From b306e787ea9f5f206aca49062ecf8ce30b2d81db Mon Sep 17 00:00:00 2001
From: Shane Freeder <theboyetronic@gmail.com>
Date: Thu, 5 Oct 2017 01:54:07 +0100
Subject: [PATCH] handle PacketPlayInKeepAlive async

In 1.12.2, Mojang moved the processing of PacketPlayInKeepAlive off the main
thread, while entirely correct for the server, this causes issues with
plugins which are expecting the PlayerQuitEvent on the main thread.

In order to counteract some bad behavior, we will post handling of the
disconnection to the main thread, but leave the actual processing of the packet
on the main thread.

diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
index d8f9a093b..f60f21fd2 100644
--- a/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/src/main/java/net/minecraft/server/PlayerConnection.java
@@ -2225,14 +2225,18 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
     }
 
     public void a(PacketPlayInKeepAlive packetplayinkeepalive) {
-        PlayerConnectionUtils.ensureMainThread(packetplayinkeepalive, this, this.player.x()); // CraftBukkit
+        //PlayerConnectionUtils.ensureMainThread(packetplayinkeepalive, this, this.player.x()); // CraftBukkit // Paper - This shouldn't be on the main thread
         if (this.g && packetplayinkeepalive.a() == this.h) {
             int i = (int) (this.d() - this.f);
 
             this.player.ping = (this.player.ping * 3 + i) / 4;
             this.g = false;
         } else if (!this.player.getName().equals(this.minecraftServer.Q())) {
-            this.disconnect(new ChatMessage("disconnect.timeout", new Object[0]));
+            // Paper start - This needs to be handled on the main thread for plugins
+            minecraftServer.postToMainThread(() -> {
+                    this.disconnect(new ChatMessage("disconnect.timeout", new Object[0]));
+            });
+            // Paper end
         }
 
     }
-- 
2.14.2