Paper/patches/server/0264-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

diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index b9fdccfc9815b0aec7bb5f5ad633c69b8eba6af2..df02d712e7daf1603885547995d69cb7fa3962ca 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -218,6 +218,10 @@ 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;
@@ -751,6 +755,15 @@ public class ServerPlayer extends Player {
         Component defaultMessage = this.getCombatTracker().getDeathMessage();
 
         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) {
@@ -898,8 +911,17 @@ 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 dd61eacfa417ed77bf09f482249bdd3a5a566ace..1ee5575d098b1727e33a00eb02e420245e4b6a15 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 {
     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() {
@@ -1446,13 +1447,12 @@ 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);
@@ -1601,7 +1601,7 @@ public abstract class LivingEntity extends Entity {
         if (!this.isRemoved() && !this.dead) {
             Entity entity = source.getEntity();
             LivingEntity entityliving = this.getKillCredit();
-
+            /* // Paper - move down to make death event cancellable - this is the runKillTrigger below
             if (this.deathScore >= 0 && entityliving != null) {
                 entityliving.awardKillScore(this, this.deathScore, source);
             }
@@ -1609,20 +1609,43 @@ public abstract class LivingEntity extends Entity {
             if (this.isSleeping()) {
                 this.stopSleeping();
             }
+             */ // Paper - move down to make death event cancellable - this is the runKillTrigger below
+
 
             this.dead = true;
-            this.getCombatTracker().recheckStatus();
+            // Paper - moved into if below
             if (this.level instanceof ServerLevel) {
                 if (entity != null) {
-                    entity.killed((ServerLevel) this.level, this);
+                    // Paper - move below into if for onKill
                 }
 
-                this.dropAllDeathLoot(source);
+                // Paper start
+                org.bukkit.event.entity.EntityDeathEvent deathEvent = this.dropAllDeathLoot(source);
+                if (deathEvent == null || !deathEvent.isCancelled()) {
+                    if (this.deathScore >= 0 && entityliving != null) {
+                        entityliving.awardKillScore(this, this.deathScore, source);
+                    }
+
+                    if (this.isSleeping()) {
+                        this.stopSleeping();
+                    }
+
+                    this.getCombatTracker().recheckStatus();
+                    if (entity != null) {
+                        entity.killed((ServerLevel) this.level, this);
+                    }
+                } else {
+                    this.dead = false;
+                    this.setHealth((float) deathEvent.getReviveHealth());
+                }
+                // Paper end
                 this.createWitherRose(entityliving);
             }
 
+            if (this.dead) { // Paper
             this.level.broadcastEntityEvent(this, (byte) 3);
             this.setPose(Pose.DYING);
+            } // Paper
         }
     }
 
@@ -1630,7 +1653,7 @@ 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();
@@ -1658,7 +1681,7 @@ public abstract class LivingEntity extends Entity {
         }
     }
 
-    protected void dropAllDeathLoot(DamageSource source) {
+    protected org.bukkit.event.entity.EntityDeathEvent dropAllDeathLoot(DamageSource source) { // Paper
         Entity entity = source.getEntity();
         int i;
 
@@ -1676,15 +1699,18 @@ public abstract class LivingEntity extends Entity {
             this.dropCustomDeathLoot(source, i, flag);
         }
         // 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() {
@@ -1762,6 +1788,7 @@ public abstract class LivingEntity extends Entity {
         return SoundEvents.GENERIC_HURT;
     }
 
+    public SoundEvent getDeathSoundPublic() { return getDeathSound(); } // Paper - public OBFHELPER
     @Nullable
     protected SoundEvent getDeathSound() {
         return SoundEvents.GENERIC_DEATH;
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 c1cdb1905536bda76f34ad3fc796996443839767..31f4e4a93ea5fd3ffe7e60dff2e2a9642b51daa2 100644
--- a/src/main/java/net/minecraft/world/entity/animal/Fox.java
+++ b/src/main/java/net/minecraft/world/entity/animal/Fox.java
@@ -691,15 +691,25 @@ public class Fox extends Animal {
     }
 
     @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 224eca7d20cf4b890a6bc1b314d566e02e716762..7281eb294ddd178ba742088d3c61bf3d529ff0c4 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
@@ -68,11 +68,19 @@ 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 d545349f659b2a164a28d06e9ff0f9fff8fa8ecf..bbde9b758643c087733064a126d90689d71830cf 100644
--- a/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
+++ b/src/main/java/net/minecraft/world/entity/decoration/ArmorStand.java
@@ -755,7 +755,8 @@ 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);
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 189e9ea6d40f560ec4e01c3c7cb71f7c2a89b442..3120bb241dfdaac4ccebf9a708b7f2187dad91bb 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -1862,7 +1862,14 @@ 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 8f44cabc1a92dc3e9afe988b23ac982e85d49fc8..9a84ac5aa03c645037daec23cc4422106a6ace1d 100644
--- a/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
+++ b/src/main/java/org/bukkit/craftbukkit/event/CraftEventFactory.java
@@ -787,9 +787,16 @@ 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()) {
@@ -805,8 +812,15 @@ public class CraftEventFactory {
         CraftPlayer entity = victim.getBukkitEntity();
         PlayerDeathEvent event = new PlayerDeathEvent(entity, drops, victim.getExpReward(), 0, deathMessage, stringDeathMessage); // Paper - Adventure
         event.setKeepInventory(keepInventory);
+        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();
@@ -823,6 +837,31 @@ 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.getDeathSoundPublic();
+        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
      */