From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.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 cd51115b7c56e7eeab1248f39a690fc91524efd7..b55d5c14000317db97f2f6e511f97ff6f03fa972 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;
             }