Fix trade list handling

api/src/main/java/com/viaversion/viaversion/api/minecraft/data/StructuredDataContainer.java

@@ -41,6 +41,13 @@ public final class StructuredDataContainer {
         this.data = data;
     }
 
+    public StructuredDataContainer(final StructuredData<?>[] dataArray) {
+        this(new Reference2ObjectOpenHashMap<>(dataArray.length));
+        for (final StructuredData<?> data : dataArray) {
+            add(data);
+        }
+    }
+
     public StructuredDataContainer() {
         this(new Reference2ObjectOpenHashMap<>());
     }
@@ -152,6 +159,10 @@ public final class StructuredDataContainer {
         return data;
     }
 
+    private <T> void add(final StructuredData<T> data) {
+        set(data.key(), data.value());
+    }
+
     @Override
     public String toString() {
         return "StructuredDataContainer{" +

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/Item.java

@@ -80,7 +80,8 @@ public interface Item {
      *
      * @return item tag
      */
-    @Nullable CompoundTag tag();
+    @Nullable
+    CompoundTag tag();
 
     /**
      * Sets the item compound tag.
@@ -97,4 +98,13 @@ public interface Item {
      * @return copy of the item
      */
     Item copy();
+
+    /**
+     * Returns true if the item is empty.
+     *
+     * @return true if the item is empty
+     */
+    default boolean isEmpty() {
+        return identifier() == 0 || amount() <= 0;
+    }
 }

api/src/main/java/com/viaversion/viaversion/api/minecraft/item/StructuredItem.java

@@ -31,8 +31,8 @@ public class StructuredItem implements Item {
     private int identifier;
     private int amount;
 
-    public StructuredItem() {
+    public StructuredItem(final int identifier, final int amount) {
-        this(0, 0, new StructuredDataContainer());
+        this(identifier, amount, new StructuredDataContainer());
     }
 
     public StructuredItem(final int identifier, final int amount, final StructuredDataContainer data) {

api/src/main/java/com/viaversion/viaversion/api/type/types/item/ItemCostType1_20_5.java

@@ -0,0 +1,64 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2024 ViaVersion and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package com.viaversion.viaversion.api.type.types.item;
+
+import com.viaversion.viaversion.api.minecraft.data.StructuredData;
+import com.viaversion.viaversion.api.minecraft.data.StructuredDataContainer;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.minecraft.item.StructuredItem;
+import com.viaversion.viaversion.api.type.OptionalType;
+import com.viaversion.viaversion.api.type.Type;
+import io.netty.buffer.ByteBuf;
+
+// Very similar to normal items (and just results in an item), except it allows non-positive amounts and has id/amount swapped because ???
+public final class ItemCostType1_20_5 extends Type<Item> {
+
+    private final Type<StructuredData<?>[]> dataArrayType;
+
+    public ItemCostType1_20_5(final Type<StructuredData<?>[]> dataArrayType) {
+        super(Item.class);
+        this.dataArrayType = dataArrayType;
+    }
+
+    @Override
+    public Item read(final ByteBuf buffer) throws Exception {
+        final int id = Type.VAR_INT.readPrimitive(buffer);
+        final int amount = Type.VAR_INT.readPrimitive(buffer);
+        final StructuredData<?>[] dataArray = dataArrayType.read(buffer);
+        return new StructuredItem(id, amount, new StructuredDataContainer(dataArray));
+    }
+
+    @Override
+    public void write(final ByteBuf buffer, final Item object) throws Exception {
+        Type.VAR_INT.writePrimitive(buffer, object.identifier());
+        Type.VAR_INT.writePrimitive(buffer, object.amount());
+        dataArrayType.write(buffer, object.structuredData().data().values().toArray(new StructuredData[0]));
+    }
+
+    public static final class OptionalItemCostType extends OptionalType<Item> {
+
+        public OptionalItemCostType(final Type<Item> type) {
+            super(type);
+        }
+    }
+}

api/src/main/java/com/viaversion/viaversion/api/type/types/version/Types1_20_5.java

@@ -23,11 +23,13 @@
 package com.viaversion.viaversion.api.type.types.version;
 
 import com.viaversion.viaversion.api.minecraft.Particle;
+import com.viaversion.viaversion.api.minecraft.data.StructuredData;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.minecraft.metadata.Metadata;
 import com.viaversion.viaversion.api.minecraft.metadata.types.MetaTypes1_20_5;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.ArrayType;
+import com.viaversion.viaversion.api.type.types.item.ItemCostType1_20_5;
 import com.viaversion.viaversion.api.type.types.item.ItemType1_20_5;
 import com.viaversion.viaversion.api.type.types.item.StructuredDataType;
 import com.viaversion.viaversion.api.type.types.metadata.MetaListType;
@@ -35,14 +37,18 @@ import com.viaversion.viaversion.api.type.types.metadata.MetadataType;
 import com.viaversion.viaversion.api.type.types.misc.ParticleType;
 import java.util.List;
 
+// Most of these are only safe to use after protocol loading
 public final class Types1_20_5 {
 
-    // Most of these are only safe to use after protocol loading
-    public static final ParticleType PARTICLE = new ParticleType();
-    public static final ArrayType<Particle> PARTICLES = new ArrayType<>(PARTICLE);
     public static final StructuredDataType STRUCTURED_DATA = new StructuredDataType();
+    public static final Type<StructuredData<?>[]> STRUCTURED_DATA_ARRAY = new ArrayType<>(STRUCTURED_DATA);
     public static final Type<Item> ITEM = new ItemType1_20_5(STRUCTURED_DATA);
     public static final Type<Item[]> ITEM_ARRAY = new ArrayType<>(ITEM);
+    public static final Type<Item> ITEM_COST = new ItemCostType1_20_5(STRUCTURED_DATA_ARRAY);
+    public static final Type<Item> OPTIONAL_ITEM_COST = new ItemCostType1_20_5.OptionalItemCostType(ITEM_COST);
+
+    public static final ParticleType PARTICLE = new ParticleType();
+    public static final ArrayType<Particle> PARTICLES = new ArrayType<>(PARTICLE);
     public static final MetaTypes1_20_5 META_TYPES = new MetaTypes1_20_5(PARTICLE, PARTICLES);
     public static final Type<Metadata> METADATA = new MetadataType(META_TYPES);
     public static final Type<List<Metadata>> METADATA_LIST = new MetaListType(METADATA);

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13_2to1_13_1/Protocol1_13_2To1_13_1.java

@@ -52,10 +52,7 @@ public class Protocol1_13_2To1_13_1 extends AbstractProtocol<ClientboundPackets1
 
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                // Parent
-                if (wrapper.passthrough(Type.BOOLEAN))
-                    wrapper.passthrough(Type.STRING);
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_13to1_12_2/Protocol1_13To1_12_2.java

@@ -520,10 +520,7 @@ public class Protocol1_13To1_12_2 extends AbstractProtocol<ClientboundPackets1_1
 
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                // Parent
-                if (wrapper.passthrough(Type.BOOLEAN))
-                    wrapper.passthrough(Type.STRING);
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/rewriter/BlockItemPacketRewriter1_20_2.java

@@ -143,10 +143,7 @@ public final class BlockItemPacketRewriter1_20_2 extends ItemRewriter<Clientboun
             final int size = wrapper.passthrough(Type.VAR_INT); // Mapping size
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                // Parent
-                if (wrapper.passthrough(Type.BOOLEAN))
-                    wrapper.passthrough(Type.STRING);
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_3to1_20_2/Protocol1_20_3To1_20_2.java

@@ -128,11 +128,7 @@ public final class Protocol1_20_3To1_20_2 extends AbstractProtocol<ClientboundPa
             final int size = wrapper.passthrough(Type.VAR_INT); // Mapping size
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                // Parent
-                if (wrapper.passthrough(Type.BOOLEAN)) {
-                    wrapper.passthrough(Type.STRING);
-                }
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_5to1_20_3/rewriter/BlockItemPacketRewriter1_20_5.java

@@ -141,12 +141,44 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
         registerSetCooldown(ClientboundPackets1_20_3.COOLDOWN);
         registerWindowItems1_17_1(ClientboundPackets1_20_3.WINDOW_ITEMS);
         registerSetSlot1_17_1(ClientboundPackets1_20_3.SET_SLOT);
-        registerAdvancements1_20_3(ClientboundPackets1_20_3.ADVANCEMENTS);
         registerEntityEquipmentArray(ClientboundPackets1_20_3.ENTITY_EQUIPMENT);
         registerClickWindow1_17_1(ServerboundPackets1_20_5.CLICK_WINDOW);
         registerCreativeInvAction(ServerboundPackets1_20_5.CREATIVE_INVENTORY_ACTION);
         registerWindowPropertyEnchantmentHandler(ClientboundPackets1_20_3.WINDOW_PROPERTY);
 
+        protocol.registerClientbound(ClientboundPackets1_20_3.ADVANCEMENTS, wrapper -> {
+            wrapper.passthrough(Type.BOOLEAN); // Reset/clear
+            int size = wrapper.passthrough(Type.VAR_INT); // Mapping size
+            for (int i = 0; i < size; i++) {
+                wrapper.passthrough(Type.STRING); // Identifier
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
+
+                // Display data
+                if (wrapper.passthrough(Type.BOOLEAN)) {
+                    wrapper.passthrough(Type.TAG); // Title
+                    wrapper.passthrough(Type.TAG); // Description
+
+                    Item item = handleNonNullItemToClient(wrapper.read(itemType()));
+                    wrapper.write(mappedItemType(), item);
+
+                    wrapper.passthrough(Type.VAR_INT); // Frame type
+                    int flags = wrapper.passthrough(Type.INT); // Flags
+                    if ((flags & 1) != 0) {
+                        wrapper.passthrough(Type.STRING); // Background texture
+                    }
+                    wrapper.passthrough(Type.FLOAT); // X
+                    wrapper.passthrough(Type.FLOAT); // Y
+                }
+
+                int requirements = wrapper.passthrough(Type.VAR_INT);
+                for (int array = 0; array < requirements; array++) {
+                    wrapper.passthrough(Type.STRING_ARRAY);
+                }
+
+                wrapper.passthrough(Type.BOOLEAN); // Send telemetry
+            }
+        });
+
         protocol.registerClientbound(ClientboundPackets1_20_3.SPAWN_PARTICLE, wrapper -> {
             final int particleId = wrapper.read(Type.VAR_INT);
 
@@ -167,7 +199,7 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
                 final int blockStateId = wrapper.read(Type.VAR_INT);
                 particle.add(Type.VAR_INT, protocol.getMappingData().getNewBlockStateId(blockStateId));
             } else if (mappings.isItemParticle(particleId)) {
-                final Item item = handleItemToClient(wrapper.read(Type.ITEM1_20_2));
+                final Item item = handleNonNullItemToClient(wrapper.read(Type.ITEM1_20_2));
                 particle.add(Types1_20_5.ITEM, item);
             }
 
@@ -201,21 +233,21 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
             final int size = wrapper.passthrough(Type.VAR_INT);
             for (int i = 0; i < size; i++) {
                 final Item input = handleItemToClient(wrapper.read(Type.ITEM1_20_2));
-                final Item output = handleItemToClient(wrapper.read(Type.ITEM1_20_2));
+                wrapper.write(Types1_20_5.ITEM_COST, input);
-                final Item secondItem = handleItemToClient(wrapper.read(Type.ITEM1_20_2));
-                wrapper.write(Types1_20_5.ITEM, input);
-                wrapper.write(Types1_20_5.ITEM, output);
-                wrapper.write(Types1_20_5.ITEM, secondItem);
 
-                wrapper.passthrough(Type.BOOLEAN); // Trade disabled
+                final Item output = handleNonNullItemToClient(wrapper.read(Type.ITEM1_20_2));
-                wrapper.passthrough(Type.INT); // Number of tools uses
+                wrapper.write(Types1_20_5.ITEM, output);
+
+                final Item secondInput = handleItemToClient(wrapper.read(Type.ITEM1_20_2));
+                wrapper.write(Types1_20_5.OPTIONAL_ITEM_COST, secondInput);
+
+                wrapper.passthrough(Type.BOOLEAN); // Out of stock
+                wrapper.passthrough(Type.INT); // Number of trade uses
                 wrapper.passthrough(Type.INT); // Maximum number of trade uses
                 wrapper.passthrough(Type.INT); // XP
                 wrapper.passthrough(Type.INT); // Special price
                 wrapper.passthrough(Type.FLOAT); // Price multiplier
                 wrapper.passthrough(Type.INT); // Demand
-
-                wrapper.write(Type.BOOLEAN, false); // Ignore tags
             }
         });
 
@@ -233,6 +265,15 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
         });
     }
 
+    public Item handleNonNullItemToClient(@Nullable Item item) {
+        item = handleItemToClient(item);
+        // Items are no longer nullable in a few places
+        if (item == null || item.isEmpty()) {
+            return new StructuredItem(1, 1);
+        }
+        return item;
+    }
+
     @Override
     public @Nullable Item handleItemToClient(@Nullable final Item item) {
         if (item == null) return null;
@@ -391,9 +432,9 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
 
         updateMobTags(data, tag);
 
-        updateItemList(data, tag, "ChargedProjectiles", StructuredDataKey.CHARGED_PROJECTILES);
+        updateItemList(data, tag, "ChargedProjectiles", StructuredDataKey.CHARGED_PROJECTILES, false);
         if (old.identifier() == 927) {
-            updateItemList(data, tag, "Items", StructuredDataKey.BUNDLE_CONTENTS);
+            updateItemList(data, tag, "Items", StructuredDataKey.BUNDLE_CONTENTS, false);
         }
 
         updateEnchantments(data, tag, "Enchantments", StructuredDataKey.ENCHANTMENTS, (hideFlagsValue & StructuredDataConverter.HIDE_ENCHANTMENTS) == 0);
@@ -884,10 +925,15 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
         data.set(StructuredDataKey.WRITTEN_BOOK_CONTENT, writtenBook);
     }
 
-    private void updateItemList(final StructuredDataContainer data, final CompoundTag tag, final String key, final StructuredDataKey<Item[]> dataKey) {
+    private void updateItemList(final StructuredDataContainer data, final CompoundTag tag, final String key, final StructuredDataKey<Item[]> dataKey, final boolean allowEmpty) {
         final ListTag<CompoundTag> itemsTag = tag.getListTag(key, CompoundTag.class);
         if (itemsTag != null) {
-            final Item[] items = itemsTag.stream().limit(256).map(this::itemFromTag).filter(Objects::nonNull).toArray(Item[]::new);
+            final Item[] items = itemsTag.stream()
+                .limit(256)
+                .map(this::itemFromTag)
+                .filter(Objects::nonNull)
+                .filter(item -> allowEmpty || !item.isEmpty())
+                .toArray(Item[]::new);
             data.set(dataKey, items);
         }
     }
@@ -1111,7 +1157,7 @@ public final class BlockItemPacketRewriter1_20_5 extends ItemRewriter<Clientboun
                 data.set(StructuredDataKey.BASE_COLOR, ((NumberTag) baseColorTag).asInt());
             }
 
-            updateItemList(data, tag, "Items", StructuredDataKey.CONTAINER);
+            updateItemList(data, tag, "Items", StructuredDataKey.CONTAINER, true);
         }
 
         final Tag skullOwnerTag = tag.remove("SkullOwner");

common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20to1_19_4/packets/InventoryPackets.java

@@ -66,10 +66,7 @@ public final class InventoryPackets extends ItemRewriter<ClientboundPackets1_19_
             int size = wrapper.passthrough(Type.VAR_INT); // Mapping size
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                if (wrapper.passthrough(Type.BOOLEAN)) {
-                    wrapper.passthrough(Type.STRING); // Parent
-                }
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {

common/src/main/java/com/viaversion/viaversion/rewriter/ItemRewriter.java

@@ -279,24 +279,32 @@ public class ItemRewriter<C extends ClientboundPacketType, S extends Serverbound
         });
     }
 
-    public void registerTradeList1_20_5(C packetType) {
+    // Hopefully the item cost weirdness is temporary
+    public void registerTradeList1_20_5(
+        final C packetType,
+        final Type<Item> costType, final Type<Item> mappedCostType,
+        final Type<Item> optionalCostType, final Type<Item> mappedOptionalCostType
+    ) {
         protocol.registerClientbound(packetType, wrapper -> {
             wrapper.passthrough(Type.VAR_INT); // Container id
             int size = wrapper.passthrough(Type.VAR_INT);
             for (int i = 0; i < size; i++) {
-                handleClientboundItem(wrapper); // Input
+                final Item input = wrapper.read(costType);
-                handleClientboundItem(wrapper); // Output
+                wrapper.write(mappedCostType, handleItemToClient(input));
-                handleClientboundItem(wrapper); // Second item
 
-                wrapper.passthrough(Type.BOOLEAN); // Trade disabled
+                handleClientboundItem(wrapper); // Result
-                wrapper.passthrough(Type.INT); // Number of tools uses
+
+                final Item secondInput = wrapper.read(optionalCostType);
+                wrapper.write(mappedOptionalCostType, handleItemToClient(secondInput));
+
+                wrapper.passthrough(Type.BOOLEAN); // Out of stock
+                wrapper.passthrough(Type.INT); // Number of trade uses
                 wrapper.passthrough(Type.INT); // Maximum number of trade uses
 
                 wrapper.passthrough(Type.INT); // XP
                 wrapper.passthrough(Type.INT); // Special price
                 wrapper.passthrough(Type.FLOAT); // Price multiplier
                 wrapper.passthrough(Type.INT); // Demand
-                wrapper.passthrough(Type.BOOLEAN); // Ignore tags
             }
         });
     }
@@ -307,10 +315,7 @@ public class ItemRewriter<C extends ClientboundPacketType, S extends Serverbound
             int size = wrapper.passthrough(Type.VAR_INT); // Mapping size
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                // Parent
-                if (wrapper.passthrough(Type.BOOLEAN))
-                    wrapper.passthrough(Type.STRING);
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {
@@ -350,11 +355,7 @@ public class ItemRewriter<C extends ClientboundPacketType, S extends Serverbound
             int size = wrapper.passthrough(Type.VAR_INT); // Mapping size
             for (int i = 0; i < size; i++) {
                 wrapper.passthrough(Type.STRING); // Identifier
-
+                wrapper.passthrough(Type.OPTIONAL_STRING); // Parent
-                // Parent
-                if (wrapper.passthrough(Type.BOOLEAN)) {
-                    wrapper.passthrough(Type.STRING);
-                }
 
                 // Display data
                 if (wrapper.passthrough(Type.BOOLEAN)) {

template/src/main/java/com/viaversion/viaversion/template/protocols/rewriter/BlockItemPacketRewriter1_99.java

@@ -59,7 +59,7 @@ public final class BlockItemPacketRewriter1_99 extends StructuredItemRewriter<Cl
         registerAdvancements1_20_3(ClientboundPackets1_20_5.ADVANCEMENTS);
         registerEntityEquipmentArray(ClientboundPackets1_20_5.ENTITY_EQUIPMENT);
         registerClickWindow1_17_1(ServerboundPackets1_20_5.CLICK_WINDOW);
-        registerTradeList1_20_5(ClientboundPackets1_20_5.TRADE_LIST);
+        registerTradeList1_20_5(ClientboundPackets1_20_5.TRADE_LIST, Types1_20_5.ITEM_COST, Types1_20_5.ITEM_COST, Types1_20_5.OPTIONAL_ITEM_COST, Types1_20_5.OPTIONAL_ITEM_COST);
         registerCreativeInvAction(ServerboundPackets1_20_5.CREATIVE_INVENTORY_ACTION);
         registerWindowPropertyEnchantmentHandler(ClientboundPackets1_20_5.WINDOW_PROPERTY);
         registerSpawnParticle1_20_5(ClientboundPackets1_20_5.SPAWN_PARTICLE, Types1_20_5.PARTICLE, Types1_20_5.PARTICLE);