Copper Hopper

Evidence

Ran on Kiln's test stand (2026-11-04): FabricMainInitializer did not start: java.lang.NoClassDefFoundError: net/minecraft/world/level/block/WeatheringCopper; FabricClientInitializer did not start: java.lang.NoClassDefFoundError: net/minecraft/client/renderer/entity/EntityRenderer.

What it needs from Kiln

• Mixin
• net.fabricmc.fabric.api.client.rendering.v1.EntityRendererRegistry
• net.fabricmc.fabric.api.object.builder.v1.block.entity.FabricBlockEntityTypeBuilder
• net.fabricmc.fabric.api.object.builder.v1.block.entity.FabricBlockEntityTypeBuilder.Factory
• net.fabricmc.fabric.api.registry.OxidizableBlocksRegistry
• net.minecraft.client.gui.screens.MenuScreens
• net.minecraft.client.gui.screens.MenuScreens.ScreenConstructor
• net.minecraft.client.gui.screens.inventory.HopperScreen
• net.minecraft.client.model.geom.ModelLayers
• net.minecraft.client.renderer.RenderPipelines
• net.minecraft.client.renderer.entity.EntityRendererProvider
• net.minecraft.client.renderer.entity.EntityRendererProvider.Context
• net.minecraft.client.renderer.entity.MinecartRenderer
• net.minecraft.core.BlockPos.MutableBlockPos
• net.minecraft.core.Direction.Axis
• net.minecraft.core.component.DataComponentPatch
• net.minecraft.util.Mth
• net.minecraft.world.Container
• net.minecraft.world.WorldlyContainer
• net.minecraft.world.entity.EntityType
• net.minecraft.world.entity.EntityType.Builder
• net.minecraft.world.entity.EntityType.EntityFactory
• net.minecraft.world.entity.EntityTypes
• net.minecraft.world.entity.MobCategory
• net.minecraft.world.entity.vehicle.minecart.MinecartHopper
• net.minecraft.world.flag.FeatureFlags
• net.minecraft.world.inventory.HopperMenu
• net.minecraft.world.inventory.MenuType
• net.minecraft.world.inventory.MenuType.MenuSupplier
• net.minecraft.world.item.MinecartItem
• net.minecraft.world.level.block.HopperBlock
• net.minecraft.world.level.block.WeatheringCopper
• net.minecraft.world.level.block.WeatheringCopper.WeatherState
• net.minecraft.world.level.block.entity.BlockEntity
• net.minecraft.world.level.block.entity.BlockEntityTicker
• net.minecraft.world.level.block.entity.BlockEntityType
• net.minecraft.world.level.block.entity.HopperBlockEntity
• net.minecraft.world.level.material.MapColor
• org.apache.logging.log4j.Level
• org.apache.logging.log4j.LogManager
• org.apache.logging.log4j.Logger
• and 18 more

On the roadmap: Minecraft's libraries and client API (0.2), Code next to data (0.3), Machines (0.4), Mixin (0.5)

In the author's words

Hopper that acts as a simple item filter.

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file copperhopper-fabric-0.25.2+26.3.jar. The scan reads the mod's classes; it does not run them.