Fix more custom ingredient implementation issues

fabric-recipe-api-v1/src/main/java/net/fabricmc/fabric/impl/recipe/ingredient/CustomIngredientImpl.java

@@ -85,7 +85,7 @@ public CustomIngredientImpl(CustomIngredient customIngredient) {
 		this.customIngredient = customIngredient;
 	}
 
-	private List<RegistryEntry<Item>> getCustomMatchingItems() {
+	public List<RegistryEntry<Item>> getCustomMatchingItems() {
 		if (customMatchingItems == null) {
 			customMatchingItems = customIngredient.getMatchingItems().toList();
 		}

fabric-recipe-api-v1/src/main/java/net/fabricmc/fabric/impl/recipe/ingredient/CustomIngredientPacketCodec.java

@@ -18,6 +18,8 @@
 
 import java.util.Set;
 
+import org.jetbrains.annotations.Nullable;
+
 import net.minecraft.network.RegistryByteBuf;
 import net.minecraft.network.codec.PacketCodec;
 import net.minecraft.recipe.Ingredient;
@@ -27,7 +29,7 @@
 import net.fabricmc.fabric.api.recipe.v1.ingredient.CustomIngredientSerializer;
 
 public class CustomIngredientPacketCodec implements PacketCodec<RegistryByteBuf, Ingredient> {
-	private static final int PACKET_MARKER = -1;
+	static final int PACKET_MARKER = -1;
 	private final PacketCodec<RegistryByteBuf, Ingredient> fallback;
 
 	public CustomIngredientPacketCodec(PacketCodec<RegistryByteBuf, Ingredient> fallback) {
@@ -72,7 +74,7 @@ public void encode(RegistryByteBuf buf, Ingredient value) {
 		packetCodec.encode(buf, customIngredient);
 	}
 
-	private static boolean shouldEncodeFallback(CustomIngredient customIngredient) {
+	static boolean shouldEncodeFallback(@Nullable CustomIngredient customIngredient) {
 		if (customIngredient == null) {
 			return true;
 		}

fabric-recipe-api-v1/src/main/java/net/fabricmc/fabric/impl/recipe/ingredient/OptionalCustomIngredientPacketCodec.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.impl.recipe.ingredient;
+
+import java.util.Optional;
+
+import net.minecraft.network.RegistryByteBuf;
+import net.minecraft.network.codec.PacketCodec;
+import net.minecraft.recipe.Ingredient;
+import net.minecraft.util.Identifier;
+
+import net.fabricmc.fabric.api.recipe.v1.ingredient.CustomIngredient;
+import net.fabricmc.fabric.api.recipe.v1.ingredient.CustomIngredientSerializer;
+
+public class OptionalCustomIngredientPacketCodec implements PacketCodec<RegistryByteBuf, Optional<Ingredient>> {
+	private final PacketCodec<RegistryByteBuf, Optional<Ingredient>> fallback;
+
+	public OptionalCustomIngredientPacketCodec(PacketCodec<RegistryByteBuf, Optional<Ingredient>> fallback) {
+		this.fallback = fallback;
+	}
+
+	@Override
+	public Optional<Ingredient> decode(RegistryByteBuf buf) {
+		int index = buf.readerIndex();
+
+		if (buf.readVarInt() != CustomIngredientPacketCodec.PACKET_MARKER) {
+			// Reset index for vanilla's normal deserialization logic.
+			buf.readerIndex(index);
+			return this.fallback.decode(buf);
+		}
+
+		Identifier type = buf.readIdentifier();
+		CustomIngredientSerializer<?> serializer = CustomIngredientSerializer.get(type);
+
+		if (serializer == null) {
+			throw new IllegalArgumentException("Cannot deserialize custom ingredient of unknown type " + type);
+		}
+
+		return Optional.of(serializer.getPacketCodec().decode(buf).toVanilla());
+	}
+
+	@Override
+	@SuppressWarnings("unchecked")
+	public void encode(RegistryByteBuf buf, Optional<Ingredient> value) {
+		if (value.isEmpty()) {
+			this.fallback.encode(buf, value);
+			return;
+		}
+
+		CustomIngredient customIngredient = value.get().getCustomIngredient();
+
+		if (CustomIngredientPacketCodec.shouldEncodeFallback(customIngredient)) {
+			// The client doesn't support this custom ingredient, so we send the matching stacks as a regular ingredient.
+			this.fallback.encode(buf, value);
+			return;
+		}
+
+		// The client supports this custom ingredient, so we send it as a custom ingredient.
+		buf.writeVarInt(CustomIngredientPacketCodec.PACKET_MARKER);
+		buf.writeIdentifier(customIngredient.getSerializer().getIdentifier());
+		PacketCodec<RegistryByteBuf, CustomIngredient> packetCodec = (PacketCodec<RegistryByteBuf, CustomIngredient>) customIngredient.getSerializer().getPacketCodec();
+		packetCodec.encode(buf, customIngredient);
+	}
+}

fabric-recipe-api-v1/src/main/java/net/fabricmc/fabric/mixin/recipe/ingredient/IngredientMixin.java

@@ -16,6 +16,8 @@
 
 package net.fabricmc.fabric.mixin.recipe.ingredient;
 
+import java.util.Optional;
+
 import com.llamalad7.mixinextras.injector.ModifyExpressionValue;
 import com.mojang.datafixers.util.Either;
 import com.mojang.serialization.Codec;
@@ -39,6 +41,7 @@
 import net.fabricmc.fabric.api.recipe.v1.ingredient.FabricIngredient;
 import net.fabricmc.fabric.impl.recipe.ingredient.CustomIngredientImpl;
 import net.fabricmc.fabric.impl.recipe.ingredient.CustomIngredientPacketCodec;
+import net.fabricmc.fabric.impl.recipe.ingredient.OptionalCustomIngredientPacketCodec;
 
 @Mixin(Ingredient.class)
 public class IngredientMixin implements FabricIngredient {
@@ -51,6 +54,30 @@ public class IngredientMixin implements FabricIngredient {
 	@Final
 	private RegistryEntryList<Item> entries;
 
+	@ModifyExpressionValue(
+			method = "<clinit>",
+			at = @At(
+					value = "INVOKE",
+					target = "Lnet/minecraft/network/codec/PacketCodec;xmap(Ljava/util/function/Function;Ljava/util/function/Function;)Lnet/minecraft/network/codec/PacketCodec;",
+					ordinal = 0
+			)
+	)
+	private static PacketCodec<RegistryByteBuf, Ingredient> useCustomIngredientPacketCodec(PacketCodec<RegistryByteBuf, Ingredient> original) {
+		return new CustomIngredientPacketCodec(original);
+	}
+
+	@ModifyExpressionValue(
+			method = "<clinit>",
+			at = @At(
+					value = "INVOKE",
+					target = "Lnet/minecraft/network/codec/PacketCodec;xmap(Ljava/util/function/Function;Ljava/util/function/Function;)Lnet/minecraft/network/codec/PacketCodec;",
+					ordinal = 1
+			)
+	)
+	private static PacketCodec<RegistryByteBuf, Optional<Ingredient>> useOptionalCustomIngredientPacketCodec(PacketCodec<RegistryByteBuf, Optional<Ingredient>> original) {
+		return new OptionalCustomIngredientPacketCodec(original);
+	}
+
 	@Inject(method = "<clinit>", at = @At("TAIL"), cancellable = true)
 	private static void injectCodec(CallbackInfo ci) {
 		Codec<CustomIngredient> customIngredientCodec = CustomIngredientImpl.CODEC.dispatch(
@@ -67,16 +94,14 @@ private static void injectCodec(CallbackInfo ci) {
 		);
 	}
 
-	@ModifyExpressionValue(
-			method = "<clinit>",
-			at = @At(
-					value = "INVOKE",
-					target = "Lnet/minecraft/network/codec/PacketCodec;xmap(Ljava/util/function/Function;Ljava/util/function/Function;)Lnet/minecraft/network/codec/PacketCodec;",
-					ordinal = 0
-			)
-	)
-	private static PacketCodec<RegistryByteBuf, Ingredient> useCustomIngredientPacketCodec(PacketCodec<RegistryByteBuf, Ingredient> original) {
-		return new CustomIngredientPacketCodec(original);
+	// Targets the lambdas in the codecs which extract the entries from an ingredient.
+	// For custom ingredients, these lambdas will only be invoked when the client does not support this ingredient.
+	// In this case, use CustomIngredientImpl#getCustomMatchingItems, which as close as we can get.
+	@Inject(method = { "method_61673", "method_61677", "method_61680" }, at = @At("HEAD"), cancellable = true)
+	private static void onGetEntries(Ingredient ingredient, CallbackInfoReturnable<RegistryEntryList<Item>> cir) {
+		if (ingredient instanceof CustomIngredientImpl customIngredient) {
+			cir.setReturnValue(RegistryEntryList.of(customIngredient.getCustomMatchingItems()));
+		}
 	}
 
 	@Inject(method = "equals(Ljava/lang/Object;)Z", at = @At("HEAD"))

fabric-recipe-api-v1/src/main/java/net/fabricmc/fabric/mixin/recipe/ingredient/ShapelessRecipeMixin.java

@@ -60,7 +60,7 @@ public void customIngredientMatch(CraftingRecipeInput recipeInput, World world,
 		if (fabric_requiresTesting) {
 			List<ItemStack> nonEmptyStacks = new ArrayList<>(recipeInput.getStackCount());
 
-			for (int i = 0; i < recipeInput.getStackCount(); ++i) {
+			for (int i = 0; i < recipeInput.size(); ++i) {
 				ItemStack stack = recipeInput.getStackInSlot(i);
 
 				if (!stack.isEmpty()) {