From 16f89f26381430a6f8232363f61cad3d1d655426 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Tue, 19 Sep 2023 21:14:45 +1000
Subject: [PATCH] Don't re-enter config state if the dimension registry did not
 change

---
 .../Protocol1_20_2To1_20.java                 |  6 ++--
 .../rewriter/EntityPacketRewriter1_20_2.java  | 11 ++++---
 .../storage/ConfigurationState.java           | 32 ++++++++-----------
 3 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/Protocol1_20_2To1_20.java b/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/Protocol1_20_2To1_20.java
index 1d0fbcc3d..2b13b6731 100644
--- a/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/Protocol1_20_2To1_20.java
+++ b/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/Protocol1_20_2To1_20.java
@@ -133,7 +133,7 @@ public final class Protocol1_20_2To1_20 extends AbstractProtocol<ClientboundPack
             wrapper.cancel();
 
             final ConfigurationState configurationState = wrapper.user().get(ConfigurationState.class);
-            if (configurationState.getReenterInfo() == null) {
+            if (configurationState.bridgePhase() != BridgePhase.REENTERING_CONFIGURATION) {
                 return;
             }
 
@@ -141,8 +141,7 @@ public final class Protocol1_20_2To1_20 extends AbstractProtocol<ClientboundPack
             configurationState.setBridgePhase(BridgePhase.CONFIGURATION);
 
             final LastResourcePack lastResourcePack = wrapper.user().get(LastResourcePack.class);
-            sendConfigurationPackets(wrapper.user(), configurationState.getReenterInfo().dimensionRegistry(), lastResourcePack);
-            configurationState.setReenterInfo(null);
+            sendConfigurationPackets(wrapper.user(), configurationState.lastDimensionRegistry(), lastResourcePack);
         });
         cancelServerbound(ServerboundPackets1_20_2.CHUNK_BATCH_RECEIVED);
 
@@ -203,7 +202,6 @@ public final class Protocol1_20_2To1_20 extends AbstractProtocol<ClientboundPack
                 if (!packetWrapper.user().isClientSide() && !Via.getPlatform().isProxy() && unmappedId == ClientboundPackets1_19_4.SYSTEM_CHAT.getId()) {
                     // Cancelling this on the Vanilla server will cause it to exceptionally resend a message
                     // Assume that we have already sent the login packet and just let it through
-                    // TODO Maybe just don't wait for the finish config response?
                     super.transform(direction, State.PLAY, packetWrapper);
                     return;
                 }
diff --git a/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/rewriter/EntityPacketRewriter1_20_2.java b/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/rewriter/EntityPacketRewriter1_20_2.java
index e4a81cb2e..517949089 100644
--- a/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/rewriter/EntityPacketRewriter1_20_2.java
+++ b/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/rewriter/EntityPacketRewriter1_20_2.java
@@ -27,7 +27,6 @@ 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.Protocol1_20_2To1_20;
-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.storage.ConfigurationState;
 import com.viaversion.viaversion.rewriter.EntityRewriter;
@@ -99,17 +98,19 @@ public final class EntityPacketRewriter1_20_2 extends EntityRewriter<Clientbound
 
                     // Debug, flat, last death pos, and portal cooldown at the end unchanged
 
-                    // Send configuration packets first before going into the play protocol state
-                    ConfigurationState configurationBridge = wrapper.user().get(ConfigurationState.class);
+                    final ConfigurationState configurationBridge = wrapper.user().get(ConfigurationState.class);
+                    if (!configurationBridge.setLastDimensionRegistry(dimensionRegistry)) {
+                        // No change, so no need to re-enter the configuration state - just let this one through
+                        return;
+                    }
+
                     if (configurationBridge.bridgePhase() == ConfigurationState.BridgePhase.NONE) {
                         // Reenter the configuration state
                         final PacketWrapper configurationPacket = wrapper.create(ClientboundPackets1_20_2.START_CONFIGURATION);
                         configurationPacket.send(Protocol1_20_2To1_20.class);
 
-                        // TODO The client clears the resource pack when reentering (?)
                         configurationBridge.setBridgePhase(ConfigurationState.BridgePhase.REENTERING_CONFIGURATION);
                         configurationBridge.setJoinGamePacket(wrapper);
-                        configurationBridge.setReenterInfo(new ConfigurationState.ReenterInfo(dimensionRegistry));
                         wrapper.cancel();
                         return;
                     }
diff --git a/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/storage/ConfigurationState.java b/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/storage/ConfigurationState.java
index 81b7f1295..0a88e0d4d 100644
--- a/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/storage/ConfigurationState.java
+++ b/common/src/main/java/com/viaversion/viaversion/protocols/protocol1_20_2to1_20/storage/ConfigurationState.java
@@ -27,6 +27,7 @@ import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class ConfigurationState implements StorableObject {
@@ -35,7 +36,7 @@ public class ConfigurationState implements StorableObject {
     private BridgePhase bridgePhase = BridgePhase.NONE;
     private QueuedPacket joinGamePacket;
     private boolean queuedJoinGame;
-    private ReenterInfo reenterInfo;
+    private CompoundTag lastDimensionRegistry;
 
     public BridgePhase bridgePhase() {
         return bridgePhase;
@@ -45,12 +46,20 @@ public class ConfigurationState implements StorableObject {
         this.bridgePhase = bridgePhase;
     }
 
-    public @Nullable ReenterInfo getReenterInfo() {
-        return reenterInfo;
+    public @Nullable CompoundTag lastDimensionRegistry() {
+        return lastDimensionRegistry;
     }
 
-    public void setReenterInfo(@Nullable final ReenterInfo reenterInfo) {
-        this.reenterInfo = reenterInfo;
+    /**
+     * Sets the last dimension registry and returns whether it differs from the previously stored one.
+     *
+     * @param dimensionRegistry dimension registry to set
+     * @return whether the dimension registry differs from the previously stored one
+     */
+    public boolean setLastDimensionRegistry(final CompoundTag dimensionRegistry) {
+        final boolean equals = Objects.equals(this.lastDimensionRegistry, dimensionRegistry);
+        this.lastDimensionRegistry = dimensionRegistry;
+        return !equals;
     }
 
     public void addPacketToQueue(final PacketWrapper wrapper, final boolean clientbound) throws Exception {
@@ -123,7 +132,6 @@ public class ConfigurationState implements StorableObject {
         packetQueue.clear();
         bridgePhase = BridgePhase.NONE;
         queuedJoinGame = false;
-        reenterInfo = null;
     }
 
     public boolean queuedOrSentJoinGame() {
@@ -181,16 +189,4 @@ public class ConfigurationState implements StorableObject {
                     '}';
         }
     }
-
-    public static final class ReenterInfo {
-        private final CompoundTag dimensionRegistry;
-
-        public ReenterInfo(final CompoundTag dimensionRegistry) {
-            this.dimensionRegistry = dimensionRegistry;
-        }
-
-        public CompoundTag dimensionRegistry() {
-            return dimensionRegistry;
-        }
-    }
 }