Start working on 23w31a

build.gradle.kts

@@ -5,7 +5,7 @@ plugins {
 
 allprojects {
     group = "com.viaversion"
-    version = "4.7.1-SNAPSHOT"
+    version = "4.8.0-23w31a-SNAPSHOT"
     description = "Allow older clients to join newer server versions."
 }
 

common/src/main/java/com/viaversion/viabackwards/api/ViaBackwardsPlatform.java

@@ -51,6 +51,7 @@ import com.viaversion.viabackwards.protocol.protocol1_19_1to1_19_3.Protocol1_19_
 import com.viaversion.viabackwards.protocol.protocol1_19_3to1_19_4.Protocol1_19_3To1_19_4;
 import com.viaversion.viabackwards.protocol.protocol1_19_4to1_20.Protocol1_19_4To1_20;
 import com.viaversion.viabackwards.protocol.protocol1_19to1_19_1.Protocol1_19To1_19_1;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.Protocol1_20To1_20_2;
 import com.viaversion.viabackwards.protocol.protocol1_9_4to1_10.Protocol1_9_4To1_10;
 import com.viaversion.viaversion.api.Via;
 import com.viaversion.viaversion.api.protocol.ProtocolManager;
@@ -61,7 +62,7 @@ import java.util.logging.Logger;
 
 public interface ViaBackwardsPlatform {
 
-    String MINIMUM_VV_VERSION = "4.7.0";
+    String MINIMUM_VV_VERSION = "4.8.0";
     String IMPL_VERSION = "$IMPL_VERSION";
 
     /**
@@ -126,6 +127,7 @@ public interface ViaBackwardsPlatform {
         protocolManager.registerProtocol(new Protocol1_19_3To1_19_4(), ProtocolVersion.v1_19_3, ProtocolVersion.v1_19_4);
 
         protocolManager.registerProtocol(new Protocol1_19_4To1_20(), ProtocolVersion.v1_19_4, ProtocolVersion.v1_20);
+        protocolManager.registerProtocol(new Protocol1_20To1_20_2(), ProtocolVersion.v1_20, ProtocolVersion.v1_20_2);
     }
 
     /**

common/src/main/java/com/viaversion/viabackwards/api/rewriters/ItemRewriter.java

@@ -40,6 +40,10 @@ public class ItemRewriter<C extends ClientboundPacketType, S extends Serverbound
         super(protocol, true);
     }
 
+    public ItemRewriter(T protocol, Type<Item> itemType, Type<Item[]> itemArrayType) {
+        super(protocol, itemType, itemArrayType, true);
+    }
+
     @Override
     public @Nullable Item handleItemToClient(@Nullable Item item) {
         if (item == null) {

common/src/main/java/com/viaversion/viabackwards/api/rewriters/ItemRewriterBase.java

@@ -21,6 +21,7 @@ import com.viaversion.viabackwards.api.BackwardsProtocol;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.protocol.packet.ClientboundPacketType;
 import com.viaversion.viaversion.api.protocol.packet.ServerboundPacketType;
+import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.CompoundTag;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.ListTag;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.StringTag;
@@ -35,7 +36,11 @@ public abstract class ItemRewriterBase<C extends ClientboundPacketType, S extend
     protected final boolean jsonNameFormat;
 
     protected ItemRewriterBase(T protocol, boolean jsonNameFormat) {
-        super(protocol);
+        this(protocol, Type.FLAT_VAR_INT_ITEM, Type.FLAT_VAR_INT_ITEM_ARRAY_VAR_INT, jsonNameFormat);
+    }
+
+    public ItemRewriterBase(T protocol, Type<Item> itemType, Type<Item[]> itemArrayType, boolean jsonNameFormat) {
+        super(protocol, itemType, itemArrayType);
         this.jsonNameFormat = jsonNameFormat;
         nbtTagName = "VB|" + protocol.getClass().getSimpleName();
     }

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_12_2to1_13/packets/BlockItemPackets1_13.java

@@ -240,7 +240,7 @@ public class BlockItemPackets1_13 extends com.viaversion.viabackwards.api.rewrit
                 map(Type.UNSIGNED_BYTE);
                 map(Type.FLAT_ITEM_ARRAY, Type.ITEM_ARRAY);
 
-                handler(itemArrayHandler(Type.ITEM_ARRAY));
+                handler(itemArrayToClientHandler(Type.ITEM_ARRAY));
             }
         });
 

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_16_4to1_17/packets/BlockItemPackets1_17.java

@@ -203,7 +203,7 @@ public final class BlockItemPackets1_17 extends ItemRewriter<ClientboundPackets1
                         wrapper.cancel();
                     }
                 });
-                handler(getSpawnParticleHandler(Type.FLAT_VAR_INT_ITEM));
+                handler(getSpawnParticleHandler());
             }
         });
 

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_18_2to1_19/packets/BlockItemPackets1_19.java

@@ -134,7 +134,7 @@ public final class BlockItemPackets1_19 extends ItemRewriter<ClientboundPackets1
                         wrapper.cancel();
                     }
                 });
-                handler(getSpawnParticleHandler(Type.FLAT_VAR_INT_ITEM));
+                handler(getSpawnParticleHandler());
             }
         });
 

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_4to1_20_2/Protocol1_20To1_20_2.java

@@ -0,0 +1,162 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2023 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2;
+
+import com.viaversion.viabackwards.api.BackwardsProtocol;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.rewriter.BlockItemPacketRewriter1_20_2;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.rewriter.EntityPacketRewriter1_20_2;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.storage.ConfigurationPacketStorage;
+import com.viaversion.viaversion.api.Via;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_19_4Types;
+import com.viaversion.viaversion.api.protocol.packet.Direction;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.protocol.packet.State;
+import com.viaversion.viaversion.api.rewriter.EntityRewriter;
+import com.viaversion.viaversion.api.rewriter.ItemRewriter;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.data.entity.EntityTrackerBase;
+import com.viaversion.viaversion.exception.CancelException;
+import com.viaversion.viaversion.libs.opennbt.tag.builtin.CompoundTag;
+import com.viaversion.viaversion.protocols.base.ClientboundLoginPackets;
+import com.viaversion.viaversion.protocols.base.ServerboundLoginPackets;
+import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ClientboundPackets1_19_4;
+import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ServerboundPackets1_19_4;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ClientboundConfigurationPackets1_20_2;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ClientboundPackets1_20_2;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ServerboundConfigurationPackets1_20_2;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ServerboundPackets1_20_2;
+import java.util.UUID;
+
+public final class Protocol1_20To1_20_2 extends BackwardsProtocol<ClientboundPackets1_20_2, ClientboundPackets1_19_4, ServerboundPackets1_20_2, ServerboundPackets1_19_4> {
+
+    private final EntityPacketRewriter1_20_2 entityPacketRewriter = new EntityPacketRewriter1_20_2(this);
+    private final BlockItemPacketRewriter1_20_2 itemPacketRewriter = new BlockItemPacketRewriter1_20_2(this);
+
+    public Protocol1_20To1_20_2() {
+        super(ClientboundPackets1_20_2.class, ClientboundPackets1_19_4.class, ServerboundPackets1_20_2.class, ServerboundPackets1_19_4.class);
+    }
+
+    @Override
+    protected void registerPackets() {
+        super.registerPackets();
+        Via.getManager().debugHandler().setEnabled(true);
+
+        registerClientbound(ClientboundPackets1_20_2.SCOREBOARD_OBJECTIVE, wrapper -> {
+            final int slot = wrapper.read(Type.VAR_INT);
+            wrapper.write(Type.BYTE, (byte) slot);
+        });
+
+        registerClientbound(State.LOGIN, ClientboundLoginPackets.GAME_PROFILE.getId(), ClientboundLoginPackets.GAME_PROFILE.getId(), wrapper -> {
+            final ServerboundLoginPackets ackPacket = ServerboundLoginPackets.LOGIN_ACKNOWLEDGED;
+            wrapper.create(ackPacket).sendToServer(Protocol1_20To1_20_2.class);
+
+            // We can't set the internal state to configuration here as protocols down the line will expect the state to be play
+            wrapper.user().put(new ConfigurationPacketStorage());
+            System.out.println(wrapper.user().getProtocolInfo().getState());
+        });
+
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.FINISH_CONFIGURATION.getId(), ClientboundConfigurationPackets1_20_2.FINISH_CONFIGURATION.getId(), wrapper -> {
+            wrapper.cancel();
+            wrapper.create(ServerboundConfigurationPackets1_20_2.FINISH_CONFIGURATION).sendToServer(Protocol1_20To1_20_2.class);
+            wrapper.user().getProtocolInfo().setState(State.PLAY);
+        });
+
+        registerServerbound(State.LOGIN, ServerboundLoginPackets.HELLO.getId(), ServerboundLoginPackets.HELLO.getId(), wrapper -> {
+            wrapper.passthrough(Type.STRING); // Name
+
+            // TODO Bad
+            final UUID uuid = wrapper.read(Type.OPTIONAL_UUID);
+            wrapper.write(Type.UUID, uuid != null ? uuid : new UUID(0, 0));
+        });
+
+        cancelClientbound(ClientboundPackets1_20_2.START_CONFIGURATION); // TODO
+
+        // Some can be directly remapped to play packets, others need to be queued
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.DISCONNECT.getId(), ClientboundPackets1_19_4.DISCONNECT.getId());
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.KEEP_ALIVE.getId(), ClientboundPackets1_19_4.KEEP_ALIVE.getId());
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.RESOURCE_PACK.getId(), ClientboundPackets1_19_4.RESOURCE_PACK.getId());
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.REGISTRY_DATA.getId(), -1, wrapper -> {
+            wrapper.cancel();
+
+            final CompoundTag registry = wrapper.read(Type.NAMELESS_NBT);
+            entityPacketRewriter.trackBiomeSize(wrapper.user(), registry);
+            entityPacketRewriter.cacheDimensionData(wrapper.user(), registry);
+            wrapper.user().get(ConfigurationPacketStorage.class).setRegistry(registry);
+        });
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.UPDATE_ENABLED_FEATURES.getId(), -1, wrapper -> {
+            wrapper.cancel();
+
+            final String[] enabledFeatures = wrapper.read(Type.STRING_ARRAY);
+            wrapper.user().get(ConfigurationPacketStorage.class).setEnabledFeatures(enabledFeatures);
+        });
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.UPDATE_TAGS.getId(), -1, wrapper -> {
+            wrapper.cancel();
+            wrapper.user().get(ConfigurationPacketStorage.class).addRawPacket(wrapper, ClientboundPackets1_19_4.TAGS);
+        });
+        registerClientbound(State.CONFIGURATION, ClientboundConfigurationPackets1_20_2.CUSTOM_PAYLOAD.getId(), -1, wrapper -> {
+            wrapper.cancel();
+            wrapper.user().get(ConfigurationPacketStorage.class).addRawPacket(wrapper, ClientboundPackets1_19_4.PLUGIN_MESSAGE);
+        });
+    }
+
+    @Override
+    public void transform(final Direction direction, final State state, final PacketWrapper wrapper) throws Exception {
+        final ConfigurationPacketStorage configurationPacketStorage = wrapper.user().get(ConfigurationPacketStorage.class);
+        if (configurationPacketStorage == null) {
+            super.transform(direction, state, wrapper);
+            return;
+        }
+        if (direction == Direction.CLIENTBOUND) {
+            super.transform(direction, State.CONFIGURATION, wrapper);
+            return;
+        }
+
+        // Map some of the packets to their configuration counterparts
+        final int id = wrapper.getId();
+        if (id == ServerboundPackets1_19_4.PLUGIN_MESSAGE.getId()) {
+            wrapper.setPacketType(ServerboundConfigurationPackets1_20_2.CUSTOM_PAYLOAD);
+        } else if (id == ServerboundPackets1_19_4.KEEP_ALIVE.getId()) {
+            wrapper.setPacketType(ServerboundConfigurationPackets1_20_2.KEEP_ALIVE);
+        } else if (id == ServerboundPackets1_19_4.PONG.getId()) {
+            wrapper.setPacketType(ServerboundConfigurationPackets1_20_2.PONG);
+        } else if (id == ServerboundPackets1_19_4.RESOURCE_PACK_STATUS.getId()) {
+            wrapper.setPacketType(ServerboundConfigurationPackets1_20_2.RESOURCE_PACK);
+        } else {
+            // Can't do
+            // TODO Queue
+            System.out.println("Cancelling: " + state + " - " + wrapper.getPacketType() + " " + wrapper.getId());
+            throw CancelException.generate();
+        }
+    }
+
+    @Override
+    public void init(final UserConnection connection) {
+        addEntityTracker(connection, new EntityTrackerBase(connection, Entity1_19_4Types.PLAYER));
+    }
+
+    @Override
+    public EntityRewriter<Protocol1_20To1_20_2> getEntityRewriter() {
+        return entityPacketRewriter;
+    }
+
+    @Override
+    public ItemRewriter<Protocol1_20To1_20_2> getItemRewriter() {
+        return itemPacketRewriter;
+    }
+}

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_4to1_20_2/rewriter/BlockItemPacketRewriter1_20_2.java

@@ -0,0 +1,300 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2023 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.rewriter;
+
+import com.viaversion.viabackwards.api.rewriters.ItemRewriter;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.Protocol1_20To1_20_2;
+import com.viaversion.viaversion.api.data.ParticleMappings;
+import com.viaversion.viaversion.api.data.entity.EntityTracker;
+import com.viaversion.viaversion.api.minecraft.chunks.Chunk;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.minecraft.metadata.ChunkPosition;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.protocols.protocol1_18to1_17_1.types.Chunk1_18Type;
+import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ServerboundPackets1_19_4;
+import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.rewriter.RecipeRewriter1_19_4;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ClientboundPackets1_20_2;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.type.ChunkType1_20_2;
+import com.viaversion.viaversion.protocols.protocol1_20to1_19_4.Protocol1_20To1_19_4;
+import com.viaversion.viaversion.util.MathUtil;
+
+public final class BlockItemPacketRewriter1_20_2 extends ItemRewriter<ClientboundPackets1_20_2, ServerboundPackets1_19_4, Protocol1_20To1_20_2> {
+
+    public BlockItemPacketRewriter1_20_2(final Protocol1_20To1_20_2 protocol) {
+        super(protocol, Type.ITEM1_20_2, Type.ITEM1_20_2_VAR_INT_ARRAY);
+    }
+
+    @Override
+    public void registerPackets() {
+        protocol.cancelClientbound(ClientboundPackets1_20_2.CHUNK_BATCH_START);
+        protocol.cancelClientbound(ClientboundPackets1_20_2.CHUNK_BATCH_FINISHED);
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.UNLOAD_CHUNK, wrapper -> {
+            final ChunkPosition chunkPosition = wrapper.read(Type.CHUNK_POSITION);
+            wrapper.write(Type.INT, chunkPosition.chunkX());
+            wrapper.write(Type.INT, chunkPosition.chunkZ());
+        });
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.NBT_QUERY, wrapper -> {
+            wrapper.passthrough(Type.VAR_INT); // Transaction id
+            wrapper.write(Type.NBT, wrapper.read(Type.NAMELESS_NBT));
+        });
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.BLOCK_ENTITY_DATA, wrapper -> {
+            wrapper.passthrough(Type.POSITION1_14); // Position
+            wrapper.passthrough(Type.VAR_INT); // Type
+            wrapper.write(Type.NBT, wrapper.read(Type.NAMELESS_NBT));
+        });
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.CHUNK_DATA, wrapper -> {
+            final EntityTracker tracker = protocol.getEntityRewriter().tracker(wrapper.user());
+            final Type<Chunk> chunkType = new ChunkType1_20_2(tracker.currentWorldSectionHeight(),
+                    MathUtil.ceilLog2(Protocol1_20To1_19_4.MAPPINGS.getBlockStateMappings().mappedSize()),
+                    MathUtil.ceilLog2(tracker.biomesSent()));
+            final Chunk chunk = wrapper.read(chunkType);
+
+            final Type<Chunk> newChunkType = new Chunk1_18Type(tracker.currentWorldSectionHeight(),
+                    MathUtil.ceilLog2(Protocol1_20To1_19_4.MAPPINGS.getBlockStateMappings().mappedSize()),
+                    MathUtil.ceilLog2(tracker.biomesSent()));
+            wrapper.write(newChunkType, chunk);
+        });
+
+        // Replace the NBT type everywhere
+        protocol.registerClientbound(ClientboundPackets1_20_2.WINDOW_ITEMS, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Type.UNSIGNED_BYTE); // Window id
+                map(Type.VAR_INT); // State id
+                handler(wrapper -> {
+                    wrapper.write(Type.FLAT_VAR_INT_ITEM_ARRAY_VAR_INT, wrapper.read(Type.ITEM1_20_2_VAR_INT_ARRAY)); // Items
+                    wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2)); // Carried item
+                });
+            }
+        });
+        protocol.registerClientbound(ClientboundPackets1_20_2.SET_SLOT, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Type.UNSIGNED_BYTE); // Window id
+                map(Type.VAR_INT); // State id
+                map(Type.SHORT); // Slot id
+                map(Type.ITEM1_20_2, Type.FLAT_VAR_INT_ITEM); // Item
+            }
+        });
+        protocol.registerClientbound(ClientboundPackets1_20_2.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
+
+                // Parent
+                if (wrapper.passthrough(Type.BOOLEAN))
+                    wrapper.passthrough(Type.STRING);
+
+                // Display data
+                if (wrapper.passthrough(Type.BOOLEAN)) {
+                    wrapper.passthrough(Type.COMPONENT); // Title
+                    wrapper.passthrough(Type.COMPONENT); // Description
+                    wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2)); // Icon
+                    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
+                }
+
+                wrapper.passthrough(Type.STRING_ARRAY); // Criteria
+
+                int arrayLength = wrapper.passthrough(Type.VAR_INT);
+                for (int array = 0; array < arrayLength; array++) {
+                    wrapper.passthrough(Type.STRING_ARRAY); // String array
+                }
+
+                wrapper.passthrough(Type.BOOLEAN); // Send telemetry
+            }
+        });
+        protocol.registerClientbound(ClientboundPackets1_20_2.ENTITY_EQUIPMENT, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Type.VAR_INT); // 0 - Entity ID
+                handler(wrapper -> {
+                    byte slot;
+                    do {
+                        slot = wrapper.passthrough(Type.BYTE);
+                        wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2));
+                    } while ((slot & 0xFFFFFF80) != 0);
+                });
+            }
+        });
+        protocol.registerServerbound(ServerboundPackets1_19_4.CLICK_WINDOW, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Type.UNSIGNED_BYTE); // Window Id
+                map(Type.VAR_INT); // State id
+                map(Type.SHORT); // Slot
+                map(Type.BYTE); // Button
+                map(Type.VAR_INT); // Mode
+
+                handler(wrapper -> {
+                    // Affected items
+                    int length = wrapper.passthrough(Type.VAR_INT);
+                    for (int i = 0; i < length; i++) {
+                        wrapper.passthrough(Type.SHORT); // Slot
+                        wrapper.write(Type.ITEM1_20_2, wrapper.read(Type.FLAT_VAR_INT_ITEM));
+                    }
+
+                    // Carried item
+                    wrapper.write(Type.ITEM1_20_2, wrapper.read(Type.FLAT_VAR_INT_ITEM));
+                });
+            }
+        });
+        protocol.registerClientbound(ClientboundPackets1_20_2.TRADE_LIST, wrapper -> {
+            wrapper.cancel();
+            wrapper.passthrough(Type.VAR_INT); // Container id
+            int size = wrapper.passthrough(Type.VAR_INT);
+            for (int i = 0; i < size; i++) {
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2)); // Input
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2)); // Output
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2)); // Second Item
+
+                wrapper.passthrough(Type.BOOLEAN); // Trade disabled
+                wrapper.passthrough(Type.INT); // Number of tools 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
+            }
+        });
+        protocol.registerServerbound(ServerboundPackets1_19_4.CREATIVE_INVENTORY_ACTION, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Type.SHORT); // 0 - Slot
+                map(Type.FLAT_VAR_INT_ITEM, Type.ITEM1_20_2); // 1 - Clicked Item
+            }
+        });
+        protocol.registerClientbound(ClientboundPackets1_20_2.SPAWN_PARTICLE, new PacketHandlers() {
+            @Override
+            public void register() {
+                map(Type.VAR_INT); // 0 - Particle ID
+                map(Type.BOOLEAN); // 1 - Long Distance
+                map(Type.DOUBLE); // 2 - X
+                map(Type.DOUBLE); // 3 - Y
+                map(Type.DOUBLE); // 4 - Z
+                map(Type.FLOAT); // 5 - Offset X
+                map(Type.FLOAT); // 6 - Offset Y
+                map(Type.FLOAT); // 7 - Offset Z
+                map(Type.FLOAT); // 8 - Particle Data
+                map(Type.INT); // 9 - Particle Count
+                handler(wrapper -> {
+                    int id = wrapper.get(Type.VAR_INT, 0);
+                    ParticleMappings mappings = Protocol1_20To1_19_4.MAPPINGS.getParticleMappings();
+                    if (mappings.isItemParticle(id)) {
+                        wrapper.write(Type.FLAT_VAR_INT_ITEM, wrapper.read(Type.ITEM1_20_2));
+                    }
+                });
+            }
+        });
+
+        new RecipeRewriter1_19_4<ClientboundPackets1_20_2>(protocol) {
+            @Override
+            public void handleCraftingShapeless(final PacketWrapper wrapper) throws Exception {
+                wrapper.passthrough(Type.STRING); // Group
+                wrapper.passthrough(Type.VAR_INT); // Crafting book category
+                handleIngredients(wrapper);
+
+                final Item result = wrapper.read(itemType());
+                rewrite(result);
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, result);
+            }
+
+            @Override
+            public void handleSmelting(final PacketWrapper wrapper) throws Exception {
+                wrapper.passthrough(Type.STRING); // Group
+                wrapper.passthrough(Type.VAR_INT); // Crafting book category
+                handleIngredient(wrapper);
+
+                final Item result = wrapper.read(itemType());
+                rewrite(result);
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, result);
+
+                wrapper.passthrough(Type.FLOAT); // EXP
+                wrapper.passthrough(Type.VAR_INT); // Cooking time
+            }
+
+            @Override
+            public void handleCraftingShaped(final PacketWrapper wrapper) throws Exception {
+                final int ingredients = wrapper.passthrough(Type.VAR_INT) * wrapper.passthrough(Type.VAR_INT);
+                wrapper.passthrough(Type.STRING); // Group
+                wrapper.passthrough(Type.VAR_INT); // Crafting book category
+                for (int i = 0; i < ingredients; i++) {
+                    handleIngredient(wrapper);
+                }
+
+                final Item result = wrapper.read(itemType());
+                rewrite(result);
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, result);
+
+                wrapper.passthrough(Type.BOOLEAN); // Show notification
+            }
+
+            @Override
+            public void handleStonecutting(final PacketWrapper wrapper) throws Exception {
+                wrapper.passthrough(Type.STRING); // Group
+                handleIngredient(wrapper);
+
+                final Item result = wrapper.read(itemType());
+                rewrite(result);
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, result);
+            }
+
+            @Override
+            public void handleSmithing(final PacketWrapper wrapper) throws Exception {
+                handleIngredient(wrapper); // Base
+                handleIngredient(wrapper); // Addition
+
+                final Item result = wrapper.read(itemType());
+                rewrite(result);
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, result);
+            }
+
+            @Override
+            public void handleSmithingTransform(final PacketWrapper wrapper) throws Exception {
+                handleIngredient(wrapper); // Template
+                handleIngredient(wrapper); // Base
+                handleIngredient(wrapper); // Additions
+
+                final Item result = wrapper.read(itemType());
+                rewrite(result);
+                wrapper.write(Type.FLAT_VAR_INT_ITEM, result);
+            }
+
+            @Override
+            protected void handleIngredient(final PacketWrapper wrapper) throws Exception {
+                final Item[] items = wrapper.read(itemArrayType());
+                wrapper.write(Type.FLAT_VAR_INT_ITEM_ARRAY_VAR_INT, items);
+                for (final Item item : items) {
+                    rewrite(item);
+                }
+            }
+        }.register(ClientboundPackets1_20_2.DECLARE_RECIPES);
+    }
+}

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_4to1_20_2/rewriter/EntityPacketRewriter1_20_2.java

@@ -0,0 +1,137 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2023 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.rewriter;
+
+import com.viaversion.viabackwards.api.rewriters.EntityRewriter;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.Protocol1_20To1_20_2;
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.storage.ConfigurationPacketStorage;
+import com.viaversion.viaversion.api.minecraft.GlobalPosition;
+import com.viaversion.viaversion.api.minecraft.entities.Entity1_19_4Types;
+import com.viaversion.viaversion.api.minecraft.entities.EntityType;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.protocol.remapper.PacketHandlers;
+import com.viaversion.viaversion.api.type.Type;
+import com.viaversion.viaversion.api.type.types.version.Types1_20;
+import com.viaversion.viaversion.api.type.types.version.Types1_20_2;
+import com.viaversion.viaversion.protocols.protocol1_19_4to1_19_3.ClientboundPackets1_19_4;
+import com.viaversion.viaversion.protocols.protocol1_20_2to1_20.packet.ClientboundPackets1_20_2;
+
+public final class EntityPacketRewriter1_20_2 extends EntityRewriter<ClientboundPackets1_20_2, Protocol1_20To1_20_2> {
+
+    public EntityPacketRewriter1_20_2(final Protocol1_20To1_20_2 protocol) {
+        super(protocol);
+    }
+
+    @Override
+    public void registerPackets() {
+        registerTrackerWithData1_19(ClientboundPackets1_20_2.SPAWN_ENTITY, Entity1_19_4Types.FALLING_BLOCK);
+        registerMetadataRewriter(ClientboundPackets1_20_2.ENTITY_METADATA, Types1_20_2.METADATA_LIST, Types1_20.METADATA_LIST);
+        registerRemoveEntities(ClientboundPackets1_20_2.REMOVE_ENTITIES);
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.JOIN_GAME, new PacketHandlers() {
+            @Override
+            public void register() {
+                handler(wrapper -> {
+                    final ConfigurationPacketStorage configurationPacketStorage = wrapper.user().get(ConfigurationPacketStorage.class);
+                    wrapper.passthrough(Type.INT); // Entity id
+                    wrapper.passthrough(Type.BOOLEAN); // Hardcore
+
+                    final String[] worlds = wrapper.read(Type.STRING_ARRAY);
+                    final int maxPlayers = wrapper.read(Type.VAR_INT);
+                    final int viewDistance = wrapper.read(Type.VAR_INT);
+                    final int simulationDistance = wrapper.read(Type.VAR_INT);
+                    final boolean reducedDebugInfo = wrapper.read(Type.BOOLEAN);
+                    final boolean showRespawnScreen = wrapper.read(Type.BOOLEAN);
+                    final String dimensionType = wrapper.read(Type.STRING);
+                    final String world = wrapper.read(Type.STRING);
+                    final long seed = wrapper.read(Type.LONG);
+
+                    wrapper.write(Type.UNSIGNED_BYTE, wrapper.read(Type.BYTE).shortValue()); // Gamemode
+                    wrapper.passthrough(Type.BYTE); // Previous gamemode
+
+                    wrapper.write(Type.STRING_ARRAY, worlds);
+                    wrapper.write(Type.NBT, configurationPacketStorage.registry());
+                    wrapper.write(Type.STRING, dimensionType);
+                    wrapper.write(Type.STRING, world);
+                    wrapper.write(Type.LONG, seed);
+                    wrapper.write(Type.VAR_INT, maxPlayers);
+                    wrapper.write(Type.VAR_INT, viewDistance);
+                    wrapper.write(Type.VAR_INT, simulationDistance);
+                    wrapper.write(Type.BOOLEAN, reducedDebugInfo);
+                    wrapper.write(Type.BOOLEAN, showRespawnScreen);
+
+                    wrapper.cancel();
+                    wrapper.send(Protocol1_20To1_20_2.class);
+
+                    final PacketWrapper featuresPacket = wrapper.create(ClientboundPackets1_19_4.UPDATE_ENABLED_FEATURES);
+                    featuresPacket.write(Type.STRING_ARRAY, configurationPacketStorage.enabledFeatures());
+                    featuresPacket.send(Protocol1_20To1_20_2.class);
+
+                    configurationPacketStorage.sendQueuedPackets(wrapper.user());
+                });
+                handler(worldDataTrackerHandlerByKey());
+            }
+        });
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.RESPAWN, new PacketHandlers() {
+            @Override
+            public void register() {
+                handler(wrapper -> {
+                    wrapper.passthrough(Type.STRING); // Dimension type
+                    wrapper.passthrough(Type.STRING); // World
+                    wrapper.passthrough(Type.LONG); // Seed
+                    wrapper.write(Type.UNSIGNED_BYTE, wrapper.read(Type.BYTE).shortValue()); // Gamemode
+                    wrapper.passthrough(Type.BYTE); // Previous gamemode
+                    wrapper.passthrough(Type.BOOLEAN); // Debug
+                    wrapper.passthrough(Type.BOOLEAN); // Flat
+
+                    final GlobalPosition lastDeathPosition = wrapper.read(Type.OPTIONAL_GLOBAL_POSITION);
+                    final int portalCooldown = wrapper.read(Type.VAR_INT);
+
+                    wrapper.passthrough(Type.BYTE); // Data to keep
+
+                    wrapper.write(Type.OPTIONAL_GLOBAL_POSITION, lastDeathPosition);
+                    wrapper.write(Type.VAR_INT, portalCooldown);
+                });
+                handler(worldDataTrackerHandlerByKey()); // Tracks world height and name for chunk data and entity (un)tracking
+            }
+        });
+
+        protocol.registerClientbound(ClientboundPackets1_20_2.ENTITY_EFFECT, wrapper -> {
+            wrapper.passthrough(Type.VAR_INT); // Entity id
+            wrapper.passthrough(Type.VAR_INT); // Effect id
+            wrapper.passthrough(Type.BYTE); // Amplifier
+            wrapper.passthrough(Type.VAR_INT); // Duration
+            wrapper.passthrough(Type.BYTE); // Flags
+            if (wrapper.passthrough(Type.BOOLEAN)) {
+                wrapper.write(Type.NBT, wrapper.read(Type.NAMELESS_NBT)); // Factor data
+            }
+        });
+    }
+
+    @Override
+    protected void registerRewrites() {
+        filter().handler((event, meta) -> meta.setMetaType(Types1_20.META_TYPES.byId(meta.metaType().typeId())));
+        filter().filterFamily(Entity1_19_4Types.DISPLAY).removeIndex(10);
+    }
+
+    @Override
+    public EntityType typeFromId(final int type) {
+        return Entity1_19_4Types.getTypeFromId(type);
+    }
+}

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_20_4to1_20_2/storage/ConfigurationPacketStorage.java

@@ -0,0 +1,95 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2023 ViaVersion and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.storage;
+
+import com.viaversion.viabackwards.protocol.protocol1_20_4to1_20_2.Protocol1_20To1_20_2;
+import com.viaversion.viaversion.api.connection.StorableObject;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.protocol.packet.PacketType;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.libs.opennbt.tag.builtin.CompoundTag;
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import java.util.ArrayList;
+import java.util.List;
+
+public final class ConfigurationPacketStorage implements StorableObject {
+
+    private final List<QueuedPacket> rawPackets = new ArrayList<>();
+    private CompoundTag registry;
+    private String[] enabledFeatures;
+
+    public CompoundTag registry() {
+        return registry;
+    }
+
+    public void setRegistry(final CompoundTag registry) {
+        this.registry = registry;
+    }
+
+    public String[] enabledFeatures() {
+        return enabledFeatures;
+    }
+
+    public void setEnabledFeatures(final String[] enabledFeatures) {
+        this.enabledFeatures = enabledFeatures;
+    }
+
+    public List<QueuedPacket> getRawPackets() {
+        return rawPackets;
+    }
+
+    public void addRawPacket(final PacketWrapper wrapper, final PacketType type) throws Exception {
+        // It's easier to just copy it to a byte array buffer than to manually read the data
+        final ByteBuf buf = Unpooled.buffer();
+        final int id = wrapper.getId();
+        //noinspection deprecation
+        wrapper.setId(-1); // Don't write the packet id to the buffer
+        wrapper.writeToBuffer(buf);
+        rawPackets.add(new QueuedPacket(buf, type));
+    }
+
+    public void sendQueuedPackets(final UserConnection connection) throws Exception {
+        for (final QueuedPacket queuedPacket : rawPackets) {
+            try {
+                final PacketWrapper packet = PacketWrapper.create(queuedPacket.packetType(), queuedPacket.buf(), connection);
+                packet.send(Protocol1_20To1_20_2.class);
+            } finally {
+                queuedPacket.buf().release();
+            }
+        }
+    }
+
+    public static final class QueuedPacket {
+        private final ByteBuf buf;
+        private final PacketType packetType;
+
+        public QueuedPacket(final ByteBuf buf, final PacketType packetType) {
+            this.buf = buf;
+            this.packetType = packetType;
+        }
+
+        public ByteBuf buf() {
+            return buf;
+        }
+
+        public PacketType packetType() {
+            return packetType;
+        }
+    }
+}

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ metadata.format.version = "1.1"
 [versions]
 
 # ViaVersion
-viaver = "4.7.1-SNAPSHOT"
+viaver = "4.8.0-23w31a-SNAPSHOT"
 
 # Common provided
 netty = "4.0.20.Final"