Paper/Spigot-Server-Patches/0253-Ignore-Dead-Entities-in-entityList-iteration.patch

From 0000000000000000000000000000000000000000 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 6943524c2dd8b12691b8ac5b08daee823ce50c3d..b67bd98cca4a06bc0ebaed577195dffc3b3251ec 100644
--- a/src/main/java/com/destroystokyo/paper/PaperCommand.java
+++ b/src/main/java/com/destroystokyo/paper/PaperCommand.java
@@ -209,6 +209,7 @@ public class PaperCommand extends Command {
                 Collection<Entity> entities = world.entitiesById.values();
                 entities.forEach(e -> {
                     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.chunkX, e.chunkZ);
diff --git a/src/main/java/net/minecraft/server/level/WorldServer.java b/src/main/java/net/minecraft/server/level/WorldServer.java
index e39f1ea4eefb0d8e0ca379b116b3699c13bb3f35..9151d84e2f6fb316525c74466589178769fbc8ef 100644
--- a/src/main/java/net/minecraft/server/level/WorldServer.java
+++ b/src/main/java/net/minecraft/server/level/WorldServer.java
@@ -1309,6 +1309,7 @@ public class WorldServer extends World implements GeneratorAccessSeed {
                 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
         }
 
@@ -1321,6 +1322,7 @@ public class WorldServer extends World implements GeneratorAccessSeed {
             this.removeEntityFromChunk(entity);
             this.entitiesById.remove(entity.getId());
             this.unregisterEntity(entity);
+            entity.shouldBeRemoved = true; // Paper
         }
     }
 
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 102c2bb98a99cdbfcdf1297341dbba91434ee0e3..046b191e771ed9be337e095214a67febd768e5f6 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -276,6 +276,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, ne
     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/world/level/chunk/Chunk.java b/src/main/java/net/minecraft/world/level/chunk/Chunk.java
index e4accac8f2e8daa58f9b0c279ffcad9347448bb0..79ff96f18c53f3d1ce4a00be2e2d8fe68f77bf54 100644
--- a/src/main/java/net/minecraft/world/level/chunk/Chunk.java
+++ b/src/main/java/net/minecraft/world/level/chunk/Chunk.java
@@ -863,6 +863,7 @@ public class Chunk implements IChunkAccess {
 
             for (int i1 = 0; i1 < l; ++i1) {
                 Entity entity1 = (Entity) list1.get(i1);
+                if (entity1.shouldBeRemoved) continue; // Paper
 
                 if (entity1.getBoundingBox().c(axisalignedbb) && entity1 != entity) {
                     if (predicate == null || predicate.test(entity1)) {
@@ -900,6 +901,7 @@ 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);
@@ -922,6 +924,7 @@ 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/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index a2b3f5106edc8328ba7edd65dedd56e0dc8d33d2..e7103b8021141071712759b1056eccb5e3da93b7 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -1040,6 +1040,7 @@ public class CraftWorld implements World {
         for (Object o : world.entitiesById.values()) {
             if (o instanceof net.minecraft.world.entity.Entity) {
                 net.minecraft.world.entity.Entity mcEnt = (net.minecraft.world.entity.Entity) o;
+                if (mcEnt.shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = mcEnt.getBukkitEntity();
 
                 // Assuming that bukkitEntity isn't null
@@ -1059,6 +1060,7 @@ public class CraftWorld implements World {
         for (Object o : world.entitiesById.values()) {
             if (o instanceof net.minecraft.world.entity.Entity) {
                 net.minecraft.world.entity.Entity mcEnt = (net.minecraft.world.entity.Entity) o;
+                if (mcEnt.shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = mcEnt.getBukkitEntity();
 
                 // Assuming that bukkitEntity isn't null
@@ -1085,6 +1087,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entitiesById.values()) {
             if (entity instanceof net.minecraft.world.entity.Entity) {
+                if (((net.minecraft.world.entity.Entity) entity).shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = ((net.minecraft.world.entity.Entity) entity).getBukkitEntity();
 
                 if (bukkitEntity == null) {
@@ -1108,6 +1111,7 @@ public class CraftWorld implements World {
 
         for (Object entity: world.entitiesById.values()) {
             if (entity instanceof net.minecraft.world.entity.Entity) {
+                if (((net.minecraft.world.entity.Entity) entity).shouldBeRemoved) continue; // Paper
                 Entity bukkitEntity = ((net.minecraft.world.entity.Entity) entity).getBukkitEntity();
 
                 if (bukkitEntity == null) {