Paper/patches/server/0251-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.

== 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 2584e8eb867dca35e945ec7ab83bc2181d7bde26..7dae09967ae47ae2ef01d1072ad98f125d0b67e9 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -248,6 +248,10 @@ public class ServerPlayer extends Player {
     private int containerCounter;
     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;
@@ -882,6 +886,15 @@ 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) {
@@ -1030,8 +1043,17 @@ 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 527af65884fd505616204876e22d54f362ce7791..d1b9726228cc0a7bdb1c570603b5d1b8a4d6debe 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -259,6 +259,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
     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() {
@@ -1522,13 +1523,12 @@ public abstract class LivingEntity extends Entity implements Attackable {
 
             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);
@@ -1679,7 +1679,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
         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);
             }
@@ -1691,24 +1691,59 @@ public abstract class LivingEntity extends Entity implements Attackable {
             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
             Level world = this.level();
 
             if (world instanceof ServerLevel) {
                 ServerLevel worldserver = (ServerLevel) world;
+                // 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 (entity == null || entity.killedEntity(worldserver, this)) {
+                    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.killedEntity((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);
             }
 
+            // Paper start
+            if (this.dead) { // Paper
+                this.level().broadcastEntityEvent(this, (byte) 3);
             this.setPose(Pose.DYING);
+            }
+            // Paper end
         }
     }
 
@@ -1716,7 +1751,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
         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();
@@ -1745,7 +1780,11 @@ public abstract class LivingEntity extends Entity implements Attackable {
         }
     }
 
-    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;
 
@@ -1760,18 +1799,27 @@ public abstract class LivingEntity extends Entity implements Attackable {
         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 a6b89a12471a8c7277b7a5aa50447ff275a667c6..efef5df4cf720058c0b07ef795cfa6a567113811 100644
--- a/src/main/java/net/minecraft/world/entity/Mob.java
+++ b/src/main/java/net/minecraft/world/entity/Mob.java
@@ -1075,7 +1075,13 @@ public abstract class Mob extends LivingEntity implements Targeting {
                 }
 
                 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 8670d8b2a08e96df787a91f36c48df8b345080dc..6124209f50300eeaab45b66c2f1a5b2944119450 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Fox.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Fox.java
@@ -712,15 +712,25 @@ 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
     }
 
     @Override
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 bb399f775a5530a01f59332848c8ab9b8eceb2b5..14edfe103e61024b569f33de0b6608f39e749319 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
@@ -70,11 +70,19 @@ 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 948ba97e318506dad96e59121297b5bf8340d2e6..810bead2f19de70786027b190137f743a0c40ee7 100644
--- a/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
+++ b/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
@@ -492,8 +492,10 @@ public class ArmorStand extends LivingEntity {
                 }
                 // CraftBukkit end
                 if (source.is(DamageTypeTags.IS_EXPLOSION)) {
-                    this.brokenByAnything(source);
-                    this.kill();
+                    // Paper start - avoid duplicate event call
+                    org.bukkit.event.entity.EntityDeathEvent event = this.brokenByAnything(source);
+                    if (!event.isCancelled()) this.kill(false);
+                    // Paper end
                     return false;
                 } else if (source.is(DamageTypeTags.IGNITES_ARMOR_STANDS)) {
                     if (this.isOnFire()) {
@@ -536,9 +538,9 @@ public class ArmorStand extends LivingEntity {
                                 this.gameEvent(GameEvent.ENTITY_DAMAGE, source.getEntity());
                                 this.lastHit = i;
                             } else {
-                                this.brokenByPlayer(source);
+                                org.bukkit.event.entity.EntityDeathEvent event = this.brokenByPlayer(source); // Paper
                                 this.showBreakingParticles();
-                                this.discard(); // CraftBukkit - SPIGOT-4890: remain as this.discard() since above damagesource method will call death event
+                                if (!event.isCancelled()) this.kill(false); // Paper - we still need to kill to follow vanilla logic (emit the game event etc...)
                             }
 
                             return true;
@@ -590,8 +592,10 @@ public class ArmorStand extends LivingEntity {
 
         f1 -= amount;
         if (f1 <= 0.5F) {
-            this.brokenByAnything(damageSource);
-            this.kill();
+            // Paper start - avoid duplicate event call
+            org.bukkit.event.entity.EntityDeathEvent event = this.brokenByAnything(damageSource);
+            if (!event.isCancelled()) this.kill(false);
+            // Paper end
         } else {
             this.setHealth(f1);
             this.gameEvent(GameEvent.ENTITY_DAMAGE, damageSource.getEntity());
@@ -599,7 +603,7 @@ public class ArmorStand extends LivingEntity {
 
     }
 
-    private void brokenByPlayer(DamageSource damageSource) {
+    private org.bukkit.event.entity.EntityDeathEvent brokenByPlayer(DamageSource damageSource) { // Paper
         ItemStack itemstack = new ItemStack(Items.ARMOR_STAND);
 
         if (this.hasCustomName()) {
@@ -607,10 +611,10 @@ public class ArmorStand extends LivingEntity {
         }
 
         this.drops.add(org.bukkit.craftbukkit.inventory.CraftItemStack.asBukkitCopy(itemstack)); // CraftBukkit - add to drops
-        this.brokenByAnything(damageSource);
+        return this.brokenByAnything(damageSource); // Paper
     }
 
-    private void brokenByAnything(DamageSource damageSource) {
+    private org.bukkit.event.entity.EntityDeathEvent brokenByAnything(DamageSource damageSource) { // Paper
         this.playBrokenSound();
         // this.dropAllDeathLoot(damagesource); // CraftBukkit - moved down
 
@@ -632,7 +636,7 @@ public class ArmorStand extends LivingEntity {
                 this.armorItems.set(i, ItemStack.EMPTY);
             }
         }
-        this.dropAllDeathLoot(damageSource); // CraftBukkit - moved from above
+        return this.dropAllDeathLoot(damageSource); // CraftBukkit - moved from above // Paper
 
     }
 
@@ -759,7 +763,16 @@ public class ArmorStand extends LivingEntity {
 
     @Override
     public void kill() {
-        org.bukkit.craftbukkit.event.CraftEventFactory.callEntityDeathEvent(this, this.drops); // CraftBukkit - call event
+        // Paper start
+        kill(true);
+    }
+
+    public void kill(boolean callEvent) {
+        if (callEvent) {
+        // Paper end
+        org.bukkit.event.entity.EntityDeathEvent event = org.bukkit.craftbukkit.event.CraftEventFactory.callEntityDeathEvent(this, this.drops); // CraftBukkit - call event // Paper - make cancellable
+        if (event.isCancelled()) return; // Paper - make cancellable
+        } // Paper
         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 8417da1eb3a440adcd425ffbda9fdcb768857afd..e55d31783396e87ef18f5b6dfc27742c0b4e3465 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -2377,7 +2377,14 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
     @Override
     public void sendHealthUpdate() {
         FoodData foodData = this.getHandle().getFoodData();
-        this.sendHealthUpdate(this.getScaledHealth(), foodData.getFoodLevel(), foodData.getSaturationLevel());
+        // Paper start - cancellable death event
+        ClientboundSetHealthPacket packet = new ClientboundSetHealthPacket(this.getScaledHealth(), foodData.getFoodLevel(), foodData.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 f55b1ccaab6f6bec89d92f79995abf331ea87c98..64ab19fdc94164f6be505dd1d2c79cf339832813 100644
--- a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -893,9 +893,16 @@ 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()) {
@@ -912,8 +919,15 @@ 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();
@@ -930,6 +944,31 @@ 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.minecraftToBukkit(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.bukkitToMinecraft(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
      */