Paper/Spigot-Server-Patches/0264-Ignore-Dead-Entities-in-entityList-iteration.patch

From 0a72bb4348272eee4bfd507865c781c5a5d198cc 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 eecf27370..d704fc79c 100644
--- a/src/main/java/com/destroystokyo/paper/PaperCommand.java
+++ b/src/main/java/com/destroystokyo/paper/PaperCommand.java
@@ -179,6 +179,7 @@ public class PaperCommand extends Command {
                         return;
                     }
                     MinecraftKey key = e.getMinecraftKey();
+                    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/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index 1d47e4737..c464d6962 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -681,6 +681,7 @@ public class Chunk implements IChunkAccess {
 
                 while (iterator.hasNext()) {
                     Entity entity1 = (Entity) iterator.next();
+                    if (entity1.shouldBeRemoved) continue; // Paper
 
                     if (entity1.getBoundingBox().c(axisalignedbb) && entity1 != entity) {
                         if (predicate == null || predicate.test(entity1)) {
@@ -718,6 +719,7 @@ public class Chunk implements IChunkAccess {
 
             while (iterator.hasNext()) {
                 T entity = (T) iterator.next(); // CraftBukkit - decompile error
+                if (entity.shouldBeRemoved) continue; // Paper
 
                 if ((entitytypes == null || entity.getEntityType() == entitytypes) && entity.getBoundingBox().c(axisalignedbb) && predicate.test(entity)) {
                     list.add(entity);
@@ -739,6 +741,7 @@ public class Chunk implements IChunkAccess {
 
             while (iterator.hasNext()) {
                 T t0 = (T) iterator.next(); // CraftBukkit - decompile error
+                if (t0.shouldBeRemoved) continue; // Paper
 
                 if (oclass.isInstance(t0) && t0.getBoundingBox().c(axisalignedbb) && (predicate == null || predicate.test(t0))) { // Spigot - instance check
                     list.add(t0);
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 09ec144eb..4880ece94 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -196,6 +196,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
     protected int numCollisions = 0; // Paper
     public void inactiveTick() { }
     // Spigot end
+    public boolean shouldBeRemoved; // Paper
 
     public float getBukkitYaw() {
         return this.yaw;
diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
index 3d5a50ddc..12cdb0cc9 100644
--- a/src/main/java/net/minecraft/server/WorldServer.java
+++ b/src/main/java/net/minecraft/server/WorldServer.java
@@ -904,7 +904,7 @@ public class WorldServer extends World {
 
         while (objectiterator.hasNext()) {
             Entity entity = (Entity) objectiterator.next();
-
+            if (entity.shouldBeRemoved) continue; // Paper
             if (entity instanceof EntityInsentient) {
                 EntityInsentient entityinsentient = (EntityInsentient) entity;
 
@@ -1225,6 +1225,7 @@ public class WorldServer extends World {
                 entity.origin = entity.getBukkitEntity().getLocation();
             }
             // Paper end
+            entity.shouldBeRemoved = false; // Paper - shouldn't be removed after being re-added
             new com.destroystokyo.paper.event.entity.EntityAddToWorldEvent(entity.getBukkitEntity()).callEvent(); // Paper - fire while valid
         }
 
@@ -1237,6 +1238,7 @@ public class WorldServer extends World {
             this.removeEntityFromChunk(entity);
             this.entitiesById.remove(entity.getId());
             this.unregisterEntity(entity);
+            entity.shouldBeRemoved = true; // Paper
         }
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 89705e5ff..fe91e08f2 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -1005,6 +1005,7 @@ public class CraftWorld implements World {
         for (Object o : world.entitiesById.values()) {
             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
@@ -1024,6 +1025,7 @@ public class CraftWorld implements World {
         for (Object o : world.entitiesById.values()) {
             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
@@ -1050,6 +1052,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entitiesById.values()) {
             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) {
@@ -1073,6 +1076,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entitiesById.values()) {
             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) {
-- 
2.25.0