From 7298adc9d9b8ef878f4be5b8799be222aa0dd90b Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Tue, 12 Jan 2021 19:04:16 +0900
Subject: [PATCH] Fix non-threadsafe usage of MultiplayerClient.IsConnected

---
 osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs    | 1 +
 .../OnlinePlay/Multiplayer/CreateMultiplayerMatchButton.cs  | 4 ++--
 .../Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs     | 4 ++--
 .../OnlinePlay/Multiplayer/MultiplayerRoomManager.cs        | 6 ++----
 4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs b/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
index 34cba09e8c..770039d79d 100644
--- a/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
+++ b/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
@@ -52,6 +52,7 @@ namespace osu.Game.Online.Multiplayer
 
         /// <summary>
         /// Whether the <see cref="StatefulMultiplayerClient"/> is currently connected.
+        /// This is NOT thread safe and usage should be scheduled.
         /// </summary>
         public abstract IBindable<bool> IsConnected { get; }
 
diff --git a/osu.Game/Screens/OnlinePlay/Multiplayer/CreateMultiplayerMatchButton.cs b/osu.Game/Screens/OnlinePlay/Multiplayer/CreateMultiplayerMatchButton.cs
index 87b0e49b5b..a13d2cf540 100644
--- a/osu.Game/Screens/OnlinePlay/Multiplayer/CreateMultiplayerMatchButton.cs
+++ b/osu.Game/Screens/OnlinePlay/Multiplayer/CreateMultiplayerMatchButton.cs
@@ -34,8 +34,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         {
             base.LoadComplete();
 
-            isConnected.BindValueChanged(_ => updateState());
-            operationInProgress.BindValueChanged(_ => updateState(), true);
+            isConnected.BindValueChanged(_ => Scheduler.AddOnce(updateState));
+            operationInProgress.BindValueChanged(_ => Scheduler.AddOnce(updateState), true);
         }
 
         private void updateState() => Enabled.Value = isConnected.Value && !operationInProgress.Value;
diff --git a/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs b/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs
index 4bee502e2e..04d9e0a72a 100644
--- a/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs
+++ b/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs
@@ -77,14 +77,14 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             });
 
             isConnected = client.IsConnected.GetBoundCopy();
-            isConnected.BindValueChanged(connected =>
+            isConnected.BindValueChanged(connected => Schedule(() =>
             {
                 if (!connected.NewValue)
                 {
                     // messaging to the user about this disconnect will be provided by the MultiplayerMatchSubScreen.
                     failAndBail();
                 }
-            }, true);
+            }), true);
 
             Debug.Assert(client.Room != null);
         }
diff --git a/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomManager.cs b/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomManager.cs
index 5c327266a3..bcae2e5cbb 100644
--- a/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomManager.cs
+++ b/osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomManager.cs
@@ -34,10 +34,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             base.LoadComplete();
 
             isConnected.BindTo(multiplayerClient.IsConnected);
-            isConnected.BindValueChanged(_ => Schedule(updatePolling));
-            JoinedRoom.BindValueChanged(_ => updatePolling());
-
-            updatePolling();
+            isConnected.BindValueChanged(_ => Scheduler.AddOnce(updatePolling));
+            JoinedRoom.BindValueChanged(_ => Scheduler.AddOnce(updatePolling), true);
         }
 
         public override void CreateRoom(Room room, Action<Room> onSuccess = null, Action<string> onError = null)