task_id stringlengths 7 9 | module stringclasses 5
values | instruction stringlengths 74 360 | context stringlengths 0 1.01k | golden_reference stringlengths 317 3.56k | eval_criteria dict |
|---|---|---|---|---|---|
API_001 | api | In NeoForge 1.21.1, register a mod item `example_item` with an EPIC rarity using DeferredRegister, and bind the registry to the correct event bus from the mod constructor. The mod id is `examplemod`. | package com.example.examplemod;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.Rarity;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.registries.DeferredItem;
import net.neoforged.neoforge.registries.DeferredRegister;
@Mod(ExampleMod.M... | {
"must_compile": true,
"required_annotations": [
"@Mod"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_002 | api | NeoForge 1.21.1: register a simple block `example_block` and its BlockItem under the same name using DeferredRegister.Blocks and DeferredRegister.Items. Bind both registries in the mod constructor. | package com.example.examplemod;
import net.minecraft.world.item.BlockItem;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.state.BlockBehaviour;
import net.minecraft.world.level.material.MapColor;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import n... | {
"must_compile": true,
"required_annotations": [
"@Mod"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_003 | api | NeoForge 1.21.1: register a `BlockEntityType` named `example_block_entity` that is valid for the block `ExampleMod.EXAMPLE_BLOCK`, bound to the mod event bus. Use BlockEntityType.Builder with a supplier. | public class ExampleBlockEntity extends BlockEntity {
public ExampleBlockEntity(BlockPos pos, BlockState state) {
super(ModBlockEntities.EXAMPLE_BLOCK_ENTITY.get(), pos, state);
}
} | package com.example.examplemod;
import com.example.examplemod.block.ExampleBlockEntity;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.level.block.entity.BlockEntityType;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.registries.D... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} |
API_004 | api | NeoForge 1.21.1: register a creative mode tab `example_tab` titled 'Example Tab' whose icon is `ExampleMod.EXAMPLE_ITEM` and which displays that item. Bind the registry to the mod event bus. | Existing item registry:
public static final DeferredRegister.Items ITEMS = DeferredRegister.createItems(MODID);
public static final DeferredItem<Item> EXAMPLE_ITEM = ITEMS.registerSimpleItem("example_item"); | package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.network.chat.Component;
import net.minecraft.world.item.CreativeModeTab;
import net.minecraft.world.item.ItemStack;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neo... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} |
API_005 | api | NeoForge 1.21.1: register a `DataComponentType<Integer>` named `charge` with an INT persistent codec and VAR_INT network codec. Use DeferredRegister over Registries.DATA_COMPONENT_TYPE and DeferredRegister#registerComponent. | package com.example.examplemod;
import com.mojang.serialization.Codec;
import net.minecraft.core.component.DataComponentType;
import net.minecraft.core.registries.Registries;
import net.minecraft.network.codec.ByteBufCodecs;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neofor... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_006 | api | NeoForge 1.21.1: register an `AttachmentType<Integer>` named `mana` that defaults to 50, is serialized with Codec.INT and survives player death (copyOnDeath). Show how to read/write it on an Entity. | package com.example.examplemod;
import com.mojang.serialization.Codec;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.attachment.AttachmentType;
import net.neoforged.neoforge.registries.DeferredRegister;
import net.neoforged.neoforge.registries.NeoForgeRegist... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_007 | api | NeoForge 1.21.1: a mod constructor receives `IEventBus modEventBus`. Explain with code which events go on the mod event bus and which go on `NeoForge.EVENT_BUS`, and demonstrate registering a `RegisterCapabilitiesEvent` listener on the correct bus from the constructor. | package com.example.examplemod;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.capabilities.Capabilities;
import net.neoforged.neoforge.capabilities.RegisterCapabilitiesEvent;
import net.neoforged.neoforge.common.NeoForge;
import net.neoforged.neoforge.event.... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_008 | api | NeoForge 1.21.1: register a creature entity `example_creature` (EntityType) and give it attributes (MAX_HEALTH 20, MOVEMENT_SPEED 0.25) via EntityAttributeCreationEvent. Show both the registry and the correct event-bus subscription. | public class ExampleCreature extends PathfinderMob {
public ExampleCreature(EntityType<? extends PathfinderMob> type, Level level) { super(type, level); }
} | package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.MobCategory;
import net.minecraft.world.entity.ai.attributes.AttributeSupplier;
import net.minecraft.world.entity.ai.attributes.Attributes;
import net.minecra... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} |
API_009 | api | NeoForge 1.21.1: register a `MenuType` for `ExampleMenu` (constructor `(int containerId, Inventory playerInv, FriendlyByteBuf data)`) using `IMenuTypeExtension.create`, and register its screen on the correct client event. Use mod id `examplemod`. | public class ExampleMenu extends AbstractContainerMenu {
public ExampleMenu(int containerId, Inventory playerInv, FriendlyByteBuf data) {
super(ModMenuTypes.EXAMPLE_MENU.get(), containerId);
}
@Override
public ItemStack quickMoveStack(Player player, int index) { return ItemStack.EMPTY; }
@Ov... | package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.inventory.MenuType;
import net.neoforged.api.Dist;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.client.event.RegisterMenuScreensEvent;
import net.neo... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} |
API_010 | api | NeoForge 1.21.1: define a serverbound custom payload `UseWandPayload(int x, int y, int z)` implementing CustomPacketPayload with a VAR_INT StreamCodec, and register a server-side handler via RegisterPayloadHandlersEvent. Mod id `examplemod`. | package com.example.examplemod.net;
import com.example.examplemod.ExampleMod;
import io.netty.buffer.ByteBuf;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
import net.minecraft.resources.ResourceLocation;
public record UseWandPayload(int x, in... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_011 | api | NeoForge 1.21.1: register a `SoundEvent` named `example_sound` using SoundEvent.createVariableRangeEvent and a fixed-range variant `example_fixed_sound` with a 32-tick range. Bind to the mod event bus. | package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.sounds.SoundEvent;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.registries.DeferredHolder;
import net.neof... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_012 | api | NeoForge 1.21.1: register a particle type `sparkle` as a `SimpleParticleType` and expose a `ParticleOptions` for spawning. Bind to the mod event bus; only registration and holder are required. | package com.example.examplemod;
import net.minecraft.core.particles.ParticleType;
import net.minecraft.core.particles.SimpleParticleType;
import net.minecraft.core.registries.Registries;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.registries.DeferredHolder... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_013 | api | NeoForge 1.21.1: register a recipe serializer for `ExampleRecipe implements Recipe<RecipeInput>` using `SimpleCraftingRecipeSerializer`, and register the matching RecipeType. Bind both to the mod event bus. | public class ExampleRecipe implements Recipe<RecipeInput> {
// 1.21.1 Recipe<T> methods: matches(RecipeInput, Level), assemble(RecipeInput, HolderLookup.Provider),
// canCraftInDimensions(int, int), getResultItem(HolderLookup.Provider), getSerializer(), getType()
} | package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.item.crafting.RecipeSerializer;
import net.minecraft.world.item.crafting.RecipeType;
import net.minecraft.world.item.crafting.SimpleCraftingRecipeSerializer;
import net.neoforged.bus.api.IEventBus;
import net.ne... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} |
API_014 | api | NeoForge 1.21.1: create a tool item `example_pickaxe` with Tiers.IRON, durability override 512, and an `Item.Properties` that also stores a custom data component `ExampleMod.CHARGE` defaulting to 0. Show the registration only. | package com.example.examplemod;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.PickaxeItem;
import net.minecraft.world.item.Tiers;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.registries.DeferredItem;
import net.neoforged.neoforge.reg... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_015 | api | NeoForge 1.21.1: register a game-bus event handler class for `LivingDeathEvent` that prints the dead entity name, using @Mod.EventBusSubscriber with the correct bus, and a mod-bus class for `FMLCommonSetupEvent`. Show both classes. | package com.example.examplemod;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.fml.event.lifecycle.FMLCommonSetupEvent;
import net.neoforged.neoforge.common.NeoForge;
import net.neoforged.neoforge.event.entity.living.LivingDeathEvent;
// GAME bus (NeoForge.EVENT... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent",
"@Mod.EventBusSubscriber"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_016 | api | NeoForge 1.21.1: register a command `/example hello` that replies 'Hello from examplemod!' via RegisterCommandsEvent. Put the handler on the correct event bus and use Brigadier's literal(). | package com.example.examplemod;
import com.mojang.brigadier.CommandDispatcher;
import com.mojang.brigadier.builder.LiteralArgumentBuilder;
import net.minecraft.commands.CommandSourceStack;
import net.minecraft.commands.Commands;
import net.minecraft.network.chat.Component;
import net.neoforged.bus.api.SubscribeEvent;
... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_017 | api | NeoForge 1.21.1: define a `ModConfigSpec` with a boolean `enabled=true` and an int `maxRange=32`, register it as a COMMON config from the mod constructor, and add a reload listener on the mod bus. | package com.example.examplemod;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.ModContainer;
import net.neoforged.fml.config.ModConfig;
import net.neoforged.fml.event.config.ModConfigEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_018 | api | NeoForge 1.21.1: register a `PoiType` named `example_poi` bound to `ExampleMod.EXAMPLE_BLOCK` with maxTickets 1 and validRange 16, and register the matching `VillagerProfession` `example_prof`. Bind to the mod event bus. | package com.example.examplemod;
import net.minecraft.core.HolderGetter;
import net.minecraft.core.HolderSet;
import net.minecraft.core.registries.BuiltInRegistries;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.entity.ai.village.poi.PoiType;
import net.minecraft.world.entity.npc.VillagerP... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_019 | api | NeoForge 1.21.1 client: register a `KeyMapping` (key R, category 'key.categories.examplemod') via RegisterKeyMappingsEvent and poll `consumeClick()` in a ClientTickEvent.Post handler. Both handlers belong on which bus? Write the class with the correct annotations. | package com.example.examplemod.client;
import com.example.examplemod.ExampleMod;
import com.mojang.blaze3d.platform.InputConstants;
import net.minecraft.client.KeyMapping;
import net.neoforged.api.Dist;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.clie... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent",
"RegisterKeyMappingsEvent",
"ClientTickEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
API_020 | api | NeoForge 1.21.1: an event handler must run ONLY on the physical client. Show a @Mod.EventBusSubscriber with dist filtering using the correct NeoForge `Dist` import, and explain why @OnlyIn must not be used. | package com.example.examplemod.client;
import com.example.examplemod.ExampleMod;
import net.neoforged.api.Dist;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.client.event.RenderLevelStageEvent;
// NeoForge: Dist lives in net.neoforged.api.Dist.
// @Onl... | {
"must_compile": true,
"required_annotations": [
"@Mod.EventBusSubscriber",
"Dist.CLIENT"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text"
],
"gametest_required": false
} | |
MIXIN_001 | mixin | Write a Mixin that logs the player's position at the END of every Player#tick(). Use @Inject at TAIL. Vanilla target (Mojang mappings): net.minecraft.world.entity.player.Player#tick()V. | Vanilla target (Mojang mappings):
package net.minecraft.world.entity.player;
public abstract class Player extends LivingEntity {
public void tick() { ... }
} | package com.example.examplemod.mixin;
import net.minecraft.world.entity.player.Player;
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.CallbackInfo;
@Mixin(Player.class... | {
"must_compile": true,
"required_annotations": [
"@Inject",
"@Mixin"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_002 | mixin | Write a Mixin that cancels ALL fire damage in LivingEntity#hurt. Target (Mojang mappings): net.minecraft.world.entity.LivingEntity#hurt(Lnet/minecraft/world/damagesource/DamageSource;F)Z. Cancel only when the DamageSource type is IN_FIRE. | package com.example.examplemod.mixin;
import net.minecraft.world.damagesource.DamageSource;
import net.minecraft.world.damagesource.DamageTypes;
import net.minecraft.world.entity.LivingEntity;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.... | {
"must_compile": true,
"required_annotations": [
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_003 | mixin | Write a @Redirect Mixin inside LivingEntity#hurt that skips the call to actuallyHurt(...) when the incoming amount is 0. Give the exact INVOKE target string in Mojang mappings. | Decompiled call site (Mojang mappings):
public boolean hurt(DamageSource source, float amount) {
...
this.actuallyHurt(source, amount);
...
} | package com.example.examplemod.mixin;
import net.minecraft.world.damagesource.DamageSource;
import net.minecraft.world.entity.LivingEntity;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Redirect;
@Mixin(LivingEntity.class)
publi... | {
"must_compile": true,
"required_annotations": [
"@Redirect"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_004 | mixin | Use @ModifyVariable to double the food parameter passed into FoodData#eat(IF)V (Mojang mappings). Modify only the first int argument, not any fields. | Vanilla target:
package net.minecraft.world.food;
public class FoodData {
public void eat(int food, float saturation) { ... }
} | package com.example.examplemod.mixin;
import net.minecraft.world.food.FoodData;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.ModifyVariable;
@Mixin(FoodData.class)
public abstract class FoodDataMixin {
// argsOnly = true r... | {
"must_compile": true,
"required_annotations": [
"@ModifyVariable"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_005 | mixin | Use @ModifyConstant to raise the hardcoded saturation cap `20` inside FoodData#eat(IF)V (Mojang mappings) to 40. | Decompiled snippet:
public void eat(int food, float saturation) {
this.foodLevel = Math.min(food + this.foodLevel, 20);
...
} | package com.example.examplemod.mixin;
import net.minecraft.world.food.FoodData;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.Constant;
import org.spongepowered.asm.mixin.injection.ModifyConstant;
@Mixin(FoodData.class)
public abstract class FoodDataConstantMixin {
@Modif... | {
"must_compile": true,
"required_annotations": [
"@ModifyConstant"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_006 | mixin | Fill in the missing pieces (FIM) of this Mixin so it shadows the private final field `cooldowns` of net.minecraft.world.entity.player.Player and prints the cooldown item count at Player#tick TAIL. The private field is declared as `private final ItemCooldowns cooldowns;`. | Partial mixin (incomplete):
package com.example.examplemod.mixin;
@Mixin(Player.class)
public abstract class PlayerShadowMixin {
// TODO: shadow `private final ItemCooldowns cooldowns`
// TODO: inject at TAIL of tick()V and print cooldowns.size()
} | package com.example.examplemod.mixin;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.item.ItemCooldowns;
import org.spongepowered.asm.mixin.Final;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.Shadow;
import org.spongepowered.asm.mixin.injection.At;
import or... | {
"must_compile": true,
"required_annotations": [
"@Shadow",
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_007 | mixin | Write an @Accessor Mixin interface exposing the private field `target` of net.minecraft.world.entity.monster.Mob (declared `private LivingEntity target;`) as a getter, and show how it is called from mod code. | package com.example.examplemod.mixin;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.monster.Mob;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.gen.Accessor;
@Mixin(Mob.class)
public interface MobAccessor {
// The accessor method name must match t... | {
"must_compile": true,
"required_annotations": [
"@Accessor"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_008 | mixin | Write an @Invoker Mixin exposing Entity's private collision callback `private void touch(Entity entity)` (Mojang mappings) as a public method named `examplemod$tryTouch`, and show a call site. | Vanilla declaration (Mojang mappings):
package net.minecraft.world.entity;
public abstract class Entity {
private void touch(Entity entity) { ... }
} | package com.example.examplemod.mixin;
import net.minecraft.world.entity.Entity;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.gen.Invoker;
@Mixin(Entity.class)
public interface EntityInvoker {
// @Invoker exposes the private method; the annotation value is the vanilla method name.
... | {
"must_compile": true,
"required_annotations": [
"@Invoker"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_009 | mixin | Use MixinExtras' @ModifyReturnValue to make Item#use return pass-through logic: if the vanilla result is `success`, return `consume` instead. Target (Mojang mappings): net.minecraft.world.item.Item#use(Lnet/minecraft/world/level/Level;Lnet/minecraft/world/entity/player/Player;Lnet/minecraft/world/InteractionHand;)Lnet/... | MixinsExtras is bundled with NeoForge 1.21.1 (com.llamalad7.mixinextras). | package com.example.examplemod.mixin;
import com.llamalad7.mixinextras.injector.ModifyReturnValue;
import net.minecraft.world.InteractionHand;
import net.minecraft.world.InteractionResultHolder;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.ItemS... | {
"must_compile": true,
"required_annotations": [
"@ModifyReturnValue"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_010 | mixin | Use MixinExtras' @WrapOperation to double the healing amount that HoneyBottleItem passes to LivingEntity#heal(float) inside finishUsingItem. Give the exact INVOKE target string. | Decompiled call site (Mojang mappings):
package net.minecraft.world.item;
public class HoneyBottleItem extends Item {
public ItemStack finishUsingItem(ItemStack stack, Level level, LivingEntity entity) {
...
entity.heal(6.0F);
...
}
} | package com.example.examplemod.mixin;
import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
import com.llamalad7.mixinextras.injector.wrapoperation.WrapOperation;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.item.HoneyBottleItem;
import org.spongepowered.asm.mixin.Mixin;
impo... | {
"must_compile": true,
"required_annotations": [
"@WrapOperation"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_011 | mixin | Write an @Inject with LocalCapture.CAPTURE_FAILHARD into Entity#move(MoverType, Vec3) that captures the local `Vec3 vec3 = this.getDeltaMovement();` assigned right after movement starts, and logs it. Provide the exact @At with INVOKE_ASSIGN. | Decompiled opening of the target (Mojang mappings):
public void move(MoverType type, Vec3 pos) {
...
Vec3 vec3 = this.getDeltaMovement();
...
} | package com.example.examplemod.mixin;
import net.minecraft.world.entity.Entity;
import net.minecraft.world.entity.MoverType;
import net.minecraft.world.phys.Vec3;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Inject;
import org.s... | {
"must_compile": true,
"required_annotations": [
"@Inject",
"LocalCapture"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_012 | mixin | Write an @Inject that runs exactly when LivingEntity#tick writes to the field `deathTime` (public int deathTime). Use a FIELD @At with the correct opcode, and complete it with the correct import for Opcodes. | Field: public int deathTime; written as this.deathTime++ inside LivingEntity#tick()V. | package com.example.examplemod.mixin;
import net.minecraft.world.entity.LivingEntity;
import org.objectweb.asm.Opcodes;
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.C... | {
"must_compile": true,
"required_annotations": [
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_013 | mixin | Write `examplemod.mixins.json`: common mixins in the package com.example.examplemod.mixin, CLIENT-only mixins in com.example.examplemod.mixin.client, refmap `examplemod.refmap.json`, Mixin 0.8.7, JAVA_21 compatibility, require=1. Explain why client mixins must go into the `client` section on a NeoForge dedicated server... | {
"required": true,
"minVersion": "0.8.5",
"package": "com.example.examplemod.mixin",
"compatibilityLevel": "JAVA_21",
"refmap": "examplemod.refmap.json",
"injectors": {
"defaultRequire": 1
},
"mixins": [
"PlayerMixin",
"LivingEntityMixin",
"MobAccessor",
"EntityInvoker"
],
"clie... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_014 | mixin | Register `examplemod.mixins.json` for NeoForge 1.21.1 in `neoforge.mods.toml` (1.21.1 style). Show the exact TOML table. Also state where the mixin config file must be located in the jar. | # neoforge.mods.toml (inside src/main/resources/META-INF/)
modLoader = "javafml"
loaderVersion = "[4,)"
license = "MIT"
[[mods]]
modId = "examplemod"
version = "1.0.0"
displayName = "Example Mod"
# Mixin configs are registered per config file, one [[mixins]] table each:
[[mixins]]
config = "examplemod.mixins.json"
[... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_015 | mixin | Write a cancellable @Inject into net.minecraft.world.item.ItemStack#isEnchantable()Z that returns false when a custom data component `ExampleMod.CURSED` is present on the stack. Explain the required return type of the CallbackInfo for a boolean method. | package com.example.examplemod.mixin;
import net.minecraft.world.item.ItemStack;
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(ItemStac... | {
"must_compile": true,
"required_annotations": [
"@Inject",
"CallbackInfoReturnable"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_016 | mixin | Write an @Inject into the HEAD of net.minecraft.world.entity.Entity#setPos(DDD)V that logs position writes only when the entity is a ServerPlayer. Explain why the instanceof check is done on the casted `this`. | package com.example.examplemod.mixin;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.entity.Entity;
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.ca... | {
"must_compile": true,
"required_annotations": [
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_017 | mixin | FIM: complete the @At("INVOKE_ASSIGN") injection that captures the boolean returned by ItemStack#hurt(int, RandomSource, ServerPlayer) inside ItemStack#hurtAndBreak(int, LivingEntity, EquipmentSlot). Vanilla 1.21.1 uses the EquipmentSlot overload. | Partial mixin:
@Mixin(ItemStack.class)
public abstract class ItemStackHurtMixin {
@Inject(
method = "hurtAndBreak(ILnet/minecraft/world/entity/LivingEntity;Lnet/minecraft/world/entity/EquipmentSlot;)V",
at = @At(/* TODO */) )
private void examplemod$onDurabilityDamage(int amount, LivingE... | package com.example.examplemod.mixin;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.util.RandomSource;
import net.minecraft.world.entity.EquipmentSlot;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.item.ItemStack;
import org.spongepowered.asm.mixin.Mixin;
import org.... | {
"must_compile": true,
"required_annotations": [
"@Inject",
"INVOKE_ASSIGN"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_018 | mixin | Write a mixin that adds a private helper method `examplemod$isFullMoon(Level)` to Player via @Unique and calls it from a TAIL injection of tick()V. Explain why @Unique is mandatory here. | package com.example.examplemod.mixin;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.world.entity.player.Player;
import net.minecraft.world.level.Level;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.Unique;
import org.spongepowered.asm.mixin.injection.At;
import org.... | {
"must_compile": true,
"required_annotations": [
"@Unique",
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} | |
MIXIN_019 | mixin | Given the decompiled vanilla method below, write the EXACT `method` and `at` target strings for an @Inject that fires when Item#appendHoverText adds its first tooltip line. Vanilla 1.21.1 signature: appendHoverText(ItemStack, Item.TooltipContext, List<Component>, TooltipFlag). | Decompiled (Mojang mappings, 1.21.1):
public void appendHoverText(ItemStack stack, Item.TooltipContext context,
List<Component> tooltip, TooltipFlag flag) {
...
} | package com.example.examplemod.mixin;
import org.spongepowered.asm.mixin.Mixin;
import org.spongepowered.asm.mixin.injection.At;
import org.spongepowered.asm.mixin.injection.Inject;
import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
@Mixin(net.minecraft.world.item.Item.class)
public abstract class It... | {
"must_compile": true,
"required_annotations": [
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIXIN_020 | mixin | A user reports: `InjectionError: Critical injection failure: @Inject annotation on examplemod$afterHurt could not find any targets matching 'hurt(Lnet/minecraft/world/damagesource/DamageSource;F)V' in net.minecraft.world.entity.LivingEntity`. Diagnose the bug and provide the corrected mixin. | Failing handler:
@Inject(method = "hurt(Lnet/minecraft/world/damagesource/DamageSource;F)V",
at = @At("TAIL"))
private void examplemod$afterHurt(CallbackInfo ci) { ... }
Actual vanilla signature (Mojang mappings):
public boolean hurt(DamageSource source, float amount) - returns boolean, not void. | /* Diagnosis:
* The declared descriptor says the method returns V ('V' = void) but LivingEntity#hurt returns
* boolean (Z). Mixin resolves `method` by exact descriptor match when a descriptor is present;
* no overload with (DamageSource, float) -> void exists, so the injection target set is EMPTY
* and Mixin's defa... | {
"must_compile": true,
"required_annotations": [
"@Inject"
],
"forbidden_apis": [
"net.minecraftforge"
],
"gametest_required": false
} |
MIG_001 | migration | Migrate this Forge 1.20.1 event handler to NeoForge 1.21.1: replace the game event bus and update all imports. | // Forge 1.20.1
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.event.entity.living.LivingDeathEvent;
import net.minecraftforge.eventbus.api.IEventBus;
import net.minecraftforge.fml.common.Mod;
@Mod("examplemod")
public class ExampleMod {
public ExampleMod() {
IEventBus bus = Min... | // NeoForge 1.21.1
package com.example.examplemod;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.common.NeoForge;
import net.neoforged.neoforge.event.entity.living.LivingDeathEvent;
@Mod(ExampleMod.MODID)
public class ExampleMod {
public static final St... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_002 | migration | Migrate these two @Mod.EventBusSubscriber classes from Forge 1.20.1 to NeoForge 1.21.1 (bus enum values changed). | // Forge 1.20.1
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
import net.minecraftforge.event.entity.playe... | // NeoForge 1.21.1
package com.example.examplemod;
import net.neoforged.api.Dist;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.fml.event.lifecycle.FMLCommonSetupEvent;
import net.neoforged.neoforge.event.entity.player.PlayerInteractEvent;
// Forge's Bus.FORGE ... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent",
"@Mod.EventBusSubscriber"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJav... |
MIG_003 | migration | Migrate this Forge 1.20.1 mod entry point (FMLJavaModLoadingContext) to the NeoForge 1.21.1 constructor-injection style. | // Forge 1.20.1
import net.minecraftforge.eventbus.api.IEventBus;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
@Mod("examplemod")
public class ExampleMod {
public ExampleMod() {
IEventBus modBus = FMLJavaModLoadingContext.get().getModEventBus(... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.item.Item;
import net.neoforged.bus.api.IEventBus;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.registries.DeferredHolder;
import net.neoforged.neoforge.registries.Deferr... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_004 | migration | Migrate this Forge 1.20.1 item that stores an `energy` value in item NBT to NeoForge 1.21.1 using a registered DataComponentType instead of CompoundTag. | // Forge 1.20.1
public class BatteryItem extends Item {
public BatteryItem(Properties props) { super(props); }
public int getEnergy(ItemStack stack) {
return stack.getOrCreateTag().getInt("energy");
}
public void setEnergy(ItemStack stack, int value) {
stack.getOrCreateTag().putInt("en... | // NeoForge 1.21.1
package com.example.examplemod;
import com.mojang.serialization.Codec;
import net.minecraft.core.component.DataComponentType;
import net.minecraft.core.registries.Registries;
import net.minecraft.network.codec.ByteBufCodecs;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.ItemS... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_005 | migration | Migrate this Forge 1.20.1 config class to NeoForge 1.21.1 (new spec class + new registration path via ModContainer). | // Forge 1.20.1
import net.minecraftforge.common.ForgeConfigSpec;
import net.minecraftforge.fml.ModLoadingContext;
import net.minecraftforge.fml.config.ModConfig;
public class Config {
public static final ForgeConfigSpec.Builder BUILDER = new ForgeConfigSpec.Builder();
public static final ForgeConfigSpec.Boole... | // NeoForge 1.21.1
package com.example.examplemod;
import net.neoforged.fml.ModContainer;
import net.neoforged.fml.config.ModConfig;
import net.neoforged.neoforge.common.ModConfigSpec;
public class Config {
public static final ModConfigSpec.Builder BUILDER = new ModConfigSpec.Builder();
public static final Mo... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_006 | migration | Migrate this Forge 1.20.1 block entity capability exposure (LazyOptional) to the NeoForge 1.21.1 capability system (RegisterCapabilitiesEvent + BlockCapability, no LazyOptional). | // Forge 1.20.1
public class StorageBlockEntity extends BlockEntity {
private final LazyOptional<net.minecraftforge.items.IItemHandler> handler =
LazyOptional.of(() -> new net.minecraftforge.items.ItemStackHandler(9));
public StorageBlockEntity(BlockPos pos, BlockState state) {
super(ModBlo... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.world.level.block.entity.BlockEntity;
import net.minecraft.world.level.block.state.BlockState;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mo... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"Forge... |
MIG_007 | migration | Migrate this Forge 1.20.1 SimpleChannel packet to NeoForge 1.21.1: CustomPacketPayload record + PayloadRegistrar registration. | // Forge 1.20.1
import net.minecraft.resources.ResourceLocation;
import net.minecraftforge.network.NetworkRegistry;
import net.minecraftforge.network.simple.SimpleChannel;
public final class Net {
private static final String VERSION = "1";
public static SimpleChannel CHANNEL = NetworkRegistry.newSimpleChannel(... | // NeoForge 1.21.1
package com.example.examplemod.net;
import com.example.examplemod.ExampleMod;
import io.netty.buffer.ByteBuf;
import net.minecraft.network.codec.ByteBufCodecs;
import net.minecraft.network.codec.StreamCodec;
import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
import net.minecraf... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"Forge... |
MIG_008 | migration | Migrate this Forge 1.20.1 spawn egg registration to NeoForge 1.21.1 (DeferredSpawnEggItem). | // Forge 1.20.1
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;
import net.minecraftforge.registries.RegistryObject;
import net.minecraftforge.common.ForgeSpawnEggItem;
public static final DeferredRegister<Item> ITEMS =
DeferredRegister.create(ForgeR... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.world.item.Item;
import net.neoforged.neoforge.registries.DeferredItem;
import net.neoforged.neoforge.registries.DeferredSpawnEggItem;
import net.neoforged.neoforge.registries.DeferredRegister;
public class ModItems {
public static final Defe... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_009 | migration | Migrate this Forge 1.20.1 player tick handler to NeoForge 1.21.1 (TickEvent was split into Pre/Post events). | // Forge 1.20.1
import net.minecraftforge.event.TickEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
@Mod.EventBusSubscriber(modid = "examplemod")
public class TickHandlers {
@SubscribeEvent
public static void onPlayerTick(TickEvent.PlayerTickEvent event) ... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.world.entity.player.Player;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.event.tick.PlayerTickEvent;
@Mod.EventBusSubscriber(modid = ExampleMod.MODID)
public class TickHandlers {
... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"Forge... |
MIG_010 | migration | Migrate this legacy (1.16-era, still compiling on 1.20.1 via old imports) text code to NeoForge 1.21.1 Component/ChatFormatting APIs. | // Legacy Forge (1.16 style retained on 1.20.1)
import net.minecraft.util.text.ITextComponent;
import net.minecraft.util.text.StringTextComponent;
import net.minecraft.util.text.TextFormatting;
public final class Messages {
public static ITextComponent status(String name, boolean ok) {
return new StringTex... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.ChatFormatting;
import net.minecraft.network.chat.Component;
import net.minecraft.network.chat.MutableComponent;
public final class Messages {
// net.minecraft.util.text.* was removed long ago; 1.21.1 uses
// Component.literal / Componen... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_011 | migration | Migrate this Forge 1.20.1 mods.toml to a complete NeoForge 1.21.1 neoforge.mods.toml (file name, loaderVersion range, dependency tables). | # Forge 1.20.1 META-INF/mods.toml
modLoader = "javafml"
loaderVersion = "[47,)"
license = "MIT"
[[mods]]
modId = "examplemod"
version = "1.0.0"
displayName = "Example Mod"
[[dependencies.examplemod]]
modId = "forge"
mandatory = true
versionRange = "[47,)"
ordering = "NONE"
side = "BOTH"
[[depende... | # NeoForge 1.21.1 META-INF/neoforge.mods.toml
# (renamed from mods.toml; `mandatory` was replaced by `type`; `forge` dependency -> `neoforge`)
modLoader = "javafml"
loaderVersion = "[4,)"
license = "MIT"
[[mods]]
modId = "examplemod"
version = "1.0.0"
displayName = "Example Mod"
[[dependencies.neoforge]]
modId = "neo... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistEx... |
MIG_012 | migration | Migrate this Forge 1.20.1 extended menu opening (NetworkHooks.openScreen) to NeoForge 1.21.1. | // Forge 1.20.1
import net.minecraftforge.network.NetworkHooks;
public static void open(BlockPos pos, ServerPlayer player, MachineBlockEntity be) {
NetworkHooks.openScreen(player, new SimpleMenuProvider(
(id, inv, p) -> new MachineMenu(id, inv, be),
Component.literal("Machine")), pos);
} | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.network.chat.Component;
import net.minecraft.server.level.ServerPlayer;
import net.minecraft.world.SimpleMenuProvider;
public final class MachineOpening {
// NetworkHooks.openScreen was removed. NeoForge routes extra open-data through
//... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_013 | migration | Migrate this Forge 1.20.1 IForgeItem#getShareTag implementation to NeoForge 1.21.1 (data components replace share tags; show the component-based equivalent). | // Forge 1.20.1
public class CoolerItem extends Item {
public CoolerItem(Properties props) { super(props); }
@Override
public CompoundTag getShareTag(ItemStack stack) {
CompoundTag tag = super.getShareTag(stack);
if (tag == null) tag = new CompoundTag();
tag.putInt("temperature", re... | // NeoForge 1.21.1
package com.example.examplemod;
import com.mojang.serialization.Codec;
import net.minecraft.core.component.DataComponentType;
import net.minecraft.core.registries.Registries;
import net.minecraft.network.codec.ByteBufCodecs;
import net.minecraft.world.item.Item;
import net.minecraft.world.item.ItemS... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_014 | migration | Migrate this Forge 1.20.1 ResourceLocation construction code to NeoForge 1.21.1 (the public constructor was removed in 1.20.6). | // Forge 1.20.1
import net.minecraft.resources.ResourceLocation;
public final class Ids {
public static final ResourceLocation TEXTURE =
new ResourceLocation("examplemod", "textures/gui/machine.png");
public static ResourceLocation of(String namespace, String path) {
return new ResourceLoc... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.resources.ResourceLocation;
public final class Ids {
// `new ResourceLocation(...)` was removed in 1.20.6; the static factories are mandatory.
public static final ResourceLocation TEXTURE =
ResourceLocation.fromNamespaceAndPa... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_015 | migration | Migrate this Forge 1.20.1 MobEffect registration to NeoForge 1.21.1 (the no-arg MobEffect constructor was removed in 1.20.5). | // Forge 1.20.1
import net.minecraft.world.effect.MobEffect;
import net.minecraft.world.effect.MobEffectCategory;
import net.minecraftforge.registries.DeferredRegister;
import net.minecraftforge.registries.ForgeRegistries;
import net.minecraftforge.registries.RegistryObject;
public static final DeferredRegister<MobEff... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.core.registries.Registries;
import net.minecraft.world.effect.MobEffect;
import net.minecraft.world.effect.MobEffectCategory;
import net.neoforged.neoforge.registries.DeferredHolder;
import net.neoforged.neoforge.registries.DeferredRegister;
publ... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_016 | migration | Migrate this Forge 1.20.1 registry lookup code (ForgeRegistries) to NeoForge 1.21.1 using BuiltInRegistries. | // Forge 1.20.1
import net.minecraftforge.registries.ForgeRegistries;
public final class Lookups {
public static Item itemById(String id) {
return ForgeRegistries.ITEMS.getValue(new ResourceLocation(id));
}
public static boolean isRegisteredItem(Item item) {
return ForgeRegistries.ITEMS.ge... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.core.registries.BuiltInRegistries;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.world.item.Item;
public final class Lookups {
// ForgeRegistries is gone; vanilla's BuiltInRegistries is the single source of truth.
... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
MIG_017 | migration | Migrate this Forge 1.20.1 EntityJoinWorldEvent handler to NeoForge 1.21.1. | // Forge 1.20.1
import net.minecraftforge.event.entity.EntityJoinWorldEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
@Mod.EventBusSubscriber(modid = "examplemod")
public class JoinHandlers {
@SubscribeEvent
public static void onJoin(EntityJoinWorldEvent ... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.world.entity.monster.Creeper;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.event.entity.EntityJoinLevelEvent;
@Mod.EventBusSubscriber(modid = ExampleMod.MODID)
public class JoinHa... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"Forge... |
MIG_018 | migration | Migrate this Forge 1.20.1 event priority subscription to NeoForge 1.21.1 (EventPriority moved packages). | // Forge 1.20.1
import net.minecraftforge.eventbus.api.EventPriority;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.event.entity.living.LivingDeathEvent;
@Mod.EventBusSubscriber(modid = "examplemod")
public class PriorityHandlers {
@Subsc... | // NeoForge 1.21.1
package com.example.examplemod;
import net.neoforged.bus.api.EventPriority;
import net.neoforged.bus.api.SubscribeEvent;
import net.neoforged.fml.common.Mod;
import net.neoforged.neoforge.event.entity.living.LivingDeathEvent;
@Mod.EventBusSubscriber(modid = ExampleMod.MODID)
public class PriorityHa... | {
"must_compile": true,
"required_annotations": [
"@SubscribeEvent"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"Forge... |
MIG_019 | migration | Migrate this Forge 1.20.1 DistExecutor client-only init to NeoForge 1.21.1 (DistExecutor was removed). | // Forge 1.20.1
import net.minecraftforge.api.distmarker.Dist;
import net.minecraftforge.fml.DistExecutor;
import net.minecraftforge.fml.common.Mod;
@Mod("examplemod")
public class ExampleMod {
public ExampleMod() {
DistExecutor.unsafeRunWhenOn(Dist.CLIENT,
() -> () -> ClientInit.registerSc... | // NeoForge 1.21.1
package com.example.examplemod;
import net.neoforged.api.Dist;
import net.neoforged.fml.ModContainer;
import net.neoforged.fml.common.Mod;
import net.neoforged.fml.loading.FMLEnvironment;
@Mod(ExampleMod.MODID)
public class ExampleMod {
public static final String MODID = "examplemod";
publ... | {
"must_compile": true,
"required_annotations": [
"@Mod"
],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec"... |
MIG_020 | migration | Migrate this Forge 1.20.1 ItemStack <-> NBT serialization to NeoForge 1.21.1 (registry access is now mandatory; use ItemStack.CODEC). | // Forge 1.20.1
import net.minecraft.nbt.CompoundTag;
import net.minecraft.world.item.ItemStack;
public final class StackIo {
public static CompoundTag save(ItemStack stack) {
CompoundTag tag = new CompoundTag();
stack.save(tag);
return tag;
}
public static ItemStack load(CompoundT... | // NeoForge 1.21.1
package com.example.examplemod;
import net.minecraft.core.HolderLookup;
import net.minecraft.nbt.CompoundTag;
import net.minecraft.nbt.NbtOps;
import net.minecraft.nbt.Tag;
import net.minecraft.world.item.ItemStack;
import com.mojang.serialization.Dynamic;
import com.mojang.serialization.DynamicOps;... | {
"must_compile": true,
"required_annotations": [],
"forbidden_apis": [
"net.minecraftforge",
"MinecraftForge.EVENT_BUS",
"net.minecraft.util.text",
"LazyOptional",
"getOrCreateTag",
"NetworkRegistry",
"SimpleChannel",
"FMLJavaModLoadingContext",
"ForgeConfigSpec",
"DistExe... |
DEBUG_001 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | ---- Minecraft Crash Report ----
// Time: 2026-01-14 19:03:22 CET
Description: Initializing game
java.lang.NoSuchMethodError: 'void net.minecraft.world.item.Item.<init>(net.minecraft.world.item.Item$Properties)'
at TRANSFORMER/fancybattery@1.4.2/net.fancybattery.BatteryItem.<init>(BatteryItem.java:12)
at TRANSFORMER... | {
"root_cause": "fancybattery was compiled against Minecraft 1.20.4. In 1.20.4 Item has no-arg-free constructor chain matching Item$Properties - the Item(Properties) constructor signature changed in 1.20.5/1.21 (Item became constructible only through deferred/Item.Properties with DataComponent support and the constru... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_002 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Worker-Main-2/ERROR] [ne.neof.ev.Reg/]: Registry Object not present: examplemod:wand_core
java.lang.IllegalStateException: Registry Object not present: examplemod:wand_core
at TRANSFORMER/examplemod@1.0.0/net.neoforged.neoforge.registries.DeferredHolder.get(DeferredHolder.java:41)
at TRANSFORMER/examplemod@1.0.0/com... | {
"root_cause": "The mod constructor reads DeferredHolder.get() during the CONSTRUCT phase, but registry entries only become available after registry events finish (new registry event system - no 'RegistryEvent.Register' phase gating). Accessing the holder before entries are bound throws 'Registry Object not present'... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_003 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [mixin/]: Mixin apply failed: mixin.examplemod.json:PlayerMixin
org.spongepowered.asm.mixin.transformer.MixinApplyError: Mixin [mixin.examplemod.json:PlayerMixin] from phase [DEFAULT] in config [mixin.examplemod.json] FAILED during APPLY
Caused by: InjectionError: Critical injection failure: @Inject annota... | {
"root_cause": "The mixin's declared method descriptor declares void ('V') as the return type, but the real LivingEntity#hurt(DamageSource, float) returns boolean ('Z'). With NeoForge 1.21.1 running Mojmap at runtime, `method` strings must match the mapped descriptor exactly; the target set is empty and Mixin's defa... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_004 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Mod 'examplemod' caused an exception during modloading
Caused by: java.lang.RuntimeException: Attempted to load class net/minecraft/client/Minecraft for invalid dist DEDICATED_SERVER
at TRANSFORMER/examplemod@1.0.0/com.example.ClientProxy.<init>(ClientProxy.java:18)
at TRANSFORMER/exampl... | {
"root_cause": "The common code path unconditionally constructs ClientProxy, whose constructor references net.minecraft.client.Minecraft - a client-only class. On a dedicated server (dist DEDICATED_SERVER) the class fails to load with 'invalid dist DEDICATED_SERVER'.",
"fix_explanation": "Never touch client classe... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_005 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.mo/]: Mod 'examplemod' failed to load
java.lang.RuntimeException: Cannot listen to event net.neoforged.neoforge.event.entity.EntityJoinLevelEvent on the MOD event bus: the event does not implement IModBusEvent
at TRANSFORMER/examplemod@1.0.0/net.neoforged.fml.ModLoader.validate(ModLoader.java:212)... | {
"root_cause": "The handler class subscribes a GAME-bus event (EntityJoinLevelEvent, a gameplay event) on the MOD event bus. NeoForge validates bus/event pairing at load: events that do not implement IModBusEvent are rejected on the mod bus.",
"fix_explanation": "Either drop the `bus = Bus.MOD` so the class lands ... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_006 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Mod file examplemod-1.0.0.jar is missing mods.toml file
net.neoforged.fml.loading.FMLLoader$ModLoadingException: Missing or invalid mod metadata
File: examplemod-1.0.0.jar
Expected: META-INF/mods.toml or META-INF/neoforge.mods.toml (found neither)
Build tool: ForgeGradle 6 (legacy 1.20.1 p... | {
"root_cause": "NeoForge 1.21.1 requires META-INF/neoforge.mods.toml. The jar was built from a 1.20.1 project whose processResources still copies META-INF/mods.toml (and the loader does not accept that legacy file for 21.x).",
"fix_explanation": "Rename resources/META-INF/mods.toml to neoforge.mods.toml, migrate i... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_007 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Missing or unsupported mandatory dependencies:
Mod File: jei-1.20.1-forge-15.2.0.27.jar
Mod: examplemod
Required by: examplemod-1.0.0.jar
Dependency: jei@[15.20.0.27,) Minecraft:[1.20.1]
Reason: dependency 'jei' targets minecraft [1.20.1] but 1.21.1 is present | {
"root_cause": "examplemod declares a mandatory dependency pinned to a JEI build compiled for 1.20.1. The loader's dependency resolution correctly refuses to run: the JEI artifact for 1.21.1 uses a different version line (JEI 19.x.x for 1.21.1 on NeoForge).",
"fix_explanation": "Update the dependency entry to the ... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_008 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Exception during mod construction of examplemod
java.lang.UnsupportedClassVersionError: com/example/ExampleMod has been compiled by a more recent version of the Java Runtime (class file version 65.0), this version of the Java Runtime recognizes class versions up to 61.0
at java.base/java.... | {
"root_cause": "The mod jar was compiled with Java 21 (class file 65) but the server JVM is Java 17 (class file 61). NeoForge 21.1.x itself targets Java 21, so the environment JVM is wrong for both the loader and the mod.",
"fix_explanation": "Run the server (and the client launcher profile) with Java 21+. This is... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_009 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [mixin/]: Mixin apply failed: mixin.examplemod.json:FoodDataMixin
org.spongepowered.asm.mixin.injection.modify.InvalidModificationException: @ModifyVariable annotation on examplemod$doubleFood could not find any matching variables in the target method
at org.spongepowered.asm.mixin.injection.modify.LocalV... | {
"root_cause": "@ModifyVariable without argsOnly=true scans LOCAL VARIABLES of the target method; at @At(\"RETURN\") the int locals available do not uniquely/deterministically match the selector (no ordinal, no explicit name given), so the discriminator finds no candidate. The intent is to modify the int PARAMETER, ... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_010 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Server thread/ERROR]: Encountered an unexpected exception
net.minecraft.ReportedException: Ticking player
Caused by: java.lang.NullPointerException: Cannot invoke "net.minecraft.world.item.ItemStack.getItem()" because "stack" is null
at TRANSFORMER/examplemod@1.0.0/com.example.WandHandler.onRightClick(WandHandler.jav... | {
"root_cause": "The RightClickItem handler dereferences event.getItemStack() without a null check. In NeoForge 1.21.1 PlayerInteractEvent.RightClickItem#getItemStack() can be null when the interaction is triggered with an empty hand.",
"fix_explanation": "Guard the handler: fetch the stack once, check for null/EMP... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_011 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Server thread/ERROR]: Failed to save chunk 12,-4 in level "ServerLevel[world]"
com.mojang.serialization.ReportedException: Loading NBT data
Caused by: net.minecraft.ReportedException: Caught exception encoding ItemStack:
java.lang.IllegalStateException: Can't serialize unregistered component examplemod:charge
at net.... | {
"root_cause": "A DataComponentType was used on ItemStacks but its DeferredRegister was never bound to the mod event bus (or the registration supplier returned null), so the component exists in memory during play but is not present in the built-in registry when ItemStack.save encodes the stack. Unregistered componen... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_012 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Mod 'examplemod' failed during construction
java.lang.NoClassDefFoundError: net/minecraftforge/event/TickEvent$PlayerTickEvent
at TRANSFORMER/examplemod@1.9.9/com.example.TickHandlers.<clinit>(TickHandlers.java:6)
Caused by: java.lang.ClassNotFoundException: net.minecraftforge.event.TickE... | {
"root_cause": "The mod is a straight jar copy from Forge 1.20.1: its TickHandlers class still imports net.minecraftforge.event.TickEvent$PlayerTickEvent. On NeoForge 21.1.x the entire net.minecraftforge namespace is absent (packages are net.neoforged.*), so the class cannot be linked.",
"fix_explanation": "Recomp... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_013 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.re.Reg/]: Exception registering examplemod:example_item
java.lang.IllegalStateException: Duplicate registry entry: examplemod:example_item (attempted re-registration)
at net.neoforged.neoforge.registries.RegisterHelper.register(RegisterHelper.java:88)
at TRANSFORMER/examplemod@1.0.0/com.example.ModIt... | {
"root_cause": "The same registry name is registered twice. Typical causes: (1) the mod calls its registration method manually in addition to DeferredRegister binding, (2) two DeferredRegister instances with the same modid register colliding names, or (3) a StaticInit-time call duplicated the register() invocation."... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_014 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Netty Server IO #1/ERROR] [ne.neof.ne.NetworkHandler]: Exception in network handler
java.lang.IllegalStateException: Attempted to modify Level 'ServerLevel[world]' from thread 'Netty Server IO #1' - world access must happen on the server thread
at net.minecraft.server.level.ServerLevel.checkThread(ServerLevel.java:XX... | {
"root_cause": "The payload handler executed game logic directly on the network thread. NeoForge payload handlers run on the network thread unless you move work onto the main thread; world/level mutations are main-thread-only.",
"fix_explanation": "Wrap the game logic in context.enqueueWork(...) (IPayloadContext) ... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_015 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Server thread/ERROR]: Block entity examplemod:storage threw exception during tick
java.lang.NullPointerException: Cannot invoke "net.neoforged.neoforge.items.IItemHandler.getSlots()" because the return value of "net.minecraft.world.level.block.entity.BlockEntity.getBlockState()" ... handler is null
at TRANSFORMER/exa... | {
"root_cause": "The block entity was half-migrated: tick code still resolves the item handler through the old LazyOptional/ForgeCapabilities path that NeoForge removed, so the lookup returns null and the NPE follows. On NeoForge 1.21.1 capability providers are registered centrally with RegisterCapabilitiesEvent and ... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_016 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Server thread/ERROR] [mixin/]: Mixin apply failed: mixin.examplemod.json:GuiMixin
org.spongepowered.asm.mixin.transformer.ClassNotFoundException: The specified target class net.minecraft.client.gui.Gui for mixin [GuiMixin] was not found
Dist: DEDICATED_SERVER
Config file: mixin.examplemod.json ("mixins" section) | {
"root_cause": "A client-only vanilla target (net.minecraft.client.gui.Gui) is listed in the COMMON `mixins` section of the config. On a dedicated server those classes never load, so Mixin cannot find the target class and the apply fails fatally.",
"fix_explanation": "Move the mixin class into the `client` section... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_017 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Failed to create mod instance of examplemod
java.lang.RuntimeException: InvokeTargetException while invoking mod constructor
Caused by: java.lang.NoSuchMethodException: com.example.ExampleMod.<init>(net.neoforged.neoforge.common.ModConfigSpec)
at net.neoforged.fml.ModContainer.construct(M... | {
"root_cause": "FML injects only a fixed set of constructor parameter types: (), (IEventBus), (ModContainer), or (IEventBus, ModContainer). A ModConfigSpec parameter is not an injectable type, so constructor lookup fails with NoSuchMethodException.",
"fix_explanation": "Change the constructor to the supported (IEv... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_018 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [Worker-Main-3/ERROR] [ne.fml.mo.Mod/]: Exception during parallel mod construction of jei
java.lang.IllegalStateException: Registry Object not present: jei:jei
at TRANSFORMER/examplemod@1.0.0/com.example.JeiBridge.<clinit>(JeiBridge.java:9)
Note: JeiBridge does `public static final Object PLUGIN = new JeiPlugin()` at ... | {
"root_cause": "During construction mods load in parallel. examplemod's static initializer touches JEI's classes (expecting JEI's registry entries to be present), but JEI's own construction may not have completed - a cross-mod construction-order dependency. Registry holders are only guaranteed after registration eve... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_019 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.mo.Mod/]: Failed to load JEI plugin service
java.util.ServiceConfigurationError: mezz.jei.api.IGuiHelper? mezz.jei.api.helpers.IGuiHelper not a provider?
Actual line in jar: META-INF/services/mezz.jei.api.IModPlugin
Caused by: java.lang.ClassNotFoundException: com.example.MyJeiPlugin
Service file... | {
"root_cause": "The JEI plugin is registered through Java's ServiceLoader: META-INF/services/mezz.jei.api.IModPlugin must list the FQCN of the provider class. The service file contains a misspelled class name (MyJeiPlguin), so ClassNotFound aborts service construction.",
"fix_explanation": "Correct the FQCN inside... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
DEBUG_020 | debug | Analyze the FML crash/log snippet below for a NeoForge 1.21.1 dedicated server. Return ONLY a JSON object with keys root_cause, fix_explanation, code_patch. Reference concrete FML/NeoForge terminology; do not give generic advice such as 'update your Java' unless the log shows a class-version error. | [main/ERROR] [ne.fml.lo.mo/]: Incompatible mod set!
Mod 'ancientsword' requires 'minecraft' version [1.20.1], but 1.21.1 is present.
Mod file: ancientsword-2.3.jar
Mod metadata: META-INF/mods.toml (declared minecraft versionRange "[1.20.1]")
Loader: NeoForge 21.1.77
Loaded mods: 47 (examplemod, jei, ancientsword, ..... | {
"root_cause": "ancientsword is a 1.20.1 build whose neoforge.mods.toml pins minecraft to [1.20.1]. The loader refuses the mod set before any class loading - this is metadata-level incompatibility, not a runtime bug.",
"fix_explanation": "Get ancientsword 2.4+ built for 1.21.1, or (if you maintain it) bump its met... | {
"must_compile": false,
"required_annotations": [],
"forbidden_apis": [],
"gametest_required": false
} |
BUILD_001 | build | Write a complete `build.gradle.kts` for a NeoForge 1.21.1 mod using NeoGradle 7 (userdev), Gradle 8.x, Java 21 toolchain, dependency net.neoforged:neoforge:21.1.77, mod id `examplemod`, with client/server/data run configs. | plugins {
id("java-library")
id("net.neoforged.gradle.userdev") version "7.0.145"
}
group = "com.example"
version = "1.0.0"
java {
toolchain {
languageVersion = JavaLanguageVersion.of(21)
}
}
base {
archivesName = "examplemod"
}
repositories {
mavenCentral()
maven("https://maven.... | {
"must_compile": false,
"required_annotations": [
"plugins {",
"net.neoforged.gradle.userdev",
"JavaLanguageVersion.of(21)",
"neoforge:21.1.77",
"runs {",
"client()",
"server()",
"data()"
],
"forbidden_apis": [
"net.minecraftforge",
"forgegradle",
"ForgeGradle"
],
... | |
BUILD_002 | build | Write a complete `neoforge.mods.toml` for NeoForge 1.21.1: mod `examplemod` v1.0.0, MIT license, required NeoForge [21.1.0,) and Minecraft [1.21.1], optional client-side JEI dependency, and a mixin config registration. | # META-INF/neoforge.mods.toml
modLoader = "javafml"
loaderVersion = "[4,)"
license = "MIT"
issueTrackerURL = "https://github.com/example/examplemod/issues"
[[mods]]
modId = "examplemod"
version = "1.0.0"
displayName = "Example Mod"
description = "An example mod for NeoForge 1.21.1."
authors = "ExampleTeam"
displayURL ... | {
"must_compile": false,
"required_annotations": [
"modLoader = \"javafml\"",
"loaderVersion = \"[4,)\"",
"[[mods]]",
"[[dependencies.neoforge]]",
"[[dependencies.minecraft]]",
"[[mixins]]",
"neoforge.mods.toml"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_003 | build | Add CurseMaven to a NeoForge 1.21.1 `build.gradle.kts` so that CurseForge-ported mods can be declared as `implementation` dependencies, and declare JEI via a curse.maven coordinate. Use content filtering so CurseMaven only serves `curse.maven`. | repositories {
exclusiveContent {
forRepository {
maven {
name = "CurseMaven"
url = uri("https://cursemaven.com")
}
}
filter {
includeGroup("curse.maven")
}
}
mavenCentral()
maven("https://maven.neoforged... | {
"must_compile": false,
"required_annotations": [
"cursemaven.com",
"curse.maven",
"exclusiveContent",
"includeGroup"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_004 | build | Configure Modrinth publishing with the Minotaur plugin in `build.gradle.kts` for a NeoForge 1.21.1 mod: project id `examplemod`, game version 1.21.1, loader `neoforge`, release type `release`, uploading the main jar. | plugins {
id("com.modrinth.minotaur") version "2.+"
}
modrinth {
token.set(providers.gradleProperty("modrinthToken").orElse(providers.environmentVariable("MODRINTH_TOKEN")))
projectId.set("examplemod")
versionNumber.set(project.version.toString())
versionType.set("release")
gameVersions.set(lis... | {
"must_compile": false,
"required_annotations": [
"com.modrinth.minotaur",
"modrinth {",
"projectId",
"gameVersions",
"loaders",
"\"1.21.1\"",
"\"neoforge\""
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_005 | build | Configure Jar-in-Jar (JiJ) in NeoGradle 7 for a NeoForge 1.21.1 mod: bundle `org.example:somelib` with a Maven version range [1.2,2.0) pinned to 1.6.1. Show both the dependency block and the task wiring that makes `assemble` produce the JiJ jar. | dependencies {
implementation("net.neoforged:neoforge:21.1.77")
jarJar(implementation("org.example:somelib:[1.2,2.0)")) {
jarJar.pin(it, "1.6.1")
}
}
tasks {
// NG7: the jarJar task bundles the pinned dependency inside the mod jar.
named("assemble") {
dependsOn("jarJar")
}
} | {
"must_compile": false,
"required_annotations": [
"jarJar(",
"jarJar.pin",
"dependsOn",
"[1.2,2.0)"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_006 | build | Harden a NeoForge 1.21.1 `build.gradle.kts`: force Java 21 for compile/runtime, UTF-8 resources, `-Xlint:deprecation` warnings, and make the build fail on warnings from javac. | java {
toolchain {
languageVersion = JavaLanguageVersion.of(21)
}
}
tasks.withType<JavaCompile>().configureEach {
options.encoding = "UTF-8"
options.compilerArgs.addAll(listOf("-Xlint:deprecation", "-Werror"))
options.release.set(21)
}
tasks.withType<ProcessResources>().configureEach {
... | {
"must_compile": false,
"required_annotations": [
"JavaLanguageVersion.of(21)",
"options.encoding = \"UTF-8\"",
"-Xlint:deprecation",
"options.release.set(21)"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_007 | build | A 1.20.1 ForgeGradle project migrates to NeoForge 1.21.1 with ModDevGradle (MDG). Write the complete `build.gradle.kts` using the `net.neoforged.moddev` plugin, including run configs and the neoforge version 21.1.77. | plugins {
id("java-library")
id("net.neoforged.moddev") version "1.0.24"
}
group = "com.example"
version = "1.0.0"
java {
toolchain {
languageVersion = JavaLanguageVersion.of(21)
}
}
neoForge {
version = "21.1.77"
parchment {
// optional: mappingsArtifact = "..."
}
run... | {
"must_compile": false,
"required_annotations": [
"net.neoforged.moddev",
"neoForge {",
"version = \"21.1.77\"",
"client()",
"server()",
"data()",
"mods {"
],
"forbidden_apis": [
"net.minecraftforge",
"forgegradle",
"ForgeGradle"
],
"gametest_required": false
} | |
BUILD_008 | build | Wire an access transformer for NeoForge 1.21.1 with NeoGradle 7: register `META-INF/accesstransformer.cfg` in the build and show the AT file using the NEW NeoForge syntax (no leading `#`) to make the private field `net.minecraft.client.Minecraft.soundHandler` public and to make `net.minecraft.world.entity.LivingEntity.... | // build.gradle.kts (NeoGradle 7)
accessTransformers {
file(project.file("src/main/resources/META-INF/accesstransformer.cfg"))
}
# src/main/resources/META-INF/accesstransformer.cfg
# NeoForge 1.20.2+ syntax: <access>[-final-f] <fully.qualified.Class>[ field:|method()|()]
public net.minecraft.client.Minecraft sound... | {
"must_compile": false,
"required_annotations": [
"accessTransformers {",
"accesstransformer.cfg",
"public net.minecraft.client.Minecraft soundHandler",
"public-f net.minecraft.world.entity.LivingEntity hurtTime"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_009 | build | Set up repositories for a NeoForge 1.21.1 project that needs: (1) NeoForged maven for the loader, (2) Modrinth maven for runtime mods, (3) CurseMaven, each with content filtering. Write the repositories block. | repositories {
mavenCentral()
maven("https://maven.neoforged.net/releases") {
content { includeGroupByRegex("net\\.neoforged.*") }
}
exclusiveContent {
forRepository {
maven("https://api.modrinth.com/maven") {
name = "Modrinth"
}
}
... | {
"must_compile": false,
"required_annotations": [
"maven.neoforged.net",
"api.modrinth.com/maven",
"cursemaven.com",
"includeGroup(\"maven.modrinth\")",
"includeGroup(\"curse.maven\")"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_010 | build | Expand `${mod_version}` / `${mc_version}` placeholders into `neoforge.mods.toml` during processResources in a Gradle 8 Kotlin DSL build, handling CRLF safely and enabling template expansion only for that file. | val modVersion = project.version.toString()
val mcVersion = "1.21.1"
tasks.processResources {
inputs.property("mod_version", modVersion)
inputs.property("mc_version", mcVersion)
filesMatching("META-INF/neoforge.mods.toml") {
expand(
"mod_version" to modVersion,
"mc_version"... | {
"must_compile": false,
"required_annotations": [
"filesMatching",
"META-INF/neoforge.mods.toml",
"expand(",
"filteringCharset"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_011 | build | Make Mixin's annotation processor generate the refmap for a NeoForge 1.21.1 NeoGradle 7 build, and register the mixin config in the mod metadata. Show the dependency line and compiler config. | dependencies {
implementation("net.neoforged:neoforge:21.1.77")
// Mixin annotation processor -> generates examplemod.refmap.json at compile time
annotationProcessor("org.spongepowered:mixin:0.8.7:processor")
}
// neoforge.mods.toml additionally needs:
// [[mixins]]
// config = "examplemod.mixins.json"
//... | {
"must_compile": false,
"required_annotations": [
"annotationProcessor",
"org.spongepowered:mixin:0.8.7",
"refmap",
"[[mixins]]"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_012 | build | Structure a multi-loader NeoForge 1.21.1 workspace: a `common` source set holding shared code and a `main` (neoforge) source set depending on it. Write the source set configuration and cross-source-set dependency in `build.gradle.kts`. | sourceSets {
val common = create("common") {
java {
srcDir("src/common/java")
}
resources {
srcDir("src/common/resources")
}
}
val main = main {
java {
srcDir("src/main/java")
}
resources {
srcDir("src/ma... | {
"must_compile": false,
"required_annotations": [
"sourceSets {",
"create(\"common\")",
"compileClasspath",
"runtimeClasspath",
"modSource"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_013 | build | Pin the Gradle distribution and configure `settings.gradle.kts` plugin resolution (Gradle Plugin Portal + NeoForged maven) for a NeoForge 1.21.1 project. Show both files. | # gradle/wrapper/gradle-wrapper.properties
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-8.9-bin.zip
networkTimeout=10000
validateDistributionUrl=true
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
// settings.gradle.kts
plu... | {
"must_compile": false,
"required_annotations": [
"gradle-8.9-bin.zip",
"pluginManagement {",
"gradlePluginPortal()",
"maven.neoforged.net/releases",
"rootProject.name"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_014 | build | Configure a data-generation run for NeoGradle 7 / NeoForge 1.21.1 that writes generated resources into `src/generated/resources` while keeping `src/main/resources` readable for `--existing`, then wire the generated folder into the source sets. | sourceSets.main {
resources {
srcDir("src/generated/resources")
}
}
runs {
data {
data()
programArguments.addAll(
"--mod", "examplemod",
"--all",
"--output", file("src/generated/resources/").absolutePath,
"--existing", file("src/main/r... | {
"must_compile": false,
"required_annotations": [
"src/generated/resources",
"--output",
"--existing",
"data()"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_015 | build | Explain and configure jar packaging for NeoForge 1.21.1: why `reobfJar` no longer exists, and make `assemble` depend on the jarJar task so the published jar contains JiJ'd dependencies. | /*
* Since NeoForge 1.20.2+ (and 1.21.x), the runtime uses Mojmap classes directly.
* There is NO SRG reobfuscation step anymore: `reobfJar` does not exist in NeoGradle 7 /
* ModDevGradle, and the plain `jar` task output is the final distributable artifact.
*/
tasks {
named("assemble") {
dependsOn("jarJ... | {
"must_compile": false,
"required_annotations": [
"reobfJar",
"jarJar",
"dependsOn",
"Mojmap"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_016 | build | Add CurseForge publishing with `curseforgegradle` for a NeoForge 1.21.1 mod: api key from gradle property/env, project id 111222, game version 1.21.1, java version 21, release type release, uploading the jar. | plugins {
id("net.darkhax.curseforgegradle") version "1.1.24"
}
tasks.create<net.darkhax.curseforgegradle.TaskPublishCurseForge>("publishCurseForge") {
apiToken = providers.gradleProperty("curseforgeToken")
.orElse(providers.environmentVariable("CURSEFORGE_TOKEN"))
.orElse("")
val mainFile... | {
"must_compile": false,
"required_annotations": [
"net.darkhax.curseforgegradle",
"TaskPublishCurseForge",
"apiToken",
"addGameVersion(\"1.21.1\")",
"addModLoader(\"NeoForge\")"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_017 | build | Write a GitHub Actions workflow that builds a NeoForge 1.21.1 mod on pushes to main: Java 21 (Temurin), Gradle 8 wrapper caching, `./gradlew build`. | name: Build
on:
push:
branches: [ main ]
pull_request:
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Set up JDK 21
uses: actions/setup-java@v4
with:
distribution: temurin
java-version: 21
- name: Setup Gradle
... | {
"must_compile": false,
"required_annotations": [
"setup-java@v4",
"java-version: 21",
"./gradlew build",
"upload-artifact@v4",
"setup-gradle@v4"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_018 | build | Write `gradle.properties` tuning for a NeoForge 1.21.1 project: 4 GB daemon heap (NeoForm needs memory), parallel execution, configuration cache, and moddev/userdev-friendly JVM args. Also declare the mod version properties. | # Memory: NeoForm/NeoForge tooling decompiles a lot; 4G heap is the practical floor.
org.gradle.jvmargs=-Xmx4G -XX:+UseParallelGC
org.gradle.parallel=true
org.gradle.caching=true
org.gradle.configuration-cache=true
# Mod metadata used by processResources expansion
mod_version=1.0.0
minecraft_version=1.21.1
neoforge_ve... | {
"must_compile": false,
"required_annotations": [
"-Xmx4G",
"org.gradle.parallel=true",
"org.gradle.caching=true",
"mod_version=",
"neoforge_version="
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_019 | build | Write the `neoforge.mods.toml` dependency tables for a mod that (a) REQUIRES neoforge [21.1.0,) and minecraft [1.21.1], (b) hard-requires a companion mod AFTER it loads on both sides, and (c) breaks on a known-broken companion version range. Use the correct `type`, `ordering`, `versionRange` and `side` fields. | [[dependencies.neoforge]]
modId = "neoforge"
type = "required"
versionRange = "[21.1.0,)"
ordering = "NONE"
side = "BOTH"
[[dependencies.minecraft]]
modId = "minecraft"
type = "required"
versionRange = "[1.21.1]"
ordering = "NONE"
side = "BOTH"
[[dependencies.companionlib]]
modId = "companionlib"
type = "required"
ve... | {
"must_compile": false,
"required_annotations": [
"type = \"required\"",
"type = \"incompatible\"",
"ordering = \"AFTER\"",
"side = \"BOTH\"",
"[21.1.0,)",
"[1.21.1]"
],
"forbidden_apis": [],
"gametest_required": false
} | |
BUILD_020 | build | Capstone migration: convert this Forge 1.20.1 Groovy build.gradle (ForgeGradle 6) to a NeoForge 1.21.1 ModDevGradle Kotlin DSL build. Preserve group/version and the client/server runs. | // Forge 1.20.1 build.gradle (Groovy, ForgeGradle 6)
plugins {
id 'net.minecraftforge.gradle' version '[6.0,6.2)'
}
version = '1.0.0'
group = 'com.example'
java {
archivesBaseName = 'examplemod'
toolchain { languageVersion = JavaLanguageVersion.of(17) }
}
minecraft {
mappings channel: 'official', ver... | // NeoForge 1.21.1 build.gradle.kts (ModDevGradle)
plugins {
id("java-library")
id("net.neoforged.moddev") version "1.0.24"
}
version = "1.0.0"
group = "com.example"
base {
archivesName = "examplemod"
}
java {
toolchain {
languageVersion = JavaLanguageVersion.of(21) // 1.21.1 requires Java 21... | {
"must_compile": false,
"required_annotations": [
"net.neoforged.moddev",
"neoForge {",
"version = \"21.1.77\"",
"JavaLanguageVersion.of(21)",
"client()",
"server()"
],
"forbidden_apis": [
"net.minecraftforge",
"forgegradle",
"ForgeGradle"
],
"gametest_required": false
} |
Check the newer (v4) version
ForgeBench v1 — independent benchmark for Minecraft-modding LLMs
Contamination-free evaluation benchmark for models fine-tuned on the
ComerX/forge-neoforge-sft-* dataset family. Targets NeoForge 1.21.1 and
Forge 1.20.1 (Mojang mappings). 100 tasks, 5 modules × 20.
Data files (what the Dataset Viewer loads)
| Config | Split | File | Rows |
|---|---|---|---|
forgebench_full |
tasks |
data/forgebench_full.jsonl |
100 |
schema_example |
examples |
data/schema_example.jsonl |
3 |
Both files are UTF-8 JSONL, one task object per line — loadable with
load_dataset("ComerX/forgebench-v1", "forgebench_full") or line-by-line with
json.loads. Everything else in the repo (harness/, template/, reports) is
tooling, not data.
Task schema (strict)
{
"task_id": "MIXIN_014",
"module": "api | mixin | migration | debug | build",
"instruction": "prompt given to the evaluated LLM",
"context": "vanilla snippet / crash log / legacy code (may be empty)",
"golden_reference": "reference answer",
"eval_criteria": {
"must_compile": true,
"required_annotations": ["@Inject"],
"forbidden_apis": ["net.minecraft.util.text"],
"gametest_required": false
}
}
context is "" for tasks that need no reference material (e.g. pure API
registration drills); it contains vanilla/legacy code or FML log excerpts for
mixin, migration and debug tasks.
Modules
| Module | Count | Task type | Grading |
|---|---|---|---|
api (API & registration) |
20 | instruction→code | compile + AST gate |
mixin (Mojmap targets) |
20 | FIM / translation | compile + AST gate |
migration (1.20.1→1.21.1) |
20 | refactoring | compile + AST gate (legacy APIs forbidden) |
debug (FML crash logs) |
20 | log analysis → JSON | judge + JSON-shape gate |
build (Gradle KTS / mods.toml) |
20 | config generation | judge + required-token gate |
Layout
data/
forgebench_full.jsonl # 100 tasks (single JSONL, one task per line)
schema_example.jsonl # 3 complete examples (Mixin / Migration / Crash log)
harness/
Dockerfile # sandbox image: JDK 21 + Gradle 8.9 + prebuilt MDK template
sandbox_runner.py # injects answer into MDK -> ./gradlew build -x test -> Pass@1
ast_eval.py # javalang AST gate: syntax, forbidden APIs, hallucinated
# imports, required annotations, version-mix penalties
gametest_runner.py # GameTest template generation + headless run
judge_prompt.txt # strict LLM-as-a-judge rubric for debug/build tasks
run_benchmark.py # driver: aggregates sandbox + AST + judge into a report
requirements.txt
template/ # minimal NeoForge 1.21.1 MDK (NeoGradle 7 userdev)
VERIFICATION.md # benchmark self-verification results (19/19)
verification_result.json # machine-readable check log
SHA256SUMS.txt # integrity manifest (sha256 of every repo file)
Running
# 0. build the sandbox image (once)
docker build -t forgebench-sandbox:1.21.1 .
# 1. produce answers.jsonl: {"task_id": ..., "answer": ...} per row
# 2a. offline static gate only
python3 harness/run_benchmark.py --data data/forgebench_full.jsonl \
--answers answers.jsonl --skip-compile --out report.json
# 2b. full compile evaluation (inside Docker)
python3 harness/run_benchmark.py --data data/forgebench_full.jsonl \
--answers answers.jsonl --out report.json
# 3. judge-graded tasks (debug/build): run your judge LLM with harness/judge_prompt.txt
# and pass scores via --scores '{"DEBUG_004": {"score": 9, "verdict": "pass"}, ...}'
Contamination status
Golden references and instructions were screened against the public SFT corpus
(ComerX/forge-neoforge-sft-v2.1.0-rc2 + -rc1, sampled shards): 0 hits
(normalized 300-char prefix containment). The benchmark tasks are synthetic
examples, not derived from any corpus repository.
Integrity
- Frozen artifact:
SHA256SUMS.txt(sha256 of every file in this repo). - The benchmark is immutable once published; changes require a new version tag.
License
MIT — applies to the benchmark data (data/), the harness (harness/), and the
MDK template (template/).
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