.2.jar%2372!/:build 10] {}
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:3101) ~[lwjgl-glfw-3.2.2.jar%2366!/:build 10] {}
	at com.mojang.blaze3d.systems.RenderSystem.flipFrame(RenderSystem.java:168) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at com.mojang.blaze3d.platform.Window.updateDisplay(Window.java:333) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:1068) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.run(Minecraft.java:665) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:205) ~[forge-1.18.2-40.1.84_mapped_official_1.18.2-recomp.jar%2388!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?] {}
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?] {}
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?] {}
	at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?] {}
	at net.minecraftforge.fml.loading.targets.ForgeClientUserdevLaunchHandler.lambda$launchService$0(ForgeClientUserdevLaunchHandler.java:24) ~[fmlloader-1.18.2-40.1.84.jar%239!/:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:53) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:71) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:106) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:77) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) [modlauncher-9.1.3.jar%2320!/:?] {}
	at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:149) [bootstraplauncher-1.0.0.jar:?] {}

 

Here is the modifier class:

package avals.storange.loot;

import com.google.gson.JsonObject;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.util.GsonHelper;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.ItemStack;
import net.minecraft.world.level.storage.loot.LootContext;
import net.minecraft.world.level.storage.loot.predicates.LootItemCondition;
import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
import net.minecraftforge.common.loot.LootModifier;
import net.minecraftforge.registries.ForgeRegistries;
import org.jetbrains.annotations.NotNull;

import java.util.List;

public class OakLeavesOrangeModifier extends LootModifier {
    private final Item orangeItem;

    protected OakLeavesOrangeModifier(LootItemCondition[] conditionsIn, Item orangeItem) {
        super(conditionsIn);
        this.orangeItem = orangeItem;
    }

    @NotNull
    @Override
    protected List<ItemStack> doApply(List<ItemStack> generatedLoot, LootContext context) {
        if(context.getRandom().nextFloat() > 0.75) {
            generatedLoot.add(new ItemStack(orangeItem));
        }
        return null;
    }

    public static class Serializer extends GlobalLootModifierSerializer<OakLeavesOrangeModifier> {

        @Override
        public OakLeavesOrangeModifier read(ResourceLocation location, JsonObject object, LootItemCondition[] ailootcondition) {
            Item orangeItem = ForgeRegistries.ITEMS.getValue(new ResourceLocation(GsonHelper.getAsString(object, "orangeItem")));
            return new OakLeavesOrangeModifier(ailootcondition, orangeItem);
        }

        @Override
        public JsonObject write(OakLeavesOrangeModifier instance) {
            JsonObject json = makeConditions(instance.conditions);
            json.addProperty("orangeItem", ForgeRegistries.ITEMS.getKey(instance.orangeItem).toString());
            return json;
        }
    }
}

Events class:

package avals.storange.event;

import avals.storange.Storange;
import avals.storange.loot.OakLeavesOrangeModifier;
import net.minecraft.resources.ResourceLocation;
import net.minecraftforge.common.loot.GlobalLootModifierSerializer;
import net.minecraftforge.event.RegistryEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;

import javax.annotation.Nonnull;

@Mod.EventBusSubscriber(modid = Storange.ID, bus = Mod.EventBusSubscriber.Bus.MOD)
public class ModWorldEvents {
    @SubscribeEvent
    public static void registerModifierSerializers(@Nonnull final RegistryEvent.Register<GlobalLootModifierSerializer<?>> event) {
        event.getRegistry().registerAll(
                new OakLeavesOrangeModifier.Serializer().setRegistryName(new ResourceLocation(Storange.ID, "oak_leaves_orange"))
        );
    }
}

Loot modifier JSON:

{
  "conditions": [
    {
      "condition": "minecraft:inverted",
      "term": {
        "condition": "minecraft:match_tool",
        "predicate": {
          "item": "minecraft:shears"
        }
      }
    },
    {
      "condition": "minecraft:inverted",
      "term": {
        "condition": "minecraft:match_tool",
        "predicate": {
          "enchantments": [
            {
              "enchantment": "minecraft:silk_touch"
            }
          ]
        }
      }
    },
    {
      "condition": "minecraft:block_state_property",
      "block": "minecraft:oak_leaves"
    }
  ],
  "orangeItem": "storange:orange",
  "type": "storange:oak_leaves_orange"
}

Global Loot Modifiers:

{
  "replace": "false",
  "entries": [
    "storange:oak_leaves_orange"
  ]
}

Thank you!

[warjort]

Quote

[22:32:19] [Render thread/ERROR] [ne.mi.co.lo.LootModifierManager/]: Couldn't parse loot modifier storange:oak_leaves_orange 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

The error says your GLM is not registered.

When it tries to get the value from the registry with than name it is null.

You should check your registration code is actually invoked and you also don't have a typo somewhere with the name.

[AvaLS]

My bad, apparently GLMs have changed quite a bit since 1.18, I’ll read up on it later and probably watch a tutorial. Thank you!