papermc/Spigot-Server-Patches/0343-Ignore-Dead-Entities-in-entityList-iteration.patch

From 9b87108547b8a12487adcc4aea181f103a24cf53 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 28 Jul 2018 12:18:27 -0400
Subject: [PATCH] Ignore Dead Entities in entityList iteration

A spigot change delays removal of entities from the entity list.
This causes a change in behavior from Vanilla where getEntities type
methods will return dead entities that they shouldn't otherwise be doing.

This will ensure that dead entities are skipped from iteration since
they shouldn't of been in the list in the first place.

diff --git a/src/main/java/com/destroystokyo/paper/PaperCommand.java b/src/main/java/com/destroystokyo/paper/PaperCommand.java
index ecd1c65a9..1898ab897 100644
--- a/src/main/java/com/destroystokyo/paper/PaperCommand.java
+++ b/src/main/java/com/destroystokyo/paper/PaperCommand.java
@@ -128,6 +128,7 @@ public class PaperCommand extends Command {
                 List<Entity> entities = world.entityList;
                 entities.forEach(e -> {
                     MinecraftKey key = EntityTypes.getKey(e);
+                    if (e.shouldBeRemoved) return; // Paper
 
                     MutablePair<Integer, Map<ChunkCoordIntPair, Integer>> info = list.computeIfAbsent(key, k -> MutablePair.of(0, Maps.newHashMap()));
                     ChunkCoordIntPair chunk = new ChunkCoordIntPair(e.getChunkX(), e.getChunkZ());
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 1e64d5fcd..45e149f4a 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -124,6 +124,7 @@ public abstract class Entity implements ICommandListener, KeyedObject { // Paper
     protected boolean E;
     private boolean aw;
     public boolean dead;
+    public boolean shouldBeRemoved; // Paper
     public float width;
     public float length;
     public float I;
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index 0dca11b2c..dadd4b839 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -1214,6 +1214,7 @@ public abstract class World implements IBlockAccess {
         }
 
         entity.valid = true; // CraftBukkit
+        entity.shouldBeRemoved = false;
         new com.destroystokyo.paper.event.entity.EntityAddToWorldEvent(entity.getBukkitEntity()).callEvent(); // Paper - fire while valid
     }
 
@@ -1279,6 +1280,7 @@ public abstract class World implements IBlockAccess {
         if (entity.aa && this.isChunkLoaded(i, j, true)) {
             this.getChunkAt(i, j).b(entity);
         }
+        entity.shouldBeRemoved = true; // Paper
 
         if (!guardEntityList) { // Spigot - It will get removed after the tick if we are ticking // Paper - always remove from current chunk above
         // CraftBukkit start - Decrement loop variable field if we've already ticked this entity
@@ -2633,6 +2635,7 @@ public abstract class World implements IBlockAccess {
 
         while (iterator.hasNext()) {
             Entity entity = (Entity) iterator.next();
+            if (entity.shouldBeRemoved) continue; // Paper
 
             if (oclass.isAssignableFrom(entity.getClass()) && predicate.apply((T) entity)) {
                 arraylist.add(entity);
@@ -2719,6 +2722,7 @@ public abstract class World implements IBlockAccess {
 
         while (iterator.hasNext()) {
             Entity entity = (Entity) iterator.next();
+            if (entity.shouldBeRemoved) continue; // Paper
             // CraftBukkit start - Split out persistent check, don't apply it to special persistent mobs
             if (entity instanceof EntityInsentient) {
                 EntityInsentient entityinsentient = (EntityInsentient) entity;
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 210e3bc4e..e6ecd1796 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -678,6 +678,7 @@ public class CraftWorld implements World {
         for (Object o : world.entityList) {
             if (o instanceof net.minecraft.server.Entity) {
                 net.minecraft.server.Entity mcEnt = (net.minecraft.server.Entity) o;
+                if (mcEnt.shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = mcEnt.getBukkitEntity();
 
                 // Assuming that bukkitEntity isn't null
@@ -696,6 +697,7 @@ public class CraftWorld implements World {
         for (Object o : world.entityList) {
             if (o instanceof net.minecraft.server.Entity) {
                 net.minecraft.server.Entity mcEnt = (net.minecraft.server.Entity) o;
+                if (mcEnt.shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = mcEnt.getBukkitEntity();
 
                 // Assuming that bukkitEntity isn't null
@@ -720,6 +722,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entityList) {
             if (entity instanceof net.minecraft.server.Entity) {
+                if (((net.minecraft.server.Entity) entity).shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = ((net.minecraft.server.Entity) entity).getBukkitEntity();
 
                 if (bukkitEntity == null) {
@@ -742,6 +745,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entityList) {
             if (entity instanceof net.minecraft.server.Entity) {
+                if (((net.minecraft.server.Entity) entity).shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = ((net.minecraft.server.Entity) entity).getBukkitEntity();
 
                 if (bukkitEntity == null) {
-- 
2.17.1