PaperMC/paper-server/patches/sources/net/minecraft/server/level/ChunkMap.java.patch

--- a/net/minecraft/server/level/ChunkMap.java
+++ b/net/minecraft/server/level/ChunkMap.java
@@ -104,6 +104,10 @@
 import org.apache.commons.lang3.mutable.MutableBoolean;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.generator.CustomChunkGenerator;
+// CraftBukkit end
+
 public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider, GeneratingChunkMap {
 
     private static final ChunkResult<List<ChunkAccess>> UNLOADED_CHUNK_LIST_RESULT = ChunkResult.error("Unloaded chunks found in range");
@@ -148,6 +152,27 @@
     private final AtomicInteger activeChunkWrites;
     public int serverViewDistance;
     private final WorldGenContext worldGenContext;
+
+    // CraftBukkit start - recursion-safe executor for Chunk loadCallback() and unloadCallback()
+    public final CallbackExecutor callbackExecutor = new CallbackExecutor();
+    public static final class CallbackExecutor implements java.util.concurrent.Executor, Runnable {
+
+        private final java.util.Queue<Runnable> queue = new java.util.ArrayDeque<>();
+
+        @Override
+        public void execute(Runnable runnable) {
+            this.queue.add(runnable);
+        }
+
+        @Override
+        public void run() {
+            Runnable task;
+            while ((task = this.queue.poll()) != null) {
+                task.run();
+            }
+        }
+    };
+    // CraftBukkit end
 
     public ChunkMap(ServerLevel world, LevelStorageSource.LevelStorageAccess session, DataFixer dataFixer, StructureTemplateManager structureTemplateManager, Executor executor, BlockableEventLoop<Runnable> mainThreadExecutor, LightChunkGetter chunkProvider, ChunkGenerator chunkGenerator, ChunkProgressListener worldGenerationProgressListener, ChunkStatusUpdateListener chunkStatusChangeListener, Supplier<DimensionDataStorage> persistentStateManagerFactory, int viewDistance, boolean dsync) {
         super(new RegionStorageInfo(session.getLevelId(), world.dimension(), "chunk"), session.getDimensionPath(world.dimension()).resolve("region"), dataFixer, dsync);
@@ -170,7 +195,13 @@
         RegistryAccess iregistrycustom = world.registryAccess();
         long j = world.getSeed();
 
-        if (chunkGenerator instanceof NoiseBasedChunkGenerator chunkgeneratorabstract) {
+        // CraftBukkit start - SPIGOT-7051: It's a rigged game! Use delegate for random state creation, otherwise it is not so random.
+        ChunkGenerator randomGenerator = chunkGenerator;
+        if (randomGenerator instanceof CustomChunkGenerator customChunkGenerator) {
+            randomGenerator = customChunkGenerator.getDelegate();
+        }
+        if (randomGenerator instanceof NoiseBasedChunkGenerator chunkgeneratorabstract) {
+            // CraftBukkit end
             this.randomState = RandomState.create((NoiseGeneratorSettings) chunkgeneratorabstract.generatorSettings().value(), (HolderGetter) iregistrycustom.lookupOrThrow(Registries.NOISE), j);
         } else {
             this.randomState = RandomState.create(NoiseGeneratorSettings.dummy(), (HolderGetter) iregistrycustom.lookupOrThrow(Registries.NOISE), j);
@@ -325,7 +356,7 @@
                         throw this.debugFuturesAndCreateReportedException(new IllegalStateException("At least one of the chunk futures were null"), "n/a");
                     }
 
-                    ChunkAccess ichunkaccess = (ChunkAccess) chunkresult.orElse((Object) null);
+                    ChunkAccess ichunkaccess = (ChunkAccess) chunkresult.orElse(null); // CraftBukkit - decompile error
 
                     if (ichunkaccess == null) {
                         return ChunkMap.UNLOADED_CHUNK_LIST_RESULT;
@@ -977,7 +1008,8 @@
                 return ichunkaccess instanceof LevelChunk ? Optional.of((LevelChunk) ichunkaccess) : Optional.empty();
             });
 
-            csvwriter.writeRow(chunkcoordintpair.x, chunkcoordintpair.z, playerchunk.getTicketLevel(), optional.isPresent(), optional.map(ChunkAccess::getPersistedStatus).orElse((Object) null), optional1.map(LevelChunk::getFullStatus).orElse((Object) null), ChunkMap.printFuture(playerchunk.getFullChunkFuture()), ChunkMap.printFuture(playerchunk.getTickingChunkFuture()), ChunkMap.printFuture(playerchunk.getEntityTickingChunkFuture()), this.distanceManager.getTicketDebugString(i), this.anyPlayerCloseEnoughForSpawning(chunkcoordintpair), optional1.map((chunk) -> {
+            // CraftBukkit - decompile error
+            csvwriter.writeRow(chunkcoordintpair.x, chunkcoordintpair.z, playerchunk.getTicketLevel(), optional.isPresent(), optional.map(ChunkAccess::getPersistedStatus).orElse(null), optional1.map(LevelChunk::getFullStatus).orElse(null), ChunkMap.printFuture(playerchunk.getFullChunkFuture()), ChunkMap.printFuture(playerchunk.getTickingChunkFuture()), ChunkMap.printFuture(playerchunk.getEntityTickingChunkFuture()), this.distanceManager.getTicketDebugString(i), this.anyPlayerCloseEnoughForSpawning(chunkcoordintpair), optional1.map((chunk) -> {
                 return chunk.getBlockEntities().size();
             }).orElse(0), tickingtracker.getTicketDebugString(i), tickingtracker.getLevel(i), optional1.map((chunk) -> {
                 return chunk.getBlockTicks().count();
@@ -990,7 +1022,7 @@
 
     private static String printFuture(CompletableFuture<ChunkResult<LevelChunk>> future) {
         try {
-            ChunkResult<LevelChunk> chunkresult = (ChunkResult) future.getNow((Object) null);
+            ChunkResult<LevelChunk> chunkresult = (ChunkResult) future.getNow(null); // CraftBukkit - decompile error
 
             return chunkresult != null ? (chunkresult.isSuccess() ? "done" : "unloaded") : "not completed";
         } catch (CompletionException completionexception) {
@@ -1002,12 +1034,14 @@
 
     private CompletableFuture<Optional<CompoundTag>> readChunk(ChunkPos chunkPos) {
         return this.read(chunkPos).thenApplyAsync((optional) -> {
-            return optional.map(this::upgradeChunkTag);
+            return optional.map((nbttagcompound) -> this.upgradeChunkTag(nbttagcompound, chunkPos)); // CraftBukkit
         }, Util.backgroundExecutor().forName("upgradeChunk"));
     }
 
-    private CompoundTag upgradeChunkTag(CompoundTag nbt) {
-        return this.upgradeChunkTag(this.level.dimension(), this.overworldDataStorage, nbt, this.generator().getTypeNameForDataFixer());
+    // CraftBukkit start
+    private CompoundTag upgradeChunkTag(CompoundTag nbttagcompound, ChunkPos chunkcoordintpair) {
+        return this.upgradeChunkTag(this.level.getTypeKey(), this.overworldDataStorage, nbttagcompound, this.generator().getTypeNameForDataFixer(), chunkcoordintpair, this.level);
+        // CraftBukkit end
     }
 
     void forEachSpawnCandidateChunk(Consumer<ChunkHolder> callback) {
@@ -1025,10 +1059,27 @@
     }
 
     public boolean anyPlayerCloseEnoughForSpawning(ChunkPos pos) {
-        return !this.distanceManager.hasPlayersNearby(pos.toLong()) ? false : this.anyPlayerCloseEnoughForSpawningInternal(pos);
+        // Spigot start
+        return this.anyPlayerCloseEnoughForSpawning(pos, false);
     }
 
+    boolean anyPlayerCloseEnoughForSpawning(ChunkPos chunkcoordintpair, boolean reducedRange) {
+        return !this.distanceManager.hasPlayersNearby(chunkcoordintpair.toLong()) ? false : this.anyPlayerCloseEnoughForSpawningInternal(chunkcoordintpair, reducedRange);
+        // Spigot end
+    }
+
     private boolean anyPlayerCloseEnoughForSpawningInternal(ChunkPos pos) {
+        // Spigot start
+        return this.anyPlayerCloseEnoughForSpawningInternal(pos, false);
+    }
+
+    private boolean anyPlayerCloseEnoughForSpawningInternal(ChunkPos chunkcoordintpair, boolean reducedRange) {
+        int chunkRange = this.level.spigotConfig.mobSpawnRange;
+        chunkRange = (chunkRange > this.level.spigotConfig.viewDistance) ? (byte) this.level.spigotConfig.viewDistance : chunkRange;
+        chunkRange = (chunkRange > 8) ? 8 : chunkRange;
+
+        double blockRange = (reducedRange) ? Math.pow(chunkRange << 4, 2) : 16384.0D;
+        // Spigot end
         Iterator iterator = this.playerMap.getAllPlayers().iterator();
 
         ServerPlayer entityplayer;
@@ -1039,7 +1090,7 @@
             }
 
             entityplayer = (ServerPlayer) iterator.next();
-        } while (!this.playerIsCloseEnoughForSpawning(entityplayer, pos));
+        } while (!this.playerIsCloseEnoughForSpawning(entityplayer, chunkcoordintpair, blockRange)); // Spigot
 
         return true;
     }
@@ -1056,7 +1107,7 @@
             while (iterator.hasNext()) {
                 ServerPlayer entityplayer = (ServerPlayer) iterator.next();
 
-                if (this.playerIsCloseEnoughForSpawning(entityplayer, pos)) {
+                if (this.playerIsCloseEnoughForSpawning(entityplayer, pos, 16384.0D)) { // Spigot
                     builder.add(entityplayer);
                 }
             }
@@ -1065,13 +1116,13 @@
         }
     }
 
-    private boolean playerIsCloseEnoughForSpawning(ServerPlayer player, ChunkPos pos) {
-        if (player.isSpectator()) {
+    private boolean playerIsCloseEnoughForSpawning(ServerPlayer entityplayer, ChunkPos chunkcoordintpair, double range) { // Spigot
+        if (entityplayer.isSpectator()) {
             return false;
         } else {
-            double d0 = ChunkMap.euclideanDistanceSquared(pos, player);
+            double d0 = ChunkMap.euclideanDistanceSquared(chunkcoordintpair, entityplayer);
 
-            return d0 < 16384.0D;
+            return d0 < range; // Spigot
         }
     }
 
@@ -1215,9 +1266,11 @@
     }
 
     public void addEntity(Entity entity) {
+        org.spigotmc.AsyncCatcher.catchOp("entity track"); // Spigot
         if (!(entity instanceof EnderDragonPart)) {
             EntityType<?> entitytypes = entity.getType();
             int i = entitytypes.clientTrackingRange() * 16;
+            i = org.spigotmc.TrackingRange.getEntityTrackingRange(entity, i); // Spigot
 
             if (i != 0) {
                 int j = entitytypes.updateInterval();
@@ -1250,6 +1303,7 @@
     }
 
     protected void removeEntity(Entity entity) {
+        org.spigotmc.AsyncCatcher.catchOp("entity untrack"); // Spigot
         if (entity instanceof ServerPlayer entityplayer) {
             this.updatePlayerStatus(entityplayer, false);
             ObjectIterator objectiterator = this.entityMap.values().iterator();
@@ -1424,7 +1478,7 @@
         public final Set<ServerPlayerConnection> seenBy = Sets.newIdentityHashSet();
 
         public TrackedEntity(final Entity entity, final int i, final int j, final boolean flag) {
-            this.serverEntity = new ServerEntity(ChunkMap.this.level, entity, j, flag, this::broadcast);
+            this.serverEntity = new ServerEntity(ChunkMap.this.level, entity, j, flag, this::broadcast, this.seenBy); // CraftBukkit
             this.entity = entity;
             this.range = i;
             this.lastSectionPos = SectionPos.of((EntityAccess) entity);
@@ -1469,6 +1523,7 @@
         }
 
         public void removePlayer(ServerPlayer player) {
+            org.spigotmc.AsyncCatcher.catchOp("player tracker clear"); // Spigot
             if (this.seenBy.remove(player.connection)) {
                 this.serverEntity.removePairing(player);
             }
@@ -1476,6 +1531,7 @@
         }
 
         public void updatePlayer(ServerPlayer player) {
+            org.spigotmc.AsyncCatcher.catchOp("player tracker update"); // Spigot
             if (player != this.entity) {
                 Vec3 vec3d = player.position().subtract(this.entity.position());
                 int i = ChunkMap.this.getPlayerViewDistance(player);
@@ -1484,6 +1540,11 @@
                 double d2 = d0 * d0;
                 boolean flag = d1 <= d2 && this.entity.broadcastToPlayer(player) && ChunkMap.this.isChunkTracked(player, this.entity.chunkPosition().x, this.entity.chunkPosition().z);
 
+                // CraftBukkit start - respect vanish API
+                if (!player.getBukkitEntity().canSee(this.entity.getBukkitEntity())) {
+                    flag = false;
+                }
+                // CraftBukkit end
                 if (flag) {
                     if (this.seenBy.add(player.connection)) {
                         this.serverEntity.addPairing(player);