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 0578d72681a0d45b6c8d1d6d04208eb14fb60083..2b4c0042b1971a9d922c8d32aa74c7f2e4c43341 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -243,6 +243,10 @@ 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;
@@ -872,6 +876,15 @@ 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) {
@@ -1023,8 +1036,17 @@ 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 f3af1c540b59819375f70ffbda6135601802cdbc..5b093a5c4ac0218dbadd6d7045266a164fcf834c 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -261,6 +261,7 @@ 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() {
@@ -1504,13 +1505,12 @@ public abstract class LivingEntity extends Entity implements Attackable {
             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);
@@ -1662,7 +1662,7 @@ 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);
             }
@@ -1674,24 +1674,56 @@ 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 (this.isSleeping()) {
+                        this.stopSleeping();
+                    }
 
-                if (entity == null || entity.killedEntity(worldserver, this)) {
+                    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);
                 }
 
-                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
         }
     }
 
@@ -1699,7 +1731,7 @@ 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();
@@ -1728,7 +1760,11 @@ 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;
 
@@ -1743,18 +1779,27 @@ 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 e1f2bb40ca7868671a869745de66f87ef3a49408..d7f24c26b0981184f43a16a27a0c5d5a931d4de3 100644
--- a/src/main/java/net/minecraft/world/entity/Mob.java
+++ b/src/main/java/net/minecraft/world/entity/Mob.java
@@ -1068,7 +1068,13 @@ 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 c2a87255178917a9555ec48ff7e705efef2da7ab..1526ca0063da0962ae781b7aa877d8cf5e1ffd73 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Fox.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Fox.java
@@ -706,15 +706,25 @@ 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 ebe207e2c4d8b7e125fec8a5182fe4882c9339e3..8ac82d3efc0f6d8ff40226e4f8084435c136eba4 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 719f68f96e58ddcdd3592131c691d21263c81915..4413b609f1250cf9477fcb3fecd7b67afee0b896 100644
--- a/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
+++ b/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
@@ -536,8 +536,9 @@ 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();
+                                if (!event.isCancelled()) // Paper
                                 this.discard(); // CraftBukkit - SPIGOT-4890: remain as this.discard() since above damagesource method will call death event
                             }
 
@@ -599,7 +600,7 @@ 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 +608,10 @@ public class ArmorStand extends LivingEntity {
         }
 
         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 +633,7 @@ 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
 
     }
 
@@ -764,7 +765,8 @@ 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 090725321690d22db7d714a794b698930b126ae1..5ce7e05e6103239b733e5d67126316f487fe10e8 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -2294,7 +2294,14 @@ 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 b77fefc9cf30fd438f557e5b56efb4c0251cb17a..68b1e24a497c052c8e20b946b5b5dabc59e7f539 100644
--- a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -824,9 +824,16 @@ 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()) {
@@ -843,8 +850,15 @@ 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();
@@ -861,6 +875,31 @@ 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
      */