From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <git@steinborn.me>
Date: Sat, 3 Oct 2020 04:15:09 -0400
Subject: [PATCH] Lazily track plugin scoreboards by default

On servers with plugins that constantly churn through scoreboards, there is a risk of
degraded GC performance due to the number of scoreboards held on by weak references.
Most plugins don't even need the (vanilla) functionality that requires all plugin
scoreboards to be tracked by the server. Instead, only track scoreboards when an
objective is added with a non-dummy criteria.

This is a breaking change, however the change is a much more sensible default. In case
this breaks your workflow you can always force all scoreboards to be tracked with
settings.track-plugin-scoreboards in paper.yml.

diff --git a/src/main/java/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 16d6ce24031590ff9dfba5c938aeb9755704798d..bd7926fa89621e8cdd0b5fdd8ed3b8c6dbfbc3ec 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -96,6 +96,11 @@ public class PaperConfig {
         maxJoinsPerTick = getInt("settings.max-joins-per-tick", 3);
     }
 
+    public static boolean trackPluginScoreboards;
+    private static void trackPluginScoreboards() {
+        trackPluginScoreboards = getBoolean("settings.track-plugin-scoreboards", false);
+    }
+
     public static void registerCommands() {
         for (Map.Entry<String, Command> entry : commands.entrySet()) {
             MinecraftServer.getServer().server.getCommandMap().register(entry.getKey(), "Paper", entry.getValue());
diff --git a/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboard.java b/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboard.java
index 59f60fcadd8767cf8698482547e8c771d970732a..7b61a2be2be0bdf06592b65be9acd4cbbae5bf7f 100644
--- a/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboard.java
+++ b/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboard.java
@@ -18,6 +18,7 @@ import org.bukkit.scoreboard.Team;
 
 public final class CraftScoreboard implements org.bukkit.scoreboard.Scoreboard {
     final Scoreboard board;
+    boolean registeredGlobally = false; // Paper
 
     CraftScoreboard(Scoreboard board) {
         this.board = board;
@@ -44,6 +45,12 @@ public final class CraftScoreboard implements org.bukkit.scoreboard.Scoreboard {
         Validate.isTrue(name.length() <= 16, "The name '" + name + "' is longer than the limit of 16 characters");
         Validate.isTrue(board.getObjective(name) == null, "An objective of name '" + name + "' already exists");
         CraftCriteria craftCriteria = CraftCriteria.getFromBukkit(criteria);
+        // Paper start - the block comment from the old registerNewObjective didnt cause a conflict when rebasing, so this block wasn't added to the adventure registerNewObjective
+        if (craftCriteria.criteria != net.minecraft.world.scores.criteria.ObjectiveCriteria.DUMMY && !registeredGlobally) {
+            net.minecraft.server.MinecraftServer.getServer().server.getScoreboardManager().registerScoreboardForVanilla(this);
+            registeredGlobally = true;
+        }
+        // Paper end
         net.minecraft.world.scores.Objective objective = board.addObjective(name, craftCriteria.criteria, io.papermc.paper.adventure.PaperAdventure.asVanilla(displayName), CraftScoreboardTranslations.fromBukkitRender(renderType));
         return new CraftObjective(this, objective);
     }
@@ -68,6 +75,12 @@ public final class CraftScoreboard implements org.bukkit.scoreboard.Scoreboard {
         net.minecraft.world.scores.Objective objective = this.board.addObjective(name, craftCriteria.criteria, CraftChatMessage.fromStringOrNull(displayName), CraftScoreboardTranslations.fromBukkitRender(renderType));
 
         CraftCriteria craftCriteria = CraftCriteria.getFromBukkit(criteria);
+        // Paper start
+        if (craftCriteria.criteria != net.minecraft.server.IScoreboardCriteria.DUMMY && !registeredGlobally) {
+            net.minecraft.server.MinecraftServer.getServer().server.getScoreboardManager().registerScoreboardForVanilla(this);
+            registeredGlobally = true;
+        }
+        // Paper end
         ScoreboardObjective objective = board.registerObjective(name, craftCriteria.criteria, CraftChatMessage.fromStringOrNull(displayName), CraftScoreboardTranslations.fromBukkitRender(renderType));
         return new CraftObjective(this, objective);*/ // Paper
         return registerNewObjective(name, criteria, io.papermc.paper.adventure.PaperAdventure.LEGACY_SECTION_UXRC.deserialize(displayName), renderType); // Paper
diff --git a/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboardManager.java b/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboardManager.java
index ff090edcc85713083449cebb22bd1490123bc1ee..8ccfe9488db44d7d2cf4040a5b4cead33da1d5f4 100644
--- a/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboardManager.java
+++ b/src/main/java/org/bukkit/craftbukkit/scoreboard/CraftScoreboardManager.java
@@ -30,6 +30,7 @@ public final class CraftScoreboardManager implements ScoreboardManager {
 
     public CraftScoreboardManager(MinecraftServer minecraftserver, net.minecraft.world.scores.Scoreboard scoreboardServer) {
         this.mainScoreboard = new CraftScoreboard(scoreboardServer);
+        mainScoreboard.registeredGlobally = true; // Paper
         this.server = minecraftserver;
         this.scoreboards.add(mainScoreboard);
     }
@@ -43,10 +44,22 @@ public final class CraftScoreboardManager implements ScoreboardManager {
     public CraftScoreboard getNewScoreboard() {
         org.spigotmc.AsyncCatcher.catchOp("scoreboard creation"); // Spigot
         CraftScoreboard scoreboard = new CraftScoreboard(new ServerScoreboard(this.server));
-        this.scoreboards.add(scoreboard);
+        // Paper start
+        if (com.destroystokyo.paper.PaperConfig.trackPluginScoreboards) {
+            scoreboard.registeredGlobally = true;
+            scoreboards.add(scoreboard);
+        }
+        // Paper end
         return scoreboard;
     }
 
+    // Paper start
+    public void registerScoreboardForVanilla(CraftScoreboard scoreboard) {
+        org.spigotmc.AsyncCatcher.catchOp("scoreboard registration");
+        scoreboards.add(scoreboard);
+    }
+    // Paper end
+
     // CraftBukkit method
     public CraftScoreboard getPlayerBoard(CraftPlayer player) {
         CraftScoreboard board = this.playerBoards.get(player);