Ensure all invocations of spectator server hub methods have their errors observed (#35488)

Fell out when attempting
ppy/osu-server-spectator#346.

Functionally, if a true non-`HubException` is produced via an invocation
of a spectator server hub method, this doesn't really do much - the
error will still log as 'unobserved' due to the default handler, it will
still show up on sentry, etc. The only difference is that it'll get
handled via the continuation installed in `FireAndForget()` rather than
the `TaskScheduler.UnobservedTaskException` event.

The only real case where this is relevant is when the server throws
`HubException`s, which will now instead bubble up to a more
human-readable form. Which is relevant to the aforementioned PR because
that one makes any hub method potentially throw a `HubException` if the
client version is too old.

Obviously this does nothing for the existing old clients.

Author: bdach

osu.Game/Online/Metadata/OnlineMetadataClient.cs

@@ -89,13 +89,13 @@ protected override void LoadComplete()
             userStatus.BindValueChanged(status =>
             {
                 if (localUser.Value is not GuestUser)
-                    UpdateStatus(status.NewValue);
+                    UpdateStatus(status.NewValue).FireAndForget();
             }, true);
 
             userActivity.BindValueChanged(activity =>
             {
                 if (localUser.Value is not GuestUser)
-                    UpdateActivity(activity.NewValue);
+                    UpdateActivity(activity.NewValue).FireAndForget();
             }, true);
         }
 
@@ -121,8 +121,8 @@ private void isConnectedChanged(ValueChangedEvent<bool> connected)
 
             if (localUser.Value is not GuestUser)
             {
-                UpdateActivity(userActivity.Value);
-                UpdateStatus(userStatus.Value);
+                UpdateActivity(userActivity.Value).FireAndForget();
+                UpdateStatus(userStatus.Value).FireAndForget();
             }
 
             if (lastQueueId.Value >= 0)

osu.Game/Online/Multiplayer/MultiplayerClient.cs

@@ -201,7 +201,7 @@ private void load()
                 if (!connected.NewValue)
                 {
                     if (Room != null)
-                        LeaveRoom();
+                        LeaveRoom().FireAndForget();
 
                     MatchmakingQueueLeft?.Invoke();
                 }
@@ -560,7 +560,7 @@ Task IMultiplayerClient.UserKicked(MultiplayerRoomUser user)
                     return;
 
                 if (user.Equals(LocalUser))
-                    LeaveRoom();
+                    LeaveRoom().FireAndForget();
 
                 handleUserLeft(user, UserKicked);
             });

osu.Game/Online/Spectator/SpectatorClient.cs

@@ -14,6 +14,7 @@
 using osu.Framework.Logging;
 using osu.Game.Beatmaps;
 using osu.Game.Online.API;
+using osu.Game.Online.Multiplayer;
 using osu.Game.Replays.Legacy;
 using osu.Game.Rulesets.Replays;
 using osu.Game.Rulesets.Replays.Types;
@@ -203,7 +204,7 @@ Task ISpectatorClient.UserEndedWatching(int userId)
 
         Task IStatefulUserHubClient.DisconnectRequested()
         {
-            Schedule(() => DisconnectInternal());
+            Schedule(() => DisconnectInternal().FireAndForget());
             return Task.CompletedTask;
         }
 
@@ -290,7 +291,7 @@ public void EndPlaying(GameplayState state)
                 else
                     currentState.State = SpectatedUserState.Quit;
 
-                EndPlayingInternal(currentState);
+                EndPlayingInternal(currentState).FireAndForget();
             });
         }
 
@@ -304,7 +305,7 @@ public virtual void WatchUser(int userId)
                 return;
             }
 
-            WatchUserInternal(userId);
+            WatchUserInternal(userId).FireAndForget();
         }
 
         public void StopWatchingUser(int userId)
@@ -321,7 +322,7 @@ public void StopWatchingUser(int userId)
 
                 watchedUsersRefCounts.Remove(userId);
                 watchedUserStates.Remove(userId);
-                StopWatchingUserInternal(userId);
+                StopWatchingUserInternal(userId).FireAndForget();
             });
         }
 

osu.Game/Screens/OnlinePlay/Matchmaking/Match/ScreenMatchmaking.cs

@@ -392,7 +392,7 @@ public override void OnResuming(ScreenTransitionEvent e)
                 return;
             }
 
-            client.ChangeState(MultiplayerUserState.Idle);
+            client.ChangeState(MultiplayerUserState.Idle).FireAndForget();
         }
 
         /// <summary>

osu.Game/Screens/OnlinePlay/Multiplayer/Multiplayer.cs

@@ -87,7 +87,7 @@ private void transitionFromResults()
             Debug.Assert(client.LocalUser != null);
 
             if (client.LocalUser.State == MultiplayerUserState.Results)
-                client.ChangeState(MultiplayerUserState.Idle);
+                client.ChangeState(MultiplayerUserState.Idle).FireAndForget();
         }
 
         protected override string ScreenTitle => "Multiplayer";

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSubScreen.cs

@@ -618,7 +618,7 @@ private void onBeatmapAvailabilityChanged(ValueChangedEvent<BeatmapAvailability>
                     updateGameplayState();
 
                     if (client.LocalUser.State == MultiplayerUserState.Ready)
-                        client.ChangeState(MultiplayerUserState.Idle);
+                        client.ChangeState(MultiplayerUserState.Idle).FireAndForget();
                     break;
             }
         }

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs

@@ -161,7 +161,7 @@ protected override void StartGameplay()
             if (client.LocalUser?.State == MultiplayerUserState.Loaded)
             {
                 loadingDisplay.Show();
-                client.ChangeState(MultiplayerUserState.ReadyForGameplay);
+                client.ChangeState(MultiplayerUserState.ReadyForGameplay).FireAndForget();
             }
 
             // This will pause the clock, pending the gameplay started callback from the server.

osu.Game/Screens/OnlinePlay/Multiplayer/Spectate/MultiSpectatorScreen.cs

@@ -296,7 +296,7 @@ public override bool OnBackButton()
             // On a manual exit, set the player back to idle unless gameplay has finished.
             // Of note, this doesn't cover exiting using alt-f4 or menu home option.
             if (multiplayerClient.Room.State != MultiplayerRoomState.Open)
-                multiplayerClient.ChangeState(MultiplayerUserState.Idle);
+                multiplayerClient.ChangeState(MultiplayerUserState.Idle).FireAndForget();
 
             return base.OnBackButton();
         }