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/PlayerAdvancements.java b/src/main/java/net/minecraft/server/PlayerAdvancements.java
index e05e5710c81b7dbb648afbfe16f843e7ae310752..77e262f2236318e053da136037332fbe6d8bf380 100644
--- a/src/main/java/net/minecraft/server/PlayerAdvancements.java
+++ b/src/main/java/net/minecraft/server/PlayerAdvancements.java
@@ -371,6 +371,7 @@ public class PlayerAdvancements {
 
     }
 
+    public final void sendUpdateIfNeeded(ServerPlayer entityPlayer) { this.flushDirty(entityPlayer); } // Paper - OBFHELPER
     public void flushDirty(ServerPlayer player) {
         if (this.isFirstPacket || !this.visibilityChanged.isEmpty() || !this.progressChanged.isEmpty()) {
             Map<ResourceLocation, 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 2984f5fa036019bb35a603690c568fc5c7b855d6..3d5f9ac267943fe2487a5cc4f9f059b169b438a8 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -307,7 +307,13 @@ public final class CraftMagicNumbers implements UnsafeValues {
                     Bukkit.getLogger().log(Level.SEVERE, "Error saving advancement " + key, ex);
                 }
 
-                MinecraftServer.getServer().getPlayerList().reloadResources();
+                // Paper start
+                //MinecraftServer.getServer().getPlayerList().reload();
+                MinecraftServer.getServer().getPlayerList().getPlayers().forEach(player -> {
+                    player.getAdvancements().reload(MinecraftServer.getServer().getAdvancements());
+                    player.getAdvancements().sendUpdateIfNeeded(player);
+                });
+                // Paper end
 
                 return bukkit;
             }