Paper/patches/server/0382-Don-t-move-existing-players-to-world-spawn.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Thu, 9 Apr 2020 21:20:33 -0400
Subject: [PATCH] Don't move existing players to world spawn

This can cause a nasty server lag the spawn chunks are not kept loaded
or they aren't finished loading yet, or if the world spawn radius is
larger than the keep loaded range.

By skipping this, we avoid potential for a large spike on server start.

diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
index 0ad3dfc469145735f1669d4ca9a79f3fecc2ad60..c2f9933796904628a55476eb9be1204b766893cf 100644
--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
+++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
@@ -322,7 +322,7 @@ public class ServerPlayer extends Player {
         this.stats = server.getPlayerList().getPlayerStats(this);
         this.advancements = server.getPlayerList().getPlayerAdvancements(this);
         this.maxUpStep = 1.0F;
-        this.fudgeSpawnLocation(world);
+        //this.fudgeSpawnLocation(world); // Paper - don't move to spawn on login, only first join
 
         this.cachedSingleHashSet = new com.destroystokyo.paper.util.misc.PooledLinkedHashSets.PooledObjectLinkedOpenHashSet<>(this); // Paper
 
@@ -540,7 +540,7 @@ public class ServerPlayer extends Player {
                 position = Vec3.atCenterOf(((ServerLevel) world).getSharedSpawnPos());
             }
             this.level = world;
-            this.setPos(position.x(), position.y(), position.z());
+            this.setPosRaw(position.x(), position.y(), position.z()); // Paper - don't register to chunks yet
         }
         this.gameMode.setLevel((ServerLevel) world);
     }
diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
index bec8969cae05c895a001888d020d61fd2d82a788..27dd95242c80d875de8f07e111f06e383eeec0d9 100644
--- a/src/main/java/net/minecraft/server/players/PlayerList.java
+++ b/src/main/java/net/minecraft/server/players/PlayerList.java
@@ -215,6 +215,8 @@ public abstract class PlayerList {
             worldserver1 = worldserver;
         }
 
+        if (nbttagcompound == null) player.fudgeSpawnLocation(worldserver1); // Paper - only move to spawn on first login, otherwise, stay where you are....
+
         player.setLevel(worldserver1);
         String s1 = "local";