Fix Player Tracking issue during join process.

Because we moved entity registration to occur before the PlayerJoinEvent occurs,
We started tracking the entity too early before it was registered to the client.

So delay tracking until after list packets have been sent.

Spigot-Server-Patches/0486-Fix-Longstanding-Broken-behavior-of-PlayerJoinEvent.patch

@@ -1,4 +1,4 @@
-From 72ebe0e580f444f77811a5526d36343b3173a962 Mon Sep 17 00:00:00 2001
+From 63418c01ebd90b30014d7c173d2d0af444e832b7 Mon Sep 17 00:00:00 2001
 From: Aikar <aikar@aikar.co>
 Date: Sun, 19 Apr 2020 00:05:46 -0400
 Subject: [PATCH] Fix Longstanding Broken behavior of PlayerJoinEvent
@@ -27,8 +27,20 @@ This was very non deterministic. This change will ensure every plugin
 receives a deterministic result, and should no longer require 1 tick
 delays anymore.
 
+diff --git a/src/main/java/net/minecraft/server/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java
+index e19342eb89..cc588d6f35 100644
+--- a/src/main/java/net/minecraft/server/PlayerChunkMap.java
++++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java
+@@ -1565,6 +1565,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
+                 .printStackTrace();
+             return;
+         }
++        if (entity instanceof EntityPlayer && !((EntityPlayer) entity).sentListPacket) return; // Delay adding to tracker until after list packets
+         // Paper end
+         if (!(entity instanceof EntityComplexPart)) {
+             if (!(entity instanceof EntityLightning)) {
 diff --git a/src/main/java/net/minecraft/server/PlayerList.java b/src/main/java/net/minecraft/server/PlayerList.java
-index 7403be0b2..e737381b3 100644
+index 7403be0b25..c2850d50d6 100644
 --- a/src/main/java/net/minecraft/server/PlayerList.java
 +++ b/src/main/java/net/minecraft/server/PlayerList.java
 @@ -175,6 +175,11 @@ public abstract class PlayerList {
@@ -43,27 +55,15 @@ index 7403be0b2..e737381b3 100644
          // CraftBukkit start
          PlayerJoinEvent playerJoinEvent = new PlayerJoinEvent(cserver.getPlayer(entityplayer), joinMessage);
          cserver.getPluginManager().callEvent(playerJoinEvent);
-@@ -206,7 +211,7 @@ public abstract class PlayerList {
-                 continue;
-             }
- 
--            entityplayer.playerConnection.sendPacket(new PacketPlayOutPlayerInfo(PacketPlayOutPlayerInfo.EnumPlayerInfoAction.ADD_PLAYER, new EntityPlayer[] { entityplayer1}));
-+            entityplayer.playerConnection.sendPacket(new PacketPlayOutPlayerInfo(PacketPlayOutPlayerInfo.EnumPlayerInfoAction.ADD_PLAYER, new EntityPlayer[]{entityplayer1}));
+@@ -209,6 +214,7 @@ public abstract class PlayerList {
+             entityplayer.playerConnection.sendPacket(new PacketPlayOutPlayerInfo(PacketPlayOutPlayerInfo.EnumPlayerInfoAction.ADD_PLAYER, new EntityPlayer[] { entityplayer1}));
          }
          entityplayer.sentListPacket = true;
++        ((WorldServer)entityplayer.world).getChunkProvider().playerChunkMap.addEntity(entityplayer); // Paper - track entity now
          // CraftBukkit end
-@@ -215,8 +220,8 @@ public abstract class PlayerList {
  
-         // CraftBukkit start - Only add if the player wasn't moved in the event
-         if (entityplayer.world == worldserver && !worldserver.getPlayers().contains(entityplayer)) {
--            worldserver.addPlayerJoin(entityplayer);
--            this.server.getBossBattleCustomData().a(entityplayer);
-+            //worldserver.addPlayerJoin(entityplayer); // Paper - moved up
-+            //this.server.getBossBattleCustomData().a(entityplayer); // Paper - moved up - if mapping changes, update above
-         }
- 
-         worldserver = server.getWorldServer(entityplayer.dimension);  // CraftBukkit - Update in case join event changed it
-@@ -234,6 +239,11 @@ public abstract class PlayerList {
+         entityplayer.playerConnection.sendPacket(new PacketPlayOutEntityMetadata(entityplayer.getId(), entityplayer.datawatcher, true)); // CraftBukkit - BungeeCord#2321, send complete data to self on spawn
+@@ -234,6 +240,11 @@ public abstract class PlayerList {
              playerconnection.sendPacket(new PacketPlayOutEntityEffect(entityplayer.getId(), mobeffect));
          }
  
@@ -75,7 +75,7 @@ index 7403be0b2..e737381b3 100644
          if (nbttagcompound != null && nbttagcompound.hasKeyOfType("RootVehicle", 10)) {
              NBTTagCompound nbttagcompound1 = nbttagcompound.getCompound("RootVehicle");
              // CraftBukkit start
-@@ -275,6 +285,10 @@ public abstract class PlayerList {
+@@ -275,6 +286,10 @@ public abstract class PlayerList {
              }
          }