From 6f343c5fc0c7e5da634a6e4565cc9c4bce62e7dc Mon Sep 17 00:00:00 2001
From: filoghost <filoghost@gmail.com>
Date: Sat, 9 Mar 2024 23:43:21 +0100
Subject: [PATCH] Fix viewers mutating after submitting async packet sending

---
 .../{DelegateViewers.java => ImmutableViewers.java}        | 7 ++++---
 .../holographicdisplays/core/tracking/LineTracker.java     | 6 ++----
 2 files changed, 6 insertions(+), 7 deletions(-)
 rename core/src/main/java/me/filoghost/holographicdisplays/core/tracking/{DelegateViewers.java => ImmutableViewers.java} (65%)

diff --git a/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/DelegateViewers.java b/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/ImmutableViewers.java
similarity index 65%
rename from core/src/main/java/me/filoghost/holographicdisplays/core/tracking/DelegateViewers.java
rename to core/src/main/java/me/filoghost/holographicdisplays/core/tracking/ImmutableViewers.java
index b240a7ad..4de646f5 100644
--- a/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/DelegateViewers.java
+++ b/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/ImmutableViewers.java
@@ -5,15 +5,16 @@
  */
 package me.filoghost.holographicdisplays.core.tracking;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.function.Consumer;
 
-public class DelegateViewers<T extends Viewer> implements Viewers<T> {
+public class ImmutableViewers<T extends Viewer> implements Viewers<T> {
 
     private final Collection<T> viewers;
 
-    public DelegateViewers(Collection<T> viewers) {
-        this.viewers = viewers;
+    public ImmutableViewers(Collection<T> viewers) {
+        this.viewers = new ArrayList<>(viewers);
     }
 
     @Override
diff --git a/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/LineTracker.java b/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/LineTracker.java
index 5ac3e470..4928dad4 100644
--- a/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/LineTracker.java
+++ b/core/src/main/java/me/filoghost/holographicdisplays/core/tracking/LineTracker.java
@@ -22,7 +22,6 @@ import java.util.concurrent.ConcurrentMap;
 public abstract class LineTracker<T extends Viewer> {
 
     private final ConcurrentMap<Player, T> viewers;
-    private final Viewers<T> iterableViewers;
 
     private String positionWorldName;
     protected PositionCoordinates positionCoordinates;
@@ -33,7 +32,6 @@ public abstract class LineTracker<T extends Viewer> {
 
     protected LineTracker() {
         this.viewers = new ConcurrentHashMap<>();
-        this.iterableViewers = new DelegateViewers<>(viewers.values());
     }
 
     protected abstract BaseHologramLine getLine();
@@ -67,7 +65,7 @@ public abstract class LineTracker<T extends Viewer> {
 
         // Then, send the changes (if any) to already tracked players
         if (sendChangesPackets && hasViewers()) {
-            sendChangesPackets(iterableViewers);
+            sendChangesPackets(new ImmutableViewers<>(viewers.values()));
         }
 
         // Finally, add/remove viewers sending them the full spawn/destroy packets
@@ -223,7 +221,7 @@ public abstract class LineTracker<T extends Viewer> {
             return;
         }
 
-        sendDestroyPackets(iterableViewers);
+        sendDestroyPackets(new ImmutableViewers<>(viewers.values()));
         viewers.clear();
     }