Guard against serializing mismatching chunk coordinate

Should help if something dumb happens

paper-server/patches/sources/net/minecraft/world/level/chunk/storage/ChunkStorage.java.patch

@@ -134,3 +134,24 @@
          CompoundTag nbttagcompound1 = new CompoundTag();
  
          nbttagcompound1.putString("dimension", worldKey.location().toString());
+@@ -108,8 +172,19 @@
+     }
+ 
+     public CompletableFuture<Void> write(ChunkPos chunkPos, Supplier<CompoundTag> nbtSupplier) {
++        // Paper start - guard against possible chunk pos desync
++        final Supplier<CompoundTag> guardedPosCheck = () -> {
++            CompoundTag nbt = nbtSupplier.get();
++            if (nbt != null && !chunkPos.equals(SerializableChunkData.getChunkCoordinate(nbt))) {
++                final String world = (ChunkStorage.this instanceof net.minecraft.server.level.ChunkMap) ? ((net.minecraft.server.level.ChunkMap) ChunkStorage.this).level.getWorld().getName() : null;
++                throw new IllegalArgumentException("Chunk coordinate and serialized data do not have matching coordinates, trying to serialize coordinate " + chunkPos
++                    + " but compound says coordinate is " + SerializableChunkData.getChunkCoordinate(nbt) + (world == null ? " for an unknown world" : (" for world: " + world)));
++            }
++            return nbt;
++        };
++        // Paper end - guard against possible chunk pos desync
+         this.handleLegacyStructureIndex(chunkPos);
+-        return this.worker.store(chunkPos, nbtSupplier);
++        return this.worker.store(chunkPos, guardedPosCheck); // Paper - guard against possible chunk pos desync
+     }
+ 
+     protected void handleLegacyStructureIndex(ChunkPos chunkPos) {

paper-server/patches/sources/net/minecraft/world/level/chunk/storage/SerializableChunkData.java.patch

@@ -10,7 +10,34 @@
  
      public static final Codec<PalettedContainer<BlockState>> BLOCK_STATE_CODEC = PalettedContainer.codecRW(Block.BLOCK_STATE_REGISTRY, BlockState.CODEC, PalettedContainer.Strategy.SECTION_STATES, Blocks.AIR.defaultBlockState());
      private static final Logger LOGGER = LogUtils.getLogger();
-@@ -110,7 +111,7 @@
+@@ -90,13 +91,25 @@
+     public static final String SECTIONS_TAG = "sections";
+     public static final String BLOCK_LIGHT_TAG = "BlockLight";
+     public static final String SKY_LIGHT_TAG = "SkyLight";
++    // Paper start - guard against serializing mismatching coordinates
++    // TODO Note: This needs to be re-checked each update
++    public static ChunkPos getChunkCoordinate(final CompoundTag chunkData) {
++        final int dataVersion = ChunkStorage.getVersion(chunkData);
++        if (dataVersion < 2842) { // Level tag is removed after this version
++            final CompoundTag levelData = chunkData.getCompound("Level");
++            return new ChunkPos(levelData.getInt("xPos"), levelData.getInt("zPos"));
++        } else {
++            return new ChunkPos(chunkData.getInt("xPos"), chunkData.getInt("zPos"));
++        }
++    }
++    // Paper end - guard against serializing mismatching coordinates
+ 
+     @Nullable
+     public static SerializableChunkData parse(LevelHeightAccessor world, RegistryAccess registryManager, CompoundTag nbt) {
+         if (!nbt.contains("Status", 8)) {
+             return null;
+         } else {
+-            ChunkPos chunkcoordintpair = new ChunkPos(nbt.getInt("xPos"), nbt.getInt("zPos"));
++            ChunkPos chunkcoordintpair = new ChunkPos(nbt.getInt("xPos"), nbt.getInt("zPos")); // Paper - guard against serializing mismatching coordinates; diff on change, see ChunkSerializer#getChunkCoordinate
+             long i = nbt.getLong("LastUpdate");
+             long j = nbt.getLong("InhabitedTime");
+             ChunkStatus chunkstatus = ChunkStatus.byName(nbt.getString("Status"));
+@@ -110,7 +123,7 @@
                  dataresult = BlendingData.Packed.CODEC.parse(NbtOps.INSTANCE, nbt.getCompound("blending_data"));
                  logger = SerializableChunkData.LOGGER;
                  Objects.requireNonNull(logger);
@@ -19,7 +46,7 @@
              } else {
                  blendingdata_d = null;
              }
-@@ -121,7 +122,7 @@
+@@ -121,7 +134,7 @@
                  dataresult = BelowZeroRetrogen.CODEC.parse(NbtOps.INSTANCE, nbt.getCompound("below_zero_retrogen"));
                  logger = SerializableChunkData.LOGGER;
                  Objects.requireNonNull(logger);
@@ -28,7 +55,7 @@
              } else {
                  belowzeroretrogen = null;
              }
-@@ -178,7 +179,7 @@
+@@ -178,7 +191,7 @@
              ListTag nbttaglist2 = nbt.getList("sections", 10);
              List<SerializableChunkData.SectionData> list4 = new ArrayList(nbttaglist2.size());
              Registry<Biome> iregistry = registryManager.lookupOrThrow(Registries.BIOME);
@@ -37,7 +64,7 @@
  
              for (int i1 = 0; i1 < nbttaglist2.size(); ++i1) {
                  CompoundTag nbttagcompound3 = nbttaglist2.getCompound(i1);
-@@ -196,17 +197,17 @@
+@@ -196,17 +209,17 @@
                          datapaletteblock = new PalettedContainer<>(Block.BLOCK_STATE_REGISTRY, Blocks.AIR.defaultBlockState(), PalettedContainer.Strategy.SECTION_STATES);
                      }
  
@@ -58,7 +85,7 @@
                  } else {
                      chunksection = null;
                  }
-@@ -217,7 +218,8 @@
+@@ -217,7 +230,8 @@
                  list4.add(new SerializableChunkData.SectionData(b0, chunksection, nibblearray, nibblearray1));
              }
  
@@ -68,34 +95,34 @@
          }
      }
  
-@@ -289,6 +291,12 @@
+@@ -287,7 +301,13 @@
+             if (this.chunkStatus.isOrAfter(ChunkStatus.INITIALIZE_LIGHT)) {
+                 protochunk.setLightEngine(levellightengine);
              }
-         }
++        }
- 
++
 +        // CraftBukkit start - load chunk persistent data from nbt - SPIGOT-6814: Already load PDC here to account for 1.17 to 1.18 chunk upgrading.
 +        if (this.persistentDataContainer instanceof CompoundTag) {
 +            ((ChunkAccess) object).persistentDataContainer.putAll((CompoundTag) this.persistentDataContainer);
-+        }
+         }
 +        // CraftBukkit end
-+
+ 
          ((ChunkAccess) object).setLightCorrect(this.lightCorrect);
          EnumSet<Heightmap.Types> enumset = EnumSet.noneOf(Heightmap.Types.class);
-         Iterator iterator1 = ((ChunkAccess) object).getPersistedStatus().heightmapsAfter().iterator();
+@@ -348,6 +368,12 @@
-@@ -346,7 +354,13 @@
- 
-     private static Codec<PalettedContainerRO<Holder<Biome>>> makeBiomeCodec(Registry<Biome> biomeRegistry) {
          return PalettedContainer.codecRO(biomeRegistry.asHolderIdMap(), biomeRegistry.holderByNameCodec(), PalettedContainer.Strategy.SECTION_BIOMES, biomeRegistry.getOrThrow(Biomes.PLAINS));
-+    }
+     }
-+
+ 
 +    // CraftBukkit start - read/write
 +    private static Codec<PalettedContainer<Holder<Biome>>> makeBiomeCodecRW(Registry<Biome> iregistry) {
 +        return PalettedContainer.codecRW(iregistry.asHolderIdMap(), iregistry.holderByNameCodec(), PalettedContainer.Strategy.SECTION_BIOMES, iregistry.getOrThrow(Biomes.PLAINS));
-     }
++    }
 +    // CraftBukkit end
- 
++
      public static SerializableChunkData copyOf(ServerLevel world, ChunkAccess chunk) {
          if (!chunk.canBeSerialized()) {
-@@ -419,7 +433,14 @@
+             throw new IllegalArgumentException("Chunk can't be serialized: " + String.valueOf(chunk));
+@@ -419,7 +445,14 @@
              });
              CompoundTag nbttagcompound1 = packStructureData(StructurePieceSerializationContext.fromLevel(world), chunkcoordintpair, chunk.getAllStarts(), chunk.getAllReferences());
  
@@ -111,7 +138,7 @@
          }
      }
  
-@@ -432,7 +453,7 @@
+@@ -432,7 +465,7 @@
          nbttagcompound.putLong("LastUpdate", this.lastUpdateTime);
          nbttagcompound.putLong("InhabitedTime", this.inhabitedTime);
          nbttagcompound.putString("Status", BuiltInRegistries.CHUNK_STATUS.getKey(this.chunkStatus).toString());
@@ -120,7 +147,7 @@
          Logger logger;
  
          if (this.blendingData != null) {
-@@ -513,6 +534,11 @@
+@@ -513,6 +546,11 @@
          });
          nbttagcompound.put("Heightmaps", nbttagcompound2);
          nbttagcompound.put("structures", this.structureData);
@@ -132,7 +159,7 @@
          return nbttagcompound;
      }
  
-@@ -623,6 +649,12 @@
+@@ -623,6 +661,12 @@
                  StructureStart structurestart = StructureStart.loadStaticStart(context, nbttagcompound1.getCompound(s), worldSeed);
  
                  if (structurestart != null) {