Hey guys,

I've been working on my custom world type lately, and I ran into an issue again. My custom world type is based off of the default world type, but I would like to replace the default fluid used below sea level by compressed ice. I noticed that vanilla defines the default fluid using the

DimensionSettings

class. I would like to use my custom settings (say "FROZEN_OVERWORLD_SETTINGS") for the NoiseChunkGenerator constructor that I pass to the ForgeWorldType constructor:

new ForgeWorldType((biomeRegistry, dimensionSettingsRegistry, seed) ->
    new NoiseChunkGenerator(new FrozenOverworldBiomeProvider(seed, false, false, biomeRegistry), seed, () -> FROZEN_OVERWORLD_SETTINGS)
)

The problem is: I can't instantiate DimensionSettings without using reflection. The constructor is private, the class is final, and there is no builder method. Using reflection seems to work when first creating a world and entering is as long as the client is left running. But after closing the game and rerunning it, I am unable to re-enter the world, instead getting the following error message:

[13:07:56] [Render thread/ERROR] [minecraft/SaveFormat]: WorldGenSettings: Unknown registry key: aid:biome_source missed input: {"minecraft:overworld":{generator:{settings:"aid:frozen_overworld",seed:-2783071959927850081L,biome_source:{seed:-2783071959927850081L,large_biomes:0b,type:"aid:biome_source"},type:"minecraft:noise"},type:"minecraft:overworld"}}; Overworld settings missing

I know this error message is referring to the registry key I use to register my biome provider codec in my FrozenOverworldBiomeProvider class:

Registry.register(Registry.BIOME_PROVIDER_CODEC, new ResourceLocation(MOD_ID, "biome_source"), CODEC);

Yet this line seems necessary, because I get this error message when creating a world without the codec being registered:

[13:27:33] [Render thread/ERROR] [minecraft/Minecraft]: Error reading worldgen settings after loading data packs: Unknown registry element RecordCodec[UnitDecoder[joienl.world.FrozenOverworldBiomeProvider$$Lambda$4386/249483336@a859c5] * Field[seed: Long] * OptionalFieldCodec[legacy_biome_init_layer: Bool][flatXmapped] * Field[large_biomes: Bool][mapResult OrElse[false]] * RegistryLookupCodec[ResourceKey[minecraft:root / minecraft:worldgen/biome]]]
[13:27:33] [Render thread/ERROR] [minecraft/ServerWorldInfo]: WorldGenSettings: Unknown registry element RecordCodec[UnitDecoder[joienl.world.FrozenOverworldBiomeProvider$$Lambda$4386/249483336@a859c5] * Field[seed: Long] * OptionalFieldCodec[legacy_biome_init_layer: Bool][flatXmapped] * Field[large_biomes: Bool][mapResult OrElse[false]] * RegistryLookupCodec[ResourceKey[minecraft:root / minecraft:worldgen/biome]]]

I am unable to reload the world at all if I don't register the codec. I just don't know where to look anymore. Any help would be greatly appreciated.

Alright, I'm an idiot. I was registering my codec in a static initialiser in the biome provider class, meaning it was only registered when the class was loaded (i.e. when creating a world with my custom world type). I moved the registration to common setup and it works fine now.