Debug option for invalid chunk data

common/src/main/java/net/caffeinemc/mods/lithium/mixin/debug/package-info.java

@@ -0,0 +1,4 @@
+@MixinConfigOption(description = "Debug features", enabled = false)
+package net.caffeinemc.mods.lithium.mixin.debug;
+
+import net.caffeinemc.gradle.MixinConfigOption;

common/src/main/java/net/caffeinemc/mods/lithium/mixin/debug/palette/ClientBoundLevelChunkPacketDataAccessor.java

@@ -0,0 +1,13 @@
+package net.caffeinemc.mods.lithium.mixin.debug.palette;
+
+import net.minecraft.network.protocol.game.ClientboundLevelChunkPacketData;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+@Mixin(ClientboundLevelChunkPacketData.class)
+public interface ClientBoundLevelChunkPacketDataAccessor {
+
+    @Accessor("buffer")
+    byte[] getBuffer();
+
+}

common/src/main/java/net/caffeinemc/mods/lithium/mixin/debug/palette/ClientPacketListenerMixin.java

@@ -0,0 +1,30 @@
+package net.caffeinemc.mods.lithium.mixin.debug.palette;
+
+import com.llamalad7.mixinextras.injector.wrapmethod.WrapMethod;
+import com.llamalad7.mixinextras.injector.wrapoperation.Operation;
+import net.minecraft.client.multiplayer.ClientPacketListener;
+import net.minecraft.network.protocol.game.ClientboundLevelChunkPacketData;
+import org.spongepowered.asm.mixin.Mixin;
+
+import java.util.Arrays;
+
+@Mixin(ClientPacketListener.class)
+public class ClientPacketListenerMixin {
+
+    @WrapMethod(
+            method = "updateLevelChunk(IILnet/minecraft/network/protocol/game/ClientboundLevelChunkPacketData;)V"
+    )
+    private void addExceptionInfo(int i, int j, ClientboundLevelChunkPacketData clientboundLevelChunkPacketData, Operation<Void> original) {
+        try {
+            original.call(i, j, clientboundLevelChunkPacketData);
+        } catch (IllegalStateException e) {
+            String message = "Exception occurred while receiving data for chunk at " + i + ", " + j + ".\n" +
+                    "**The following may include sensitive data, e.g. text that is written with blocks or built \n" +
+                    "structures. Make sure the chunk with chunk coordinates " + i + ", " + j + " does not contain block\n" +
+                    "or biome structures (e.g. your non-pseudonym name written with blocks) that you do not want\n" +
+                    "published. This does not include block entities or items.**\n" +
+                    "Possible sensitive chunk biome and blockstate data: " + Arrays.toString(((ClientBoundLevelChunkPacketDataAccessor) clientboundLevelChunkPacketData).getBuffer());
+            throw new IllegalStateException(message, e);
+        }
+    }
+}

common/src/main/java/net/caffeinemc/mods/lithium/mixin/debug/palette/PalettedContainerMixin.java

@@ -0,0 +1,44 @@
+package net.caffeinemc.mods.lithium.mixin.debug.palette;
+
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.util.BitStorage;
+import net.minecraft.world.level.chunk.MissingPaletteEntryException;
+import net.minecraft.world.level.chunk.Palette;
+import net.minecraft.world.level.chunk.PalettedContainer;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(PalettedContainer.class)
+public class PalettedContainerMixin<T> {
+
+    @Shadow
+    private volatile PalettedContainer.Data<T> data;
+
+    @Inject(
+            method = "read", at = @At("RETURN")
+    )
+    private void checkConsistency(FriendlyByteBuf friendlyByteBuf, CallbackInfo ci) {
+        BitStorage storage = this.data.storage();
+        Palette<T> palette = this.data.palette();
+        int i = -1;
+        int index = -1;
+        try {
+            for (i = 0; i < storage.getSize(); i++) {
+                index = storage.get(i);
+                T t = palette.valueFor(index);
+                //noinspection ConstantValue
+                if (t == null) {
+                    throw new MissingPaletteEntryException(index);
+                }
+            }
+        } catch (Exception e) {
+            String builder = "Received invalid paletted container data!\n" +
+                    "Entry at index " + i + " has palette index " + index + ".\n" +
+                    "Palette: " + palette + " Size: " + palette.getSize() + "\n";
+            throw new IllegalStateException(builder, e);
+        }
+    }
+}

common/src/main/java/net/caffeinemc/mods/lithium/mixin/debug/palette/package-info.java

@@ -0,0 +1,4 @@
+@MixinConfigOption(description = "Clients check the chunk section data when receiving a chunk data packet.")
+package net.caffeinemc.mods.lithium.mixin.debug.palette;
+
+import net.caffeinemc.gradle.MixinConfigOption;

common/src/main/resources/lithium.mixins.json

@@ -242,6 +242,9 @@
   ],
   "client" : [
     "chunk.entity_class_groups.ClientLevelMixin",
+    "debug.palette.ClientBoundLevelChunkPacketDataAccessor",
+    "debug.palette.ClientPacketListenerMixin",
+    "debug.palette.PalettedContainerMixin",
     "util.accessors.TransientEntitySectionManagerAccessor"
   ]
 }

lithium-fabric-mixin-config.md

@@ -267,6 +267,14 @@ Send updates to hoppers when adding inventory block entities to chunks when worl
 Requirements:
 - `mixin.util.block_entity_retrieval=true`  
 
+### `mixin.debug`
+(default: `false`)  
+Debug features
+
+### `mixin.debug.palette`
+(default: `true`)  
+Clients check the chunk section data when receiving a chunk data packet.
+
 ### `mixin.entity`
 (default: `true`)  
 Various entity optimizations
@@ -505,7 +513,9 @@ Access chunks of worlds, chunk caches and chunk regions directly.
 
 ### `mixin.util.chunk_status_tracking`
 (default: `true`)  
-Allows reacting to changes of the load status of chunks.
+Allows reacting to changes of the load status of chunks.  
+Requirements:
+- `mixin.util.accessors=true`  
 
 ### `mixin.util.data_storage`
 (default: `true`)  

lithium-neoforge-mixin-config.md

@@ -253,6 +253,14 @@ Uses fastutil hashmaps for gamerules
 (default: `true`)  
 Uses custom hashset/list combination for faster mob spawn checks
 
+### `mixin.debug`
+(default: `false`)  
+Debug features
+
+### `mixin.debug.palette`
+(default: `true`)  
+Clients check the chunk section data when receiving a chunk data packet.
+
 ### `mixin.entity`
 (default: `true`)  
 Various entity optimizations
@@ -482,7 +490,9 @@ Access chunks of worlds, chunk caches and chunk regions directly.
 
 ### `mixin.util.chunk_status_tracking`
 (default: `true`)  
-Allows reacting to changes of the load status of chunks.
+Allows reacting to changes of the load status of chunks.  
+Requirements:
+- `mixin.util.accessors=true`  
 
 ### `mixin.util.data_storage`
 (default: `true`)