fix: improve biome setting to avoid writing directly to chunk (#2757)

* fix: improve biome setting to avoid writing directly to chunk

 - Removes possibility of writing to the LevelChunkSection biomes PalettedContainer whilst it is being read for sending packets
 - I believe this occured mostly on clipboard operations where blocks are written before biomes, so chunks are being sent whilst writing biomes
 - This would explain why the error reported in the below issue (and others) is/was so rare
 - Of course I could be completely wrong about all of this, but given the line in LevelChunkSection#write that the error seems to consistently occur on is when writing biomes to the packet, and that the only place I can find in FAWE where we write to a "live" PalettedContainer is for biomes, I am reasonably confident that this is the cause
 - Should address #2729

* Remove self-refraction-check

worldedit-bukkit/adapters/adapter-1_20_5/src/main/java/com/sk89q/worldedit/bukkit/adapter/impl/fawe/v1_20_R4/PaperweightGetBlocks.java

@@ -29,7 +29,11 @@ import com.sk89q.worldedit.world.biome.BiomeTypes;
 import com.sk89q.worldedit.world.block.BlockTypesCache;
 import io.papermc.lib.PaperLib;
 import io.papermc.paper.event.block.BeaconDeactivatedEvent;
-import net.minecraft.core.*;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.Holder;
+import net.minecraft.core.IdMap;
+import net.minecraft.core.Registry;
+import net.minecraft.core.SectionPos;
 import net.minecraft.nbt.IntTag;
 import net.minecraft.server.dedicated.DedicatedServer;
 import net.minecraft.server.level.ServerLevel;
@@ -43,7 +47,14 @@ import net.minecraft.world.level.biome.Biome;
 import net.minecraft.world.level.block.entity.BeaconBlockEntity;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.state.BlockState;
-import net.minecraft.world.level.chunk.*;
+import net.minecraft.world.level.chunk.DataLayer;
+import net.minecraft.world.level.chunk.HashMapPalette;
+import net.minecraft.world.level.chunk.LevelChunk;
+import net.minecraft.world.level.chunk.LevelChunkSection;
+import net.minecraft.world.level.chunk.LinearPalette;
+import net.minecraft.world.level.chunk.Palette;
+import net.minecraft.world.level.chunk.PalettedContainer;
+import net.minecraft.world.level.chunk.PalettedContainerRO;
 import net.minecraft.world.level.levelgen.Heightmap;
 import net.minecraft.world.level.lighting.LevelLightEngine;
 import org.apache.logging.log4j.Logger;
@@ -53,7 +64,17 @@ import org.bukkit.craftbukkit.block.CraftBlock;
 import org.bukkit.event.entity.CreatureSpawnEvent;
 
 import javax.annotation.Nonnull;
-import java.util.*;
+import java.util.AbstractSet;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Future;
@@ -499,7 +520,14 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
                                         }
                                     }
                                 } else {
-                                    setBiomesToPalettedContainer(biomes, setSectionIndex, existingSection.getBiomes());
+                                    PalettedContainer<Holder<Biome>> paletteBiomes = setBiomesToPalettedContainer(
+                                            biomes,
+                                            setSectionIndex,
+                                            existingSection.getBiomes()
+                                    );
+                                    if (paletteBiomes != null) {
+                                        PaperweightPlatformAdapter.setBiomesToChunkSection(existingSection, paletteBiomes);
+                                    }
                                 }
                             }
                         }
@@ -541,11 +569,7 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
                         if (existingSection == null) {
                             PalettedContainer<Holder<Biome>> biomeData = biomes == null ? new PalettedContainer<>(
                                     biomeHolderIdMap,
-                                    biomeHolderIdMap.byIdOrThrow(WorldEditPlugin
-                                            .getInstance()
-                                            .getBukkitImplAdapter()
-                                            .getInternalBiomeId(
-                                                    BiomeTypes.PLAINS)),
+                                    biomeHolderIdMap.byIdOrThrow(adapter.getInternalBiomeId(BiomeTypes.PLAINS)),
                                     PalettedContainer.Strategy.SECTION_BIOMES
                             ) : PaperweightPlatformAdapter.getBiomePalettedContainer(biomes[setSectionIndex], biomeHolderIdMap);
                             newSection = PaperweightPlatformAdapter.newChunkSection(
@@ -612,18 +636,15 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
                                     existingSection.getBiomes()
                             );
 
-                            newSection =
-                                    PaperweightPlatformAdapter.newChunkSection(
-                                            layerNo,
-                                            this::loadPrivately,
-                                            setArr,
-                                            adapter,
-                                            biomeRegistry,
-                                            biomeData
-                                    );
-                            if (!PaperweightPlatformAdapter.setSectionAtomic(
-                                    levelChunkSections,
-                                    existingSection,
+                            newSection = PaperweightPlatformAdapter.newChunkSection(
+                                    layerNo,
+                                    this::loadPrivately,
+                                    setArr,
+                                    adapter,
+                                    biomeRegistry,
+                                    biomeData != null ? biomeData : (PalettedContainer<Holder<Biome>>) existingSection.getBiomes()
+                            );
+                            if (!PaperweightPlatformAdapter.setSectionAtomic(levelChunkSections, existingSection,
                                     newSection,
                                     getSectionIndex
                             )) {
@@ -832,7 +853,7 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
                             }
                             if (callback == null) {
                                 if (finalizer != null) {
-                                    finalizer.run();
+                                    queueHandler.async(finalizer, null);
                                 }
                                 return null;
                             } else {
@@ -1089,9 +1110,13 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
             final int sectionIndex,
             final PalettedContainerRO<Holder<Biome>> data
     ) {
+        BiomeType[] sectionBiomes;
+        if (biomes == null || (sectionBiomes = biomes[sectionIndex]) == null) {
+            return null;
+        }
         PalettedContainer<Holder<Biome>> biomeData;
         if (data instanceof PalettedContainer<Holder<Biome>> palettedContainer) {
-            biomeData = palettedContainer;
+            biomeData = palettedContainer.copy();
         } else {
             LOGGER.warn(
                     "Cannot correctly set biomes to world, existing biomes may be lost. Expected class " +
@@ -1101,10 +1126,6 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
             );
             biomeData = data.recreate();
         }
-        BiomeType[] sectionBiomes;
-        if (biomes == null || (sectionBiomes = biomes[sectionIndex]) == null) {
-            return biomeData;
-        }
         for (int y = 0, index = 0; y < 4; y++) {
             for (int z = 0; z < 4; z++) {
                 for (int x = 0; x < 4; x++, index++) {
@@ -1116,10 +1137,7 @@ public class PaperweightGetBlocks extends CharGetBlocks implements BukkitGetBloc
                             x,
                             y,
                             z,
-                            biomeHolderIdMap.byIdOrThrow(WorldEditPlugin
-                                    .getInstance()
-                                    .getBukkitImplAdapter()
-                                    .getInternalBiomeId(biomeType))
+                            biomeHolderIdMap.byIdOrThrow(adapter.getInternalBiomeId(biomeType))
                     );
                 }
             }

worldedit-bukkit/adapters/adapter-1_20_5/src/main/java/com/sk89q/worldedit/bukkit/adapter/impl/fawe/v1_20_R4/PaperweightPlatformAdapter.java

@@ -10,7 +10,6 @@ import com.fastasyncworldedit.core.math.BitArrayUnstretched;
 import com.fastasyncworldedit.core.util.MathMan;
 import com.fastasyncworldedit.core.util.ReflectionUtils;
 import com.fastasyncworldedit.core.util.TaskManager;
-import com.mojang.datafixers.util.Either;
 import com.sk89q.worldedit.bukkit.WorldEditPlugin;
 import com.sk89q.worldedit.bukkit.adapter.BukkitImplAdapter;
 import com.sk89q.worldedit.bukkit.adapter.Refraction;
@@ -77,7 +76,6 @@ import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Semaphore;
 import java.util.concurrent.TimeUnit;
@@ -98,7 +96,7 @@ public final class PaperweightPlatformAdapter extends NMSAdapter {
 
     private static final Field fieldTickingFluidCount;
     private static final Field fieldTickingBlockCount;
-    private static final Field fieldNonEmptyBlockCount;
+    private static final Field fieldBiomes;
 
     private static final MethodHandle methodGetVisibleChunk;
 
@@ -142,8 +140,8 @@ public final class PaperweightPlatformAdapter extends NMSAdapter {
             fieldTickingFluidCount.setAccessible(true);
             fieldTickingBlockCount = LevelChunkSection.class.getDeclaredField(Refraction.pickName("tickingBlockCount", "f"));
             fieldTickingBlockCount.setAccessible(true);
-            fieldNonEmptyBlockCount = LevelChunkSection.class.getDeclaredField(Refraction.pickName("nonEmptyBlockCount", "e"));
-            fieldNonEmptyBlockCount.setAccessible(true);
+            fieldBiomes = LevelChunkSection.class.getDeclaredField(Refraction.pickName("biomes", "i"));
+            fieldBiomes.setAccessible(true);
 
             Method getVisibleChunkIfPresent = ChunkMap.class.getDeclaredMethod(Refraction.pickName(
                     "getVisibleChunkIfPresent",
@@ -405,7 +403,7 @@ public final class PaperweightPlatformAdapter extends NMSAdapter {
             @Nullable PalettedContainer<Holder<Biome>> biomes
     ) {
         if (set == null) {
-            return newChunkSection(layer, biomeRegistry, biomes);
+            return newChunkSection(biomeRegistry, biomes);
         }
         final int[] blockToPalette = FaweCache.INSTANCE.BLOCK_TO_PALETTE.get();
         final int[] paletteToBlock = FaweCache.INSTANCE.PALETTE_TO_BLOCK.get();
@@ -495,7 +493,6 @@ public final class PaperweightPlatformAdapter extends NMSAdapter {
 
     @SuppressWarnings("deprecation") // Only deprecated in paper
     private static LevelChunkSection newChunkSection(
-            int layer,
             Registry<Biome> biomeRegistry,
             @Nullable PalettedContainer<Holder<Biome>> biomes
     ) {
@@ -510,6 +507,14 @@ public final class PaperweightPlatformAdapter extends NMSAdapter {
         return new LevelChunkSection(dataPaletteBlocks, biomes);
     }
 
+    public static void setBiomesToChunkSection(LevelChunkSection section, PalettedContainer<Holder<Biome>> biomes) {
+        try {
+            fieldBiomes.set(section, biomes);
+        } catch (IllegalAccessException e) {
+            LOGGER.error("Could not set biomes to chunk section", e);
+        }
+    }
+
     /**
      * Create a new {@link PalettedContainer<Biome>}. Should only be used if no biome container existed beforehand.
      */