From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Fri, 3 Sep 2021 15:50:25 +0100
Subject: [PATCH] Do not process entity loads in CraftChunk#getEntities

This re-introduces the issue behind #5872 but fixes #6543
The logic here is generally flawed however somewhat of a nuance,
upstream uses managedBlock which is basically needed to process
the posted entity adds, but, has the side-effect of processing any
chunk loads which has the naunce of stacking up and either causing a
massive performance hit, or can potentially lead the server to crash.

This issue is particularly noticable on paper due to the cumulative efforts
to drastically improve chunk loading speeds which means that there is much more
of a chance that we're about to eat a dirtload of chunk load callbacks, thus
making this issue much more of an issue

diff --git a/src/main/java/org/bukkit/craftbukkit/CraftChunk.java b/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
index 87368816fdb23f804752351de502126f2cd062c7..3eefcae565ced131ad2924290423fd0b3249ccde 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftChunk.java
@@ -123,30 +123,6 @@ public class CraftChunk implements Chunk {
             this.getWorld().getChunkAt(x, z); // Transient load for this tick
         }
 
-        PersistentEntitySectionManager<net.minecraft.world.entity.Entity> entityManager = this.getCraftWorld().getHandle().entityManager;
-        long pair = ChunkPos.asLong(x, z);
-
-        if (entityManager.areEntitiesLoaded(pair)) { // PAIL rename isEntitiesLoaded
-            return getCraftWorld().getHandle().getChunkEntities(this.x, this.z); // Paper - optimise this
-        }
-
-        entityManager.ensureChunkQueuedForLoad(pair); // Start entity loading
-
-        // now we wait until the entities are loaded,
-        // the converting from NBT to entity object is done on the main Thread which is why we wait
-        this.getCraftWorld().getHandle().getServer().managedBlock(() -> {
-            boolean status = entityManager.areEntitiesLoaded(pair);
-            // only execute inbox if our entities are not present
-            if (status) {
-                return true;
-            }
-            // tick loading inbox, which loads the created entities to the world
-            // (if present)
-            entityManager.tick();
-            // check if our entities are loaded
-            return entityManager.areEntitiesLoaded(pair);
-        });
-
         return getCraftWorld().getHandle().getChunkEntities(this.x, this.z); // Paper - optimise this
     }