From 4cc3321d54b2e2e57ebb09b1cb240135d421ec4d Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Tue, 20 Apr 2021 21:20:08 +0900
Subject: [PATCH] Fix potential doubling of events

---
 osu.Game/Online/Spectator/SpectatorStreamingClient.cs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/osu.Game/Online/Spectator/SpectatorStreamingClient.cs b/osu.Game/Online/Spectator/SpectatorStreamingClient.cs
index 13b12d9add..378096c7fb 100644
--- a/osu.Game/Online/Spectator/SpectatorStreamingClient.cs
+++ b/osu.Game/Online/Spectator/SpectatorStreamingClient.cs
@@ -303,13 +303,14 @@ namespace osu.Game.Online.Spectator
         /// <param name="runOnceImmediately">Whether the action provided in <paramref name="callback"/> should be run once immediately for all users currently playing.</param>
         public void BindUserBeganPlaying(Action<int, SpectatorState> callback, bool runOnceImmediately = false)
         {
-            OnUserBeganPlaying += callback;
-
-            if (!runOnceImmediately)
-                return;
-
+            // The lock is taken before the event is subscribed to to prevent doubling of events.
             lock (userLock)
             {
+                OnUserBeganPlaying += callback;
+
+                if (!runOnceImmediately)
+                    return;
+
                 foreach (var (userId, state) in playingUserStates)
                     callback(userId, state);
             }