Paper/nms-patches/Entity.patch

--- a/net/minecraft/server/Entity.java
+++ b/net/minecraft/server/Entity.java
@@ -20,8 +20,57 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+// CraftBukkit start
+import org.bukkit.Bukkit;
+import org.bukkit.Location;
+import org.bukkit.Server;
+import org.bukkit.block.BlockFace;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Hanging;
+import org.bukkit.entity.LivingEntity;
+import org.bukkit.entity.Vehicle;
+import org.bukkit.event.entity.EntityCombustByEntityEvent;
+import org.bukkit.event.hanging.HangingBreakByEntityEvent;
+import org.bukkit.event.vehicle.VehicleBlockCollisionEvent;
+import org.bukkit.event.vehicle.VehicleEnterEvent;
+import org.bukkit.event.vehicle.VehicleExitEvent;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.entity.CraftEntity;
+import org.bukkit.craftbukkit.entity.CraftPlayer;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.entity.Pose;
+import org.bukkit.event.entity.EntityAirChangeEvent;
+import org.bukkit.event.entity.EntityCombustEvent;
+import org.bukkit.event.entity.EntityDropItemEvent;
+import org.bukkit.event.entity.EntityPortalEvent;
+import org.bukkit.event.entity.EntityPoseChangeEvent;
+import org.bukkit.event.player.PlayerTeleportEvent;
+import org.bukkit.plugin.PluginManager;
+// CraftBukkit end
+
 public abstract class Entity implements INamableTileEntity, ICommandListener {
 
+    // CraftBukkit start
+    private static final int CURRENT_LEVEL = 2;
+    static boolean isLevelAtLeast(NBTTagCompound tag, int level) {
+        return tag.hasKey("Bukkit.updateLevel") && tag.getInt("Bukkit.updateLevel") >= level;
+    }
+
+    protected CraftEntity bukkitEntity;
+
+    public CraftEntity getBukkitEntity() {
+        if (bukkitEntity == null) {
+            bukkitEntity = CraftEntity.getEntity(world.getServer(), this);
+        }
+        return bukkitEntity;
+    }
+
+    @Override
+    public CommandSender getBukkitSender(CommandListenerWrapper wrapper) {
+        return getBukkitEntity();
+    }
+    // CraftBukkit end
+
     protected static final Logger LOGGER = LogManager.getLogger();
     private static final AtomicInteger entityCount = new AtomicInteger();
     private static final List<ItemStack> c = Collections.emptyList();
@@ -106,6 +155,16 @@
     private long aH;
     private EntitySize size;
     private float headHeight;
+    // CraftBukkit start
+    public boolean persist = true;
+    public boolean valid;
+    public org.bukkit.projectiles.ProjectileSource projectileSource; // For projectiles only
+    public boolean forceExplosionKnockback; // SPIGOT-949
+
+    public float getBukkitYaw() {
+        return this.yaw;
+    }
+    // CraftBukkit end
 
     public Entity(EntityTypes<?> entitytypes, World world) {
         this.id = Entity.entityCount.incrementAndGet();
@@ -204,6 +263,12 @@
     }
 
     protected void b(EntityPose entitypose) {
+        // CraftBukkit start
+        if (entitypose == this.Z()) {
+            return;
+        }
+        this.world.getServer().getPluginManager().callEvent(new EntityPoseChangeEvent(this.getBukkitEntity(), Pose.values()[entitypose.ordinal()]));
+        // CraftBukkit end
         this.datawatcher.set(Entity.X, entitypose);
     }
 
@@ -212,6 +277,33 @@
     }
 
     protected void setYawPitch(float f, float f1) {
+        // CraftBukkit start - yaw was sometimes set to NaN, so we need to set it back to 0
+        if (Float.isNaN(f)) {
+            f = 0;
+        }
+
+        if (f == Float.POSITIVE_INFINITY || f == Float.NEGATIVE_INFINITY) {
+            if (this instanceof EntityPlayer) {
+                this.world.getServer().getLogger().warning(this.getName() + " was caught trying to crash the server with an invalid yaw");
+                ((CraftPlayer) this.getBukkitEntity()).kickPlayer("Infinite yaw (Hacking?)");
+            }
+            f = 0;
+        }
+
+        // pitch was sometimes set to NaN, so we need to set it back to 0
+        if (Float.isNaN(f1)) {
+            f1 = 0;
+        }
+
+        if (f1 == Float.POSITIVE_INFINITY || f1 == Float.NEGATIVE_INFINITY) {
+            if (this instanceof EntityPlayer) {
+                this.world.getServer().getLogger().warning(this.getName() + " was caught trying to crash the server with an invalid pitch");
+                ((CraftPlayer) this.getBukkitEntity()).kickPlayer("Infinite pitch (Hacking?)");
+            }
+            f1 = 0;
+        }
+        // CraftBukkit end
+
         this.yaw = f % 360.0F;
         this.pitch = f1 % 360.0F;
     }
@@ -224,6 +316,7 @@
         float f1 = this.size.height;
 
         this.a(new AxisAlignedBB(d0 - (double) f, d1, d2 - (double) f, d0 + (double) f, d1 + (double) f1, d2 + (double) f));
+        if (valid) ((WorldServer) world).chunkCheck(this); // CraftBukkit
     }
 
     public void tick() {
@@ -234,6 +327,15 @@
         this.entityBaseTick();
     }
 
+    // CraftBukkit start
+    public void postTick() {
+        // No clean way to break out of ticking once the entity has been copied to a new world, so instead we move the portalling later in the tick cycle
+        if (!(this instanceof EntityPlayer)) {
+            this.doPortalTick();
+        }
+    }
+    // CraftBukkit end
+
     public void entityBaseTick() {
         this.world.getMethodProfiler().enter("entityBaseTick");
         if (this.isPassenger() && this.getVehicle().dead) {
@@ -250,7 +352,7 @@
         this.lastZ = this.locZ;
         this.lastPitch = this.pitch;
         this.lastYaw = this.yaw;
-        this.doPortalTick();
+        if (this instanceof EntityPlayer) this.doPortalTick(); // CraftBukkit - // Moved up to postTick
         this.az();
         this.m();
         if (this.world.isClientSide) {
@@ -300,12 +402,44 @@
 
     protected void burnFromLava() {
         if (!this.isFireProof()) {
-            this.setOnFire(15);
+            // CraftBukkit start - Fallen in lava TODO: this event spams!
+            if (this instanceof EntityLiving && fireTicks <= 0) {
+                // not on fire yet
+                // TODO: shouldn't be sending null for the block
+                org.bukkit.block.Block damager = null; // ((WorldServer) this.l).getWorld().getBlockAt(i, j, k);
+                org.bukkit.entity.Entity damagee = this.getBukkitEntity();
+                EntityCombustEvent combustEvent = new org.bukkit.event.entity.EntityCombustByBlockEvent(damager, damagee, 15);
+                this.world.getServer().getPluginManager().callEvent(combustEvent);
+
+                if (!combustEvent.isCancelled()) {
+                    this.setOnFire(combustEvent.getDuration(), false);
+                }
+            } else {
+                // This will be called every single tick the entity is in lava, so don't throw an event
+                this.setOnFire(15, false);
+            }
+            // CraftBukkit end - we also don't throw an event unless the object in lava is living, to save on some event calls
             this.damageEntity(DamageSource.LAVA, 4.0F);
         }
     }
 
     public void setOnFire(int i) {
+        // CraftBukkit start
+        this.setOnFire(i, true);
+    }
+
+    public void setOnFire(int i, boolean callEvent) {
+        if (callEvent) {
+            EntityCombustEvent event = new EntityCombustEvent(this.getBukkitEntity(), i);
+            this.world.getServer().getPluginManager().callEvent(event);
+
+            if (event.isCancelled()) {
+                return;
+            }
+
+            i = event.getDuration();
+        }
+        // CraftBukkit end
         int j = i * 20;
 
         if (this instanceof EntityLiving) {
@@ -401,6 +535,28 @@
                 block1.a((IBlockAccess) this.world, this);
             }
 
+            // CraftBukkit start
+            if (positionChanged && getBukkitEntity() instanceof Vehicle) {
+                Vehicle vehicle = (Vehicle) this.getBukkitEntity();
+                org.bukkit.block.Block bl = this.world.getWorld().getBlockAt(MathHelper.floor(this.locX), MathHelper.floor(this.locY), MathHelper.floor(this.locZ));
+
+                if (vec3d1.x > vec3d.x) {
+                    bl = bl.getRelative(BlockFace.EAST);
+                } else if (vec3d.x < vec3d.x) {
+                    bl = bl.getRelative(BlockFace.WEST);
+                } else if (vec3d1.z > vec3d.z) {
+                    bl = bl.getRelative(BlockFace.SOUTH);
+                } else if (vec3d1.z < vec3d.z) {
+                    bl = bl.getRelative(BlockFace.NORTH);
+                }
+
+                if (bl.getType() != org.bukkit.Material.AIR) {
+                    VehicleBlockCollisionEvent event = new VehicleBlockCollisionEvent(vehicle, bl);
+                    world.getServer().getPluginManager().callEvent(event);
+                }
+            }
+            // CraftBukkit end
+
             if (this.playStepSound() && (!this.onGround || !this.isSneaking() || !(this instanceof EntityHuman)) && !this.isPassenger()) {
                 double d0 = vec3d1.x;
                 double d1 = vec3d1.y;
@@ -454,7 +610,14 @@
                 if (!flag) {
                     ++this.fireTicks;
                     if (this.fireTicks == 0) {
-                        this.setOnFire(8);
+                        // CraftBukkit start
+                        EntityCombustEvent event = new org.bukkit.event.entity.EntityCombustByBlockEvent(null, getBukkitEntity(), 8);
+                        world.getServer().getPluginManager().callEvent(event);
+
+                        if (!event.isCancelled()) {
+                            this.setOnFire(event.getDuration(), false);
+                        }
+                        // CraftBukkit end
                     }
                 }
 
@@ -565,7 +728,7 @@
         VoxelShape voxelshape = this.world.getWorldBorder().a();
         Stream<VoxelShape> stream = VoxelShapes.c(voxelshape, VoxelShapes.a(axisalignedbb.shrink(1.0E-7D)), OperatorBoolean.AND) ? Stream.empty() : Stream.of(voxelshape);
         AxisAlignedBB axisalignedbb1 = axisalignedbb.a(vec3d).g(1.0E-7D);
-        Stream stream1 = this.world.getEntities(this, axisalignedbb1).stream().filter((entity) -> {
+        Stream<AxisAlignedBB> stream1 = this.world.getEntities(this, axisalignedbb1).stream().filter((entity) -> { // CraftBukkit - decompile error
             return !this.x(entity);
         }).flatMap((entity) -> {
             return Stream.of(entity.ap(), this.j(entity));
@@ -649,6 +812,7 @@
         this.locX = (axisalignedbb.minX + axisalignedbb.maxX) / 2.0D;
         this.locY = axisalignedbb.minY;
         this.locZ = (axisalignedbb.minZ + axisalignedbb.maxZ) / 2.0D;
+        if (valid) ((WorldServer) world).chunkCheck(this); // CraftBukkit
     }
 
     protected SoundEffect getSoundSwim() {
@@ -820,7 +984,7 @@
         return null;
     }
 
-    protected void burn(int i) {
+    protected void burn(float i) { // CraftBukkit - int -> float
         if (!this.isFireProof()) {
             this.damageEntity(DamageSource.FIRE, (float) i);
         }
@@ -1053,6 +1217,13 @@
     }
 
     public void spawnIn(World world) {
+        // CraftBukkit start
+        if (world == null) {
+            die();
+            this.world = ((CraftWorld) Bukkit.getServer().getWorlds().get(0)).getHandle();
+            return;
+        }
+        // CraftBukkit end
         this.world = world;
     }
 
@@ -1078,6 +1249,7 @@
             this.lastYaw -= 360.0F;
         }
 
+        world.getChunkAt((int) Math.floor(this.locX) >> 4, (int) Math.floor(this.locZ) >> 4); // CraftBukkit
         this.setPosition(this.locX, this.locY, this.locZ);
         this.setYawPitch(f, f1);
     }
@@ -1246,7 +1418,7 @@
     public boolean c(NBTTagCompound nbttagcompound) {
         String s = this.getSaveID();
 
-        if (!this.dead && s != null) {
+        if (this.persist && !this.dead && s != null) { // CraftBukkit - persist flag
             nbttagcompound.setString("id", s);
             this.save(nbttagcompound);
             return true;
@@ -1265,6 +1437,18 @@
             Vec3D vec3d = this.getMot();
 
             nbttagcompound.set("Motion", this.a(vec3d.x, vec3d.y, vec3d.z));
+
+            // CraftBukkit start - Checking for NaN pitch/yaw and resetting to zero
+            // TODO: make sure this is the best way to address this.
+            if (Float.isNaN(this.yaw)) {
+                this.yaw = 0;
+            }
+
+            if (Float.isNaN(this.pitch)) {
+                this.pitch = 0;
+            }
+            // CraftBukkit end
+
             nbttagcompound.set("Rotation", this.a(this.yaw, this.pitch));
             nbttagcompound.setFloat("FallDistance", this.fallDistance);
             nbttagcompound.setShort("Fire", (short) this.fireTicks);
@@ -1274,6 +1458,12 @@
             nbttagcompound.setBoolean("Invulnerable", this.invulnerable);
             nbttagcompound.setInt("PortalCooldown", this.portalCooldown);
             nbttagcompound.a("UUID", this.getUniqueID());
+            // CraftBukkit start
+            // PAIL: Check above UUID reads 1.8 properly, ie: UUIDMost / UUIDLeast
+            nbttagcompound.setLong("WorldUUIDLeast", ((WorldServer) this.world).getDataManager().getUUID().getLeastSignificantBits());
+            nbttagcompound.setLong("WorldUUIDMost", ((WorldServer) this.world).getDataManager().getUUID().getMostSignificantBits());
+            nbttagcompound.setInt("Bukkit.updateLevel", CURRENT_LEVEL);
+            // CraftBukkit end
             IChatBaseComponent ichatbasecomponent = this.getCustomName();
 
             if (ichatbasecomponent != null) {
@@ -1331,6 +1521,11 @@
                 }
             }
 
+            // CraftBukkit start - stores eventually existing bukkit values
+            if (this.bukkitEntity != null) {
+                this.bukkitEntity.storeBukkitValues(nbttagcompound);
+            }
+            // CraftBukkit end
             return nbttagcompound;
         } catch (Throwable throwable) {
             CrashReport crashreport = CrashReport.a(throwable, "Saving entity NBT");
@@ -1414,6 +1609,42 @@
             } else {
                 throw new IllegalStateException("Entity has invalid position");
             }
+
+            // CraftBukkit start
+            if (this instanceof EntityLiving) {
+                EntityLiving entity = (EntityLiving) this;
+
+                // Reset the persistence for tamed animals
+                if (entity instanceof EntityTameableAnimal && !isLevelAtLeast(nbttagcompound, 2) && !nbttagcompound.getBoolean("PersistenceRequired")) {
+                    EntityInsentient entityinsentient = (EntityInsentient) entity;
+                    entityinsentient.persistent = !entityinsentient.isTypeNotPersistent(0);
+                }
+            }
+            // CraftBukkit end
+
+            // CraftBukkit start - Reset world
+            if (this instanceof EntityPlayer) {
+                Server server = Bukkit.getServer();
+                org.bukkit.World bworld = null;
+
+                // TODO: Remove World related checks, replaced with WorldUID
+                String worldName = nbttagcompound.getString("world");
+
+                if (nbttagcompound.hasKey("WorldUUIDMost") && nbttagcompound.hasKey("WorldUUIDLeast")) {
+                    UUID uid = new UUID(nbttagcompound.getLong("WorldUUIDMost"), nbttagcompound.getLong("WorldUUIDLeast"));
+                    bworld = server.getWorld(uid);
+                } else {
+                    bworld = server.getWorld(worldName);
+                }
+
+                if (bworld == null) {
+                    bworld = ((org.bukkit.craftbukkit.CraftServer) server).getServer().getWorldServer(DimensionManager.OVERWORLD).getWorld();
+                }
+
+                spawnIn(bworld == null? null : ((CraftWorld) bworld).getHandle());
+            }
+            // CraftBukkit end
+
         } catch (Throwable throwable) {
             CrashReport crashreport = CrashReport.a(throwable, "Loading entity NBT");
             CrashReportSystemDetails crashreportsystemdetails = crashreport.a("Entity being loaded");
@@ -1489,9 +1720,22 @@
         } else if (this.world.isClientSide) {
             return null;
         } else {
+            // CraftBukkit start - Capture drops for death event
+            if (this instanceof EntityLiving && !((EntityLiving) this).forceDrops) {
+                ((EntityLiving) this).drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asBukkitCopy(itemstack));
+                return null;
+            }
+            // CraftBukkit end
             EntityItem entityitem = new EntityItem(this.world, this.locX, this.locY + (double) f, this.locZ, itemstack);
 
             entityitem.defaultPickupDelay();
+            // CraftBukkit start
+            EntityDropItemEvent event = new EntityDropItemEvent(this.getBukkitEntity(), (org.bukkit.entity.Item) entityitem.getBukkitEntity());
+            Bukkit.getPluginManager().callEvent(event);
+            if (event.isCancelled()) {
+                return null;
+            }
+            // CraftBukkit end
             this.world.addEntity(entityitem);
             return entityitem;
         }
@@ -1595,7 +1839,7 @@
             }
 
             this.vehicle = entity;
-            this.vehicle.addPassenger(this);
+            if (!this.vehicle.addPassenger(this)) this.vehicle = null; // CraftBukkit
             return true;
         }
     }
@@ -1620,15 +1864,36 @@
             Entity entity = this.vehicle;
 
             this.vehicle = null;
-            entity.removePassenger(this);
+            if (!entity.removePassenger(this)) this.vehicle = entity; // CraftBukkit
         }
 
     }
 
-    protected void addPassenger(Entity entity) {
+    protected boolean addPassenger(Entity entity) { // CraftBukkit
         if (entity.getVehicle() != this) {
             throw new IllegalStateException("Use x.startRiding(y), not y.addPassenger(x)");
         } else {
+            // CraftBukkit start
+            com.google.common.base.Preconditions.checkState(!entity.passengers.contains(this), "Circular entity riding! %s %s", this, entity);
+
+            CraftEntity craft = (CraftEntity) entity.getBukkitEntity().getVehicle();
+            Entity orig = craft == null ? null : craft.getHandle();
+            if (getBukkitEntity() instanceof Vehicle && entity.getBukkitEntity() instanceof LivingEntity) {
+                VehicleEnterEvent event = new VehicleEnterEvent(
+                        (Vehicle) getBukkitEntity(),
+                         entity.getBukkitEntity()
+                );
+                // Suppress during worldgen
+                if (this.valid) {
+                    Bukkit.getPluginManager().callEvent(event);
+                }
+                CraftEntity craftn = (CraftEntity) entity.getBukkitEntity().getVehicle();
+                Entity n = craftn == null ? null : craftn.getHandle();
+                if (event.isCancelled() || n != orig) {
+                    return false;
+                }
+            }
+            // CraftBukkit end
             if (!this.world.isClientSide && entity instanceof EntityHuman && !(this.getRidingPassenger() instanceof EntityHuman)) {
                 this.passengers.add(0, entity);
             } else {
@@ -1636,15 +1901,33 @@
             }
 
         }
+        return true; // CraftBukkit
     }
 
-    protected void removePassenger(Entity entity) {
+    protected boolean removePassenger(Entity entity) { // CraftBukkit
         if (entity.getVehicle() == this) {
             throw new IllegalStateException("Use x.stopRiding(y), not y.removePassenger(x)");
         } else {
+            // CraftBukkit start
+            CraftEntity craft = (CraftEntity) entity.getBukkitEntity().getVehicle();
+            Entity orig = craft == null ? null : craft.getHandle();
+            if (getBukkitEntity() instanceof Vehicle && entity.getBukkitEntity() instanceof LivingEntity) {
+                VehicleExitEvent event = new VehicleExitEvent(
+                        (Vehicle) getBukkitEntity(),
+                        (LivingEntity) entity.getBukkitEntity()
+                );
+                Bukkit.getPluginManager().callEvent(event);
+                CraftEntity craftn = (CraftEntity) entity.getBukkitEntity().getVehicle();
+                Entity n = craftn == null ? null : craftn.getHandle();
+                if (event.isCancelled() || n != orig) {
+                    return false;
+                }
+            }
+            // CraftBukkit end
             this.passengers.remove(entity);
             entity.j = 60;
         }
+        return true; // CraftBukkit
     }
 
     protected boolean q(Entity entity) {
@@ -1687,11 +1970,17 @@
             int i = this.ab();
 
             if (this.ai) {
-                if (this.world.getMinecraftServer().getAllowNether() && !this.isPassenger() && this.aj++ >= i) {
+                if ((true || this.world.getMinecraftServer().getAllowNether()) && !this.isPassenger() && this.aj++ >= i) { // CraftBukkit
                     this.world.getMethodProfiler().enter("portal");
                     this.aj = i;
                     this.portalCooldown = this.aW();
-                    this.a(this.world.worldProvider.getDimensionManager() == DimensionManager.NETHER ? DimensionManager.OVERWORLD : DimensionManager.NETHER);
+                    // CraftBukkit start
+                    if (this instanceof EntityPlayer) {
+                        ((EntityPlayer) this).a(this.world.worldProvider.getDimensionManager() == DimensionManager.NETHER ? DimensionManager.OVERWORLD : DimensionManager.NETHER, PlayerTeleportEvent.TeleportCause.NETHER_PORTAL);
+                    } else {
+                        this.a(this.world.worldProvider.getDimensionManager() == DimensionManager.NETHER ? DimensionManager.OVERWORLD : DimensionManager.NETHER);
+                    }
+                    // CraftBukkit end
                     this.world.getMethodProfiler().exit();
                 }
 
@@ -1771,6 +2060,13 @@
     }
 
     public void setSwimming(boolean flag) {
+        // CraftBukkit start
+        if (this.isSwimming() != flag && this instanceof EntityLiving) {
+            if (CraftEventFactory.callToggleSwimEvent((EntityLiving) this, flag).isCancelled()) {
+                return;
+            }
+        }
+        // CraftBukkit end
         this.setFlag(4, flag);
     }
 
@@ -1831,16 +2127,56 @@
     }
 
     public void setAirTicks(int i) {
-        this.datawatcher.set(Entity.AIR_TICKS, i);
+        // CraftBukkit start
+        EntityAirChangeEvent event = new EntityAirChangeEvent(this.getBukkitEntity(), i);
+        // Suppress during worldgen
+        if (this.valid) {
+            event.getEntity().getServer().getPluginManager().callEvent(event);
+        }
+        if (event.isCancelled()) {
+            return;
+        }
+        this.datawatcher.set(Entity.AIR_TICKS, event.getAmount());
+        // CraftBukkit end
     }
 
     public void onLightningStrike(EntityLightning entitylightning) {
         ++this.fireTicks;
+        // CraftBukkit start
+        final org.bukkit.entity.Entity thisBukkitEntity = this.getBukkitEntity();
+        final org.bukkit.entity.Entity stormBukkitEntity = entitylightning.getBukkitEntity();
+        final PluginManager pluginManager = Bukkit.getPluginManager();
+        // CraftBukkit end
+
         if (this.fireTicks == 0) {
-            this.setOnFire(8);
+            // CraftBukkit start - Call a combust event when lightning strikes
+            EntityCombustByEntityEvent entityCombustEvent = new EntityCombustByEntityEvent(stormBukkitEntity, thisBukkitEntity, 8);
+            pluginManager.callEvent(entityCombustEvent);
+            if (!entityCombustEvent.isCancelled()) {
+                this.setOnFire(entityCombustEvent.getDuration(), false);
+            }
+            // CraftBukkit end
+        }
+
+        // CraftBukkit start
+        if (thisBukkitEntity instanceof Hanging) {
+            HangingBreakByEntityEvent hangingEvent = new HangingBreakByEntityEvent((Hanging) thisBukkitEntity, stormBukkitEntity);
+            pluginManager.callEvent(hangingEvent);
+
+            if (hangingEvent.isCancelled()) {
+                return;
+            }
         }
 
-        this.damageEntity(DamageSource.LIGHTNING, 5.0F);
+        if (this.isFireProof()) {
+            return;
+        }
+        CraftEventFactory.entityDamage = entitylightning;
+        if (!this.damageEntity(DamageSource.LIGHTNING, 5.0F)) {
+            CraftEventFactory.entityDamage = null;
+            return;
+        }
+        // CraftBukkit end
     }
 
     public void j(boolean flag) {
@@ -1988,20 +2324,33 @@
 
     @Nullable
     public Entity a(DimensionManager dimensionmanager) {
+        // CraftBukkit start
+        return teleportTo(dimensionmanager, null);
+    }
+
+    @Nullable
+    public Entity teleportTo(DimensionManager dimensionmanager, BlockPosition location) {
+        // CraftBukkit end
         if (!this.world.isClientSide && !this.dead) {
             this.world.getMethodProfiler().enter("changeDimension");
             MinecraftServer minecraftserver = this.getMinecraftServer();
             DimensionManager dimensionmanager1 = this.dimension;
             WorldServer worldserver = minecraftserver.getWorldServer(dimensionmanager1);
             WorldServer worldserver1 = minecraftserver.getWorldServer(dimensionmanager);
+            // CraftBukkit start
+            if (worldserver1 == null){
+                return null;
+            }
 
-            this.dimension = dimensionmanager;
-            this.decouple();
+            // this.dimension = dimensionmanager;
+            // this.decouple();
+            // CraftBukkit end
             this.world.getMethodProfiler().enter("reposition");
             Vec3D vec3d = this.getMot();
             float f = 0.0F;
-            BlockPosition blockposition;
+            BlockPosition blockposition = location; // CraftBukkit
 
+        if (blockposition == null) { // CraftBukkit
             if (dimensionmanager1 == DimensionManager.THE_END && dimensionmanager == DimensionManager.OVERWORLD) {
                 blockposition = worldserver1.getHighestBlockYAt(HeightMap.Type.MOTION_BLOCKING_NO_LEAVES, worldserver1.getSpawn());
             } else if (dimensionmanager == DimensionManager.THE_END) {
@@ -2039,6 +2388,25 @@
                 vec3d = shapedetector_c.b;
                 f = (float) shapedetector_c.c;
             }
+        } // CraftBukkit
+
+            // CraftBukkit start
+            Location enter = this.getBukkitEntity().getLocation();
+            Location exit = new Location(worldserver1.getWorld(), blockposition.getX(), blockposition.getY(), blockposition.getZ());
+
+            EntityPortalEvent event = new EntityPortalEvent(this.getBukkitEntity(), enter, exit);
+            event.getEntity().getServer().getPluginManager().callEvent(event);
+            if (event.isCancelled() || event.getTo() == null || event.getTo().getWorld() == null || !this.isAlive()) {
+                return null;
+            }
+
+            exit = event.getTo();
+            worldserver1 = ((CraftWorld) exit.getWorld()).getHandle();
+            blockposition = new BlockPosition(exit.getX(), exit.getY(), exit.getZ());
+
+            this.dimension = dimensionmanager;
+            this.decouple();
+            // CraftBukkit end
 
             this.world.getMethodProfiler().exitEnter("reloading");
             Entity entity = this.getEntityType().a((World) worldserver1);
@@ -2048,6 +2416,14 @@
                 entity.setPositionRotation(blockposition, entity.yaw + f, entity.pitch);
                 entity.setMot(vec3d);
                 worldserver1.addEntityTeleport(entity);
+                // CraftBukkit start - Forward the CraftEntity to the new entity
+                this.getBukkitEntity().setHandle(entity);
+                entity.bukkitEntity = this.getBukkitEntity();
+
+                if (this instanceof EntityInsentient) {
+                    ((EntityInsentient)this).unleash(true, false); // Unleash to prevent duping of leads.
+                }
+                // CraftBukkit end
             }
 
             this.dead = true;
@@ -2239,7 +2615,26 @@
     }
 
     public void a(AxisAlignedBB axisalignedbb) {
-        this.boundingBox = axisalignedbb;
+        // CraftBukkit start - block invalid bounding boxes
+        double minX = axisalignedbb.minX,
+                minY = axisalignedbb.minY,
+                minZ = axisalignedbb.minZ,
+                maxX = axisalignedbb.maxX,
+                maxY = axisalignedbb.maxY,
+                maxZ = axisalignedbb.maxZ;
+        double len = axisalignedbb.maxX - axisalignedbb.minX;
+        if (len < 0) maxX = minX;
+        if (len > 64) maxX = minX + 64.0;
+
+        len = axisalignedbb.maxY - axisalignedbb.minY;
+        if (len < 0) maxY = minY;
+        if (len > 64) maxY = minY + 64.0;
+
+        len = axisalignedbb.maxZ - axisalignedbb.minZ;
+        if (len < 0) maxZ = minZ;
+        if (len > 64) maxZ = minZ + 64.0;
+        this.boundingBox = new AxisAlignedBB(minX, minY, minZ, maxX, maxY, maxZ);
+        // CraftBukkit end
     }
 
     protected float getHeadHeight(EntityPose entitypose, EntitySize entitysize) {