Merge c14fe21219 into be05f2a1c2

It's not allowed to call `LoadComponentsAsync()` on a background thread:

	fd64f2f0d4/osu.Framework/Graphics/Containers/CompositeDrawable.cs (L147)

and in this case the event that causes the LCA call is dispatched from a
websocket client, which is not on the update thread, so scheduling is
required.

osu.Game/Overlays/MedalAnimation.cs

@@ -245,18 +245,19 @@ namespace osu.Game.Overlays
             this.FadeOut(200);
         }
 
-        public void Dismiss()
+        public bool Dismiss()
         {
             if (drawableMedal != null && drawableMedal.State != DisplayState.Full)
             {
                 // if we haven't yet, play out the animation fully
                 drawableMedal.State = DisplayState.Full;
                 FinishTransforms(true);
-                return;
+                return false;
             }
 
             Hide();
             Expire();
+            return true;
         }
 
         private partial class BackgroundStrip : Container

osu.Game/Overlays/MedalOverlay.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
-using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
@@ -35,7 +34,7 @@ namespace osu.Game.Overlays
         private IAPIProvider api { get; set; } = null!;
 
         private Container<Drawable> medalContainer = null!;
-        private MedalAnimation? lastAnimation;
+        private MedalAnimation? currentMedalDisplay;
 
         [BackgroundDependencyLoader]
         private void load()
@@ -54,11 +53,12 @@ namespace osu.Game.Overlays
         {
             base.LoadComplete();
 
-            OverlayActivationMode.BindValueChanged(val =>
-            {
-                if (val.NewValue == OverlayActivation.All && (queuedMedals.Any() || medalContainer.Any() || lastAnimation?.IsLoaded == false))
-                    Show();
-            }, true);
+            OverlayActivationMode.BindValueChanged(_ => showNextMedal(), true);
+        }
+
+        public override void Hide()
+        {
+            // don't allow hiding the overlay via any method other than our own.
         }
 
         private void handleMedalMessages(SocketMessage obj)
@@ -83,34 +83,18 @@ namespace osu.Game.Overlays
 
             var medalAnimation = new MedalAnimation(medal);
 
-            queuedMedals.Enqueue(medalAnimation);
             Logger.Log($"Queueing medal unlock for \"{medal.Name}\" ({queuedMedals.Count} to display)");
 
-            if (OverlayActivationMode.Value == OverlayActivation.All)
-                Scheduler.AddOnce(Show);
-        }
-
-        protected override void Update()
-        {
-            base.Update();
-
-            if (medalContainer.Any() || lastAnimation?.IsLoaded == false)
-                return;
-
-            if (!queuedMedals.TryDequeue(out lastAnimation))
+            Schedule(() => LoadComponentAsync(medalAnimation, m =>
             {
-                Logger.Log("All queued medals have been displayed!");
-                Hide();
-                return;
-            }
-
-            Logger.Log($"Preparing to display \"{lastAnimation.Medal.Name}\"");
-            LoadComponentAsync(lastAnimation, medalContainer.Add);
+                queuedMedals.Enqueue(m);
+                showNextMedal();
+            }));
         }
 
         protected override bool OnClick(ClickEvent e)
         {
-            lastAnimation?.Dismiss();
+            progressDisplayByUser();
             return true;
         }
 
@@ -118,19 +102,54 @@ namespace osu.Game.Overlays
         {
             if (e.Action == GlobalAction.Back)
             {
-                lastAnimation?.Dismiss();
+                progressDisplayByUser();
                 return true;
             }
 
             return base.OnPressed(e);
         }
 
+        private void progressDisplayByUser()
+        {
+            // Dismissing may sometimes play out the medal animation rather than immediately dismissing.
+            if (currentMedalDisplay?.Dismiss() == false)
+                return;
+
+            currentMedalDisplay = null;
+            showNextMedal();
+        }
+
+        private void showNextMedal()
+        {
+            // If already displayed, keep displaying medals regardless of activation mode changes.
+            if (OverlayActivationMode.Value != OverlayActivation.All && State.Value == Visibility.Hidden)
+                return;
+
+            // A medal is already displaying.
+            if (currentMedalDisplay != null)
+                return;
+
+            if (queuedMedals.TryDequeue(out currentMedalDisplay))
+            {
+                Logger.Log($"Displaying \"{currentMedalDisplay.Medal.Name}\"");
+                medalContainer.Add(currentMedalDisplay);
+                Show();
+            }
+            else if (State.Value == Visibility.Visible)
+            {
+                Logger.Log("All queued medals have been displayed, hiding overlay!");
+                base.Hide();
+            }
+        }
+
         protected override void Dispose(bool isDisposing)
         {
-            base.Dispose(isDisposing);
-
+            // this event subscription fires async loads, which hard-fail if `CompositeDrawable.disposalCancellationSource` is canceled, which happens in the base call.
+            // therefore, unsubscribe from this event early to reduce the chances of a stray event firing at an inconvenient spot.
             if (api.IsNotNull())
                 api.NotificationsClient.MessageReceived -= handleMedalMessages;
+
+            base.Dispose(isDisposing);
         }
     }
 }