Fix mob spawning

We should only iterate over the local region's entities, not the
global entity list to set up the spawner state, as everything else
about the spawner state (player count / chunk count) is regionised.
Additionally, move the last spawner state to regionised state so that
paper mobcaps command functions as expected.

patches/server/0004-Threaded-Regions.patch

@@ -5309,7 +5309,7 @@ index 0000000000000000000000000000000000000000..a40b88fbee7b92de38b49c4dfa7c2796
 +}
 diff --git a/src/main/java/io/papermc/paper/threadedregions/RegionisedWorldData.java b/src/main/java/io/papermc/paper/threadedregions/RegionisedWorldData.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..8317638bdb40764c389a68ced176e6d334eeb599
+index 0000000000000000000000000000000000000000..af875578822408fdc914548409dcb83a247c7c04
 --- /dev/null
 +++ b/src/main/java/io/papermc/paper/threadedregions/RegionisedWorldData.java
 @@ -0,0 +1,664 @@
@@ -5340,29 +5340,27 @@ index 0000000000000000000000000000000000000000..8317638bdb40764c389a68ced176e6d3
 +import net.minecraft.server.level.ServerLevel;
 +import net.minecraft.server.level.ServerPlayer;
 +import net.minecraft.server.network.ServerGamePacketListenerImpl;
-+import net.minecraft.util.Mth;
++import net.minecraft.util.VisibleForDebug;
 +import net.minecraft.world.entity.Entity;
 +import net.minecraft.world.entity.Mob;
 +import net.minecraft.world.entity.ai.village.VillageSiege;
 +import net.minecraft.world.entity.item.ItemEntity;
 +import net.minecraft.world.level.BlockEventData;
 +import net.minecraft.world.level.ChunkPos;
++import net.minecraft.world.level.NaturalSpawner;
 +import net.minecraft.world.level.block.Block;
 +import net.minecraft.world.level.block.entity.BlockEntity;
 +import net.minecraft.world.level.block.entity.TickingBlockEntity;
 +import net.minecraft.world.level.chunk.LevelChunk;
-+import net.minecraft.world.level.gameevent.GameEvent;
 +import net.minecraft.world.level.material.Fluid;
 +import net.minecraft.world.level.redstone.CollectingNeighborUpdater;
 +import net.minecraft.world.level.redstone.NeighborUpdater;
 +import net.minecraft.world.phys.AABB;
-+import net.minecraft.world.phys.Vec3;
 +import net.minecraft.world.ticks.LevelTicks;
 +import org.bukkit.craftbukkit.block.CraftBlockState;
 +import org.bukkit.craftbukkit.util.UnsafeList;
-+import org.bukkit.entity.SpawnCategory;
 +import org.slf4j.Logger;
-+
++import javax.annotation.Nullable;
 +import java.util.ArrayDeque;
 +import java.util.ArrayList;
 +import java.util.Arrays;
@@ -5371,7 +5369,6 @@ index 0000000000000000000000000000000000000000..8317638bdb40764c389a68ced176e6d3
 +import java.util.Iterator;
 +import java.util.List;
 +import java.util.Map;
-+import java.util.concurrent.atomic.AtomicReference;
 +import java.util.function.Consumer;
 +import java.util.function.Predicate;
 +
@@ -5680,6 +5677,9 @@ index 0000000000000000000000000000000000000000..8317638bdb40764c389a68ced176e6d3
 +    public final TempCollisionList<AABB> tempCollisionList = new TempCollisionList<>();
 +    public final TempCollisionList<Entity> tempEntitiesList = new TempCollisionList<>();
 +    public int currentPrimedTnt = 0; // Spigot
++    @Nullable
++    @VisibleForDebug
++    public NaturalSpawner.SpawnState lastSpawnState;
 +
 +    // not transient
 +    public java.util.ArrayDeque<net.minecraft.world.level.block.RedstoneTorchBlock.Toggle> redstoneUpdateInfos;
@@ -13260,10 +13260,10 @@ index 88fca8b160df6804f30ed2cf8cf1f645085434e2..341650384498eebe3f7a3315c398bec9
      }
  
 diff --git a/src/main/java/net/minecraft/server/level/ServerChunkCache.java b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
-index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2ce7719ede 100644
+index 736f37979c882e41e7571202df38eb6a2923fcb0..09a6a74f9bbcbbfba8bfc0424cde60002343b1af 100644
 --- a/src/main/java/net/minecraft/server/level/ServerChunkCache.java
 +++ b/src/main/java/net/minecraft/server/level/ServerChunkCache.java
-@@ -61,7 +61,7 @@ public class ServerChunkCache extends ChunkSource {
+@@ -61,73 +61,42 @@ public class ServerChunkCache extends ChunkSource {
      public final ServerChunkCache.MainThreadExecutor mainThreadProcessor;
      public final ChunkMap chunkMap;
      private final DimensionDataStorage dataStorage;
@@ -13272,9 +13272,13 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
      public boolean spawnEnemies = true;
      public boolean spawnFriendlies = true;
      private static final int CACHE_SIZE = 4;
-@@ -72,62 +72,33 @@ public class ServerChunkCache extends ChunkSource {
+     private final long[] lastChunkPos = new long[4];
-     @VisibleForDebug
+     private final ChunkStatus[] lastChunkStatus = new ChunkStatus[4];
-     private NaturalSpawner.SpawnState lastSpawnState;
+     private final ChunkAccess[] lastChunk = new ChunkAccess[4];
+-    @Nullable
+-    @VisibleForDebug
+-    private NaturalSpawner.SpawnState lastSpawnState;
++    // Folia - moved to regionised world data
      // Paper start
 -    final com.destroystokyo.paper.util.concurrent.WeakSeqLock loadedChunkMapSeqLock = new com.destroystokyo.paper.util.concurrent.WeakSeqLock();
 -    final it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap<LevelChunk> loadedChunkMap = new it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap<>(8192, 0.5f);
@@ -13345,7 +13349,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
      }
  
      public final LevelChunk getChunkAtIfLoadedMainThreadNoCache(int x, int z) {
-@@ -142,7 +113,7 @@ public class ServerChunkCache extends ChunkSource {
+@@ -142,7 +111,7 @@ public class ServerChunkCache extends ChunkSource {
          return (LevelChunk)this.getChunk(x, z, ChunkStatus.FULL, true);
      }
  
@@ -13354,7 +13358,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
  
      public void getEntityTickingChunkAsync(int x, int z, java.util.function.Consumer<LevelChunk> onLoad) {
          io.papermc.paper.chunk.system.ChunkSystem.scheduleTickingState(
-@@ -293,8 +264,7 @@ public class ServerChunkCache extends ChunkSource {
+@@ -293,8 +262,7 @@ public class ServerChunkCache extends ChunkSource {
          this.distanceManager.removeTicket(ticketType, chunkPos, ticketLevel, identifier);
      }
  
@@ -13364,7 +13368,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
      // Paper end
  
      public ServerChunkCache(ServerLevel world, LevelStorageSource.LevelStorageAccess session, DataFixer dataFixer, StructureTemplateManager structureTemplateManager, Executor workerExecutor, ChunkGenerator chunkGenerator, int viewDistance, int simulationDistance, boolean dsync, ChunkProgressListener worldGenerationProgressListener, ChunkStatusUpdateListener chunkStatusChangeListener, Supplier<DimensionDataStorage> persistentStateManagerFactory) {
-@@ -368,26 +338,7 @@ public class ServerChunkCache extends ChunkSource {
+@@ -368,26 +336,7 @@ public class ServerChunkCache extends ChunkSource {
      public LevelChunk getChunkAtIfLoadedImmediately(int x, int z) {
          long k = ChunkPos.asLong(x, z);
  
@@ -13392,7 +13396,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
      }
      // Paper end
      // Paper start - async chunk io
-@@ -483,6 +434,7 @@ public class ServerChunkCache extends ChunkSource {
+@@ -483,6 +432,7 @@ public class ServerChunkCache extends ChunkSource {
      }
  
      public CompletableFuture<Either<ChunkAccess, ChunkHolder.ChunkLoadingFailure>> getChunkFuture(int chunkX, int chunkZ, ChunkStatus leastStatus, boolean create) {
@@ -13400,7 +13404,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
          boolean flag1 = io.papermc.paper.util.TickThread.isTickThread(); // Paper - rewrite chunk system
          CompletableFuture completablefuture;
  
-@@ -659,10 +611,11 @@ public class ServerChunkCache extends ChunkSource {
+@@ -659,10 +609,11 @@ public class ServerChunkCache extends ChunkSource {
      }
  
      private void tickChunks() {
@@ -13414,7 +13418,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
          boolean flag = this.level.isDebug();
  
          if (flag) {
-@@ -670,9 +623,11 @@ public class ServerChunkCache extends ChunkSource {
+@@ -670,9 +621,11 @@ public class ServerChunkCache extends ChunkSource {
          } else {
              // Paper start - optimize isOutisdeRange
              ChunkMap playerChunkMap = this.chunkMap;
@@ -13428,7 +13432,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
                      continue;
                  }
  
-@@ -685,8 +640,9 @@ public class ServerChunkCache extends ChunkSource {
+@@ -685,8 +638,9 @@ public class ServerChunkCache extends ChunkSource {
  
                  com.destroystokyo.paper.event.entity.PlayerNaturallySpawnCreaturesEvent event = new com.destroystokyo.paper.event.entity.PlayerNaturallySpawnCreaturesEvent(player.getBukkitEntity(), (byte)chunkRange);
                  event.callEvent();
@@ -13440,7 +13444,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
                      continue;
                  }
  
-@@ -694,7 +650,7 @@ public class ServerChunkCache extends ChunkSource {
+@@ -694,7 +648,7 @@ public class ServerChunkCache extends ChunkSource {
                  int chunkX = io.papermc.paper.util.MCUtil.getChunkCoordinate(player.getX());
                  int chunkZ = io.papermc.paper.util.MCUtil.getChunkCoordinate(player.getZ());
  
@@ -13449,7 +13453,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
                  player.lastEntitySpawnRadiusSquared = (double)((range << 4) * (range << 4)); // used in anyPlayerCloseEnoughForSpawning
                  player.playerNaturallySpawnedEvent = event;
              }
-@@ -704,23 +660,16 @@ public class ServerChunkCache extends ChunkSource {
+@@ -704,26 +658,19 @@ public class ServerChunkCache extends ChunkSource {
  
              gameprofilerfiller.push("pollingChunks");
              int k = this.level.getGameRules().getInt(GameRules.RULE_RANDOMTICKING);
@@ -13472,12 +13476,16 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
 -            }
 -            // Paper end
 +            // Folia start - threaded regions - revert per-player mob caps
-+            spawnercreature_d = this.spawnFriendlies || this.spawnEnemies ? NaturalSpawner.createState(l, this.level.getAllEntities(), this::getFullChunk, new LocalMobCapCalculator(this.chunkMap)) : null;
++            spawnercreature_d = this.spawnFriendlies || this.spawnEnemies ? NaturalSpawner.createState(l, regionisedWorldData.getLocalEntities(), this::getFullChunk, new LocalMobCapCalculator(this.chunkMap)) : null; // Folia - region threading
 +            // Folia end - threaded regions - revert per-player mob caps
              this.level.timings.countNaturalMobs.stopTiming(); // Paper - timings
  
-             this.lastSpawnState = spawnercreature_d;
+-            this.lastSpawnState = spawnercreature_d;
-@@ -731,17 +680,17 @@ public class ServerChunkCache extends ChunkSource {
++            regionisedWorldData.lastSpawnState = spawnercreature_d; // Folia - region threading
+             gameprofilerfiller.popPush("filteringLoadedChunks");
+             // Paper - moved down
+             this.level.timings.chunkTicks.startTiming(); // Paper
+@@ -731,17 +678,17 @@ public class ServerChunkCache extends ChunkSource {
              // Paper - moved down
  
              gameprofilerfiller.popPush("spawnAndTick");
@@ -13500,7 +13508,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
                  while (iterator1.hasNext()) {
                      shuffled.add(iterator1.next());
                  }
-@@ -791,14 +740,14 @@ public class ServerChunkCache extends ChunkSource {
+@@ -791,14 +738,14 @@ public class ServerChunkCache extends ChunkSource {
              // Paper start - use set of chunks requiring updates, rather than iterating every single one loaded
              gameprofilerfiller.popPush("broadcast");
              this.level.timings.broadcastChunkUpdates.startTiming(); // Paper - timing
@@ -13519,7 +13527,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
                      }
                  }
              }
-@@ -806,8 +755,8 @@ public class ServerChunkCache extends ChunkSource {
+@@ -806,8 +753,8 @@ public class ServerChunkCache extends ChunkSource {
              gameprofilerfiller.pop();
              // Paper end - use set of chunks requiring updates, rather than iterating every single one loaded
              // Paper start - controlled flush for entity tracker packets
@@ -13530,7 +13538,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
                  net.minecraft.server.network.ServerGamePacketListenerImpl connection = player.connection;
                  if (connection != null) {
                      connection.connection.disableAutomaticFlush();
-@@ -880,14 +829,19 @@ public class ServerChunkCache extends ChunkSource {
+@@ -880,14 +827,19 @@ public class ServerChunkCache extends ChunkSource {
  
      @Override
      public void onLightUpdate(LightLayer type, SectionPos pos) {
@@ -13552,7 +13560,17 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
      }
  
      public <T> void addRegionTicket(TicketType<T> ticketType, ChunkPos pos, int radius, T argument) {
-@@ -992,8 +946,43 @@ public class ServerChunkCache extends ChunkSource {
+@@ -959,7 +911,8 @@ public class ServerChunkCache extends ChunkSource {
+     @Nullable
+     @VisibleForDebug
+     public NaturalSpawner.SpawnState getLastSpawnState() {
+-        return this.lastSpawnState;
++        io.papermc.paper.threadedregions.RegionisedWorldData worldData = this.level.getCurrentWorldData(); // Folia - region threading
++        return worldData == null ? null : worldData.lastSpawnState; // Folia - region threading
+     }
+ 
+     public void removeTicketsOnClosing() {
+@@ -992,8 +945,43 @@ public class ServerChunkCache extends ChunkSource {
              return ServerChunkCache.this.mainThread;
          }
  
@@ -13596,7 +13614,7 @@ index 736f37979c882e41e7571202df38eb6a2923fcb0..06ad3857f04ec073ae753b6569c5ae2c
              ServerChunkCache.this.level.getProfiler().incrementCounter("runTask");
              super.doRunTask(task);
          }
-@@ -1001,11 +990,16 @@ public class ServerChunkCache extends ChunkSource {
+@@ -1001,11 +989,16 @@ public class ServerChunkCache extends ChunkSource {
          @Override
          // CraftBukkit start - process pending Chunk loadCallback() and unloadCallback() after each run task
          public boolean pollTask() {