From c2d1aef7ed491a82d01740c0a1de7b458ba1358e Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 7 Jan 2017 16:06:44 -0500
Subject: [PATCH] Enforce Sync Chunk Unloads

Unloading Chunks async is extremely dangerous. This will force it to main
the same way we handle async chunk loads.

diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 84fcebd710..9cd991c3e7 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -224,6 +224,7 @@ public class CraftWorld implements World {
     }
 
     private boolean unloadChunk0(int x, int z, boolean save) {
+        Boolean result = MCUtil.ensureMain("Unload Chunk", () -> { // Paper - Ensure never async
         net.minecraft.server.Chunk chunk = world.getChunkProviderServer().getChunkIfLoaded(x, z);
         if (chunk == null) {
             return true;
@@ -231,6 +232,7 @@ public class CraftWorld implements World {
 
         // If chunk had previously been queued to save, must do save to avoid loss of that data
         return world.getChunkProviderServer().unloadChunk(chunk, chunk.mustSave || save);
+        }); return result != null ? result : false; // Paper - Ensure never async
     }
 
     public boolean regenerateChunk(int x, int z) {
-- 
2.18.0