From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: jmp <jasonpenilla2@me.com>
Date: Sat, 31 Oct 2020 11:49:01 -0700
Subject: [PATCH] Fix client lag on advancement loading

When new advancements are added via the UnsafeValues#loadAdvancement
API, it triggers a full datapack reload when this is not necessary. The
advancement is already loaded directly into the advancement registry,
and the point of saving the advancement to the Bukkit datapack seems to
be for persistence. By removing the call to reload datapacks when an
advancement is loaded, the client no longer completely freezes up when
adding a new advancement.
To ensure the client still receives the updated advancement data, we
manually reload the advancement data for all players, which
normally takes place as a part of the datapack reloading.

diff --git a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
index 17789407b9e86896a963a305a13357286aa5f319..c680319e4040be2b60795b22a5e65d6444cc67ed 100644
--- a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
+++ b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
@@ -78,6 +78,7 @@ public class AdvancementDataPlayer {
 
     }
 
+    public final void reload(AdvancementDataWorld advancementDataWorld) { this.a(advancementDataWorld); } // Paper - OBFHELPER
     public void a(AdvancementDataWorld advancementdataworld) {
         this.a();
         this.data.clear();
@@ -374,6 +375,7 @@ public class AdvancementDataPlayer {
 
     }
 
+    public final void sendUpdateIfNeeded(EntityPlayer entityPlayer) { this.b(entityPlayer); } // Paper - OBFHELPER
     public void b(EntityPlayer entityplayer) {
         if (this.m || !this.i.isEmpty() || !this.j.isEmpty()) {
             Map<MinecraftKey, AdvancementProgress> map = Maps.newHashMap();
diff --git a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
index ed926fc6ebbabd50a73d216a9e018a9427f5b128..0f7f1503d07bdff7ce7644dfe21e444adb52c7db 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -282,7 +282,13 @@ public final class CraftMagicNumbers implements UnsafeValues {
                     Bukkit.getLogger().log(Level.SEVERE, "Error saving advancement " + key, ex);
                 }
 
-                MinecraftServer.getServer().getPlayerList().reload();
+                // Paper start
+                //MinecraftServer.getServer().getPlayerList().reload();
+                MinecraftServer.getServer().getPlayerList().getPlayers().forEach(player -> {
+                    player.getAdvancementData().reload(MinecraftServer.getServer().getAdvancementData());
+                    player.getAdvancementData().sendUpdateIfNeeded(player);
+                });
+                // Paper end
 
                 return bukkit;
             }
