From cd9083a28d860b7f0fa2d5b3cc59d88f45d474fc Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 3 May 2020 14:25:55 -0400
Subject: [PATCH] Sync position on teleportation

We've seen many a cases where the "last good" x/y/z is desynced from
the x/y/z that is checked for moving too fast.

Theory is that when you have multiple movement packets queued up,
and the player is teleported after the first then the 2nd and 3rd come in,
it is triggering a massive movement velocity.

This will ensure that the servers position is synchronized anytime player is teleported.

diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
index 02bda8bee4..a188d9f3b6 100644
--- a/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/src/main/java/net/minecraft/server/PlayerConnection.java
@@ -500,6 +500,7 @@ public class PlayerConnection implements PacketListenerPlayIn {
             this.o = this.teleportPos.x;
             this.p = this.teleportPos.y;
             this.q = this.teleportPos.z;
+            this.syncPosition(); // Paper
             if (this.player.H()) {
                 this.player.I();
             }
@@ -1271,6 +1272,7 @@ public class PlayerConnection implements PacketListenerPlayIn {
 
         this.A = this.e;
         this.player.setLocation(d0, d1, d2, f, f1);
+        this.syncPosition(); // Paper
         this.player.playerConnection.sendPacket(new PacketPlayOutPosition(d0 - d3, d1 - d4, d2 - d5, f - f2, f1 - f3, set, this.teleportAwait));
     }
 
-- 
2.26.0