From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Denery <dorofeevij@gmail.com>
Date: Sun, 6 Nov 2022 02:02:46 +0300
Subject: [PATCH] Fix player kick on shutdown

Fix preemptive player kick on a server shutdown.
If you update minecraft version / upstream and something is changed in this method make sure that a server doesn't disconnect a player preemptively,
also check if all packets are ignored during the shutdown process.
See net.minecraft.network.Connection#channelRead0(ChannelHandlerContext, Packet) and net.minecraft.util.thread.BlockableEventLoop#executeIfPossible(Runnable)

diff --git a/src/main/java/net/minecraft/network/protocol/PacketUtils.java b/src/main/java/net/minecraft/network/protocol/PacketUtils.java
index 047fc7206131e0f36ab45d04e98b7a235431e342..ae052902ccaa0959882be26bbe2f3c93bfd463d2 100644
--- a/src/main/java/net/minecraft/network/protocol/PacketUtils.java
+++ b/src/main/java/net/minecraft/network/protocol/PacketUtils.java
@@ -25,7 +25,7 @@ public class PacketUtils {
 
     public static <T extends PacketListener> void ensureRunningOnSameThread(Packet<T> packet, T listener, BlockableEventLoop<?> engine) throws RunningOnDifferentThreadException {
         if (!engine.isSameThread()) {
-            engine.executeIfPossible(() -> {
+            engine.execute(() -> { // Paper - Fix preemptive player kick on a server shutdown.
                 if (MinecraftServer.getServer().hasStopped() || (listener instanceof ServerCommonPacketListenerImpl && ((ServerCommonPacketListenerImpl) listener).processedDisconnect)) return; // CraftBukkit, MC-142590
                 if (listener.shouldHandleMessage(packet)) {
                     co.aikar.timings.Timing timing = co.aikar.timings.MinecraftTimings.getPacketTiming(packet); // Paper - timings