4.0.1 Release

Fixes #381 (dirty hotfix)

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,5 +1,6 @@
 name: Bug Report
 description: Report a bug or console error
+labels: [unconfirmed]
 
 body:
   - type: markdown

build.gradle.kts

@@ -5,7 +5,7 @@ plugins {
 
 allprojects {
     group = "com.viaversion"
-    version = "4.0.0"
+    version = "4.0.1"
     description = "Allow older clients to join newer server versions."
 }
 

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

@@ -43,6 +43,7 @@ import com.viaversion.viabackwards.protocol.protocol1_16_2to1_16_3.Protocol1_16_
 import com.viaversion.viabackwards.protocol.protocol1_16_3to1_16_4.Protocol1_16_3To1_16_4;
 import com.viaversion.viabackwards.protocol.protocol1_16_4to1_17.Protocol1_16_4To1_17;
 import com.viaversion.viabackwards.protocol.protocol1_16to1_16_1.Protocol1_16To1_16_1;
+import com.viaversion.viabackwards.protocol.protocol1_17to1_17_1.Protocol1_17To1_17_1;
 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;
@@ -54,7 +55,7 @@ import java.util.logging.Logger;
 
 public interface ViaBackwardsPlatform {
 
-    String MINIMUM_VV_VERSION = "4.0.0";
+    String MINIMUM_VV_VERSION = "4.0.1";
     String IMPL_VERSION = "$IMPL_VERSION";
 
     /**
@@ -104,6 +105,7 @@ public interface ViaBackwardsPlatform {
         protocolManager.registerProtocol(new Protocol1_16_3To1_16_4(), ProtocolVersion.v1_16_3, ProtocolVersion.v1_16_4);
 
         protocolManager.registerProtocol(new Protocol1_16_4To1_17(), ProtocolVersion.v1_16_4, ProtocolVersion.v1_17);
+        protocolManager.registerProtocol(new Protocol1_17To1_17_1(), ProtocolVersion.v1_17, ProtocolVersion.v1_17_1);
     }
 
     /**

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

@@ -174,6 +174,8 @@ public abstract class LegacyBlockItemRewriter<T extends BackwardsProtocol> exten
             tags.put(pos, tag);
 
             // Handle given Block Entities
+            if (pos.getY() < 0 || pos.getY() > 255) continue; // 1.17
+
             ChunkSection section = chunk.getSections()[pos.getY() >> 4];
             if (section == null) continue;
 

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_10to1_11/packets/BlockItemPackets1_11.java

@@ -62,7 +62,7 @@ public class BlockItemPackets1_11 extends LegacyBlockItemRewriter<Protocol1_10To
         protocol.registerClientbound(ClientboundPackets1_9_3.SET_SLOT, new PacketRemapper() {
             @Override
             public void registerMap() {
-                map(Type.BYTE); // 0 - Window ID
+                map(Type.UNSIGNED_BYTE); // 0 - Window ID
                 map(Type.SHORT); // 1 - Slot ID
                 map(Type.ITEM); // 2 - Slot Value
 

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

@@ -271,7 +271,7 @@ public class BlockItemPackets1_13 extends com.viaversion.viabackwards.api.rewrit
         protocol.registerClientbound(ClientboundPackets1_13.SET_SLOT, new PacketRemapper() {
             @Override
             public void registerMap() {
-                map(Type.BYTE);
+                map(Type.UNSIGNED_BYTE);
                 map(Type.SHORT);
                 map(Type.FLAT_ITEM, Type.ITEM);
 
@@ -302,6 +302,11 @@ public class BlockItemPackets1_13 extends com.viaversion.viabackwards.api.rewrit
                         if (!provider.isHandled(id)) continue;
 
                         int sectionIndex = ((NumberTag) tag.get("y")).asInt() >> 4;
+                        if (sectionIndex < 0 || sectionIndex > 15) {
+                            // 1.17 chunks
+                            continue;
+                        }
+
                         ChunkSection section = chunk.getSections()[sectionIndex];
 
                         int x = ((NumberTag) tag.get("x")).asInt();

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_12_2to1_13/packets/PlayerPacket1_13.java

@@ -187,7 +187,7 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                             UUID uuid = packetWrapper.passthrough(Type.UUID);
                             if (action == 0) { // Add
                                 String name = packetWrapper.passthrough(Type.STRING);
-                                storage.usernames.put(uuid, name);
+                                storage.usernames().put(uuid, name);
                                 int nProperties = packetWrapper.passthrough(Type.VAR_INT);
                                 for (int j = 0; j < nProperties; j++) {
                                     packetWrapper.passthrough(Type.STRING);
@@ -210,7 +210,7 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                                     packetWrapper.passthrough(Type.COMPONENT);
                                 }
                             } else if (action == 4) { // Remove Player
-                                storage.usernames.remove(uuid);
+                                storage.usernames().remove(uuid);
                             }
                         }
                     }
@@ -313,11 +313,12 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
 
                     TabCompleteStorage storage = wrapper.user().get(TabCompleteStorage.class);
 
-                    if (!storage.commands.isEmpty()) {
-                        storage.commands.clear();
+                    if (!storage.commands().isEmpty()) {
+                        storage.commands().clear();
                     }
 
                     int size = wrapper.read(Type.VAR_INT);
+                    boolean initialNodes = true;
                     for (int i = 0; i < size; i++) {
                         byte flags = wrapper.read(Type.BYTE);
                         wrapper.read(Type.VAR_INT_ARRAY_PRIMITIVE); // Children indices
@@ -326,11 +327,14 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                         }
 
                         byte nodeType = (byte) (flags & 0x03);
+                        if (initialNodes && nodeType == 2) {
+                            initialNodes = false;
+                        }
+
                         if (nodeType == 1 || nodeType == 2) { // Literal/argument node
                             String name = wrapper.read(Type.STRING);
-
-                            if (nodeType == 1) {
-                                storage.commands.add('/' + name);
+                            if (nodeType == 1 && initialNodes) {
+                                storage.commands().add('/' + name);
                             }
                         }
 
@@ -353,25 +357,25 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                     @Override
                     public void handle(PacketWrapper wrapper) throws Exception {
                         TabCompleteStorage storage = wrapper.user().get(TabCompleteStorage.class);
-                        if (storage.lastRequest == null) {
+                        if (storage.lastRequest() == null) {
                             wrapper.cancel();
                             return;
                         }
-                        if (storage.lastId != wrapper.read(Type.VAR_INT)) wrapper.cancel();
+                        if (storage.lastId() != wrapper.read(Type.VAR_INT)) wrapper.cancel();
                         int start = wrapper.read(Type.VAR_INT);
                         int length = wrapper.read(Type.VAR_INT);
 
-                        int lastRequestPartIndex = storage.lastRequest.lastIndexOf(' ') + 1;
+                        int lastRequestPartIndex = storage.lastRequest().lastIndexOf(' ') + 1;
                         if (lastRequestPartIndex != start) wrapper.cancel(); // Client only replaces after space
 
-                        if (length != storage.lastRequest.length() - lastRequestPartIndex) {
+                        if (length != storage.lastRequest().length() - lastRequestPartIndex) {
                             wrapper.cancel(); // We can't set the length in previous versions
                         }
 
                         int count = wrapper.passthrough(Type.VAR_INT);
                         for (int i = 0; i < count; i++) {
                             String match = wrapper.read(Type.STRING);
-                            wrapper.write(Type.STRING, (start == 0 && !storage.lastAssumeCommand ? "/" : "") + match);
+                            wrapper.write(Type.STRING, (start == 0 && !storage.isLastAssumeCommand() ? "/" : "") + match);
                             // Ignore tooltip
                             if (wrapper.read(Type.BOOLEAN)) {
                                 wrapper.read(Type.STRING);
@@ -396,14 +400,14 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                     if (!assumeCommand && !command.startsWith("/")) {
                         // Complete usernames for non-commands
                         String buffer = command.substring(command.lastIndexOf(' ') + 1);
-                        for (String value : storage.usernames.values()) {
+                        for (String value : storage.usernames().values()) {
                             if (startsWithIgnoreCase(value, buffer)) {
                                 suggestions.add(value);
                             }
                         }
-                    } else if (!storage.commands.isEmpty() && !command.contains(" ")) {
+                    } else if (!storage.commands().isEmpty() && !command.contains(" ")) {
                         // Complete commands names with values from 'Declare Commands' packet
-                        for (String value : storage.commands) {
+                        for (String value : storage.commands()) {
                             if (startsWithIgnoreCase(value, command)) {
                                 suggestions.add(value);
                             }
@@ -418,7 +422,7 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                             response.write(Type.STRING, value);
                         }
                         response.scheduleSend(Protocol1_12_2To1_13.class);
-                        storage.lastRequest = null;
+                        storage.setLastRequest(null);
                         return;
                     }
 
@@ -430,9 +434,9 @@ public class PlayerPacket1_13 extends RewriterBase<Protocol1_12_2To1_13> {
                     wrapper.write(Type.VAR_INT, id);
                     wrapper.write(Type.STRING, command);
 
-                    storage.lastId = id;
-                    storage.lastAssumeCommand = assumeCommand;
-                    storage.lastRequest = command;
+                    storage.setLastId(id);
+                    storage.setLastAssumeCommand(assumeCommand);
+                    storage.setLastRequest(command);
                 });
             }
         });

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_12_2to1_13/storage/TabCompleteStorage.java

@@ -26,9 +26,41 @@ import java.util.Set;
 import java.util.UUID;
 
 public class TabCompleteStorage implements StorableObject {
-    public int lastId;
-    public String lastRequest;
-    public boolean lastAssumeCommand;
-    public Map<UUID, String> usernames = new HashMap<>();
-    public Set<String> commands = new HashSet<>();
+    private final Map<UUID, String> usernames = new HashMap<>();
+    private final Set<String> commands = new HashSet<>();
+    private int lastId;
+    private String lastRequest;
+    private boolean lastAssumeCommand;
+
+    public Map<UUID, String> usernames() {
+        return usernames;
+    }
+
+    public Set<String> commands() {
+        return commands;
+    }
+
+    public int lastId() {
+        return lastId;
+    }
+
+    public void setLastId(final int lastId) {
+        this.lastId = lastId;
+    }
+
+    public String lastRequest() {
+        return lastRequest;
+    }
+
+    public void setLastRequest(String lastRequest) {
+        this.lastRequest = lastRequest;
+    }
+
+    public boolean isLastAssumeCommand() {
+        return lastAssumeCommand;
+    }
+
+    public void setLastAssumeCommand(boolean lastAssumeCommand) {
+        this.lastAssumeCommand = lastAssumeCommand;
+    }
 }

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_13_1to1_13_2/packets/InventoryPackets1_13_2.java

@@ -31,7 +31,7 @@ public class InventoryPackets1_13_2 {
         protocol.registerClientbound(ClientboundPackets1_13.SET_SLOT, new PacketRemapper() {
             @Override
             public void registerMap() {
-                map(Type.BYTE); // 0 - Window ID
+                map(Type.UNSIGNED_BYTE); // 0 - Window ID
                 map(Type.SHORT); // 1 - Slot ID
                 map(Type.FLAT_VAR_INT_ITEM, Type.FLAT_ITEM); // 2 - Slot Value
             }

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_13_2to1_14/packets/EntityPackets1_14.java

@@ -393,6 +393,7 @@ public class EntityPackets1_14 extends LegacyEntityRewriter<Protocol1_13_2To1_14
 
         filter().handler((event, meta) -> {
             EntityType type = event.entityType();
+            if (type == null) return;
             if (type.isOrHasParent(Entity1_14Types.ABSTRACT_ILLAGER_BASE) || type == Entity1_14Types.RAVAGER || type == Entity1_14Types.WITCH) {
                 int index = event.index();
                 if (index == 14) {
@@ -473,13 +474,6 @@ public class EntityPackets1_14 extends LegacyEntityRewriter<Protocol1_13_2To1_14
         // Something
         filter().removeIndex(6);
 
-        filter().handler((event, meta) -> {
-            int typeId = meta.metaType().typeId();
-            if (typeId > 15) {
-                ViaBackwards.getPlatform().getLogger().warning("New 1.14 metadata was not handled: " + meta + " entity: " + event.entityType());
-            }
-        });
-
         filter().type(Entity1_14Types.OCELOT).index(13).handler((event, meta) -> {
             event.setIndex(15);
             meta.setTypeAndValue(MetaType1_13_2.VarInt, 0);

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_14_4to1_15/packets/EntityPackets1_15.java

@@ -29,6 +29,7 @@ import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.version.Types1_14;
+import com.viaversion.viaversion.protocols.protocol1_14to1_13_2.ServerboundPackets1_14;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.ClientboundPackets1_15;
 
 import java.util.ArrayList;
@@ -50,7 +51,7 @@ public class EntityPackets1_15 extends EntityRewriter<Protocol1_14_4To1_15> {
                     if (!wrapper.user().get(ImmediateRespawn.class).isImmediateRespawn()) return;
 
                     // Instantly request respawn when 1.15 gamerule is set
-                    PacketWrapper statusPacket = wrapper.create(0x04);
+                    PacketWrapper statusPacket = wrapper.create(ServerboundPackets1_14.CLIENT_STATUS);
                     statusPacket.write(Type.VAR_INT, 0);
                     statusPacket.sendToServer(Protocol1_14_4To1_15.class);
                 });
@@ -122,7 +123,10 @@ public class EntityPackets1_15 extends EntityRewriter<Protocol1_14_4To1_15> {
 
                 handler(getTrackerHandler(Entity1_15Types.PLAYER, Type.INT));
 
-                handler(wrapper -> wrapper.user().get(ImmediateRespawn.class).setImmediateRespawn(wrapper.read(Type.BOOLEAN)));
+                handler(wrapper -> {
+                    boolean immediateRespawn = !wrapper.read(Type.BOOLEAN); // Inverted
+                    wrapper.user().get(ImmediateRespawn.class).setImmediateRespawn(immediateRespawn);
+                });
             }
         });
 

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_15_2to1_16/packets/EntityPackets1_16.java

@@ -30,9 +30,11 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_14;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.protocol.remapper.ValueTransformer;
+import com.viaversion.viaversion.api.protocol.version.ProtocolVersion;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.Particle;
 import com.viaversion.viaversion.api.type.types.version.Types1_14;
+import com.viaversion.viaversion.api.type.types.version.Types1_16;
 import com.viaversion.viaversion.libs.gson.JsonElement;
 import com.viaversion.viaversion.protocols.protocol1_15to1_14_4.ClientboundPackets1_15;
 import com.viaversion.viaversion.protocols.protocol1_16to1_15_2.ClientboundPackets1_16;
@@ -113,7 +115,9 @@ public class EntityPackets1_16 extends EntityRewriter<Protocol1_15_2To1_16> {
 
                     // Send a dummy respawn with a different dimension if the world name was different and the same dimension was used
                     if (clientWorld.getEnvironment() != null && dimension == clientWorld.getEnvironment().getId()
-                            && (wrapper.user().isClientSide() || Via.getPlatform().isProxy() || !nextWorldName.equals(worldNameTracker.getWorldName()))) {
+                            && (wrapper.user().isClientSide() || Via.getPlatform().isProxy()
+                            || wrapper.user().getProtocolInfo().getProtocolVersion() <= ProtocolVersion.v1_12_2.getVersion() // Hotfix for https://github.com/ViaVersion/ViaBackwards/issues/381
+                            || !nextWorldName.equals(worldNameTracker.getWorldName()))) {
                         PacketWrapper packet = wrapper.create(ClientboundPackets1_15.RESPAWN);
                         packet.write(Type.INT, dimension == 0 ? -1 : 0);
                         packet.write(Type.LONG, 0L);
@@ -176,7 +180,7 @@ public class EntityPackets1_16 extends EntityRewriter<Protocol1_15_2To1_16> {
         registerTracker(ClientboundPackets1_16.SPAWN_PAINTING, Entity1_16Types.PAINTING);
         registerTracker(ClientboundPackets1_16.SPAWN_PLAYER, Entity1_16Types.PLAYER);
         registerRemoveEntities(ClientboundPackets1_16.DESTROY_ENTITIES);
-        registerMetadataRewriter(ClientboundPackets1_16.ENTITY_METADATA, Types1_14.METADATA_LIST);
+        registerMetadataRewriter(ClientboundPackets1_16.ENTITY_METADATA, Types1_16.METADATA_LIST, Types1_14.METADATA_LIST);
 
         protocol.registerClientbound(ClientboundPackets1_16.ENTITY_PROPERTIES, new PacketRemapper() {
             @Override

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_16_4to1_17/Protocol1_16_4To1_17.java

@@ -187,7 +187,9 @@ public final class Protocol1_16_4To1_17 extends BackwardsProtocol<ClientboundPac
                     wrapper.cancel();
 
                     // Plugins expecting a real response will have to handle this accordingly themselves
+                    int id = wrapper.read(Type.INT);
                     PacketWrapper pongPacket = wrapper.create(ServerboundPackets1_17.PONG);
+                    pongPacket.write(Type.INT, id);
                     pongPacket.sendToServer(Protocol1_16_4To1_17.class);
                 });
             }

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

@@ -109,7 +109,7 @@ public final class BlockItemPackets1_17 extends ItemRewriter<Protocol1_16_4To1_1
                 map(Type.INT); // Particle count
                 handler(wrapper -> {
                     int id = wrapper.get(Type.INT, 0);
-                    if (id == 15) {
+                    if (id == 16) {
                         wrapper.passthrough(Type.FLOAT); // R
                         wrapper.passthrough(Type.FLOAT); // G
                         wrapper.passthrough(Type.FLOAT); // B
@@ -119,7 +119,7 @@ public final class BlockItemPackets1_17 extends ItemRewriter<Protocol1_16_4To1_1
                         wrapper.read(Type.FLOAT); // R
                         wrapper.read(Type.FLOAT); // G
                         wrapper.read(Type.FLOAT); // B
-                    } else if (id == 36) {
+                    } else if (id == 37) {
                         // Vibration signal - no nice mapping possible without tracking entity positions and doing particle tasks
                         wrapper.cancel();
                     }
@@ -307,9 +307,10 @@ public final class BlockItemPackets1_17 extends ItemRewriter<Protocol1_16_4To1_1
                     boolean hasMarkers = wrapper.read(Type.BOOLEAN);
                     if (!hasMarkers) {
                         wrapper.write(Type.VAR_INT, 0); // Array size
+                    } else {
+                        MapColorRewriter.getRewriteHandler(MapColorRewrites::getMappedColor).handle(wrapper);
                     }
                 });
-                handler(MapColorRewriter.getRewriteHandler(MapColorRewrites::getMappedColor));
             }
         });
     }

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_16_4to1_17/packets/EntityPackets1_17.java

@@ -28,7 +28,7 @@ import com.viaversion.viaversion.api.minecraft.metadata.types.MetaType1_14;
 import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
 import com.viaversion.viaversion.api.type.Type;
 import com.viaversion.viaversion.api.type.types.Particle;
-import com.viaversion.viaversion.api.type.types.version.Types1_14;
+import com.viaversion.viaversion.api.type.types.version.Types1_16;
 import com.viaversion.viaversion.api.type.types.version.Types1_17;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.CompoundTag;
 import com.viaversion.viaversion.libs.opennbt.tag.builtin.IntTag;
@@ -46,12 +46,12 @@ public final class EntityPackets1_17 extends EntityRewriter<Protocol1_16_4To1_17
 
     @Override
     protected void registerPackets() {
-        registerTrackerWithData(ClientboundPackets1_17.SPAWN_ENTITY, Entity1_16_2Types.FALLING_BLOCK);
+        registerTrackerWithData(ClientboundPackets1_17.SPAWN_ENTITY, Entity1_17Types.FALLING_BLOCK);
         registerSpawnTracker(ClientboundPackets1_17.SPAWN_MOB);
-        registerTracker(ClientboundPackets1_17.SPAWN_EXPERIENCE_ORB, Entity1_16_2Types.EXPERIENCE_ORB);
-        registerTracker(ClientboundPackets1_17.SPAWN_PAINTING, Entity1_16_2Types.PAINTING);
-        registerTracker(ClientboundPackets1_17.SPAWN_PLAYER, Entity1_16_2Types.PLAYER);
-        registerMetadataRewriter(ClientboundPackets1_17.ENTITY_METADATA, Types1_17.METADATA_LIST, Types1_14.METADATA_LIST);
+        registerTracker(ClientboundPackets1_17.SPAWN_EXPERIENCE_ORB, Entity1_17Types.EXPERIENCE_ORB);
+        registerTracker(ClientboundPackets1_17.SPAWN_PAINTING, Entity1_17Types.PAINTING);
+        registerTracker(ClientboundPackets1_17.SPAWN_PLAYER, Entity1_17Types.PLAYER);
+        registerMetadataRewriter(ClientboundPackets1_17.ENTITY_METADATA, Types1_17.METADATA_LIST, Types1_16.METADATA_LIST);
 
         protocol.registerClientbound(ClientboundPackets1_17.REMOVE_ENTITY, ClientboundPackets1_16_2.DESTROY_ENTITIES, new PacketRemapper() {
             @Override
@@ -83,7 +83,7 @@ public final class EntityPackets1_17 extends EntityRewriter<Protocol1_16_4To1_17
                         wrapper.set(Type.BYTE, 0, (byte) 0);
                     }
                 });
-                handler(getTrackerHandler(Entity1_16_2Types.PLAYER, Type.INT));
+                handler(getTrackerHandler(Entity1_17Types.PLAYER, Type.INT));
                 handler(worldDataTrackerHandler(1));
                 handler(wrapper -> {
                     CompoundTag registry = wrapper.get(Type.NBT, 0);

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_17to1_17_1/Protocol1_17To1_17_1.java

@@ -0,0 +1,178 @@
+/*
+ * This file is part of ViaBackwards - https://github.com/ViaVersion/ViaBackwards
+ * Copyright (C) 2016-2021 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_17to1_17_1;
+
+import com.viaversion.viabackwards.api.BackwardsProtocol;
+import com.viaversion.viabackwards.protocol.protocol1_17to1_17_1.storage.InventoryStateIds;
+import com.viaversion.viaversion.api.connection.UserConnection;
+import com.viaversion.viaversion.api.minecraft.item.Item;
+import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.api.protocol.remapper.PacketRemapper;
+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;
+import com.viaversion.viaversion.libs.opennbt.tag.builtin.Tag;
+import com.viaversion.viaversion.protocols.protocol1_17_1to1_17.ClientboundPackets1_17_1;
+import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.ClientboundPackets1_17;
+import com.viaversion.viaversion.protocols.protocol1_17to1_16_4.ServerboundPackets1_17;
+
+public final class Protocol1_17To1_17_1 extends BackwardsProtocol<ClientboundPackets1_17_1, ClientboundPackets1_17, ServerboundPackets1_17, ServerboundPackets1_17> {
+
+    private static final int MAX_PAGE_LENGTH = 8192;
+    private static final int MAX_TITLE_LENGTH = 128;
+    private static final int MAX_PAGES = 200; // Actually limited to 100 when handling the read packet, but /shrug
+
+    public Protocol1_17To1_17_1() {
+        super(ClientboundPackets1_17_1.class, ClientboundPackets1_17.class, ServerboundPackets1_17.class, ServerboundPackets1_17.class);
+    }
+
+    @Override
+    protected void registerPackets() {
+        registerClientbound(ClientboundPackets1_17_1.REMOVE_ENTITIES, null, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    int[] entityIds = wrapper.read(Type.VAR_INT_ARRAY_PRIMITIVE);
+                    wrapper.cancel();
+                    for (int entityId : entityIds) {
+                        // Send individual remove packets
+                        PacketWrapper newPacket = wrapper.create(ClientboundPackets1_17.REMOVE_ENTITY);
+                        newPacket.write(Type.VAR_INT, entityId);
+                        newPacket.send(Protocol1_17To1_17_1.class);
+                    }
+                });
+            }
+        });
+
+        registerClientbound(ClientboundPackets1_17_1.CLOSE_WINDOW, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    short containerId = wrapper.passthrough(Type.UNSIGNED_BYTE);
+                    wrapper.user().get(InventoryStateIds.class).removeStateId(containerId);
+                });
+            }
+        });
+        registerClientbound(ClientboundPackets1_17_1.SET_SLOT, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    short containerId = wrapper.passthrough(Type.UNSIGNED_BYTE);
+                    int stateId = wrapper.read(Type.VAR_INT);
+                    wrapper.user().get(InventoryStateIds.class).setStateId(containerId, stateId);
+                });
+            }
+        });
+        registerClientbound(ClientboundPackets1_17_1.WINDOW_ITEMS, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    short containerId = wrapper.passthrough(Type.UNSIGNED_BYTE);
+                    int stateId = wrapper.read(Type.VAR_INT);
+                    wrapper.user().get(InventoryStateIds.class).setStateId(containerId, stateId);
+
+                    // Length is encoded as a var int in 1.17.1
+                    wrapper.write(Type.FLAT_VAR_INT_ITEM_ARRAY, wrapper.read(Type.FLAT_VAR_INT_ITEM_ARRAY_VAR_INT));
+
+                    // Carried item - should work without adding it to the array above
+                    wrapper.read(Type.FLAT_VAR_INT_ITEM);
+                });
+            }
+        });
+
+        registerServerbound(ServerboundPackets1_17.CLOSE_WINDOW, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    short containerId = wrapper.passthrough(Type.UNSIGNED_BYTE);
+                    wrapper.user().get(InventoryStateIds.class).removeStateId(containerId);
+                });
+            }
+        });
+        registerServerbound(ServerboundPackets1_17.CLICK_WINDOW, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    short containerId = wrapper.passthrough(Type.UNSIGNED_BYTE);
+                    int stateId = wrapper.user().get(InventoryStateIds.class).removeStateId(containerId);
+                    wrapper.write(Type.VAR_INT, stateId == Integer.MAX_VALUE ? 0 : stateId);
+                });
+            }
+        });
+
+        registerServerbound(ServerboundPackets1_17.EDIT_BOOK, new PacketRemapper() {
+            @Override
+            public void registerMap() {
+                handler(wrapper -> {
+                    Item item = wrapper.read(Type.FLAT_VAR_INT_ITEM);
+                    boolean signing = wrapper.read(Type.BOOLEAN);
+                    wrapper.passthrough(Type.VAR_INT); // Slot comes first
+
+                    CompoundTag tag = item.tag();
+                    ListTag pagesTag;
+                    StringTag titleTag = null;
+                    // Sanity checks
+                    if (tag == null || (pagesTag = tag.get("pages")) == null
+                            || (signing && (titleTag = tag.get("title")) == null)) {
+                        wrapper.write(Type.VAR_INT, 0); // Pages length
+                        wrapper.write(Type.BOOLEAN, false); // Optional title
+                        return;
+                    }
+
+                    // Write pages - limit them first
+                    if (pagesTag.size() > MAX_PAGES) {
+                        pagesTag = new ListTag(pagesTag.getValue().subList(0, MAX_PAGES));
+                    }
+
+                    wrapper.write(Type.VAR_INT, pagesTag.size());
+                    for (Tag pageTag : pagesTag) {
+                        String page = ((StringTag) pageTag).getValue();
+                        // Limit page length
+                        if (page.length() > MAX_PAGE_LENGTH) {
+                            page = page.substring(0, MAX_PAGE_LENGTH);
+                        }
+
+                        wrapper.write(Type.STRING, page);
+                    }
+
+                    // Write optional title
+                    wrapper.write(Type.BOOLEAN, signing);
+                    if (signing) {
+                        if (titleTag == null) {
+                            titleTag = tag.get("title");
+                        }
+
+                        // Limit title length
+                        String title = titleTag.getValue();
+                        if (title.length() > MAX_TITLE_LENGTH) {
+                            title = title.substring(0, MAX_TITLE_LENGTH);
+                        }
+
+                        wrapper.write(Type.STRING, title);
+                    }
+                });
+            }
+        });
+    }
+
+    @Override
+    public void init(UserConnection connection) {
+        connection.put(new InventoryStateIds());
+    }
+}

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_17to1_17_1/storage/InventoryStateIds.java

@@ -0,0 +1,39 @@
+/*
+ * This file is part of ViaVersion - https://github.com/ViaVersion/ViaVersion
+ * Copyright (C) 2016-2021 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_17to1_17_1.storage;
+
+import com.viaversion.viaversion.api.connection.StorableObject;
+import com.viaversion.viaversion.libs.fastutil.ints.Int2IntMap;
+import com.viaversion.viaversion.libs.fastutil.ints.Int2IntOpenHashMap;
+
+public final class InventoryStateIds implements StorableObject {
+    private final Int2IntMap ids = new Int2IntOpenHashMap();
+
+    public InventoryStateIds() {
+        // Inventory ids are unsigned bytes, so this is safe to do
+        ids.defaultReturnValue(Integer.MAX_VALUE);
+    }
+
+    public void setStateId(short containerId, int id) {
+        ids.put(containerId, id);
+    }
+
+    public int removeStateId(short containerId) {
+        return ids.remove(containerId);
+    }
+}

fabric/src/main/java/com/viaversion/viabackwards/ViaFabricAddon.java

@@ -33,9 +33,9 @@ public class ViaFabricAddon implements ViaBackwardsPlatform, Runnable {
 
     @Override
     public void run() {
-        Path configDirPath = FabricLoader.getInstance().getConfigDirectory().toPath().resolve("ViaBackwards");
+        Path configDirPath = FabricLoader.getInstance().getConfigDir().resolve("ViaBackwards");
         configDir = configDirPath.toFile();
-        this.init(configDirPath.resolve("config.yml").toFile());
+        this.init(getDataFolder());
     }
 
     @Override

gradle/libs.versions.toml

@@ -3,7 +3,7 @@ metadata.format.version = "1.0"
 [versions]
 
 # ViaVersion
-viaver = "4.0.0-1.17-rc2-SNAPSHOT"
+viaver = "4.0.1-1.17.1-rc1-SNAPSHOT"
 
 # Common provided
 netty = "4.0.20.Final"
@@ -17,7 +17,7 @@ paper = "1.16.5-R0.1-SNAPSHOT"
 bungee = "1.16-R0.5-SNAPSHOT"
 sponge = "5.0.0"
 velocity = "3.0.0-SNAPSHOT"
-fabricLoader = "0.4.8+build.154"
+fabricLoader = "0.11.6"
 
 
 [libraries]

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

settings.gradle.kts

@@ -5,6 +5,7 @@ rootProject.name = "viabackwards-parent"
 
 dependencyResolutionManagement {
     repositories {
+        mavenLocal()
         maven("https://repo.viaversion.com")
         maven("https://papermc.io/repo/repository/maven-public/")
         maven("https://oss.sonatype.org/content/repositories/snapshots/")