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 8e760445885f6ab92f60db0ee2a02d098b5e5f03..7a8a1960882e291c46301d07da3e1c5415516893 100644
--- a/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
+++ b/src/main/java/net/minecraft/server/AdvancementDataPlayer.java
@@ -97,6 +97,7 @@ public class AdvancementDataPlayer {
 
     }
 
+    public final void reload(AdvancementDataWorld advancementDataWorld) { this.a(advancementDataWorld); } // Paper - OBFHELPER
     public void a(AdvancementDataWorld advancementdataworld) {
         this.a();
         this.data.clear();
@@ -393,6 +394,7 @@ 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 a1c918e84627d79f6665237851f614880a9da6f7..74ebd6257ca7c87bcedff831d213273e7d542612 100644
--- a/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
+++ b/src/main/java/org/bukkit/craftbukkit/util/CraftMagicNumbers.java
@@ -309,7 +309,13 @@ 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;
             }