PaperMC/paper-server/nms-patches/net/minecraft/world/entity/player/EntityHuman.patch

--- a/net/minecraft/world/entity/player/EntityHuman.java
+++ b/net/minecraft/world/entity/player/EntityHuman.java
@@ -113,6 +113,19 @@
 import net.minecraft.world.scores.ScoreboardTeam;
 import net.minecraft.world.scores.ScoreboardTeamBase;
 
+// CraftBukkit start
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
+import org.bukkit.craftbukkit.util.CraftVector;
+import org.bukkit.entity.Item;
+import org.bukkit.entity.Player;
+import org.bukkit.event.entity.CreatureSpawnEvent;
+import org.bukkit.event.entity.EntityCombustByEntityEvent;
+import org.bukkit.event.entity.EntityExhaustionEvent;
+import org.bukkit.event.player.PlayerDropItemEvent;
+import org.bukkit.event.player.PlayerVelocityEvent;
+// CraftBukkit end
+
 public abstract class EntityHuman extends EntityLiving {
 
     public static final String UUID_PREFIX_OFFLINE_PLAYER = "OfflinePlayer:";
@@ -126,7 +139,8 @@
     public static final float SWIMMING_BB_HEIGHT = 0.6F;
     public static final float DEFAULT_EYE_HEIGHT = 1.62F;
     public static final EntitySize STANDING_DIMENSIONS = EntitySize.b(0.6F, 1.8F);
-    private static final Map<EntityPose, EntitySize> POSES = ImmutableMap.builder().put(EntityPose.STANDING, EntityHuman.STANDING_DIMENSIONS).put(EntityPose.SLEEPING, EntityHuman.SLEEPING_DIMENSIONS).put(EntityPose.FALL_FLYING, EntitySize.b(0.6F, 0.6F)).put(EntityPose.SWIMMING, EntitySize.b(0.6F, 0.6F)).put(EntityPose.SPIN_ATTACK, EntitySize.b(0.6F, 0.6F)).put(EntityPose.CROUCHING, EntitySize.b(0.6F, 1.5F)).put(EntityPose.DYING, EntitySize.c(0.2F, 0.2F)).build();
+    // CraftBukkit - decompile error
+    private static final Map<EntityPose, EntitySize> POSES = ImmutableMap.<EntityPose, EntitySize>builder().put(EntityPose.STANDING, EntityHuman.STANDING_DIMENSIONS).put(EntityPose.SLEEPING, EntityHuman.SLEEPING_DIMENSIONS).put(EntityPose.FALL_FLYING, EntitySize.b(0.6F, 0.6F)).put(EntityPose.SWIMMING, EntitySize.b(0.6F, 0.6F)).put(EntityPose.SPIN_ATTACK, EntitySize.b(0.6F, 0.6F)).put(EntityPose.CROUCHING, EntitySize.b(0.6F, 1.5F)).put(EntityPose.DYING, EntitySize.c(0.2F, 0.2F)).build();
     private static final int FLY_ACHIEVEMENT_SPEED = 25;
     private static final DataWatcherObject<Float> DATA_PLAYER_ABSORPTION_ID = DataWatcher.a(EntityHuman.class, DataWatcherRegistry.FLOAT);
     private static final DataWatcherObject<Integer> DATA_SCORE_ID = DataWatcher.a(EntityHuman.class, DataWatcherRegistry.INT);
@@ -136,10 +150,10 @@
     protected static final DataWatcherObject<NBTTagCompound> DATA_SHOULDER_RIGHT = DataWatcher.a(EntityHuman.class, DataWatcherRegistry.COMPOUND_TAG);
     private long timeEntitySatOnShoulder;
     private final PlayerInventory inventory = new PlayerInventory(this);
-    protected InventoryEnderChest enderChestInventory = new InventoryEnderChest();
+    protected InventoryEnderChest enderChestInventory = new InventoryEnderChest(this); // CraftBukkit - add "this" to constructor
     public final ContainerPlayer inventoryMenu;
     public Container containerMenu;
-    protected FoodMetaData foodData = new FoodMetaData();
+    protected FoodMetaData foodData = new FoodMetaData(this); // CraftBukkit - add "this" to constructor
     protected int jumpTriggerTime;
     public float oBob;
     public float bob;
@@ -166,6 +180,16 @@
     @Nullable
     public EntityFishingHook fishing;
 
+    // CraftBukkit start
+    public boolean fauxSleeping;
+    public int oldLevel = -1;
+
+    @Override
+    public CraftHumanEntity getBukkitEntity() {
+        return (CraftHumanEntity) super.getBukkitEntity();
+    }
+    // CraftBukkit end
+
     public EntityHuman(World world, BlockPosition blockposition, float f, GameProfile gameprofile) {
         super(EntityTypes.PLAYER, world);
         this.lastItemInMainHand = ItemStack.EMPTY;
@@ -304,7 +328,7 @@
         ItemStack itemstack = this.getEquipment(EnumItemSlot.HEAD);
 
         if (itemstack.a(Items.TURTLE_HELMET) && !this.a((Tag) TagsFluid.WATER)) {
-            this.addEffect(new MobEffect(MobEffects.WATER_BREATHING, 200, 0, false, false, true));
+            this.addEffect(new MobEffect(MobEffects.WATER_BREATHING, 200, 0, false, false, true), org.bukkit.event.entity.EntityPotionEffectEvent.Cause.TURTLE_HELMET); // CraftBukkit
         }
 
     }
@@ -496,7 +520,8 @@
 
         if (this.level.getDifficulty() == EnumDifficulty.PEACEFUL && this.level.getGameRules().getBoolean(GameRules.RULE_NATURAL_REGENERATION)) {
             if (this.getHealth() < this.getMaxHealth() && this.tickCount % 20 == 0) {
-                this.heal(1.0F);
+                // CraftBukkit - added regain reason of "REGEN" for filtering purposes.
+                this.heal(1.0F, org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason.REGEN);
             }
 
             if (this.foodData.c() && this.tickCount % 10 == 0) {
@@ -545,7 +570,7 @@
             }
 
             if (!list1.isEmpty()) {
-                this.c((Entity) SystemUtils.a((List) list1, this.random));
+                this.c((Entity) SystemUtils.a(list1, this.random)); // CraftBukkit - decompile error
             }
         }
 
@@ -684,6 +709,30 @@
                 entityitem.setMot((double) (-f3 * f2 * 0.3F) + Math.cos((double) f5) * (double) f6, (double) (-f1 * 0.3F + 0.1F + (this.random.nextFloat() - this.random.nextFloat()) * 0.1F), (double) (f4 * f2 * 0.3F) + Math.sin((double) f5) * (double) f6);
             }
 
+            // CraftBukkit start - fire PlayerDropItemEvent
+            Player player = (Player) this.getBukkitEntity();
+            Item drop = (Item) entityitem.getBukkitEntity();
+
+            PlayerDropItemEvent event = new PlayerDropItemEvent(player, drop);
+            this.level.getCraftServer().getPluginManager().callEvent(event);
+
+            if (event.isCancelled()) {
+                org.bukkit.inventory.ItemStack cur = player.getInventory().getItemInHand();
+                if (flag1 && (cur == null || cur.getAmount() == 0)) {
+                    // The complete stack was dropped
+                    player.getInventory().setItemInHand(drop.getItemStack());
+                } else if (flag1 && cur.isSimilar(drop.getItemStack()) && cur.getAmount() < cur.getMaxStackSize() && drop.getItemStack().getAmount() == 1) {
+                    // Only one item is dropped
+                    cur.setAmount(cur.getAmount() + 1);
+                    player.getInventory().setItemInHand(cur);
+                } else {
+                    // Fallback
+                    player.getInventory().addItem(drop.getItemStack());
+                }
+                return null;
+            }
+            // CraftBukkit end
+
             return entityitem;
         }
     }
@@ -810,16 +859,17 @@
         if (this.isInvulnerable(damagesource)) {
             return false;
         } else if (this.abilities.invulnerable && !damagesource.ignoresInvulnerability()) {
+            this.forceExplosionKnockback = true; // SPIGOT-5258 - Make invulnerable players get knockback from explosions
             return false;
         } else {
             this.noActionTime = 0;
             if (this.dV()) {
                 return false;
             } else {
-                this.releaseShoulderEntities();
+                // this.releaseShoulderEntities(); // CraftBukkit - moved down
                 if (damagesource.w()) {
                     if (this.level.getDifficulty() == EnumDifficulty.PEACEFUL) {
-                        f = 0.0F;
+                        return false; // CraftBukkit - f = 0.0f -> return false
                     }
 
                     if (this.level.getDifficulty() == EnumDifficulty.EASY) {
@@ -831,7 +881,13 @@
                     }
                 }
 
-                return f == 0.0F ? false : super.damageEntity(damagesource, f);
+                // CraftBukkit start - Don't filter out 0 damage
+                boolean damaged = super.damageEntity(damagesource, f);
+                if (damaged) {
+                    this.releaseShoulderEntities();
+                }
+                return damaged;
+                // CraftBukkit end
             }
         }
     }
@@ -851,10 +907,29 @@
     }
 
     public boolean a(EntityHuman entityhuman) {
-        ScoreboardTeamBase scoreboardteambase = this.getScoreboardTeam();
-        ScoreboardTeamBase scoreboardteambase1 = entityhuman.getScoreboardTeam();
+        // CraftBukkit start - Change to check OTHER player's scoreboard team according to API
+        // To summarize this method's logic, it's "Can parameter hurt this"
+        org.bukkit.scoreboard.Team team;
+        if (entityhuman instanceof EntityPlayer) {
+            EntityPlayer thatPlayer = (EntityPlayer) entityhuman;
+            team = thatPlayer.getBukkitEntity().getScoreboard().getPlayerTeam(thatPlayer.getBukkitEntity());
+            if (team == null || team.allowFriendlyFire()) {
+                return true;
+            }
+        } else {
+            // This should never be called, but is implemented anyway
+            org.bukkit.OfflinePlayer thisPlayer = entityhuman.level.getCraftServer().getOfflinePlayer(entityhuman.getName());
+            team = entityhuman.level.getCraftServer().getScoreboardManager().getMainScoreboard().getPlayerTeam(thisPlayer);
+            if (team == null || team.allowFriendlyFire()) {
+                return true;
+            }
+        }
 
-        return scoreboardteambase == null ? true : (!scoreboardteambase.isAlly(scoreboardteambase1) ? true : scoreboardteambase.allowFriendlyFire());
+        if (this instanceof EntityPlayer) {
+            return !team.hasPlayer(((EntityPlayer) this).getBukkitEntity());
+        }
+        return !team.hasPlayer(this.level.getCraftServer().getOfflinePlayer(this.getName()));
+        // CraftBukkit end
     }
 
     @Override
@@ -896,8 +971,13 @@
         }
     }
 
+    // CraftBukkit start
     @Override
-    protected void damageEntity0(DamageSource damagesource, float f) {
+    protected boolean damageEntity0(DamageSource damagesource, float f) { // void -> boolean
+        if (true) {
+            return super.damageEntity0(damagesource, f);
+        }
+        // CraftBukkit end
         if (!this.isInvulnerable(damagesource)) {
             f = this.applyArmorModifier(damagesource, f);
             f = this.applyMagicModifier(damagesource, f);
@@ -912,7 +992,7 @@
             }
 
             if (f != 0.0F) {
-                this.applyExhaustion(damagesource.getExhaustionCost());
+                this.applyExhaustion(damagesource.getExhaustionCost(), EntityExhaustionEvent.ExhaustionReason.DAMAGED); // CraftBukkit - EntityExhaustionEvent
                 float f3 = this.getHealth();
 
                 this.setHealth(this.getHealth() - f);
@@ -923,6 +1003,7 @@
 
             }
         }
+        return false; // CraftBukkit
     }
 
     @Override
@@ -1082,7 +1163,7 @@
 
                 f *= 0.2F + f2 * f2 * 0.8F;
                 f1 *= f2;
-                this.resetAttackCooldown();
+                // this.resetAttackCooldown(); // CraftBukkit - Moved to EntityLiving to reset the cooldown after the damage is dealt
                 if (f > 0.0F || f1 > 0.0F) {
                     boolean flag = f2 > 0.9F;
                     boolean flag1 = false;
@@ -1121,8 +1202,15 @@
                     if (entity instanceof EntityLiving) {
                         f3 = ((EntityLiving) entity).getHealth();
                         if (j > 0 && !entity.isBurning()) {
-                            flag4 = true;
-                            entity.setOnFire(1);
+                            // CraftBukkit start - Call a combust event when somebody hits with a fire enchanted item
+                            EntityCombustByEntityEvent combustEvent = new EntityCombustByEntityEvent(this.getBukkitEntity(), entity.getBukkitEntity(), 1);
+                            org.bukkit.Bukkit.getPluginManager().callEvent(combustEvent);
+
+                            if (!combustEvent.isCancelled()) {
+                                flag4 = true;
+                                entity.setOnFire(combustEvent.getDuration(), false);
+                            }
+                            // CraftBukkit end
                         }
                     }
 
@@ -1150,8 +1238,11 @@
                                 EntityLiving entityliving = (EntityLiving) iterator.next();
 
                                 if (entityliving != this && entityliving != entity && !this.p(entityliving) && (!(entityliving instanceof EntityArmorStand) || !((EntityArmorStand) entityliving).isMarker()) && this.f((Entity) entityliving) < 9.0D) {
+                                    // CraftBukkit start - Only apply knockback if the damage hits
+                                    if (entityliving.damageEntity(DamageSource.playerAttack(this).sweep(), f4)) {
                                     entityliving.p(0.4000000059604645D, (double) MathHelper.sin(this.getYRot() * 0.017453292F), (double) (-MathHelper.cos(this.getYRot() * 0.017453292F)));
-                                    entityliving.damageEntity(DamageSource.playerAttack(this), f4);
+                                    }
+                                    // CraftBukkit end
                                 }
                             }
 
@@ -1160,9 +1251,26 @@
                         }
 
                         if (entity instanceof EntityPlayer && entity.hurtMarked) {
+                            // CraftBukkit start - Add Velocity Event
+                            boolean cancelled = false;
+                            Player player = (Player) entity.getBukkitEntity();
+                            org.bukkit.util.Vector velocity = CraftVector.toBukkit(vec3d);
+
+                            PlayerVelocityEvent event = new PlayerVelocityEvent(player, velocity.clone());
+                            level.getCraftServer().getPluginManager().callEvent(event);
+
+                            if (event.isCancelled()) {
+                                cancelled = true;
+                            } else if (!velocity.equals(event.getVelocity())) {
+                                player.setVelocity(event.getVelocity());
+                            }
+
+                            if (!cancelled) {
                             ((EntityPlayer) entity).connection.sendPacket(new PacketPlayOutEntityVelocity(entity));
                             entity.hurtMarked = false;
                             entity.setMot(vec3d);
+                            }
+                            // CraftBukkit end
                         }
 
                         if (flag2) {
@@ -1207,7 +1315,14 @@
 
                             this.a(StatisticList.DAMAGE_DEALT, Math.round(f5 * 10.0F));
                             if (j > 0) {
-                                entity.setOnFire(j * 4);
+                                // CraftBukkit start - Call a combust event when somebody hits with a fire enchanted item
+                                EntityCombustByEntityEvent combustEvent = new EntityCombustByEntityEvent(this.getBukkitEntity(), entity.getBukkitEntity(), j * 4);
+                                org.bukkit.Bukkit.getPluginManager().callEvent(combustEvent);
+
+                                if (!combustEvent.isCancelled()) {
+                                    entity.setOnFire(combustEvent.getDuration(), false);
+                                }
+                                // CraftBukkit end
                             }
 
                             if (this.level instanceof WorldServer && f5 > 2.0F) {
@@ -1217,12 +1332,17 @@
                             }
                         }
 
-                        this.applyExhaustion(0.1F);
+                        this.applyExhaustion(0.1F, EntityExhaustionEvent.ExhaustionReason.ATTACK); // CraftBukkit - EntityExhaustionEvent
                     } else {
                         this.level.playSound((EntityHuman) null, this.locX(), this.locY(), this.locZ(), SoundEffects.PLAYER_ATTACK_NODAMAGE, this.getSoundCategory(), 1.0F, 1.0F);
                         if (flag4) {
                             entity.extinguish();
                         }
+                        // CraftBukkit start - resync on cancelled event
+                        if (this instanceof EntityPlayer) {
+                            ((EntityPlayer) this).getBukkitEntity().updateInventory();
+                        }
+                        // CraftBukkit end
                     }
                 }
 
@@ -1295,6 +1415,12 @@
     public void a(ItemStack itemstack, ItemStack itemstack1, ClickAction clickaction) {}
 
     public Either<EntityHuman.EnumBedResult, Unit> sleep(BlockPosition blockposition) {
+        // CraftBukkit start
+        return this.sleep(blockposition, false);
+    }
+
+    public Either<EntityHuman.EnumBedResult, Unit> sleep(BlockPosition blockposition, boolean force) {
+        // CraftBukkit end
         this.entitySleep(blockposition);
         this.sleepCounter = 0;
         return Either.right(Unit.INSTANCE);
@@ -1379,9 +1505,9 @@
         super.jump();
         this.a(StatisticList.JUMP);
         if (this.isSprinting()) {
-            this.applyExhaustion(0.2F);
+            this.applyExhaustion(0.2F, EntityExhaustionEvent.ExhaustionReason.JUMP_SPRINT); // CraftBukkit - EntityExhaustionEvent
         } else {
-            this.applyExhaustion(0.05F);
+            this.applyExhaustion(0.05F, EntityExhaustionEvent.ExhaustionReason.JUMP); // CraftBukkit - EntityExhaustionEvent
         }
 
     }
@@ -1415,7 +1541,11 @@
             this.setMot(vec3d2.x, d3 * 0.6D, vec3d2.z);
             this.flyingSpeed = f;
             this.fallDistance = 0.0F;
-            this.setFlag(7, false);
+            // CraftBukkit start
+            if (getFlag(7) && !org.bukkit.craftbukkit.event.CraftEventFactory.callToggleGlideEvent(this, false).isCancelled()) {
+                this.setFlag(7, false);
+            }
+            // CraftBukkit end
         } else {
             super.g(vec3d);
         }
@@ -1450,19 +1580,19 @@
                 i = Math.round((float) Math.sqrt(d0 * d0 + d1 * d1 + d2 * d2) * 100.0F);
                 if (i > 0) {
                     this.a(StatisticList.SWIM_ONE_CM, i);
-                    this.applyExhaustion(0.01F * (float) i * 0.01F);
+                    this.applyExhaustion(0.01F * (float) i * 0.01F, EntityExhaustionEvent.ExhaustionReason.SWIM); // CraftBukkit - EntityExhaustionEvent
                 }
             } else if (this.a((Tag) TagsFluid.WATER)) {
                 i = Math.round((float) Math.sqrt(d0 * d0 + d1 * d1 + d2 * d2) * 100.0F);
                 if (i > 0) {
                     this.a(StatisticList.WALK_UNDER_WATER_ONE_CM, i);
-                    this.applyExhaustion(0.01F * (float) i * 0.01F);
+                    this.applyExhaustion(0.01F * (float) i * 0.01F, EntityExhaustionEvent.ExhaustionReason.WALK_UNDERWATER); // CraftBukkit - EntityExhaustionEvent
                 }
             } else if (this.isInWater()) {
                 i = Math.round((float) Math.sqrt(d0 * d0 + d2 * d2) * 100.0F);
                 if (i > 0) {
                     this.a(StatisticList.WALK_ON_WATER_ONE_CM, i);
-                    this.applyExhaustion(0.01F * (float) i * 0.01F);
+                    this.applyExhaustion(0.01F * (float) i * 0.01F, EntityExhaustionEvent.ExhaustionReason.WALK_ON_WATER); // CraftBukkit - EntityExhaustionEvent
                 }
             } else if (this.isClimbing()) {
                 if (d1 > 0.0D) {
@@ -1473,13 +1603,13 @@
                 if (i > 0) {
                     if (this.isSprinting()) {
                         this.a(StatisticList.SPRINT_ONE_CM, i);
-                        this.applyExhaustion(0.1F * (float) i * 0.01F);
+                        this.applyExhaustion(0.1F * (float) i * 0.01F, EntityExhaustionEvent.ExhaustionReason.SPRINT); // CraftBukkit - EntityExhaustionEvent
                     } else if (this.isCrouching()) {
                         this.a(StatisticList.CROUCH_ONE_CM, i);
-                        this.applyExhaustion(0.0F * (float) i * 0.01F);
+                        this.applyExhaustion(0.0F * (float) i * 0.01F, EntityExhaustionEvent.ExhaustionReason.CROUCH); // CraftBukkit - EntityExhaustionEvent
                     } else {
                         this.a(StatisticList.WALK_ONE_CM, i);
-                        this.applyExhaustion(0.0F * (float) i * 0.01F);
+                        this.applyExhaustion(0.0F * (float) i * 0.01F, EntityExhaustionEvent.ExhaustionReason.WALK); // CraftBukkit - EntityExhaustionEvent
                     }
                 }
             } else if (this.isGliding()) {
@@ -1545,12 +1675,24 @@
     }
 
     public void startGliding() {
-        this.setFlag(7, true);
+        // CraftBukkit start
+        if (!org.bukkit.craftbukkit.event.CraftEventFactory.callToggleGlideEvent(this, true).isCancelled()) {
+            this.setFlag(7, true);
+        } else {
+            // SPIGOT-5542: must toggle like below
+            this.setFlag(7, true);
+            this.setFlag(7, false);
+        }
+        // CraftBukkit end
     }
 
     public void stopGliding() {
+        // CraftBukkit start
+        if (!org.bukkit.craftbukkit.event.CraftEventFactory.callToggleGlideEvent(this, false).isCancelled()) {
         this.setFlag(7, true);
         this.setFlag(7, false);
+        }
+        // CraftBukkit end
     }
 
     @Override
@@ -1640,10 +1782,21 @@
         return this.experienceLevel >= 30 ? 112 + (this.experienceLevel - 30) * 9 : (this.experienceLevel >= 15 ? 37 + (this.experienceLevel - 15) * 5 : 7 + this.experienceLevel * 2);
     }
 
+    // CraftBukkit start
     public void applyExhaustion(float f) {
+        this.applyExhaustion(f, EntityExhaustionEvent.ExhaustionReason.UNKNOWN);
+    }
+
+    public void applyExhaustion(float f, EntityExhaustionEvent.ExhaustionReason reason) {
+        // CraftBukkit end
         if (!this.abilities.invulnerable) {
             if (!this.level.isClientSide) {
-                this.foodData.a(f);
+                // CraftBukkit start
+                EntityExhaustionEvent event = CraftEventFactory.callPlayerExhaustionEvent(this, reason, f);
+                if (!event.isCancelled()) {
+                    this.foodData.a(event.getExhaustion()); // PAIL rename addExhaustion
+                }
+                // CraftBukkit end
             }
 
         }
@@ -1720,15 +1873,22 @@
 
     @Override
     public void setSlot(EnumItemSlot enumitemslot, ItemStack itemstack) {
+        // CraftBukkit start
+        this.setSlot(enumitemslot, itemstack, false);
+    }
+
+    @Override
+    public void setSlot(EnumItemSlot enumitemslot, ItemStack itemstack, boolean silent) {
+        // CraftBukkit end
         this.f(itemstack);
         if (enumitemslot == EnumItemSlot.MAINHAND) {
-            this.playEquipSound(itemstack);
+            this.playEquipSound(itemstack, silent); // CraftBukkit
             this.inventory.items.set(this.inventory.selected, itemstack);
         } else if (enumitemslot == EnumItemSlot.OFFHAND) {
-            this.playEquipSound(itemstack);
+            this.playEquipSound(itemstack, silent); // CraftBukkit
             this.inventory.offhand.set(0, itemstack);
         } else if (enumitemslot.a() == EnumItemSlot.Function.ARMOR) {
-            this.playEquipSound(itemstack);
+            this.playEquipSound(itemstack, silent); // CraftBukkit
             this.inventory.armor.set(enumitemslot.b(), itemstack);
         }
 
@@ -1769,26 +1929,31 @@
 
     protected void releaseShoulderEntities() {
         if (this.timeEntitySatOnShoulder + 20L < this.level.getTime()) {
-            this.spawnEntityFromShoulder(this.getShoulderEntityLeft());
-            this.setShoulderEntityLeft(new NBTTagCompound());
-            this.spawnEntityFromShoulder(this.getShoulderEntityRight());
-            this.setShoulderEntityRight(new NBTTagCompound());
+            // CraftBukkit start
+            if (this.spawnEntityFromShoulder(this.getShoulderEntityLeft())) {
+                this.setShoulderEntityLeft(new NBTTagCompound());
+            }
+            if (this.spawnEntityFromShoulder(this.getShoulderEntityRight())) {
+                this.setShoulderEntityRight(new NBTTagCompound());
+            }
+            // CraftBukkit end
         }
 
     }
 
-    private void spawnEntityFromShoulder(NBTTagCompound nbttagcompound) {
+    private boolean spawnEntityFromShoulder(NBTTagCompound nbttagcompound) { // CraftBukkit void->boolean
         if (!this.level.isClientSide && !nbttagcompound.isEmpty()) {
-            EntityTypes.a(nbttagcompound, this.level).ifPresent((entity) -> {
+            return EntityTypes.a(nbttagcompound, this.level).map((entity) -> { // CraftBukkit
                 if (entity instanceof EntityTameableAnimal) {
                     ((EntityTameableAnimal) entity).setOwnerUUID(this.uuid);
                 }
 
                 entity.setPosition(this.locX(), this.locY() + 0.699999988079071D, this.locZ());
-                ((WorldServer) this.level).addEntitySerialized(entity);
-            });
+                return ((WorldServer) this.level).addEntitySerialized(entity, CreatureSpawnEvent.SpawnReason.SHOULDER_ENTITY); // CraftBukkit
+            }).orElse(true); // CraftBukkit
         }
 
+        return true; // CraftBukkit
     }
 
     @Override