Song select not loading maps

[Valerus9]

Type

Game behaviour

Bug description

When I entered song select I got an "unhandled error" message and the maps wouldn't load. I had to re enter the song select screen to load the songs.

Screenshots or videos

2025-04-15.07-11-14.mp4

Version

2025.321.0-lazer

Logs

compressed-logs.zip

[bdach]

Log shows the classic

2025-04-15 05:07:34 [error]: An unhandled error has occurred.
2025-04-15 05:07:34 [error]: System.ArgumentException: Destination array was not long enough. Check the destination index, length, and the array's lower bounds. (Parameter 'destinationArray')
2025-04-15 05:07:34 [error]: at System.Array.CopyImpl(Array sourceArray, Int32 sourceIndex, Array destinationArray, Int32 destinationIndex, Int32 length, Boolean reliable)
2025-04-15 05:07:34 [error]: at System.Array.Copy(Array sourceArray, Int32 sourceIndex, Array destinationArray, Int32 destinationIndex, Int32 length)
2025-04-15 05:07:34 [error]: at System.Collections.Generic.List`1.CopyTo(T[] array, Int32 arrayIndex)
2025-04-15 05:07:34 [error]: at osu.Framework.Bindables.BindableList`1.CopyTo(T[] array, Int32 arrayIndex)
2025-04-15 05:07:34 [error]: at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
2025-04-15 05:07:34 [error]: at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
2025-04-15 05:07:34 [error]: at osu.Framework.Bindables.BindableList`1.Parse(Object input, IFormatProvider provider)
2025-04-15 05:07:34 [error]: at osu.Framework.Bindables.BindableList`1.BindTo(BindableList`1 them)
2025-04-15 05:07:34 [error]: at osu.Framework.Bindables.BindableList`1.osu.Framework.Bindables.IBindable.BindTo(IBindable them)
2025-04-15 05:07:34 [error]: at osu.Framework.Bindables.IBindable.GetBoundCopyImplementation[T](T source)
2025-04-15 05:07:34 [error]: at osu.Framework.Bindables.BindableList`1.GetBoundCopy()
2025-04-15 05:07:34 [error]: at osu.Game.Database.RealmDetachedBeatmapStore.GetBeatmapSets(Nullable`1 cancellationToken)
2025-04-15 05:07:34 [error]: at osu.Game.Screens.Select.BeatmapCarousel.load(OsuConfigManager config, AudioManager audio, BeatmapStore beatmaps, Nullable`1 cancellationToken)
2025-04-15 05:07:34 [error]: at osu.Game.Screens.Select.BeatmapCarousel.<>c.<RegisterForDependencyActivation>b__111_0(Object t, IReadOnlyDependencyContainer d)
2025-04-15 05:07:34 [error]: at osu.Framework.Allocation.DependencyActivator.<Activate>g__activateRecursively|8_0[T](Object obj, IReadOnlyDependencyContainer dependencies, Type currentType)
2025-04-15 05:07:34 [error]: at osu.Framework.Allocation.DependencyActivator.Activate[T](T obj, IReadOnlyDependencyContainer dependencies)
2025-04-15 05:07:34 [error]: at osu.Framework.Allocation.DependencyContainer.Inject[T](T instance)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Drawable.InjectDependencies(IReadOnlyDependencyContainer dependencies)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Containers.CompositeDrawable.InjectDependencies(IReadOnlyDependencyContainer dependencies)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Drawable.load(IFrameBasedClock clock, IReadOnlyDependencyContainer dependencies)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Drawable.Load(IFrameBasedClock clock, IReadOnlyDependencyContainer dependencies, Boolean isDirectAsyncContext)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Drawable.LoadFromAsync(IFrameBasedClock clock, IReadOnlyDependencyContainer dependencies, Boolean isDirectAsyncContext)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Containers.CompositeDrawable.loadComponents[TLoadable](List`1 components, IReadOnlyDependencyContainer dependencies, Boolean isDirectAsyncContext, CancellationToken cancellation)
2025-04-15 05:07:34 [error]: at osu.Framework.Graphics.Containers.CompositeDrawable.<>c__DisplayClass13_0`1.<LoadComponentsAsync>b__1()
2025-04-15 05:07:34 [error]: at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)

It looks like a no-brainer fix maybe (just move the bind to LoadComplete()) but I worry it's going to like destroy performance on large beatmap collections.

Maybe not worth fixing before new song select. cc @peppy

[Valerus9]

I found a simple fix for it. By going back to main menu and then re enter song select it starts the beatmap loading again and this time it loaded.

[peppy]

It looks like a no-brainer fix maybe (just move the bind to LoadComplete()) but I worry it's going to like destroy performance on large beatmap collections.

It would mean that the loadNewRoot would no longer be asynchronously loading, meaning the song select load process would break (and cause a stutter on first load to perform the root initialisation).

A fix for this would IMO be to fix thread safety of the retrieval function, so we don't have to worry about this in the first place. I see the GetBoundCopy as an internal implementation detail to BeatmapStore that shouldn't be of concern to the consumer of it:

diff --git a/osu.Game/Database/RealmDetachedBeatmapStore.cs b/osu.Game/Database/RealmDetachedBeatmapStore.cs
index b05e07ef31..6954bb320a 100644
--- a/osu.Game/Database/RealmDetachedBeatmapStore.cs
+++ b/osu.Game/Database/RealmDetachedBeatmapStore.cs
@@ -30,7 +30,8 @@ public partial class RealmDetachedBeatmapStore : BeatmapStore
         public override IBindableList<BeatmapSetInfo> GetBeatmapSets(CancellationToken? cancellationToken)
         {
             loaded.Wait(cancellationToken ?? CancellationToken.None);
-            return detachedBeatmapSets.GetBoundCopy();
+            lock (detachedBeatmapSets)
+                return detachedBeatmapSets.GetBoundCopy();
         }
 
         [BackgroundDependencyLoader]
@@ -65,8 +66,11 @@ private void beatmapSetsChanged(IRealmCollection<BeatmapSetInfo> sender, ChangeS
                         {
                             var detached = frozenSets.Detach();
 
-                            detachedBeatmapSets.Clear();
-                            detachedBeatmapSets.AddRange(detached);
+                            lock (detachedBeatmapSets)
+                            {
+                                detachedBeatmapSets.Clear();
+                                detachedBeatmapSets.AddRange(detached);
+                            }
                         });
                     }
                     finally
@@ -116,22 +120,28 @@ protected override void Update()
             if (!loaded.IsSet)
                 return;
 
-            // If this ever leads to performance issues, we could dequeue a limited number of operations per update frame.
-            while (pendingOperations.TryDequeue(out var op))
+            if (pendingOperations.Count == 0)
+                return;
+
+            lock (detachedBeatmapSets)
             {
-                switch (op.Type)
+                // If this ever leads to performance issues, we could dequeue a limited number of operations per update frame.
+                while (pendingOperations.TryDequeue(out var op))
                 {
-                    case OperationType.Insert:
-                        detachedBeatmapSets.Insert(op.Index, op.BeatmapSet!);
-                        break;
+                    switch (op.Type)
+                    {
+                        case OperationType.Insert:
+                            detachedBeatmapSets.Insert(op.Index, op.BeatmapSet!);
+                            break;
 
-                    case OperationType.Update:
-                        detachedBeatmapSets.ReplaceRange(op.Index, 1, new[] { op.BeatmapSet! });
-                        break;
+                        case OperationType.Update:
+                            detachedBeatmapSets.ReplaceRange(op.Index, 1, new[] { op.BeatmapSet! });
+                            break;
 
-                    case OperationType.Remove:
-                        detachedBeatmapSets.RemoveAt(op.Index);
-                        break;
+                        case OperationType.Remove:
+                            detachedBeatmapSets.RemoveAt(op.Index);
+                            break;
+                    }
                 }
             }
         }

@bdach thoughts on this? if you agree i'll PR it as a fix.

[bdach]

On a five-second look I don't see anything particularly wrong with the patch proposed.