Paper/Spigot-Server-Patches/0453-Fix-unregistering-entities-from-unloading-chunks.patch

From cbf316e677e64ca1dbea8c01d6af80ef4f9124d2 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Tue, 31 Mar 2020 03:01:45 -0400
Subject: [PATCH] Fix unregistering entities from unloading chunks

CraftBukkit caused a regression here by making unloading chunks not
have a ticket added and returning unloaded future.

This caused entities who were killed in same tick their chunk is unloading
to not be able to be removed from the chunk.

This then results in dead entities lingering in the Chunk.

Combine that with a buggy detail of the previous implementation of
the Dupe UUID patch, then this was the likely source of the "Ghost entities"

diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
index 23527809ce..941eee838b 100644
--- a/src/main/java/net/minecraft/server/WorldServer.java
+++ b/src/main/java/net/minecraft/server/WorldServer.java
@@ -1483,9 +1483,9 @@ public class WorldServer extends World {
     }
 
     private void removeEntityFromChunk(Entity entity) {
-        IChunkAccess ichunkaccess = this.getChunkAt(entity.chunkX, entity.chunkZ, ChunkStatus.FULL, false);
+        Chunk ichunkaccess = entity.getCurrentChunk(); // Paper - getChunkAt(x,z,full,false) is broken by CraftBukkit as it won't return an unloading chunk. Use our current chunk reference as this points to what chunk they need to be removed from anyways
 
-        if (ichunkaccess instanceof Chunk) {
+        if (ichunkaccess != null) { // Paper
             ((Chunk) ichunkaccess).b(entity);
         }
 
-- 
2.25.1
Updated Upstream (Bukkit/CraftBukkit) Upstream has released updates that appears to apply and compile correctly. This update has not been tested by PaperMC and as with ANY update, please do your own testing Bukkit Changes: 122289ff Add FaceAttachable interface to handle Grindstone facing in common with Switches a6db750e SPIGOT-5647: ZombieVillager entity should have getVillagerType() CraftBukkit Changes: bbe3d58e SPIGOT-5650: Lectern.setPage(int) causes a NullPointerException 3075579f Add FaceAttachable interface to handle Grindstone facing in common with Switches 95bd4238 SPIGOT-5647: ZombieVillager entity should have getVillagerType() 4d975ac3 SPIGOT-5617: setBlockData does not work when NotPlayEvent is called by redstone current 2020-04-02 23:07:06 +02:00			`From cbf316e677e64ca1dbea8c01d6af80ef4f9124d2 Mon Sep 17 00:00:00 2001`
Fix unregistering entities from unloading chunks CraftBukkit caused a regression here by making unloading chunks not have a ticket added and returning unloaded future. This caused entities who were killed in same tick their chunk is unloading to not be able to be removed from the chunk. This then results in dead entities lingering in the Chunk. Combine that with a buggy detail of the previous implementation of the Dupe UUID patch, then this was the likely source of the "Ghost entities" 2020-03-31 09:05:04 +02:00			`From: Aikar <aikar@aikar.co>`
			`Date: Tue, 31 Mar 2020 03:01:45 -0400`
			`Subject: [PATCH] Fix unregistering entities from unloading chunks`

			`CraftBukkit caused a regression here by making unloading chunks not`
			`have a ticket added and returning unloaded future.`

			`This caused entities who were killed in same tick their chunk is unloading`
			`to not be able to be removed from the chunk.`

			`This then results in dead entities lingering in the Chunk.`

			`Combine that with a buggy detail of the previous implementation of`
			`the Dupe UUID patch, then this was the likely source of the "Ghost entities"`

			`diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java`
Fix bug in double register fix could accidently delay entity reg by a tick if the bug this was fixing was encountered 2020-03-31 09:52:30 +02:00			`index 23527809ce..941eee838b 100644`
Fix unregistering entities from unloading chunks CraftBukkit caused a regression here by making unloading chunks not have a ticket added and returning unloaded future. This caused entities who were killed in same tick their chunk is unloading to not be able to be removed from the chunk. This then results in dead entities lingering in the Chunk. Combine that with a buggy detail of the previous implementation of the Dupe UUID patch, then this was the likely source of the "Ghost entities" 2020-03-31 09:05:04 +02:00			`--- a/src/main/java/net/minecraft/server/WorldServer.java`
			`+++ b/src/main/java/net/minecraft/server/WorldServer.java`
Fix bug in double register fix could accidently delay entity reg by a tick if the bug this was fixing was encountered 2020-03-31 09:52:30 +02:00			`@@ -1483,9 +1483,9 @@ public class WorldServer extends World {`
Fix unregistering entities from unloading chunks CraftBukkit caused a regression here by making unloading chunks not have a ticket added and returning unloaded future. This caused entities who were killed in same tick their chunk is unloading to not be able to be removed from the chunk. This then results in dead entities lingering in the Chunk. Combine that with a buggy detail of the previous implementation of the Dupe UUID patch, then this was the likely source of the "Ghost entities" 2020-03-31 09:05:04 +02:00			`}`

			`private void removeEntityFromChunk(Entity entity) {`
			`- IChunkAccess ichunkaccess = this.getChunkAt(entity.chunkX, entity.chunkZ, ChunkStatus.FULL, false);`
			`+ Chunk ichunkaccess = entity.getCurrentChunk(); // Paper - getChunkAt(x,z,full,false) is broken by CraftBukkit as it won't return an unloading chunk. Use our current chunk reference as this points to what chunk they need to be removed from anyways`

			`- if (ichunkaccess instanceof Chunk) {`
			`+ if (ichunkaccess != null) { // Paper`
			`((Chunk) ichunkaccess).b(entity);`
			`}`

			`--`
			`2.25.1`