Paper/patches/server/0255-Improve-death-events.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Phoenix616 <mail@moep.tv>
Date: Tue, 21 Aug 2018 01:39:35 +0100
Subject: [PATCH] Improve death events

This adds the ability to cancel the death events and to modify the sound
an entity makes when dying. (In cases were no sound should it will be
called with shouldPlaySound set to false allowing unsilencing of silent
entities)

It makes handling of entity deaths a lot nicer as you no longer need
to listen on the damage event and calculate if the entity dies yourself
to cancel the death which has the benefit of also receiving the dropped
items and experience which is otherwise only properly possible by using
internal code.

TODO 1.17: this needs to be checked (actually get off your lazy ass and cancel the events) for the following entities,
maybe more (please check patch overrides for drops for more):
- players, armor stands, foxes, chested donkeys/llamas

== AT ==
public net.minecraft.world.entity.LivingEntity getDeathSound()Lnet/minecraft/sounds/SoundEvent;
public net.minecraft.world.entity.LivingEntity getSoundVolume()F

diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index cd392d316f35ac488c49ad8c34c0273bbccc6a1c..db02d7938c79995b8acc4184c1be2fe39cbf479c 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -235,6 +235,10 @@ public class ServerPlayer extends Player {
     public int latency;
     public boolean wonGame;
     private int containerUpdateDelay; // Paper
+    // Paper start - cancellable death event
+    public boolean queueHealthUpdatePacket = false;
+    public net.minecraft.network.protocol.game.ClientboundSetHealthPacket queuedHealthUpdatePacket;
+    // Paper end
 
     // CraftBukkit start
     public String displayName;
@@ -823,6 +827,15 @@ public class ServerPlayer extends Player {
         String deathmessage = defaultMessage.getString();
         this.keepLevel = keepInventory; // SPIGOT-2222: pre-set keepLevel
         org.bukkit.event.entity.PlayerDeathEvent event = CraftEventFactory.callPlayerDeathEvent(this, loot, PaperAdventure.asAdventure(defaultMessage), defaultMessage.getString(), keepInventory); // Paper - Adventure
+        // Paper start - cancellable death event
+        if (event.isCancelled()) {
+            // make compatible with plugins that might have already set the health in an event listener
+            if (this.getHealth() <= 0) {
+                this.setHealth((float) event.getReviveHealth());
+            }
+            return;
+        }
+        // Paper end
 
         // SPIGOT-943 - only call if they have an inventory open
         if (this.containerMenu != this.inventoryMenu) {
@@ -968,8 +981,17 @@ public class ServerPlayer extends Player {
                         }
                     }
                 }
-
-                return super.hurt(source, amount);
+                // Paper start - cancellable death events
+                //return super.hurt(source, amount);
+                this.queueHealthUpdatePacket = true;
+                boolean damaged = super.hurt(source, amount);
+                this.queueHealthUpdatePacket = false;
+                if (this.queuedHealthUpdatePacket != null) {
+                    this.connection.send(this.queuedHealthUpdatePacket);
+                    this.queuedHealthUpdatePacket = null;
+                }
+                return damaged;
+                // Paper end
             }
         }
     }
diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 49ae203d493b1d43ee5c3623f5317499ffe55523..24a07ef9f5cbed34d1aefccda9fe655b7dfef7ec 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -263,6 +263,7 @@ public abstract class LivingEntity extends Entity {
     public Set<UUID> collidableExemptions = new HashSet<>();
     public boolean bukkitPickUpLoot;
     public org.bukkit.craftbukkit.entity.CraftLivingEntity getBukkitLivingEntity() { return (org.bukkit.craftbukkit.entity.CraftLivingEntity) super.getBukkitEntity(); } // Paper
+    public boolean silentDeath = false; // Paper - mark entity as dying silently for cancellable death event
 
     @Override
     public float getBukkitYaw() {
@@ -1466,13 +1467,12 @@ public abstract class LivingEntity extends Entity {
             if (knockbackCancelled) this.level.broadcastEntityEvent(this, (byte) 2); // Paper - Disable explosion knockback
             if (this.isDeadOrDying()) {
                 if (!this.checkTotemDeathProtection(source)) {
-                    SoundEvent soundeffect = this.getDeathSound();
-
-                    if (flag1 && soundeffect != null) {
-                        this.playSound(soundeffect, this.getSoundVolume(), this.getVoicePitch());
-                    }
+                    // Paper start - moved into CraftEventFactory event caller for cancellable death event
+                    this.silentDeath = !flag1; // mark entity as dying silently
+                    // Paper end
 
                     this.die(source);
+                    this.silentDeath = false; // Paper - cancellable death event - reset to default
                 }
             } else if (flag1) {
                 this.playHurtSound(source);
@@ -1624,7 +1624,7 @@ public abstract class LivingEntity extends Entity {
         if (!this.isRemoved() && !this.dead) {
             Entity entity = damageSource.getEntity();
             LivingEntity entityliving = this.getKillCredit();
-
+            /* // Paper - move down to make death event cancellable - this is the awardKillScore below
             if (this.deathScore >= 0 && entityliving != null) {
                 entityliving.awardKillScore(this, this.deathScore, damageSource);
             }
@@ -1636,20 +1636,53 @@ public abstract class LivingEntity extends Entity {
             if (!this.level.isClientSide && this.hasCustomName()) {
                 if (org.spigotmc.SpigotConfig.logNamedDeaths) LivingEntity.LOGGER.info("Named entity {} died: {}", this, this.getCombatTracker().getDeathMessage().getString()); // Spigot
             }
+             */ // Paper - move down to make death event cancellable - this is the awardKillScore below
 
             this.dead = true;
-            this.getCombatTracker().recheckStatus();
+            // Paper - moved into if below
             if (this.level instanceof ServerLevel) {
-                if (entity == null || entity.wasKilled((ServerLevel) this.level, this)) {
+                // Paper - move below into if for onKill
+
+                // Paper start
+                org.bukkit.event.entity.EntityDeathEvent deathEvent = this.dropAllDeathLoot(damageSource);
+                if (deathEvent == null || !deathEvent.isCancelled()) {
+                    if (this.deathScore >= 0 && entityliving != null) {
+                        entityliving.awardKillScore(this, this.deathScore, damageSource);
+                    }
+                    // Paper start - clear equipment if event is not cancelled
+                    if (this instanceof Mob) {
+                        for (EquipmentSlot slot : this.clearedEquipmentSlots) {
+                            this.setItemSlot(slot, ItemStack.EMPTY);
+                        }
+                        this.clearedEquipmentSlots.clear();
+                    }
+                    // Paper end
+
+                    if (this.isSleeping()) {
+                        this.stopSleeping();
+                    }
+
+                    if (!this.level.isClientSide && this.hasCustomName()) {
+                        if (org.spigotmc.SpigotConfig.logNamedDeaths) LivingEntity.LOGGER.info("Named entity {} died: {}", this, this.getCombatTracker().getDeathMessage().getString()); // Spigot
+                    }
+
+                    this.getCombatTracker().recheckStatus();
+                    if (entity != null) {
+                        entity.wasKilled((ServerLevel) this.level, this);
+                    }
                     this.gameEvent(GameEvent.ENTITY_DIE);
-                    this.dropAllDeathLoot(damageSource);
-                    this.createWitherRose(entityliving);
+                } else {
+                    this.dead = false;
+                    this.setHealth((float) deathEvent.getReviveHealth());
                 }
-
-                this.level.broadcastEntityEvent(this, (byte) 3);
+                // Paper end
+                this.createWitherRose(entityliving);
             }
 
+            if (this.dead) { // Paper
+            this.level.broadcastEntityEvent(this, (byte) 3);
             this.setPose(Pose.DYING);
+            } // Paper
         }
     }
 
@@ -1657,7 +1690,7 @@ public abstract class LivingEntity extends Entity {
         if (!this.level.isClientSide) {
             boolean flag = false;
 
-            if (adversary instanceof WitherBoss) {
+            if (this.dead && adversary instanceof WitherBoss) { // Paper
                 if (this.level.getGameRules().getBoolean(GameRules.RULE_MOBGRIEFING)) {
                     BlockPos blockposition = this.blockPosition();
                     BlockState iblockdata = Blocks.WITHER_ROSE.defaultBlockState();
@@ -1686,7 +1719,11 @@ public abstract class LivingEntity extends Entity {
         }
     }
 
-    protected void dropAllDeathLoot(DamageSource source) {
+    // Paper start
+    protected boolean clearEquipmentSlots = true;
+    protected Set<EquipmentSlot> clearedEquipmentSlots = new java.util.HashSet<>();
+    protected org.bukkit.event.entity.EntityDeathEvent dropAllDeathLoot(DamageSource source) {
+    // Paper end
         Entity entity = source.getEntity();
         int i;
 
@@ -1701,18 +1738,27 @@ public abstract class LivingEntity extends Entity {
         this.dropEquipment(); // CraftBukkit - from below
         if (this.shouldDropLoot() && this.level.getGameRules().getBoolean(GameRules.RULE_DOMOBLOOT)) {
             this.dropFromLootTable(source, flag);
+            // Paper start
+            final boolean prev = this.clearEquipmentSlots;
+            this.clearEquipmentSlots = false;
+            this.clearedEquipmentSlots.clear();
+            // Paper end
             this.dropCustomDeathLoot(source, i, flag);
+            this.clearEquipmentSlots = prev; // Paper
         }
         // CraftBukkit start - Call death event
-        CraftEventFactory.callEntityDeathEvent(this, this.drops);
+        org.bukkit.event.entity.EntityDeathEvent deathEvent = CraftEventFactory.callEntityDeathEvent(this, this.drops); // Paper
+        this.postDeathDropItems(deathEvent); // Paper
         this.drops = new ArrayList<>();
         // CraftBukkit end
 
         // this.dropInventory();// CraftBukkit - moved up
         this.dropExperience();
+        return deathEvent; // Paper
     }
 
     protected void dropEquipment() {}
+    protected void postDeathDropItems(org.bukkit.event.entity.EntityDeathEvent event) {} // Paper - method for post death logic that cannot be ran before the event is potentially cancelled
 
     // CraftBukkit start
     public int getExpReward() {
diff --git a/src/main/java/net/minecraft/world/entity/Mob.java b/src/main/java/net/minecraft/world/entity/Mob.java
index 6f728231a7b326e605d6ddb8e4cd6f0f0aec820b..f61a4409ebb5ed89e5a5cfe0488498a52faa2346 100644
--- a/src/main/java/net/minecraft/world/entity/Mob.java
+++ b/src/main/java/net/minecraft/world/entity/Mob.java
@@ -1036,7 +1036,13 @@ public abstract class Mob extends LivingEntity {
                 }
 
                 this.spawnAtLocation(itemstack);
+                if (this.clearEquipmentSlots) { // Paper
                 this.setItemSlot(enumitemslot, ItemStack.EMPTY);
+                // Paper start
+                } else {
+                    this.clearedEquipmentSlots.add(enumitemslot);
+                }
+                // Paper end
             }
         }
 
diff --git a/src/main/java/net/minecraft/world/entity/animal/Fox.java b/src/main/java/net/minecraft/world/entity/animal/Fox.java
index dd124ccbdc7efe0e41b3a04abddcb328cac44948..f4cfefd72704b3423392ffeb57e78c5d6410ff6f 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Fox.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Fox.java
@@ -705,15 +705,25 @@ public class Fox extends Animal implements VariantHolder<Fox.Type> {
     }
 
     @Override
-    protected void dropAllDeathLoot(DamageSource source) {
-        ItemStack itemstack = this.getItemBySlot(EquipmentSlot.MAINHAND);
+    // Paper start - Cancellable death event
+    protected org.bukkit.event.entity.EntityDeathEvent dropAllDeathLoot(DamageSource source) {
+        ItemStack itemstack = this.getItemBySlot(EquipmentSlot.MAINHAND).copy(); // Paper - modified by supercall
+
+        org.bukkit.event.entity.EntityDeathEvent deathEvent = super.dropAllDeathLoot(source);
+
+        // Below is code to drop
+
+        if (deathEvent == null || deathEvent.isCancelled()) {
+            return deathEvent;
+        }
+        // Paper end
 
         if (!itemstack.isEmpty()) {
             this.spawnAtLocation(itemstack);
             this.setItemSlot(EquipmentSlot.MAINHAND, ItemStack.EMPTY);
         }
 
-        super.dropAllDeathLoot(source);
+        return deathEvent; // Paper
     }
 
     public static boolean isPathClear(Fox fox, LivingEntity chasedEntity) {
diff --git a/src/main/java/net/minecraft/world/entity/animal/horse/AbstractChestedHorse.java b/src/main/java/net/minecraft/world/entity/animal/horse/AbstractChestedHorse.java
index 65dd844b9b38730a819158e1023c4abd829b52bb..170411b42aeef69c796d1409b59c3eb69f78c710 100644
--- a/src/main/java/net/minecraft/world/entity/animal/horse/AbstractChestedHorse.java
+++ b/src/main/java/net/minecraft/world/entity/animal/horse/AbstractChestedHorse.java
@@ -69,11 +69,19 @@ public abstract class AbstractChestedHorse extends AbstractHorse {
                 this.spawnAtLocation(Blocks.CHEST);
             }
 
-            this.setChest(false);
+            //this.setCarryingChest(false); // Paper - moved to post death logic
         }
 
     }
 
+    // Paper start
+    protected void postDeathDropItems(org.bukkit.event.entity.EntityDeathEvent event) {
+        if (this.hasChest() && (event == null || !event.isCancelled())) {
+            this.setChest(false);
+        }
+    }
+    // Paper end
+
     @Override
     public void addAdditionalSaveData(CompoundTag nbt) {
         super.addAdditionalSaveData(nbt);
diff --git a/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java b/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
index f70f75867a8f03d42f240a0d007d2221269f2fdb..e463ae13ce6f65675c2b6d553ecf91db5a047dbc 100644
--- a/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
+++ b/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
@@ -753,7 +753,8 @@ public class ArmorStand extends LivingEntity {
 
     @Override
     public void kill() {
-        org.bukkit.craftbukkit.event.CraftEventFactory.callEntityDeathEvent(this, drops); // CraftBukkit - call event
+        org.bukkit.event.entity.EntityDeathEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callEntityDeathEvent(this, drops); // CraftBukkit - call event // Paper - make cancellable
+        if (event.isCancelled()) return; // Paper - make cancellable
         this.remove(Entity.RemovalReason.KILLED);
         this.gameEvent(GameEvent.ENTITY_DIE);
     }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 06ca78e5b4b9da5d932a0fb1b53abe4811522547..d37d33b0c522235c063887e45a77edbde9e0b064 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -2169,7 +2169,14 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
     }
 
     public void sendHealthUpdate() {
-        this.getHandle().connection.send(new ClientboundSetHealthPacket(this.getScaledHealth(), this.getHandle().getFoodData().getFoodLevel(), this.getHandle().getFoodData().getSaturationLevel()));
+        // Paper start - cancellable death event
+        ClientboundSetHealthPacket packet = new ClientboundSetHealthPacket(this.getScaledHealth(), this.getHandle().getFoodData().getFoodLevel(), this.getHandle().getFoodData().getSaturationLevel());
+        if (this.getHandle().queueHealthUpdatePacket) {
+            this.getHandle().queuedHealthUpdatePacket = packet;
+        } else {
+            this.getHandle().connection.send(packet);
+        }
+        // Paper end
     }
 
     public void injectScaledMaxHealth(Collection<AttributeInstance> collection, boolean force) {
diff --git a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
index 67d820fb9aa00a3275cc3e23461864b496d738aa..6e533fdcd0671892a0e9dbfc99662feb433a5cf8 100644
--- a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -807,9 +807,16 @@ public class CraftEventFactory {
     public static EntityDeathEvent callEntityDeathEvent(net.minecraft.world.entity.LivingEntity victim, List<org.bukkit.inventory.ItemStack> drops) {
         CraftLivingEntity entity = (CraftLivingEntity) victim.getBukkitEntity();
         EntityDeathEvent event = new EntityDeathEvent(entity, drops, victim.getExpReward());
+        populateFields(victim, event); // Paper - make cancellable
         CraftWorld world = (CraftWorld) entity.getWorld();
         Bukkit.getServer().getPluginManager().callEvent(event);
 
+        // Paper start - make cancellable
+        if (event.isCancelled()) {
+            return event;
+        }
+        playDeathSound(victim, event);
+        // Paper end
         victim.expToDrop = event.getDroppedExp();
 
         for (org.bukkit.inventory.ItemStack stack : event.getDrops()) {
@@ -826,8 +833,15 @@ public class CraftEventFactory {
         PlayerDeathEvent event = new PlayerDeathEvent(entity, drops, victim.getExpReward(), 0, deathMessage, stringDeathMessage); // Paper - Adventure
         event.setKeepInventory(keepInventory);
         event.setKeepLevel(victim.keepLevel); // SPIGOT-2222: pre-set keepLevel
+        populateFields(victim, event); // Paper - make cancellable
         org.bukkit.World world = entity.getWorld();
         Bukkit.getServer().getPluginManager().callEvent(event);
+        // Paper start - make cancellable
+        if (event.isCancelled()) {
+            return event;
+        }
+        playDeathSound(victim, event);
+        // Paper end
 
         victim.keepLevel = event.getKeepLevel();
         victim.newLevel = event.getNewLevel();
@@ -844,6 +858,31 @@ public class CraftEventFactory {
         return event;
     }
 
+    // Paper start - helper methods for making death event cancellable
+    // Add information to death event
+    private static void populateFields(net.minecraft.world.entity.LivingEntity victim, EntityDeathEvent event) {
+        event.setReviveHealth(event.getEntity().getAttribute(org.bukkit.attribute.Attribute.GENERIC_MAX_HEALTH).getValue());
+        event.setShouldPlayDeathSound(!victim.silentDeath && !victim.isSilent());
+        net.minecraft.sounds.SoundEvent soundEffect = victim.getDeathSound();
+        event.setDeathSound(soundEffect != null ? org.bukkit.craftbukkit.CraftSound.getBukkit(soundEffect) : null);
+        event.setDeathSoundCategory(org.bukkit.SoundCategory.valueOf(victim.getSoundSource().name()));
+        event.setDeathSoundVolume(victim.getSoundVolume());
+        event.setDeathSoundPitch(victim.getVoicePitch());
+    }
+
+    // Play death sound manually
+    private static void playDeathSound(net.minecraft.world.entity.LivingEntity victim, EntityDeathEvent event) {
+        if (event.shouldPlayDeathSound() && event.getDeathSound() != null && event.getDeathSoundCategory() != null) {
+            net.minecraft.world.entity.player.Player source = victim instanceof net.minecraft.world.entity.player.Player ? (net.minecraft.world.entity.player.Player) victim : null;
+            double x = event.getEntity().getLocation().getX();
+            double y = event.getEntity().getLocation().getY();
+            double z = event.getEntity().getLocation().getZ();
+            net.minecraft.sounds.SoundEvent soundEffect = org.bukkit.craftbukkit.CraftSound.getSoundEffect(event.getDeathSound());
+            net.minecraft.sounds.SoundSource soundCategory = net.minecraft.sounds.SoundSource.valueOf(event.getDeathSoundCategory().name());
+            victim.level.playSound(source, x, y, z, soundEffect, soundCategory, event.getDeathSoundVolume(), event.getDeathSoundPitch());
+        }
+    }
+    // Paper end
     /**
      * Server methods
      */