Paper/paper-server/nms-patches/net/minecraft/server/level/WorldServer.patch

--- a/net/minecraft/server/level/WorldServer.java
+++ b/net/minecraft/server/level/WorldServer.java
@@ -171,6 +171,23 @@
 import net.minecraft.world.ticks.TickListServer;
 import org.slf4j.Logger;
 
+// CraftBukkit start
+import net.minecraft.world.level.biome.WorldChunkManager;
+import net.minecraft.world.level.dimension.WorldDimension;
+import net.minecraft.world.level.levelgen.ChunkGeneratorAbstract;
+import net.minecraft.world.level.levelgen.ChunkProviderFlat;
+import net.minecraft.world.level.storage.WorldDataServer;
+import org.bukkit.Bukkit;
+import org.bukkit.WeatherType;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.craftbukkit.generator.CustomWorldChunkManager;
+import org.bukkit.craftbukkit.util.WorldUUID;
+import org.bukkit.event.entity.CreatureSpawnEvent;
+import org.bukkit.event.server.MapInitializeEvent;
+import org.bukkit.event.weather.LightningStrikeEvent;
+import org.bukkit.event.world.TimeSkipEvent;
+// CraftBukkit end
+
 public class WorldServer extends World implements GeneratorAccessSeed {
 
     public static final BlockPosition END_SPAWN_POINT = new BlockPosition(100, 50, 0);
@@ -184,7 +201,7 @@
     final List<EntityPlayer> players;
     private final ChunkProviderServer chunkSource;
     private final MinecraftServer server;
-    public final IWorldDataServer serverLevelData;
+    public final WorldDataServer serverLevelData; // CraftBukkit - type
     private int lastSpawnChunkRadius;
     final EntityTickList entityTickList;
     public final PersistentEntitySectionManager<Entity> entityManager;
@@ -211,12 +228,30 @@
     private final boolean tickTime;
     private final RandomSequences randomSequences;
 
-    public WorldServer(MinecraftServer minecraftserver, Executor executor, Convertable.ConversionSession convertable_conversionsession, IWorldDataServer iworlddataserver, ResourceKey<World> resourcekey, WorldDimension worlddimension, WorldLoadListener worldloadlistener, boolean flag, long i, List<MobSpawner> list, boolean flag1, @Nullable RandomSequences randomsequences) {
-        IRegistryCustom.Dimension iregistrycustom_dimension = minecraftserver.registryAccess();
-        Holder holder = worlddimension.type();
+    // CraftBukkit start
+    public final Convertable.ConversionSession convertable;
+    public final UUID uuid;
 
-        Objects.requireNonNull(minecraftserver);
-        super(iworlddataserver, resourcekey, iregistrycustom_dimension, holder, minecraftserver::getProfiler, false, flag, i, minecraftserver.getMaxChainedNeighborUpdates());
+    public Chunk getChunkIfLoaded(int x, int z) {
+        return this.chunkSource.getChunk(x, z, false);
+    }
+
+    @Override
+    public ResourceKey<WorldDimension> getTypeKey() {
+        return convertable.dimensionType;
+    }
+
+    // Add env and gen to constructor, IWorldDataServer -> WorldDataServer
+    public WorldServer(MinecraftServer minecraftserver, Executor executor, Convertable.ConversionSession convertable_conversionsession, WorldDataServer iworlddataserver, ResourceKey<World> resourcekey, WorldDimension worlddimension, WorldLoadListener worldloadlistener, boolean flag, long i, List<MobSpawner> list, boolean flag1, @Nullable RandomSequences randomsequences, org.bukkit.World.Environment env, org.bukkit.generator.ChunkGenerator gen, org.bukkit.generator.BiomeProvider biomeProvider) {
+        // IRegistryCustom.Dimension iregistrycustom_dimension = minecraftserver.registryAccess(); // CraftBukkit - decompile error
+        // Holder holder = worlddimension.type(); // CraftBukkit - decompile error
+
+        // Objects.requireNonNull(minecraftserver); // CraftBukkit - decompile error
+        super(iworlddataserver, resourcekey, minecraftserver.registryAccess(), worlddimension.type(), minecraftserver::getProfiler, false, flag, i, minecraftserver.getMaxChainedNeighborUpdates(), gen, biomeProvider, env);
+        this.pvpMode = minecraftserver.isPvpAllowed();
+        convertable = convertable_conversionsession;
+        uuid = WorldUUID.getUUID(convertable_conversionsession.levelDirectory.path().toFile());
+        // CraftBukkit end
         this.players = Lists.newArrayList();
         this.entityTickList = new EntityTickList();
         this.blockTicks = new TickListServer<>(this::isPositionTickingWithEntitiesLoaded, this.getProfilerSupplier());
@@ -231,6 +266,22 @@
         this.customSpawners = list;
         this.serverLevelData = iworlddataserver;
         ChunkGenerator chunkgenerator = worlddimension.generator();
+        // CraftBukkit start
+        serverLevelData.setWorld(this);
+
+        if (biomeProvider != null) {
+            WorldChunkManager worldChunkManager = new CustomWorldChunkManager(getWorld(), biomeProvider, server.registryAccess().registryOrThrow(Registries.BIOME));
+            if (chunkgenerator instanceof ChunkGeneratorAbstract cga) {
+                chunkgenerator = new ChunkGeneratorAbstract(worldChunkManager, cga.settings);
+            } else if (chunkgenerator instanceof ChunkProviderFlat cpf) {
+                chunkgenerator = new ChunkProviderFlat(cpf.settings(), worldChunkManager);
+            }
+        }
+
+        if (gen != null) {
+            chunkgenerator = new org.bukkit.craftbukkit.generator.CustomChunkGenerator(this, chunkgenerator, gen);
+        }
+        // CraftBukkit end
         boolean flag2 = minecraftserver.forceSynchronousWrites();
         DataFixer datafixer = minecraftserver.getFixerUpper();
         EntityPersistentStorage<Entity> entitypersistentstorage = new EntityStorage(new SimpleRegionStorage(new RegionStorageInfo(convertable_conversionsession.getLevelId(), resourcekey, "entities"), convertable_conversionsession.getDimensionPath(resourcekey).resolve("entities"), datafixer, flag2, DataFixTypes.ENTITY_CHUNK), this, minecraftserver);
@@ -258,9 +309,9 @@
         long l = minecraftserver.getWorldData().worldGenOptions().seed();
 
         this.structureCheck = new StructureCheck(this.chunkSource.chunkScanner(), this.registryAccess(), minecraftserver.getStructureManager(), resourcekey, chunkgenerator, this.chunkSource.randomState(), this, chunkgenerator.getBiomeSource(), l, datafixer);
-        this.structureManager = new StructureManager(this, minecraftserver.getWorldData().worldGenOptions(), this.structureCheck);
-        if (this.dimension() == World.END && this.dimensionTypeRegistration().is(BuiltinDimensionTypes.END)) {
-            this.dragonFight = new EnderDragonBattle(this, l, minecraftserver.getWorldData().endDragonFightData());
+        this.structureManager = new StructureManager(this, this.serverLevelData.worldGenOptions(), structureCheck); // CraftBukkit
+        if ((this.dimension() == World.END && this.dimensionTypeRegistration().is(BuiltinDimensionTypes.END)) || env == org.bukkit.World.Environment.THE_END) { // CraftBukkit - Allow to create EnderDragonBattle in default and custom END
+            this.dragonFight = new EnderDragonBattle(this, this.serverLevelData.worldGenOptions().seed(), this.serverLevelData.endDragonFightData()); // CraftBukkit
         } else {
             this.dragonFight = null;
         }
@@ -270,6 +321,7 @@
         this.randomSequences = (RandomSequences) Objects.requireNonNullElseGet(randomsequences, () -> {
             return (RandomSequences) this.getDataStorage().computeIfAbsent(RandomSequences.factory(l), "random_sequences");
         });
+        this.getCraftServer().addWorld(this.getWorld()); // CraftBukkit
     }
 
     /** @deprecated */
@@ -314,12 +366,20 @@
         long j;
 
         if (this.sleepStatus.areEnoughSleeping(i) && this.sleepStatus.areEnoughDeepSleeping(i, this.players)) {
+            // CraftBukkit start
+            j = this.levelData.getDayTime() + 24000L;
+            TimeSkipEvent event = new TimeSkipEvent(this.getWorld(), TimeSkipEvent.SkipReason.NIGHT_SKIP, (j - j % 24000L) - this.getDayTime());
             if (this.getGameRules().getBoolean(GameRules.RULE_DAYLIGHT)) {
-                j = this.levelData.getDayTime() + 24000L;
-                this.setDayTime(j - j % 24000L);
+                getCraftServer().getPluginManager().callEvent(event);
+                if (!event.isCancelled()) {
+                    this.setDayTime(this.getDayTime() + event.getSkipAmount());
+                }
             }
 
-            this.wakeUpAllPlayers();
+            if (!event.isCancelled()) {
+                this.wakeUpAllPlayers();
+            }
+            // CraftBukkit end
             if (this.getGameRules().getBoolean(GameRules.RULE_WEATHER_CYCLE) && this.isRaining()) {
                 this.resetWeatherCycle();
             }
@@ -354,7 +414,7 @@
 
         this.handlingTick = false;
         gameprofilerfiller.pop();
-        boolean flag1 = !this.players.isEmpty() || !this.getForcedChunks().isEmpty();
+        boolean flag1 = true || !this.players.isEmpty() || !this.getForcedChunks().isEmpty(); // CraftBukkit - this prevents entity cleanup, other issues on servers with no players
 
         if (flag1) {
             this.resetEmptyTime();
@@ -370,7 +430,7 @@
 
             this.entityTickList.forEach((entity) -> {
                 if (!entity.isRemoved()) {
-                    if (this.shouldDiscardEntity(entity)) {
+                    if (false && this.shouldDiscardEntity(entity)) { // CraftBukkit - We prevent spawning in general, so this butchering is not needed
                         entity.discard();
                     } else if (!tickratemanager.isEntityFrozen(entity)) {
                         gameprofilerfiller.push("checkDespawn");
@@ -442,7 +502,7 @@
 
     private void wakeUpAllPlayers() {
         this.sleepStatus.removeAllSleepers();
-        ((List) this.players.stream().filter(EntityLiving::isSleeping).collect(Collectors.toList())).forEach((entityplayer) -> {
+        (this.players.stream().filter(EntityLiving::isSleeping).collect(Collectors.toList())).forEach((entityplayer) -> { // CraftBukkit - decompile error
             entityplayer.stopSleepInBed(false, false);
         });
     }
@@ -469,7 +529,7 @@
                         entityhorseskeleton.setTrap(true);
                         entityhorseskeleton.setAge(0);
                         entityhorseskeleton.setPos((double) blockposition.getX(), (double) blockposition.getY(), (double) blockposition.getZ());
-                        this.addFreshEntity(entityhorseskeleton);
+                        this.addFreshEntity(entityhorseskeleton, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.LIGHTNING); // CraftBukkit
                     }
                 }
 
@@ -478,7 +538,7 @@
                 if (entitylightning != null) {
                     entitylightning.moveTo(Vec3D.atBottomCenterOf(blockposition));
                     entitylightning.setVisualOnly(flag1);
-                    this.addFreshEntity(entitylightning);
+                    this.strikeLightning(entitylightning, org.bukkit.event.weather.LightningStrikeEvent.Cause.WEATHER); // CraftBukkit
                 }
             }
         }
@@ -534,7 +594,7 @@
         BiomeBase biomebase = (BiomeBase) this.getBiome(blockposition1).value();
 
         if (biomebase.shouldFreeze(this, blockposition2)) {
-            this.setBlockAndUpdate(blockposition2, Blocks.ICE.defaultBlockState());
+            org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition2, Blocks.ICE.defaultBlockState(), null); // CraftBukkit
         }
 
         if (this.isRaining()) {
@@ -550,10 +610,10 @@
                         IBlockData iblockdata1 = (IBlockData) iblockdata.setValue(BlockSnow.LAYERS, j + 1);
 
                         Block.pushEntitiesUp(iblockdata, iblockdata1, this, blockposition1);
-                        this.setBlockAndUpdate(blockposition1, iblockdata1);
+                        org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition1, iblockdata1, null); // CraftBukkit
                     }
                 } else {
-                    this.setBlockAndUpdate(blockposition1, Blocks.SNOW.defaultBlockState());
+                    org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(this, blockposition1, Blocks.SNOW.defaultBlockState(), null); // CraftBukkit
                 }
             }
 
@@ -714,6 +774,7 @@
             this.rainLevel = MathHelper.clamp(this.rainLevel, 0.0F, 1.0F);
         }
 
+        /* CraftBukkit start
         if (this.oRainLevel != this.rainLevel) {
             this.server.getPlayerList().broadcastAll(new PacketPlayOutGameStateChange(PacketPlayOutGameStateChange.RAIN_LEVEL_CHANGE, this.rainLevel), this.dimension());
         }
@@ -732,15 +793,48 @@
             this.server.getPlayerList().broadcastAll(new PacketPlayOutGameStateChange(PacketPlayOutGameStateChange.RAIN_LEVEL_CHANGE, this.rainLevel));
             this.server.getPlayerList().broadcastAll(new PacketPlayOutGameStateChange(PacketPlayOutGameStateChange.THUNDER_LEVEL_CHANGE, this.thunderLevel));
         }
+        // */
+        for (int idx = 0; idx < this.players.size(); ++idx) {
+            if (((EntityPlayer) this.players.get(idx)).level() == this) {
+                ((EntityPlayer) this.players.get(idx)).tickWeather();
+            }
+        }
+
+        if (flag != this.isRaining()) {
+            // Only send weather packets to those affected
+            for (int idx = 0; idx < this.players.size(); ++idx) {
+                if (((EntityPlayer) this.players.get(idx)).level() == this) {
+                    ((EntityPlayer) this.players.get(idx)).setPlayerWeather((!flag ? WeatherType.DOWNFALL : WeatherType.CLEAR), false);
+                }
+            }
+        }
+        for (int idx = 0; idx < this.players.size(); ++idx) {
+            if (((EntityPlayer) this.players.get(idx)).level() == this) {
+                ((EntityPlayer) this.players.get(idx)).updateWeather(this.oRainLevel, this.rainLevel, this.oThunderLevel, this.thunderLevel);
+            }
+        }
+        // CraftBukkit end
 
     }
 
     @VisibleForTesting
     public void resetWeatherCycle() {
-        this.serverLevelData.setRainTime(0);
+        // CraftBukkit start
         this.serverLevelData.setRaining(false);
-        this.serverLevelData.setThunderTime(0);
+        // If we stop due to everyone sleeping we should reset the weather duration to some other random value.
+        // Not that everyone ever manages to get the whole server to sleep at the same time....
+        if (!this.serverLevelData.isRaining()) {
+            this.serverLevelData.setRainTime(0);
+        }
+        // CraftBukkit end
         this.serverLevelData.setThundering(false);
+        // CraftBukkit start
+        // If we stop due to everyone sleeping we should reset the weather duration to some other random value.
+        // Not that everyone ever manages to get the whole server to sleep at the same time....
+        if (!this.serverLevelData.isThundering()) {
+            this.serverLevelData.setThunderTime(0);
+        }
+        // CraftBukkit end
     }
 
     public void resetEmptyTime() {
@@ -775,6 +869,7 @@
         });
         gameprofilerfiller.incrementCounter("tickNonPassenger");
         entity.tick();
+        entity.postTick(); // CraftBukkit
         this.getProfiler().pop();
         Iterator iterator = entity.getPassengers().iterator();
 
@@ -798,6 +893,7 @@
                 });
                 gameprofilerfiller.incrementCounter("tickPassenger");
                 entity1.rideTick();
+                entity1.postTick(); // CraftBukkit
                 gameprofilerfiller.pop();
                 Iterator iterator = entity1.getPassengers().iterator();
 
@@ -822,6 +918,7 @@
         ChunkProviderServer chunkproviderserver = this.getChunkSource();
 
         if (!flag1) {
+            org.bukkit.Bukkit.getPluginManager().callEvent(new org.bukkit.event.world.WorldSaveEvent(getWorld())); // CraftBukkit
             if (iprogressupdate != null) {
                 iprogressupdate.progressStartNoAbort(IChatBaseComponent.translatable("menu.savingLevel"));
             }
@@ -839,11 +936,19 @@
             }
 
         }
+
+        // CraftBukkit start - moved from MinecraftServer.saveChunks
+        WorldServer worldserver1 = this;
+
+        serverLevelData.setWorldBorder(worldserver1.getWorldBorder().createSettings());
+        serverLevelData.setCustomBossEvents(this.server.getCustomBossEvents().save(this.registryAccess()));
+        convertable.saveDataTag(this.server.registryAccess(), this.serverLevelData, this.server.getPlayerList().getSingleplayerData());
+        // CraftBukkit end
     }
 
     private void saveLevelData() {
         if (this.dragonFight != null) {
-            this.server.getWorldData().setEndDragonFightData(this.dragonFight.saveData());
+            this.serverLevelData.setEndDragonFightData(this.dragonFight.saveData()); // CraftBukkit
         }
 
         this.getChunkSource().getDataStorage().save();
@@ -908,18 +1013,40 @@
 
     @Override
     public boolean addFreshEntity(Entity entity) {
-        return this.addEntity(entity);
+        // CraftBukkit start
+        return this.addFreshEntity(entity, CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    @Override
+    public boolean addFreshEntity(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
+        return this.addEntity(entity, reason);
+        // CraftBukkit end
     }
 
     public boolean addWithUUID(Entity entity) {
-        return this.addEntity(entity);
+        // CraftBukkit start
+        return this.addWithUUID(entity, CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    public boolean addWithUUID(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
+        return this.addEntity(entity, reason);
+        // CraftBukkit end
     }
 
     public void addDuringTeleport(Entity entity) {
+        // CraftBukkit start
+        // SPIGOT-6415: Don't call spawn event for entities which travel trough worlds,
+        // since it is only an implementation detail, that a new entity is created when
+        // they are traveling between worlds.
+        this.addDuringTeleport(entity, null);
+    }
+
+    public void addDuringTeleport(Entity entity, CreatureSpawnEvent.SpawnReason reason) {
+        // CraftBukkit end
         if (entity instanceof EntityPlayer entityplayer) {
             this.addPlayer(entityplayer);
         } else {
-            this.addEntity(entity);
+            this.addEntity(entity, reason); // CraftBukkit
         }
 
     }
@@ -944,24 +1071,37 @@
         this.entityManager.addNewEntity(entityplayer);
     }
 
-    private boolean addEntity(Entity entity) {
+    // CraftBukkit start
+    private boolean addEntity(Entity entity, CreatureSpawnEvent.SpawnReason spawnReason) {
         if (entity.isRemoved()) {
-            WorldServer.LOGGER.warn("Tried to add entity {} but it was marked as removed already", EntityTypes.getKey(entity.getType()));
+            // WorldServer.LOGGER.warn("Tried to add entity {} but it was marked as removed already", EntityTypes.getKey(entity.getType())); // CraftBukkit
             return false;
         } else {
+            // SPIGOT-6415: Don't call spawn event when reason is null. For example when an entity teleports to a new world.
+            if (spawnReason != null && !CraftEventFactory.doEntityAddEventCalling(this, entity, spawnReason)) {
+                return false;
+            }
+            // CraftBukkit end
+
             return this.entityManager.addNewEntity(entity);
         }
     }
 
     public boolean tryAddFreshEntityWithPassengers(Entity entity) {
-        Stream stream = entity.getSelfAndPassengers().map(Entity::getUUID);
+        // CraftBukkit start
+        return this.tryAddFreshEntityWithPassengers(entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    public boolean tryAddFreshEntityWithPassengers(Entity entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason reason) {
+        // CraftBukkit end
+        Stream<UUID> stream = entity.getSelfAndPassengers().map(Entity::getUUID); // CraftBukkit - decompile error
         PersistentEntitySectionManager persistententitysectionmanager = this.entityManager;
 
         Objects.requireNonNull(this.entityManager);
         if (stream.anyMatch(persistententitysectionmanager::isLoaded)) {
             return false;
         } else {
-            this.addFreshEntityWithPassengers(entity);
+            this.addFreshEntityWithPassengers(entity, reason); // CraftBukkit
             return true;
         }
     }
@@ -972,13 +1112,35 @@
     }
 
     public void removePlayerImmediately(EntityPlayer entityplayer, Entity.RemovalReason entity_removalreason) {
-        entityplayer.remove(entity_removalreason);
+        entityplayer.remove(entity_removalreason, null); // CraftBukkit - add Bukkit remove cause
     }
 
+    // CraftBukkit start
+    public boolean strikeLightning(Entity entitylightning) {
+        return this.strikeLightning(entitylightning, LightningStrikeEvent.Cause.UNKNOWN);
+    }
+
+    public boolean strikeLightning(Entity entitylightning, LightningStrikeEvent.Cause cause) {
+        LightningStrikeEvent lightning = CraftEventFactory.callLightningStrikeEvent((org.bukkit.entity.LightningStrike) entitylightning.getBukkitEntity(), cause);
+
+        if (lightning.isCancelled()) {
+            return false;
+        }
+
+        return this.addFreshEntity(entitylightning);
+    }
+    // CraftBukkit end
+
     @Override
     public void destroyBlockProgress(int i, BlockPosition blockposition, int j) {
         Iterator iterator = this.server.getPlayerList().getPlayers().iterator();
 
+        // CraftBukkit start
+        EntityHuman entityhuman = null;
+        Entity entity = this.getEntity(i);
+        if (entity instanceof EntityHuman) entityhuman = (EntityHuman) entity;
+        // CraftBukkit end
+
         while (iterator.hasNext()) {
             EntityPlayer entityplayer = (EntityPlayer) iterator.next();
 
@@ -987,6 +1149,12 @@
                 double d1 = (double) blockposition.getY() - entityplayer.getY();
                 double d2 = (double) blockposition.getZ() - entityplayer.getZ();
 
+                // CraftBukkit start
+                if (entityhuman != null && !entityplayer.getBukkitEntity().canSee(entityhuman.getBukkitEntity())) {
+                    continue;
+                }
+                // CraftBukkit end
+
                 if (d0 * d0 + d1 * d1 + d2 * d2 < 1024.0D) {
                     entityplayer.connection.send(new PacketPlayOutBlockBreakAnimation(i, blockposition, j));
                 }
@@ -1047,7 +1215,18 @@
             Iterator iterator = this.navigatingMobs.iterator();
 
             while (iterator.hasNext()) {
-                EntityInsentient entityinsentient = (EntityInsentient) iterator.next();
+                // CraftBukkit start - fix SPIGOT-6362
+                EntityInsentient entityinsentient;
+                try {
+                    entityinsentient = (EntityInsentient) iterator.next();
+                } catch (java.util.ConcurrentModificationException ex) {
+                    // This can happen because the pathfinder update below may trigger a chunk load, which in turn may cause more navigators to register
+                    // In this case we just run the update again across all the iterators as the chunk will then be loaded
+                    // As this is a relative edge case it is much faster than copying navigators (on either read or write)
+                    sendBlockUpdated(blockposition, iblockdata, iblockdata1, i);
+                    return;
+                }
+                // CraftBukkit end
                 NavigationAbstract navigationabstract = entityinsentient.getNavigation();
 
                 if (navigationabstract.shouldRecomputePath(blockposition)) {
@@ -1109,6 +1288,11 @@
     @Override
     public Explosion explode(@Nullable Entity entity, @Nullable DamageSource damagesource, @Nullable ExplosionDamageCalculator explosiondamagecalculator, double d0, double d1, double d2, float f, boolean flag, World.a world_a, ParticleParam particleparam, ParticleParam particleparam1, Holder<SoundEffect> holder) {
         Explosion explosion = this.explode(entity, damagesource, explosiondamagecalculator, d0, d1, d2, f, flag, world_a, false, particleparam, particleparam1, holder);
+        // CraftBukkit start
+        if (explosion.wasCanceled) {
+            return explosion;
+        }
+        // CraftBukkit end
 
         if (!explosion.interactsWithBlocks()) {
             explosion.clearToBlow();
@@ -1181,13 +1365,20 @@
     }
 
     public <T extends ParticleParam> int sendParticles(T t0, double d0, double d1, double d2, int i, double d3, double d4, double d5, double d6) {
-        PacketPlayOutWorldParticles packetplayoutworldparticles = new PacketPlayOutWorldParticles(t0, false, d0, d1, d2, (float) d3, (float) d4, (float) d5, (float) d6, i);
+        // CraftBukkit - visibility api support
+        return sendParticles(null, t0, d0, d1, d2, i, d3, d4, d5, d6, false);
+    }
+
+    public <T extends ParticleParam> int sendParticles(EntityPlayer sender, T t0, double d0, double d1, double d2, int i, double d3, double d4, double d5, double d6, boolean force) {
+        PacketPlayOutWorldParticles packetplayoutworldparticles = new PacketPlayOutWorldParticles(t0, force, d0, d1, d2, (float) d3, (float) d4, (float) d5, (float) d6, i);
+        // CraftBukkit end
         int j = 0;
 
         for (int k = 0; k < this.players.size(); ++k) {
             EntityPlayer entityplayer = (EntityPlayer) this.players.get(k);
+            if (sender != null && !entityplayer.getBukkitEntity().canSee(sender.getBukkitEntity())) continue; // CraftBukkit
 
-            if (this.sendParticles(entityplayer, false, d0, d1, d2, packetplayoutworldparticles)) {
+            if (this.sendParticles(entityplayer, force, d0, d1, d2, packetplayoutworldparticles)) { // CraftBukkit
                 ++j;
             }
         }
@@ -1238,7 +1429,7 @@
 
     @Nullable
     public BlockPosition findNearestMapStructure(TagKey<Structure> tagkey, BlockPosition blockposition, int i, boolean flag) {
-        if (!this.server.getWorldData().worldGenOptions().generateStructures()) {
+        if (!this.serverLevelData.worldGenOptions().generateStructures()) { // CraftBukkit
             return null;
         } else {
             Optional<HolderSet.Named<Structure>> optional = this.registryAccess().registryOrThrow(Registries.STRUCTURE).getTag(tagkey);
@@ -1280,11 +1471,22 @@
     @Nullable
     @Override
     public WorldMap getMapData(MapId mapid) {
-        return (WorldMap) this.getServer().overworld().getDataStorage().get(WorldMap.factory(), mapid.key());
+        // CraftBukkit start
+        WorldMap worldmap = (WorldMap) this.getServer().overworld().getDataStorage().get(WorldMap.factory(), mapid.key());
+        if (worldmap != null) {
+            worldmap.id = mapid;
+        }
+        return worldmap;
+        // CraftBukkit end
     }
 
     @Override
     public void setMapData(MapId mapid, WorldMap worldmap) {
+        // CraftBukkit start
+        worldmap.id = mapid;
+        MapInitializeEvent event = new MapInitializeEvent(worldmap.mapView);
+        Bukkit.getServer().getPluginManager().callEvent(event);
+        // CraftBukkit end
         this.getServer().overworld().getDataStorage().set(mapid.key(), worldmap);
     }
 
@@ -1595,6 +1797,11 @@
     @Override
     public void blockUpdated(BlockPosition blockposition, Block block) {
         if (!this.isDebug()) {
+            // CraftBukkit start
+            if (populating) {
+                return;
+            }
+            // CraftBukkit end
             this.updateNeighborsAt(blockposition, block);
         }
 
@@ -1614,12 +1821,12 @@
     }
 
     public boolean isFlat() {
-        return this.server.getWorldData().isFlatWorld();
+        return this.serverLevelData.isFlatWorld(); // CraftBukkit
     }
 
     @Override
     public long getSeed() {
-        return this.server.getWorldData().worldGenOptions().seed();
+        return this.serverLevelData.worldGenOptions().seed(); // CraftBukkit
     }
 
     @Nullable
@@ -1642,7 +1849,7 @@
     private static <T> String getTypeCount(Iterable<T> iterable, Function<T, String> function) {
         try {
             Object2IntOpenHashMap<String> object2intopenhashmap = new Object2IntOpenHashMap();
-            Iterator iterator = iterable.iterator();
+            Iterator<T> iterator = iterable.iterator(); // CraftBukkit - decompile error
 
             while (iterator.hasNext()) {
                 T t0 = iterator.next();
@@ -1651,7 +1858,7 @@
                 object2intopenhashmap.addTo(s, 1);
             }
 
-            return (String) object2intopenhashmap.object2IntEntrySet().stream().sorted(Comparator.comparing(Entry::getIntValue).reversed()).limit(5L).map((entry) -> {
+            return (String) object2intopenhashmap.object2IntEntrySet().stream().sorted(Comparator.comparing(Entry<String>::getIntValue).reversed()).limit(5L).map((entry) -> { // CraftBukkit - decompile error
                 String s1 = (String) entry.getKey();
 
                 return s1 + ":" + entry.getIntValue();
@@ -1796,6 +2003,8 @@
             }
 
             entity.updateDynamicGameEventListener(DynamicGameEventListener::add);
+            entity.inWorld = true; // CraftBukkit - Mark entity as in world
+            entity.valid = true; // CraftBukkit
         }
 
         public void onTrackingEnd(Entity entity) {
@@ -1827,6 +2036,14 @@
             }
 
             entity.updateDynamicGameEventListener(DynamicGameEventListener::remove);
+            // CraftBukkit start
+            entity.valid = false;
+            if (!(entity instanceof EntityPlayer)) {
+                for (EntityPlayer player : players) {
+                    player.getBukkitEntity().onEntityRemove(entity);
+                }
+            }
+            // CraftBukkit end
         }
 
         public void onSectionChange(Entity entity) {