Fix NeoForge fluid ingredient types not being registered (#1783)

Author: Technici4n

src/main/java/net/neoforged/neoforge/common/NeoForgeMod.java

@@ -535,6 +535,7 @@ public NeoForgeMod(IEventBus modEventBus, Dist dist, ModContainer container) {
         ITEM_SUB_PREDICATES.register(modEventBus);
         SLOT_DISPLAY_TYPES.register(modEventBus);
         INGREDIENT_TYPES.register(modEventBus);
+        FLUID_INGREDIENT_TYPES.register(modEventBus);
         CONDITION_CODECS.register(modEventBus);
         GLOBAL_LOOT_MODIFIER_SERIALIZERS.register(modEventBus);
         NeoForge.EVENT_BUS.addListener(this::serverStopping);

src/main/java/net/neoforged/neoforge/fluids/crafting/FluidIngredientCodecs.java

@@ -24,7 +24,9 @@ public class FluidIngredientCodecs {
     static Codec<FluidIngredient> codec() {
         return Codec.xor(
                 NeoForgeRegistries.FLUID_INGREDIENT_TYPES.byNameCodec().<FluidIngredient>dispatch("neoforge:ingredient_type", FluidIngredient::getType, FluidIngredientType::codec),
-                SimpleFluidIngredient.CODEC).xmap(either -> either.map(i -> i, i -> i), ingredient -> switch (ingredient) {
+                // Use lazy: SimpleFluidIngredient.CODEC is initialized after FluidIngredient.CODEC which lives in a superclass.
+                Codec.lazyInitialized(() -> SimpleFluidIngredient.CODEC))
+                .xmap(either -> either.map(i -> i, i -> i), ingredient -> switch (ingredient) {
                     case SimpleFluidIngredient simple -> Either.right(simple);
                     default -> Either.left(ingredient);
                 });

tests/src/junit/java/net/neoforged/neoforge/unittest/FluidIngredientTests.java

@@ -5,6 +5,7 @@
 
 package net.neoforged.neoforge.unittest;
 
+import com.mojang.serialization.JsonOps;
 import java.util.List;
 import java.util.stream.Stream;
 import net.minecraft.core.component.DataComponentPatch;
@@ -17,6 +18,7 @@
 import net.neoforged.neoforge.fluids.crafting.CompoundFluidIngredient;
 import net.neoforged.neoforge.fluids.crafting.DataComponentFluidIngredient;
 import net.neoforged.neoforge.fluids.crafting.FluidIngredient;
+import net.neoforged.neoforge.fluids.crafting.IntersectionFluidIngredient;
 import net.neoforged.testframework.junit.EphemeralTestServerProvider;
 import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
@@ -74,6 +76,7 @@ void fluidIngredientComponentMatchingWorks(boolean strict, MinecraftServer serve
                 .isEqualTo(!strict);
     }
 
+    @Test
     void singleFluidIngredientIgnoresSizeAndData(MinecraftServer server) {
         var ingredient = FluidIngredient.of(Fluids.WATER);
 
@@ -85,4 +88,30 @@ void singleFluidIngredientIgnoresSizeAndData(MinecraftServer server) {
                 .withFailMessage("Single fluid ingredient should match regardless of fluid data!")
                 .isTrue();
     }
+
+    @Test
+    void customFluidIngredientSerialization(MinecraftServer server) {
+        var ingredient1 = FluidIngredient.of(Fluids.WATER, Fluids.LAVA);
+        var ingredient2 = FluidIngredient.of(Fluids.LAVA);
+        var intersection = IntersectionFluidIngredient.of(ingredient1, ingredient2);
+
+        var ops = server.registryAccess().createSerializationContext(JsonOps.INSTANCE);
+        var result = FluidIngredient.CODEC.encodeStart(ops, intersection)
+                .getOrThrow(error -> new RuntimeException("Failed to serialize ingredient: " + error));
+
+        var deserialized = FluidIngredient.CODEC.decode(ops, result)
+                .getOrThrow(error -> new RuntimeException("Failed to deserialize ingredient: " + error))
+                .getFirst();
+
+        if (!(deserialized instanceof IntersectionFluidIngredient)) {
+            throw new AssertionError("Deserialized ingredient is not an IntersectionFluidIngredient! Got " + deserialized);
+        }
+
+        if (deserialized.test(new FluidStack(Fluids.WATER, 1))) {
+            throw new AssertionError("Deserialized ingredient should not match water!");
+        }
+        if (!deserialized.test(new FluidStack(Fluids.LAVA, 1))) {
+            throw new AssertionError("Deserialized ingredient should match lava!");
+        }
+    }
 }