Merge pull request #33049 from peppy/carousel-manifest-filters

Ensure carousel filters are manifested to lists at each step

osu.Game/Graphics/Carousel/Carousel.cs

@@ -265,7 +265,7 @@ namespace osu.Game.Graphics.Carousel
 
             // Copy must be performed on update thread for now (see ConfigureAwait above).
             // Could potentially be optimised in the future if it becomes an issue.
-            IEnumerable<CarouselItem> items = new List<CarouselItem>(Items.Select(m => new CarouselItem(m)));
+            List<CarouselItem> items = new List<CarouselItem>(Items.Select(m => new CarouselItem(m)));
 
             await Task.Run(async () =>
             {
@@ -275,6 +275,11 @@ namespace osu.Game.Graphics.Carousel
                     {
                         log($"Performing {filter.GetType().ReadableName()}");
                         items = await filter.Run(items, cts.Token).ConfigureAwait(false);
+
+                        // To avoid shooting ourselves in the foot, ensure that we manifest a list after each filter.
+                        //
+                        // A future improvement may be passing a reference list through each filter rather than copying each time,
+                        // but this is the safest approach.
                     }
 
                     log("Updating Y positions");
@@ -292,7 +297,7 @@ namespace osu.Game.Graphics.Carousel
             Schedule(() =>
             {
                 log("Items ready for display");
-                carouselItems = items.ToList();
+                carouselItems = items;
                 displayedRange = null;
 
                 // Need to call this to ensure correct post-selection logic is handled on the new items list.

osu.Game/Graphics/Carousel/ICarouselFilter.cs

@@ -18,6 +18,6 @@ namespace osu.Game.Graphics.Carousel
         /// <param name="items">The items to be filtered.</param>
         /// <param name="cancellationToken">A cancellation token.</param>
         /// <returns>The post-filtered items.</returns>
-        Task<IEnumerable<CarouselItem>> Run(IEnumerable<CarouselItem> items, CancellationToken cancellationToken);
+        Task<List<CarouselItem>> Run(IEnumerable<CarouselItem> items, CancellationToken cancellationToken);
     }
 }

osu.Game/Screens/SelectV2/BeatmapCarouselFilterGrouping.cs

@@ -36,7 +36,7 @@ namespace osu.Game.Screens.SelectV2
             this.getCriteria = getCriteria;
         }
 
-        public async Task<IEnumerable<CarouselItem>> Run(IEnumerable<CarouselItem> items, CancellationToken cancellationToken)
+        public async Task<List<CarouselItem>> Run(IEnumerable<CarouselItem> items, CancellationToken cancellationToken)
         {
             return await Task.Run(() =>
             {

osu.Game/Screens/SelectV2/BeatmapCarouselFilterSorting.cs

@@ -23,7 +23,7 @@ namespace osu.Game.Screens.SelectV2
             this.getCriteria = getCriteria;
         }
 
-        public async Task<IEnumerable<CarouselItem>> Run(IEnumerable<CarouselItem> items, CancellationToken cancellationToken) => await Task.Run(() =>
+        public async Task<List<CarouselItem>> Run(IEnumerable<CarouselItem> items, CancellationToken cancellationToken) => await Task.Run(() =>
         {
             var criteria = getCriteria();
 
@@ -55,7 +55,7 @@ namespace osu.Game.Screens.SelectV2
                 }
 
                 return comparison;
-            }));
+            })).ToList();
         }, cancellationToken).ConfigureAwait(false);
     }
 }