Backport to 1.21.1: Add a biome villager types data map to replace VillagerType#BY_BIOME

patches/net/minecraft/world/entity/npc/VillagerType.java.patch

@@ -0,0 +1,21 @@
+--- a/net/minecraft/world/entity/npc/VillagerType.java
++++ b/net/minecraft/world/entity/npc/VillagerType.java
+@@ -21,6 +_,8 @@
+     public static final VillagerType SWAMP = register("swamp");
+     public static final VillagerType TAIGA = register("taiga");
+     private final String name;
++    /** Neo: use the {@link net.neoforged.neoforge.registries.datamaps.builtin.NeoForgeDataMaps#VILLAGER_TYPES data map} instead as this field will be ignored in future versions */
++    @Deprecated
+     private static final Map<ResourceKey<Biome>, VillagerType> BY_BIOME = Util.make(Maps.newHashMap(), p_35834_ -> {
+         p_35834_.put(Biomes.BADLANDS, DESERT);
+         p_35834_.put(Biomes.DESERT, DESERT);
+@@ -67,6 +_,9 @@
+     }
+
+     public static VillagerType byBiome(Holder<Biome> p_204074_) {
++        var fromDataMap = p_204074_.getData(net.neoforged.neoforge.registries.datamaps.builtin.NeoForgeDataMaps.VILLAGER_TYPES);
++        if (fromDataMap != null) return fromDataMap.type();
++        // TODO - 1.22: remove fallback
+         return p_204074_.unwrapKey().map(BY_BIOME::get).orElse(PLAINS);
+     }
+ }

src/generated/resources/data/neoforge/data_maps/worldgen/biome/villager_types.json

@@ -0,0 +1,91 @@
+{
+  "values": {
+    "minecraft:badlands": {
+      "villager_type": "minecraft:desert"
+    },
+    "minecraft:bamboo_jungle": {
+      "villager_type": "minecraft:jungle"
+    },
+    "minecraft:deep_frozen_ocean": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:desert": {
+      "villager_type": "minecraft:desert"
+    },
+    "minecraft:eroded_badlands": {
+      "villager_type": "minecraft:desert"
+    },
+    "minecraft:frozen_ocean": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:frozen_peaks": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:frozen_river": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:grove": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:ice_spikes": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:jagged_peaks": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:jungle": {
+      "villager_type": "minecraft:jungle"
+    },
+    "minecraft:mangrove_swamp": {
+      "villager_type": "minecraft:swamp"
+    },
+    "minecraft:old_growth_pine_taiga": {
+      "villager_type": "minecraft:taiga"
+    },
+    "minecraft:old_growth_spruce_taiga": {
+      "villager_type": "minecraft:taiga"
+    },
+    "minecraft:savanna": {
+      "villager_type": "minecraft:savanna"
+    },
+    "minecraft:savanna_plateau": {
+      "villager_type": "minecraft:savanna"
+    },
+    "minecraft:snowy_beach": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:snowy_plains": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:snowy_slopes": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:snowy_taiga": {
+      "villager_type": "minecraft:snow"
+    },
+    "minecraft:sparse_jungle": {
+      "villager_type": "minecraft:jungle"
+    },
+    "minecraft:swamp": {
+      "villager_type": "minecraft:swamp"
+    },
+    "minecraft:taiga": {
+      "villager_type": "minecraft:taiga"
+    },
+    "minecraft:windswept_forest": {
+      "villager_type": "minecraft:taiga"
+    },
+    "minecraft:windswept_gravelly_hills": {
+      "villager_type": "minecraft:taiga"
+    },
+    "minecraft:windswept_hills": {
+      "villager_type": "minecraft:taiga"
+    },
+    "minecraft:windswept_savanna": {
+      "villager_type": "minecraft:savanna"
+    },
+    "minecraft:wooded_badlands": {
+      "villager_type": "minecraft:desert"
+    }
+  }
+}

src/main/java/net/neoforged/neoforge/common/data/internal/NeoForgeDataMapsProvider.java

@@ -24,8 +24,10 @@
 import net.minecraft.world.entity.ai.behavior.WorkAtComposter;
 import net.minecraft.world.entity.animal.Parrot;
 import net.minecraft.world.entity.npc.VillagerProfession;
+import net.minecraft.world.entity.npc.VillagerType;
 import net.minecraft.world.item.HoneycombItem;
 import net.minecraft.world.item.Item;
+import net.minecraft.world.level.biome.Biome;
 import net.minecraft.world.level.block.ComposterBlock;
 import net.minecraft.world.level.block.WeatheringCopper;
 import net.minecraft.world.level.block.entity.AbstractFurnaceBlockEntity;
@@ -35,6 +37,7 @@
 import net.minecraft.world.level.storage.loot.LootTable;
 import net.neoforged.fml.util.ObfuscationReflectionHelper;
 import net.neoforged.neoforge.common.data.DataMapProvider;
+import net.neoforged.neoforge.registries.datamaps.builtin.BiomeVillagerType;
 import net.neoforged.neoforge.registries.datamaps.builtin.Compostable;
 import net.neoforged.neoforge.registries.datamaps.builtin.FurnaceFuel;
 import net.neoforged.neoforge.registries.datamaps.builtin.MonsterRoomMob;
@@ -56,6 +59,10 @@ protected void gather() {
         final List<Item> villagerCompostables = ObfuscationReflectionHelper.getPrivateValue(WorkAtComposter.class, null, "COMPOSTABLE_ITEMS");
         ComposterBlock.COMPOSTABLES.forEach((item, chance) -> compostables.add(item.asItem().builtInRegistryHolder(), new Compostable(chance, villagerCompostables.contains(item.asItem())), false));
 
+        final var biomeVillagers = builder(NeoForgeDataMaps.VILLAGER_TYPES);
+        ObfuscationReflectionHelper.<Map<ResourceKey<Biome>, VillagerType>, VillagerType>getPrivateValue(VillagerType.class, null, "BY_BIOME")
+                .forEach((biome, type) -> biomeVillagers.add(biome, new BiomeVillagerType(type), false));
+
         final var fuels = builder(NeoForgeDataMaps.FURNACE_FUELS);
         AbstractFurnaceBlockEntity.buildFuels((value, time) -> value.ifLeft(item -> fuels.add(item.builtInRegistryHolder(), new FurnaceFuel(time), false))
                 .ifRight(tag -> fuels.add(tag, new FurnaceFuel(time), false)));

src/main/java/net/neoforged/neoforge/registries/datamaps/builtin/BiomeVillagerType.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforge.registries.datamaps.builtin;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import net.minecraft.core.registries.BuiltInRegistries;
+import net.minecraft.world.entity.npc.VillagerType;
+
+/**
+ * Data map value for {@linkplain NeoForgeDataMaps#VILLAGER_TYPES biome villager types}.
+ *
+ * @param type the type of the villagers present in this biome
+ */
+public record BiomeVillagerType(VillagerType type) {
+    public static final Codec<BiomeVillagerType> TYPE_CODEC = BuiltInRegistries.VILLAGER_TYPE.byNameCodec()
+            .xmap(BiomeVillagerType::new, BiomeVillagerType::type);
+    public static final Codec<BiomeVillagerType> CODEC = Codec.withAlternative(
+            RecordCodecBuilder.create(in -> in.group(
+                    BuiltInRegistries.VILLAGER_TYPE.byNameCodec().fieldOf("villager_type").forGetter(BiomeVillagerType::type)).apply(in, BiomeVillagerType::new)),
+            TYPE_CODEC);
+}

src/main/java/net/neoforged/neoforge/registries/datamaps/builtin/NeoForgeDataMaps.java

@@ -11,10 +11,12 @@
 import net.minecraft.world.entity.ai.behavior.GiveGiftToHero;
 import net.minecraft.world.entity.animal.Parrot;
 import net.minecraft.world.entity.npc.VillagerProfession;
+import net.minecraft.world.entity.npc.VillagerType;
 import net.minecraft.world.item.HoneycombItem;
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.crafting.RecipeType;
+import net.minecraft.world.level.biome.Biome;
 import net.minecraft.world.level.block.Block;
 import net.minecraft.world.level.block.ComposterBlock;
 import net.minecraft.world.level.block.WeatheringCopper;
@@ -128,6 +130,19 @@ public class NeoForgeDataMaps {
     public static final DataMapType<GameEvent, VibrationFrequency> VIBRATION_FREQUENCIES = DataMapType.builder(
             id("vibration_frequencies"), Registries.GAME_EVENT, VibrationFrequency.CODEC).synced(VibrationFrequency.FREQUENCY_CODEC, false).build();
 
+    /**
+     * The {@linkplain Biome} data map that replaces {@link VillagerType#BY_BIOME}.
+     * <p>
+     * The location of this data map is {@code neoforge/data_maps/worldgen/biome/villager_types.json}, and the values are objects with 1 field:
+     * <ul>
+     * <li>{@code villager_type}, villager type ID - the type of the villagers present in the biome</li>
+     * </ul>
+     *
+     * The use of a string as the value is also possible, though discouraged in case more options are added in the future.
+     */
+    public static final DataMapType<Biome, BiomeVillagerType> VILLAGER_TYPES = DataMapType.builder(
+            id("villager_types"), Registries.BIOME, BiomeVillagerType.CODEC).synced(BiomeVillagerType.TYPE_CODEC, false).build();
+
     /**
      * The {@linkplain Block} data map that replaces {@link HoneycombItem#WAXABLES}.
      * <p>
@@ -154,6 +169,7 @@ private static void register(final RegisterDataMapTypesEvent event) {
         event.register(PARROT_IMITATIONS);
         event.register(RAID_HERO_GIFTS);
         event.register(VIBRATION_FREQUENCIES);
+        event.register(VILLAGER_TYPES);
         event.register(WAXABLES);
     }
 }