Merge pull request #10118 from peppy/fix-collection-delete-crash

Fix hard crash on deleting a collection with no collection selected

osu.Android.props

@@ -51,7 +51,7 @@
     <Reference Include="Java.Interop" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Game.Resources" Version="2020.903.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2020.903.0" />
+    <PackageReference Include="ppy.osu.Game.Resources" Version="2020.904.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2020.910.0" />
   </ItemGroup>
 </Project>

osu.Game.Rulesets.Catch.Tests/CatchBeatmapConversionTest.cs

@@ -14,6 +14,7 @@ using osu.Game.Tests.Beatmaps;
 namespace osu.Game.Rulesets.Catch.Tests
 {
     [TestFixture]
+    [Timeout(10000)]
     public class CatchBeatmapConversionTest : BeatmapConversionTest<ConvertValue>
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Catch";

osu.Game.Rulesets.Catch/Beatmaps/CatchBeatmap.cs

@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Objects;
 
@@ -23,19 +22,19 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
                 {
                     Name = @"Fruit Count",
                     Content = fruits.ToString(),
-                    Icon = FontAwesome.Regular.Circle
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles),
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Juice Stream Count",
                     Content = juiceStreams.ToString(),
-                    Icon = FontAwesome.Regular.Circle
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders),
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Banana Shower Count",
                     Content = bananaShowers.ToString(),
-                    Icon = FontAwesome.Regular.Circle
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Spinners),
                 }
             };
         }

osu.Game.Rulesets.Catch/CatchRuleset.cs

@@ -21,13 +21,11 @@ using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Scoring;
 using System;
-using osu.Framework.Testing;
 using osu.Game.Rulesets.Catch.Skinning;
 using osu.Game.Skinning;
 
 namespace osu.Game.Rulesets.Catch
 {
-    [ExcludeFromDynamicCompile]
     public class CatchRuleset : Ruleset, ILegacyRuleset
     {
         public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => new DrawableCatchRuleset(this, beatmap, mods);

osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyAttributes.cs

@@ -8,6 +8,5 @@ namespace osu.Game.Rulesets.Catch.Difficulty
     public class CatchDifficultyAttributes : DifficultyAttributes
     {
         public double ApproachRate;
-        public int MaxCombo;
     }
 }

osu.Game.Rulesets.Mania.Tests/ManiaBeatmapConversionTest.cs

@@ -14,11 +14,13 @@ using osu.Game.Tests.Beatmaps;
 namespace osu.Game.Rulesets.Mania.Tests
 {
     [TestFixture]
+    [Timeout(10000)]
     public class ManiaBeatmapConversionTest : BeatmapConversionTest<ManiaConvertMapping, ConvertValue>
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Mania";
 
         [TestCase("basic")]
+        [TestCase("zero-length-slider")]
         public void Test(string name) => base.Test(name);
 
         protected override IEnumerable<ConvertValue> CreateConvertValue(HitObject hitObject)

osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmap.cs

@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.UI;
@@ -41,14 +40,14 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
                 new BeatmapStatistic
                 {
                     Name = @"Note Count",
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles),
                     Content = notes.ToString(),
-                    Icon = FontAwesome.Regular.Circle
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Hold Note Count",
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders),
                     Content = holdnotes.ToString(),
-                    Icon = FontAwesome.Regular.Circle
                 },
             };
         }

osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs

@@ -5,7 +5,6 @@ using osu.Game.Rulesets.Mania.Objects;
 using System;
 using System.Linq;
 using System.Collections.Generic;
-using osu.Framework.Utils;
 using osu.Game.Audio;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Objects;
@@ -167,8 +166,10 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
 
                     var positionData = original as IHasPosition;
 
-                    for (double time = original.StartTime; !Precision.DefinitelyBigger(time, generator.EndTime); time += generator.SegmentDuration)
+                    for (int i = 0; i <= generator.SpanCount; i++)
                     {
+                        double time = original.StartTime + generator.SegmentDuration * i;
+
                         recordNote(time, positionData?.Position ?? Vector2.Zero);
                         computeDensity(time);
                     }

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/DistanceObjectPatternGenerator.cs

@@ -27,8 +27,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
         public readonly double EndTime;
         public readonly double SegmentDuration;
-
-        private readonly int spanCount;
+        public readonly int SpanCount;
 
         private PatternType convertType;
 
@@ -42,20 +41,20 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
             var distanceData = hitObject as IHasDistance;
             var repeatsData = hitObject as IHasRepeats;
 
-            spanCount = repeatsData?.SpanCount() ?? 1;
+            SpanCount = repeatsData?.SpanCount() ?? 1;
 
             TimingControlPoint timingPoint = beatmap.ControlPointInfo.TimingPointAt(hitObject.StartTime);
             DifficultyControlPoint difficultyPoint = beatmap.ControlPointInfo.DifficultyPointAt(hitObject.StartTime);
 
             // The true distance, accounting for any repeats
-            double distance = (distanceData?.Distance ?? 0) * spanCount;
+            double distance = (distanceData?.Distance ?? 0) * SpanCount;
             // The velocity of the osu! hit object - calculated as the velocity of a slider
             double osuVelocity = osu_base_scoring_distance * beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier * difficultyPoint.SpeedMultiplier / timingPoint.BeatLength;
             // The duration of the osu! hit object
             double osuDuration = distance / osuVelocity;
 
             EndTime = hitObject.StartTime + osuDuration;
-            SegmentDuration = (EndTime - HitObject.StartTime) / spanCount;
+            SegmentDuration = (EndTime - HitObject.StartTime) / SpanCount;
         }
 
         public override IEnumerable<Pattern> Generate()
@@ -96,7 +95,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
                 return pattern;
             }
 
-            if (spanCount > 1)
+            if (SpanCount > 1)
             {
                 if (SegmentDuration <= 90)
                     return generateRandomHoldNotes(HitObject.StartTime, 1);
@@ -104,7 +103,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
                 if (SegmentDuration <= 120)
                 {
                     convertType |= PatternType.ForceNotStack;
-                    return generateRandomNotes(HitObject.StartTime, spanCount + 1);
+                    return generateRandomNotes(HitObject.StartTime, SpanCount + 1);
                 }
 
                 if (SegmentDuration <= 160)
@@ -117,7 +116,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
                 if (duration >= 4000)
                     return generateNRandomNotes(HitObject.StartTime, 0.23, 0, 0);
 
-                if (SegmentDuration > 400 && spanCount < TotalColumns - 1 - RandomStart)
+                if (SegmentDuration > 400 && SpanCount < TotalColumns - 1 - RandomStart)
                     return generateTiledHoldNotes(HitObject.StartTime);
 
                 return generateHoldAndNormalNotes(HitObject.StartTime);
@@ -251,7 +250,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
             int column = GetColumn((HitObject as IHasXPosition)?.X ?? 0, true);
             bool increasing = Random.NextDouble() > 0.5;
 
-            for (int i = 0; i <= spanCount; i++)
+            for (int i = 0; i <= SpanCount; i++)
             {
                 addToPattern(pattern, column, startTime, startTime);
                 startTime += SegmentDuration;
@@ -302,7 +301,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             int nextColumn = GetColumn((HitObject as IHasXPosition)?.X ?? 0, true);
 
-            for (int i = 0; i <= spanCount; i++)
+            for (int i = 0; i <= SpanCount; i++)
             {
                 addToPattern(pattern, nextColumn, startTime, startTime);
 
@@ -393,7 +392,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             var pattern = new Pattern();
 
-            int columnRepeat = Math.Min(spanCount, TotalColumns);
+            int columnRepeat = Math.Min(SpanCount, TotalColumns);
 
             int nextColumn = GetColumn((HitObject as IHasXPosition)?.X ?? 0, true);
             if (convertType.HasFlag(PatternType.ForceNotStack) && PreviousPattern.ColumnWithObjects < TotalColumns)
@@ -447,7 +446,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             var rowPattern = new Pattern();
 
-            for (int i = 0; i <= spanCount; i++)
+            for (int i = 0; i <= SpanCount; i++)
             {
                 if (!(ignoreHead && startTime == HitObject.StartTime))
                 {

osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs

@@ -11,6 +11,7 @@ using osu.Game.Rulesets.Mania.Beatmaps;
 using osu.Game.Rulesets.Mania.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Mania.Difficulty.Skills;
 using osu.Game.Rulesets.Mania.Mods;
+using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Scoring;
@@ -43,6 +44,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
                 Mods = mods,
                 // Todo: This int cast is temporary to achieve 1:1 results with osu!stable, and should be removed in the future
                 GreatHitWindow = (int)(hitWindows.WindowFor(HitResult.Great)) / clockRate,
+                MaxCombo = beatmap.HitObjects.Sum(h => h is HoldNote ? 2 : 1),
                 Skills = skills
             };
         }

osu.Game.Rulesets.Mania/Edit/HoldNoteCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mania.Edit.Blueprints;
@@ -14,6 +16,8 @@ namespace osu.Game.Rulesets.Mania.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new HoldNotePlacementBlueprint();
     }
 }

osu.Game.Rulesets.Mania/Edit/NoteCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mania.Edit.Blueprints;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Mania.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new NotePlacementBlueprint();
     }
 }

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -12,7 +12,6 @@ using System.Linq;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Input.Bindings;
-using osu.Framework.Testing;
 using osu.Game.Graphics;
 using osu.Game.Rulesets.Mania.Replays;
 using osu.Game.Rulesets.Replays.Types;
@@ -35,7 +34,6 @@ using osu.Game.Screens.Ranking.Statistics;
 
 namespace osu.Game.Rulesets.Mania
 {
-    [ExcludeFromDynamicCompile]
     public class ManiaRuleset : Ruleset, ILegacyRuleset
     {
         /// <summary>

osu.Game.Rulesets.Mania/Resources/Testing/Beatmaps/zero-length-slider-expected-conversion.json

@@ -0,0 +1,14 @@
+{
+    "Mappings": [{
+        "RandomW": 3083084786,
+        "RandomX": 273326509,
+        "RandomY": 273553282,
+        "RandomZ": 2659838971,
+        "StartTime": 4836,
+        "Objects": [{
+            "StartTime": 4836,
+            "EndTime": 4836,
+            "Column": 0
+        }]
+    }]
+}

osu.Game.Rulesets.Mania/Resources/Testing/Beatmaps/zero-length-slider.osu

@@ -0,0 +1,20 @@
+osu file format v14
+
+[General]
+StackLeniency: 0.7
+Mode: 0
+
+[Difficulty]
+HPDrainRate:1
+CircleSize:4
+OverallDifficulty:1
+ApproachRate:9
+SliderMultiplier:2.5
+SliderTickRate:0.5
+
+[TimingPoints]
+34,431.654676258993,4,1,0,50,1,0
+4782,-66.6666666666667,4,1,0,20,0,0
+
+[HitObjects]
+15,199,4836,22,0,L,1,46.8750017881394

osu.Game.Rulesets.Osu.Tests/OsuBeatmapConversionTest.cs

@@ -12,6 +12,7 @@ using osu.Game.Tests.Beatmaps;
 namespace osu.Game.Rulesets.Osu.Tests
 {
     [TestFixture]
+    [Timeout(10000)]
     public class OsuBeatmapConversionTest : BeatmapConversionTest<ConvertValue>
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Osu";

osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmap.cs

@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Osu.Objects;
 
@@ -23,19 +22,19 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
                 {
                     Name = @"Circle Count",
                     Content = circles.ToString(),
-                    Icon = FontAwesome.Regular.Circle
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles),
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Slider Count",
                     Content = sliders.ToString(),
-                    Icon = FontAwesome.Regular.Circle
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders),
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Spinner Count",
                     Content = spinners.ToString(),
-                    Icon = FontAwesome.Regular.Circle
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Spinners),
                 }
             };
         }

osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyAttributes.cs

@@ -11,6 +11,5 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         public double SpeedStrain;
         public double ApproachRate;
         public double OverallDifficulty;
-        public int MaxCombo;
     }
 }

osu.Game.Rulesets.Osu/Edit/HitCircleCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Osu.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new HitCirclePlacementBlueprint();
     }
 }

osu.Game.Rulesets.Osu/Edit/OsuHitObjectComposer.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Caching;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -38,6 +39,13 @@ namespace osu.Game.Rulesets.Osu.Edit
             new SpinnerCompositionTool()
         };
 
+        private readonly BindableBool distanceSnapToggle = new BindableBool(true) { Description = "Distance Snap" };
+
+        protected override IEnumerable<BindableBool> Toggles => new[]
+        {
+            distanceSnapToggle
+        };
+
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -45,6 +53,7 @@ namespace osu.Game.Rulesets.Osu.Edit
 
             EditorBeatmap.SelectedHitObjects.CollectionChanged += (_, __) => updateDistanceSnapGrid();
             EditorBeatmap.PlacementObject.ValueChanged += _ => updateDistanceSnapGrid();
+            distanceSnapToggle.ValueChanged += _ => updateDistanceSnapGrid();
         }
 
         protected override ComposeBlueprintContainer CreateBlueprintContainer(IEnumerable<DrawableHitObject> hitObjects)
@@ -87,6 +96,10 @@ namespace osu.Game.Rulesets.Osu.Edit
         {
             distanceSnapGridContainer.Clear();
             distanceSnapGridCache.Invalidate();
+            distanceSnapGrid = null;
+
+            if (!distanceSnapToggle.Value)
+                return;
 
             switch (BlueprintContainer.CurrentTool)
             {

osu.Game.Rulesets.Osu/Edit/SliderCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Osu.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new SliderPlacementBlueprint();
     }
 }

osu.Game.Rulesets.Osu/Edit/SpinnerCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.Spinners;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Osu.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Spinners);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new SpinnerPlacementBlueprint();
     }
 }

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -30,14 +30,12 @@ using osu.Game.Scoring;
 using osu.Game.Skinning;
 using System;
 using System.Linq;
-using osu.Framework.Testing;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Osu.Statistics;
 using osu.Game.Screens.Ranking.Statistics;
 
 namespace osu.Game.Rulesets.Osu
 {
-    [ExcludeFromDynamicCompile]
     public class OsuRuleset : Ruleset, ILegacyRuleset
     {
         public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => new DrawableOsuRuleset(this, beatmap, mods);

osu.Game.Rulesets.Osu/Skinning/LegacySliderBody.cs

@@ -18,6 +18,10 @@ namespace osu.Game.Rulesets.Osu.Skinning
         {
             private const float shadow_portion = 1 - (OsuLegacySkinTransformer.LEGACY_CIRCLE_RADIUS / OsuHitObject.OBJECT_RADIUS);
 
+            protected new float CalculatedBorderPortion
+                // Roughly matches osu!stable's slider border portions.
+                => base.CalculatedBorderPortion * 0.77f;
+
             public new Color4 AccentColour => new Color4(base.AccentColour.R, base.AccentColour.G, base.AccentColour.B, base.AccentColour.A * 0.70f);
 
             protected override Color4 ColourAt(float position)

osu.Game.Rulesets.Osu/Statistics/AccuracyHeatmap.cs

@@ -192,7 +192,7 @@ namespace osu.Game.Rulesets.Osu.Statistics
 
         protected void AddPoint(Vector2 start, Vector2 end, Vector2 hitPoint, float radius)
         {
-            if (pointGrid.Content.Length == 0)
+            if (pointGrid.Content.Count == 0)
                 return;
 
             double angle1 = Math.Atan2(end.Y - hitPoint.Y, hitPoint.X - end.X); // Angle between the end point and the hit point.

osu.Game.Rulesets.Taiko.Tests/TaikoBeatmapConversionTest.cs

@@ -12,6 +12,7 @@ using osu.Game.Tests.Beatmaps;
 namespace osu.Game.Rulesets.Taiko.Tests
 {
     [TestFixture]
+    [Timeout(10000)]
     public class TaikoBeatmapConversionTest : BeatmapConversionTest<ConvertValue>
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Taiko";

osu.Game.Rulesets.Taiko/Beatmaps/TaikoBeatmap.cs

@@ -3,7 +3,6 @@
 
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Taiko.Objects;
 
@@ -22,20 +21,20 @@ namespace osu.Game.Rulesets.Taiko.Beatmaps
                 new BeatmapStatistic
                 {
                     Name = @"Hit Count",
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles),
                     Content = hits.ToString(),
-                    Icon = FontAwesome.Regular.Circle
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Drumroll Count",
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders),
                     Content = drumrolls.ToString(),
-                    Icon = FontAwesome.Regular.Circle
                 },
                 new BeatmapStatistic
                 {
                     Name = @"Swell Count",
+                    CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Spinners),
                     Content = swells.ToString(),
-                    Icon = FontAwesome.Regular.Circle
                 }
             };
         }

osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyAttributes.cs

@@ -8,6 +8,5 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
     public class TaikoDifficultyAttributes : DifficultyAttributes
     {
         public double GreatHitWindow;
-        public int MaxCombo;
     }
 }

osu.Game.Rulesets.Taiko/Edit/DrumRollCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Taiko.Edit.Blueprints;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Taiko.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new DrumRollPlacementBlueprint();
     }
 }

osu.Game.Rulesets.Taiko/Edit/HitCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Taiko.Edit.Blueprints;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Taiko.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new HitPlacementBlueprint();
     }
 }

osu.Game.Rulesets.Taiko/Edit/SwellCompositionTool.cs

@@ -1,6 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Taiko.Edit.Blueprints;
@@ -15,6 +17,8 @@ namespace osu.Game.Rulesets.Taiko.Edit
         {
         }
 
+        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Spinners);
+
         public override PlacementBlueprint CreatePlacementBlueprint() => new SwellPlacementBlueprint();
     }
 }

osu.Game.Rulesets.Taiko/TaikoRuleset.cs

@@ -22,7 +22,6 @@ using osu.Game.Rulesets.Taiko.Scoring;
 using osu.Game.Scoring;
 using System;
 using System.Linq;
-using osu.Framework.Testing;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Taiko.Edit;
 using osu.Game.Rulesets.Taiko.Objects;
@@ -32,7 +31,6 @@ using osu.Game.Skinning;
 
 namespace osu.Game.Rulesets.Taiko
 {
-    [ExcludeFromDynamicCompile]
     public class TaikoRuleset : Ruleset, ILegacyRuleset
     {
         public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => new DrawableTaikoRuleset(this, beatmap, mods);

osu.Game.Tests/Beatmaps/Formats/LegacyBeatmapEncoderTest.cs

@@ -10,6 +10,7 @@ using System.Text;
 using NUnit.Framework;
 using osu.Framework.Audio.Track;
 using osu.Framework.Graphics.Textures;
+using osu.Framework.IO.Stores;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Beatmaps.Formats;
@@ -19,6 +20,7 @@ using osu.Game.Rulesets.Catch;
 using osu.Game.Rulesets.Mania;
 using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Taiko;
+using osu.Game.Skinning;
 using osu.Game.Tests.Resources;
 
 namespace osu.Game.Tests.Beatmaps.Formats
@@ -26,18 +28,33 @@ namespace osu.Game.Tests.Beatmaps.Formats
     [TestFixture]
     public class LegacyBeatmapEncoderTest
     {
-        private static IEnumerable<string> allBeatmaps => TestResources.GetStore().GetAvailableResources().Where(res => res.EndsWith(".osu"));
+        private static readonly DllResourceStore beatmaps_resource_store = TestResources.GetStore();
+
+        private static IEnumerable<string> allBeatmaps = beatmaps_resource_store.GetAvailableResources().Where(res => res.EndsWith(".osu"));
 
         [TestCaseSource(nameof(allBeatmaps))]
         public void TestEncodeDecodeStability(string name)
         {
-            var decoded = decodeFromLegacy(TestResources.GetStore().GetStream(name));
-            var decodedAfterEncode = decodeFromLegacy(encodeToLegacy(decoded));
+            var decoded = decodeFromLegacy(beatmaps_resource_store.GetStream(name), name);
+            var decodedAfterEncode = decodeFromLegacy(encodeToLegacy(decoded), name);
 
-            sort(decoded);
-            sort(decodedAfterEncode);
+            sort(decoded.beatmap);
+            sort(decodedAfterEncode.beatmap);
 
-            Assert.That(decodedAfterEncode.Serialize(), Is.EqualTo(decoded.Serialize()));
+            Assert.That(decodedAfterEncode.beatmap.Serialize(), Is.EqualTo(decoded.beatmap.Serialize()));
+            Assert.IsTrue(areComboColoursEqual(decodedAfterEncode.beatmapSkin.Configuration, decoded.beatmapSkin.Configuration));
+        }
+
+        private bool areComboColoursEqual(IHasComboColours a, IHasComboColours b)
+        {
+            // equal to null, no need to SequenceEqual
+            if (a.ComboColours == null && b.ComboColours == null)
+                return true;
+
+            if (a.ComboColours == null || b.ComboColours == null)
+                return false;
+
+            return a.ComboColours.SequenceEqual(b.ComboColours);
         }
 
         private void sort(IBeatmap beatmap)
@@ -50,18 +67,31 @@ namespace osu.Game.Tests.Beatmaps.Formats
             }
         }
 
-        private IBeatmap decodeFromLegacy(Stream stream)
+        private (IBeatmap beatmap, TestLegacySkin beatmapSkin) decodeFromLegacy(Stream stream, string name)
         {
             using (var reader = new LineBufferedReader(stream))
-                return convert(new LegacyBeatmapDecoder { ApplyOffsets = false }.Decode(reader));
+            {
+                var beatmap = new LegacyBeatmapDecoder { ApplyOffsets = false }.Decode(reader);
+                var beatmapSkin = new TestLegacySkin(beatmaps_resource_store, name);
+                return (convert(beatmap), beatmapSkin);
+            }
         }
 
-        private Stream encodeToLegacy(IBeatmap beatmap)
+        private class TestLegacySkin : LegacySkin
         {
+            public TestLegacySkin(IResourceStore<byte[]> storage, string fileName)
+                : base(new SkinInfo { Name = "Test Skin", Creator = "Craftplacer" }, storage, null, fileName)
+            {
+            }
+        }
+
+        private Stream encodeToLegacy((IBeatmap beatmap, ISkin beatmapSkin) fullBeatmap)
+        {
+            var (beatmap, beatmapSkin) = fullBeatmap;
             var stream = new MemoryStream();
 
             using (var writer = new StreamWriter(stream, Encoding.UTF8, 1024, true))
-                new LegacyBeatmapEncoder(beatmap).Encode(writer);
+                new LegacyBeatmapEncoder(beatmap, beatmapSkin).Encode(writer);
 
             stream.Position = 0;
 

osu.Game.Tests/Beatmaps/IO/ImportBeatmapTest.cs

@@ -15,8 +15,10 @@ using osu.Framework.Extensions;
 using osu.Framework.Logging;
 using osu.Game.Beatmaps;
 using osu.Game.IO;
+using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Tests.Resources;
+using osu.Game.Users;
 using SharpCompress.Archives;
 using SharpCompress.Archives.Zip;
 using SharpCompress.Common;
@@ -32,7 +34,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportWhenClosed()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportWhenClosed)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -49,7 +51,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportThenDelete()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportThenDelete)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -70,7 +72,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportThenImport()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportThenImport)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -96,7 +98,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportThenImportWithReZip()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportThenImportWithReZip)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -154,7 +156,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportThenImportWithChangedFile()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportThenImportWithChangedFile)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -205,7 +207,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportThenImportWithDifferentFilename()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportThenImportWithDifferentFilename)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -257,7 +259,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportCorruptThenImport()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportCorruptThenImport)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -299,7 +301,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestRollbackOnFailure()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestRollbackOnFailure)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -376,7 +378,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportThenDeleteThenImport()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportThenDeleteThenImport)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -404,7 +406,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportThenDeleteThenImportWithOnlineIDMismatch(bool set)
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost($"{nameof(TestImportThenDeleteThenImportWithOnlineIDMismatch)}-{set}"))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(set.ToString()))
             {
                 try
                 {
@@ -438,7 +440,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         public async Task TestImportWithDuplicateBeatmapIDs()
         {
             // unfortunately for the time being we need to reference osu.Framework.Desktop for a game host here.
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportWithDuplicateBeatmapIDs)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -524,7 +526,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportWhenFileOpen()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportWhenFileOpen)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -546,7 +548,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportWithDuplicateHashes()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportWithDuplicateHashes)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -588,7 +590,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportNestedStructure()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportNestedStructure)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -633,7 +635,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestImportWithIgnoredDirectoryInArchive()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestImportWithIgnoredDirectoryInArchive)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -687,7 +689,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestUpdateBeatmapInfo()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestUpdateBeatmapInfo)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -717,7 +719,7 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Test]
         public async Task TestUpdateBeatmapFile()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost(nameof(TestUpdateBeatmapFile)))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -756,6 +758,63 @@ namespace osu.Game.Tests.Beatmaps.IO
             }
         }
 
+        [Test]
+        public void TestCreateNewEmptyBeatmap()
+        {
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    var osu = loadOsu(host);
+                    var manager = osu.Dependencies.Get<BeatmapManager>();
+
+                    var working = manager.CreateNew(new OsuRuleset().RulesetInfo, User.SYSTEM_USER);
+
+                    manager.Save(working.BeatmapInfo, working.Beatmap);
+
+                    var retrievedSet = manager.GetAllUsableBeatmapSets()[0];
+
+                    // Check that the new file is referenced correctly by attempting a retrieval
+                    Beatmap updatedBeatmap = (Beatmap)manager.GetWorkingBeatmap(retrievedSet.Beatmaps[0]).Beatmap;
+                    Assert.That(updatedBeatmap.HitObjects.Count, Is.EqualTo(0));
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
+        [Test]
+        public void TestCreateNewBeatmapWithObject()
+        {
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    var osu = loadOsu(host);
+                    var manager = osu.Dependencies.Get<BeatmapManager>();
+
+                    var working = manager.CreateNew(new OsuRuleset().RulesetInfo, User.SYSTEM_USER);
+
+                    ((Beatmap)working.Beatmap).HitObjects.Add(new HitCircle { StartTime = 5000 });
+
+                    manager.Save(working.BeatmapInfo, working.Beatmap);
+
+                    var retrievedSet = manager.GetAllUsableBeatmapSets()[0];
+
+                    // Check that the new file is referenced correctly by attempting a retrieval
+                    Beatmap updatedBeatmap = (Beatmap)manager.GetWorkingBeatmap(retrievedSet.Beatmaps[0]).Beatmap;
+                    Assert.That(updatedBeatmap.HitObjects.Count, Is.EqualTo(1));
+                    Assert.That(updatedBeatmap.HitObjects[0].StartTime, Is.EqualTo(5000));
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
         public static async Task<BeatmapSetInfo> LoadOszIntoOsu(OsuGameBase osu, string path = null, bool virtualTrack = false)
         {
             var temp = path ?? TestResources.GetTestBeatmapForImport(virtualTrack);

osu.Game.Tests/Collections/IO/ImportCollectionsTest.cs

@@ -0,0 +1,221 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Platform;
+using osu.Game.Collections;
+using osu.Game.Tests.Resources;
+
+namespace osu.Game.Tests.Collections.IO
+{
+    [TestFixture]
+    public class ImportCollectionsTest
+    {
+        [Test]
+        public async Task TestImportEmptyDatabase()
+        {
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    var osu = loadOsu(host);
+
+                    await osu.CollectionManager.Import(new MemoryStream());
+
+                    Assert.That(osu.CollectionManager.Collections.Count, Is.Zero);
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
+        [Test]
+        public async Task TestImportWithNoBeatmaps()
+        {
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    var osu = loadOsu(host);
+
+                    await osu.CollectionManager.Import(TestResources.OpenResource("Collections/collections.db"));
+
+                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(2));
+
+                    Assert.That(osu.CollectionManager.Collections[0].Name.Value, Is.EqualTo("First"));
+                    Assert.That(osu.CollectionManager.Collections[0].Beatmaps.Count, Is.Zero);
+
+                    Assert.That(osu.CollectionManager.Collections[1].Name.Value, Is.EqualTo("Second"));
+                    Assert.That(osu.CollectionManager.Collections[1].Beatmaps.Count, Is.Zero);
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
+        [Test]
+        public async Task TestImportWithBeatmaps()
+        {
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    var osu = loadOsu(host, true);
+
+                    await osu.CollectionManager.Import(TestResources.OpenResource("Collections/collections.db"));
+
+                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(2));
+
+                    Assert.That(osu.CollectionManager.Collections[0].Name.Value, Is.EqualTo("First"));
+                    Assert.That(osu.CollectionManager.Collections[0].Beatmaps.Count, Is.EqualTo(1));
+
+                    Assert.That(osu.CollectionManager.Collections[1].Name.Value, Is.EqualTo("Second"));
+                    Assert.That(osu.CollectionManager.Collections[1].Beatmaps.Count, Is.EqualTo(12));
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
+        [Test]
+        public async Task TestImportMalformedDatabase()
+        {
+            bool exceptionThrown = false;
+            UnhandledExceptionEventHandler setException = (_, __) => exceptionThrown = true;
+
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    AppDomain.CurrentDomain.UnhandledException += setException;
+
+                    var osu = loadOsu(host, true);
+
+                    using (var ms = new MemoryStream())
+                    {
+                        using (var bw = new BinaryWriter(ms, Encoding.UTF8, true))
+                        {
+                            for (int i = 0; i < 10000; i++)
+                                bw.Write((byte)i);
+                        }
+
+                        ms.Seek(0, SeekOrigin.Begin);
+
+                        await osu.CollectionManager.Import(ms);
+                    }
+
+                    Assert.That(host.UpdateThread.Running, Is.True);
+                    Assert.That(exceptionThrown, Is.False);
+                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(0));
+                }
+                finally
+                {
+                    host.Exit();
+                    AppDomain.CurrentDomain.UnhandledException -= setException;
+                }
+            }
+        }
+
+        [Test]
+        public async Task TestSaveAndReload()
+        {
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
+            {
+                try
+                {
+                    var osu = loadOsu(host, true);
+
+                    await osu.CollectionManager.Import(TestResources.OpenResource("Collections/collections.db"));
+
+                    // Move first beatmap from second collection into the first.
+                    osu.CollectionManager.Collections[0].Beatmaps.Add(osu.CollectionManager.Collections[1].Beatmaps[0]);
+                    osu.CollectionManager.Collections[1].Beatmaps.RemoveAt(0);
+
+                    // Rename the second collecction.
+                    osu.CollectionManager.Collections[1].Name.Value = "Another";
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+
+            using (HeadlessGameHost host = new HeadlessGameHost("TestSaveAndReload"))
+            {
+                try
+                {
+                    var osu = loadOsu(host, true);
+
+                    Assert.That(osu.CollectionManager.Collections.Count, Is.EqualTo(2));
+
+                    Assert.That(osu.CollectionManager.Collections[0].Name.Value, Is.EqualTo("First"));
+                    Assert.That(osu.CollectionManager.Collections[0].Beatmaps.Count, Is.EqualTo(2));
+
+                    Assert.That(osu.CollectionManager.Collections[1].Name.Value, Is.EqualTo("Another"));
+                    Assert.That(osu.CollectionManager.Collections[1].Beatmaps.Count, Is.EqualTo(11));
+                }
+                finally
+                {
+                    host.Exit();
+                }
+            }
+        }
+
+        private TestOsuGameBase loadOsu(GameHost host, bool withBeatmap = false)
+        {
+            var osu = new TestOsuGameBase(withBeatmap);
+
+#pragma warning disable 4014
+            Task.Run(() => host.Run(osu));
+#pragma warning restore 4014
+
+            waitForOrAssert(() => osu.IsLoaded, @"osu! failed to start in a reasonable amount of time");
+
+            return osu;
+        }
+
+        private void waitForOrAssert(Func<bool> result, string failureMessage, int timeout = 60000)
+        {
+            Task task = Task.Run(() =>
+            {
+                while (!result()) Thread.Sleep(200);
+            });
+
+            Assert.IsTrue(task.Wait(timeout), failureMessage);
+        }
+
+        private class TestOsuGameBase : OsuGameBase
+        {
+            public CollectionManager CollectionManager { get; private set; }
+
+            private readonly bool withBeatmap;
+
+            public TestOsuGameBase(bool withBeatmap)
+            {
+                this.withBeatmap = withBeatmap;
+            }
+
+            [BackgroundDependencyLoader]
+            private void load()
+            {
+                // Beatmap must be imported before the collection manager is loaded.
+                if (withBeatmap)
+                    BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).Wait();
+
+                AddInternal(CollectionManager = new CollectionManager(Storage));
+            }
+        }
+    }
+}

osu.Game.Tests/Editing/LegacyEditorBeatmapPatcherTest.cs

@@ -351,7 +351,7 @@ namespace osu.Game.Tests.Editing
             using (var encoded = new MemoryStream())
             {
                 using (var sw = new StreamWriter(encoded))
-                    new LegacyBeatmapEncoder(beatmap).Encode(sw);
+                    new LegacyBeatmapEncoder(beatmap, null).Encode(sw);
 
                 return encoded.ToArray();
             }

osu.Game.Tests/Scores/IO/ImportScoreTest.cs

@@ -27,7 +27,7 @@ namespace osu.Game.Tests.Scores.IO
         [Test]
         public async Task TestBasicImport()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost("TestBasicImport"))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -66,7 +66,7 @@ namespace osu.Game.Tests.Scores.IO
         [Test]
         public async Task TestImportMods()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost("TestImportMods"))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -92,7 +92,7 @@ namespace osu.Game.Tests.Scores.IO
         [Test]
         public async Task TestImportStatistics()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost("TestImportStatistics"))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -122,7 +122,7 @@ namespace osu.Game.Tests.Scores.IO
         [Test]
         public async Task TestImportWithDeletedBeatmapSet()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost("TestImportWithDeletedBeatmapSet"))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {
@@ -159,7 +159,7 @@ namespace osu.Game.Tests.Scores.IO
         [Test]
         public async Task TestOnlineScoreIsAvailableLocally()
         {
-            using (HeadlessGameHost host = new CleanRunHeadlessGameHost("TestOnlineScoreIsAvailableLocally"))
+            using (HeadlessGameHost host = new CleanRunHeadlessGameHost())
             {
                 try
                 {

osu.Game.Tests/Visual/Collections/TestSceneManageCollectionsDialog.cs

@@ -0,0 +1,244 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Platform;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Collections;
+using osu.Game.Overlays;
+using osu.Game.Overlays.Dialog;
+using osu.Game.Rulesets;
+using osu.Game.Tests.Resources;
+using osuTK;
+using osuTK.Input;
+
+namespace osu.Game.Tests.Visual.Collections
+{
+    public class TestSceneManageCollectionsDialog : OsuManualInputManagerTestScene
+    {
+        protected override Container<Drawable> Content => content;
+
+        private readonly Container content;
+        private readonly DialogOverlay dialogOverlay;
+        private readonly CollectionManager manager;
+
+        private RulesetStore rulesets;
+        private BeatmapManager beatmapManager;
+
+        private ManageCollectionsDialog dialog;
+
+        public TestSceneManageCollectionsDialog()
+        {
+            base.Content.AddRange(new Drawable[]
+            {
+                manager = new CollectionManager(LocalStorage),
+                content = new Container { RelativeSizeAxes = Axes.Both },
+                dialogOverlay = new DialogOverlay()
+            });
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(GameHost host)
+        {
+            Dependencies.Cache(rulesets = new RulesetStore(ContextFactory));
+            Dependencies.Cache(beatmapManager = new BeatmapManager(LocalStorage, ContextFactory, rulesets, null, Audio, host, Beatmap.Default));
+
+            beatmapManager.Import(TestResources.GetTestBeatmapForImport()).Wait();
+        }
+
+        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
+        {
+            var dependencies = new DependencyContainer(base.CreateChildDependencies(parent));
+            dependencies.Cache(manager);
+            dependencies.Cache(dialogOverlay);
+            return dependencies;
+        }
+
+        [SetUp]
+        public void SetUp() => Schedule(() =>
+        {
+            manager.Collections.Clear();
+            Child = dialog = new ManageCollectionsDialog();
+        });
+
+        [SetUpSteps]
+        public void SetUpSteps()
+        {
+            AddStep("show dialog", () => dialog.Show());
+        }
+
+        [Test]
+        public void TestHideDialog()
+        {
+            AddWaitStep("wait for animation", 3);
+            AddStep("hide dialog", () => dialog.Hide());
+        }
+
+        [Test]
+        public void TestLastItemIsPlaceholder()
+        {
+            AddAssert("last item is placeholder", () => !manager.Collections.Contains(dialog.ChildrenOfType<DrawableCollectionListItem>().Last().Model));
+        }
+
+        [Test]
+        public void TestAddCollectionExternal()
+        {
+            AddStep("add collection", () => manager.Collections.Add(new BeatmapCollection { Name = { Value = "First collection" } }));
+            assertCollectionCount(1);
+            assertCollectionName(0, "First collection");
+
+            AddStep("add another collection", () => manager.Collections.Add(new BeatmapCollection { Name = { Value = "Second collection" } }));
+            assertCollectionCount(2);
+            assertCollectionName(1, "Second collection");
+        }
+
+        [Test]
+        public void TestFocusPlaceholderDoesNotCreateCollection()
+        {
+            AddStep("focus placeholder", () =>
+            {
+                InputManager.MoveMouseTo(dialog.ChildrenOfType<DrawableCollectionListItem>().Last());
+                InputManager.Click(MouseButton.Left);
+            });
+
+            assertCollectionCount(0);
+        }
+
+        [Test]
+        public void TestAddCollectionViaPlaceholder()
+        {
+            DrawableCollectionListItem placeholderItem = null;
+
+            AddStep("focus placeholder", () =>
+            {
+                InputManager.MoveMouseTo(placeholderItem = dialog.ChildrenOfType<DrawableCollectionListItem>().Last());
+                InputManager.Click(MouseButton.Left);
+            });
+
+            // Done directly via the collection since InputManager methods cannot add text to textbox...
+            AddStep("change collection name", () => placeholderItem.Model.Name.Value = "a");
+            assertCollectionCount(1);
+            AddAssert("collection now exists", () => manager.Collections.Contains(placeholderItem.Model));
+
+            AddAssert("last item is placeholder", () => !manager.Collections.Contains(dialog.ChildrenOfType<DrawableCollectionListItem>().Last().Model));
+        }
+
+        [Test]
+        public void TestRemoveCollectionExternal()
+        {
+            AddStep("add two collections", () => manager.Collections.AddRange(new[]
+            {
+                new BeatmapCollection { Name = { Value = "1" } },
+                new BeatmapCollection { Name = { Value = "2" } },
+            }));
+
+            AddStep("remove first collection", () => manager.Collections.RemoveAt(0));
+            assertCollectionCount(1);
+            assertCollectionName(0, "2");
+        }
+
+        [Test]
+        public void TestRemoveCollectionViaButton()
+        {
+            AddStep("add two collections", () => manager.Collections.AddRange(new[]
+            {
+                new BeatmapCollection { Name = { Value = "1" } },
+                new BeatmapCollection { Name = { Value = "2" }, Beatmaps = { beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0] } },
+            }));
+
+            assertCollectionCount(2);
+
+            AddStep("click first delete button", () =>
+            {
+                InputManager.MoveMouseTo(dialog.ChildrenOfType<DrawableCollectionListItem.DeleteButton>().First(), new Vector2(5, 0));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("dialog not displayed", () => dialogOverlay.CurrentDialog == null);
+            assertCollectionCount(1);
+            assertCollectionName(0, "2");
+
+            AddStep("click first delete button", () =>
+            {
+                InputManager.MoveMouseTo(dialog.ChildrenOfType<DrawableCollectionListItem.DeleteButton>().First(), new Vector2(5, 0));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("dialog displayed", () => dialogOverlay.CurrentDialog is DeleteCollectionDialog);
+            AddStep("click confirmation", () =>
+            {
+                InputManager.MoveMouseTo(dialogOverlay.CurrentDialog.ChildrenOfType<PopupDialogButton>().First());
+                InputManager.Click(MouseButton.Left);
+            });
+
+            assertCollectionCount(0);
+        }
+
+        [Test]
+        public void TestCollectionNotRemovedWhenDialogCancelled()
+        {
+            AddStep("add two collections", () => manager.Collections.AddRange(new[]
+            {
+                new BeatmapCollection { Name = { Value = "1" }, Beatmaps = { beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0] } },
+            }));
+
+            assertCollectionCount(1);
+
+            AddStep("click first delete button", () =>
+            {
+                InputManager.MoveMouseTo(dialog.ChildrenOfType<DrawableCollectionListItem.DeleteButton>().First(), new Vector2(5, 0));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("dialog displayed", () => dialogOverlay.CurrentDialog is DeleteCollectionDialog);
+            AddStep("click cancellation", () =>
+            {
+                InputManager.MoveMouseTo(dialogOverlay.CurrentDialog.ChildrenOfType<PopupDialogButton>().Last());
+                InputManager.Click(MouseButton.Left);
+            });
+
+            assertCollectionCount(1);
+        }
+
+        [Test]
+        public void TestCollectionRenamedExternal()
+        {
+            AddStep("add two collections", () => manager.Collections.AddRange(new[]
+            {
+                new BeatmapCollection { Name = { Value = "1" } },
+                new BeatmapCollection { Name = { Value = "2" } },
+            }));
+
+            AddStep("change first collection name", () => manager.Collections[0].Name.Value = "First");
+
+            assertCollectionName(0, "First");
+        }
+
+        [Test]
+        public void TestCollectionRenamedOnTextChange()
+        {
+            AddStep("add two collections", () => manager.Collections.AddRange(new[]
+            {
+                new BeatmapCollection { Name = { Value = "1" } },
+                new BeatmapCollection { Name = { Value = "2" } },
+            }));
+
+            assertCollectionCount(2);
+
+            AddStep("change first collection name", () => dialog.ChildrenOfType<TextBox>().First().Text = "First");
+            AddAssert("collection has new name", () => manager.Collections[0].Name.Value == "First");
+        }
+
+        private void assertCollectionCount(int count)
+            => AddUntilStep($"{count} collections shown", () => dialog.ChildrenOfType<DrawableCollectionListItem>().Count(i => i.IsCreated.Value) == count);
+
+        private void assertCollectionName(int index, string name)
+            => AddUntilStep($"item {index + 1} has correct name", () => dialog.ChildrenOfType<DrawableCollectionListItem>().ElementAt(index).ChildrenOfType<TextBox>().First().Text == name);
+    }
+}

osu.Game.Tests/Visual/Editing/TestSceneEditorChangeStates.cs

@@ -18,6 +18,8 @@ namespace osu.Game.Tests.Visual.Editing
 
         protected override Ruleset CreateEditorRuleset() => new OsuRuleset();
 
+        protected new TestEditor Editor => (TestEditor)base.Editor;
+
         public override void SetUpSteps()
         {
             base.SetUpSteps();
@@ -35,6 +37,7 @@ namespace osu.Game.Tests.Visual.Editing
             addUndoSteps();
 
             AddAssert("no change occurred", () => hitObjectCount == editorBeatmap.HitObjects.Count);
+            AddAssert("no unsaved changes", () => !Editor.HasUnsavedChanges);
         }
 
         [Test]
@@ -47,6 +50,7 @@ namespace osu.Game.Tests.Visual.Editing
             addRedoSteps();
 
             AddAssert("no change occurred", () => hitObjectCount == editorBeatmap.HitObjects.Count);
+            AddAssert("no unsaved changes", () => !Editor.HasUnsavedChanges);
         }
 
         [Test]
@@ -64,9 +68,11 @@ namespace osu.Game.Tests.Visual.Editing
 
             AddStep("add hitobject", () => editorBeatmap.Add(expectedObject = new HitCircle { StartTime = 1000 }));
             AddAssert("hitobject added", () => addedObject == expectedObject);
+            AddAssert("unsaved changes", () => Editor.HasUnsavedChanges);
 
             addUndoSteps();
             AddAssert("hitobject removed", () => removedObject == expectedObject);
+            AddAssert("no unsaved changes", () => !Editor.HasUnsavedChanges);
         }
 
         [Test]
@@ -94,6 +100,17 @@ namespace osu.Game.Tests.Visual.Editing
             addRedoSteps();
             AddAssert("hitobject added", () => addedObject.StartTime == expectedObject.StartTime); // Can't compare via equality (new hitobject instance)
             AddAssert("no hitobject removed", () => removedObject == null);
+            AddAssert("unsaved changes", () => Editor.HasUnsavedChanges);
+        }
+
+        [Test]
+        public void TestAddObjectThenSaveHasNoUnsavedChanges()
+        {
+            AddStep("add hitobject", () => editorBeatmap.Add(new HitCircle { StartTime = 1000 }));
+
+            AddAssert("unsaved changes", () => Editor.HasUnsavedChanges);
+            AddStep("save changes", () => Editor.Save());
+            AddAssert("no unsaved changes", () => !Editor.HasUnsavedChanges);
         }
 
         [Test]
@@ -120,6 +137,7 @@ namespace osu.Game.Tests.Visual.Editing
             addUndoSteps();
             AddAssert("hitobject added", () => addedObject.StartTime == expectedObject.StartTime); // Can't compare via equality (new hitobject instance)
             AddAssert("no hitobject removed", () => removedObject == null);
+            AddAssert("unsaved changes", () => Editor.HasUnsavedChanges); // 2 steps performed, 1 undone
         }
 
         [Test]
@@ -148,19 +166,24 @@ namespace osu.Game.Tests.Visual.Editing
             addRedoSteps();
             AddAssert("hitobject removed", () => removedObject.StartTime == expectedObject.StartTime); // Can't compare via equality (new hitobject instance after undo)
             AddAssert("no hitobject added", () => addedObject == null);
+            AddAssert("no changes", () => !Editor.HasUnsavedChanges); // end result is empty beatmap, matching original state
         }
 
-        private void addUndoSteps() => AddStep("undo", () => ((TestEditor)Editor).Undo());
+        private void addUndoSteps() => AddStep("undo", () => Editor.Undo());
 
-        private void addRedoSteps() => AddStep("redo", () => ((TestEditor)Editor).Redo());
+        private void addRedoSteps() => AddStep("redo", () => Editor.Redo());
 
         protected override Editor CreateEditor() => new TestEditor();
 
-        private class TestEditor : Editor
+        protected class TestEditor : Editor
         {
             public new void Undo() => base.Undo();
 
             public new void Redo() => base.Redo();
+
+            public new void Save() => base.Save();
+
+            public new bool HasUnsavedChanges => base.HasUnsavedChanges;
         }
     }
 }

osu.Game.Tests/Visual/Editing/TestSceneEditorComposeRadioButtons.cs

@@ -3,6 +3,7 @@
 
 using NUnit.Framework;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
 using osu.Game.Screens.Edit.Components.RadioButtons;
 
 namespace osu.Game.Tests.Visual.Editing
@@ -22,7 +23,7 @@ namespace osu.Game.Tests.Visual.Editing
                 {
                     new RadioButton("Item 1", () => { }),
                     new RadioButton("Item 2", () => { }),
-                    new RadioButton("Item 3", () => { }),
+                    new RadioButton("Item 3", () => { }, () => new SpriteIcon { Icon = FontAwesome.Regular.Angry }),
                     new RadioButton("Item 4", () => { }),
                     new RadioButton("Item 5", () => { })
                 }

osu.Game.Tests/Visual/Editing/TestSceneSetupScreen.cs

@@ -0,0 +1,32 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Osu.Beatmaps;
+using osu.Game.Screens.Edit;
+using osu.Game.Screens.Edit.Setup;
+
+namespace osu.Game.Tests.Visual.Editing
+{
+    [TestFixture]
+    public class TestSceneSetupScreen : EditorClockTestScene
+    {
+        [Cached(typeof(EditorBeatmap))]
+        [Cached(typeof(IBeatSnapProvider))]
+        private readonly EditorBeatmap editorBeatmap;
+
+        public TestSceneSetupScreen()
+        {
+            editorBeatmap = new EditorBeatmap(new OsuBeatmap());
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Beatmap.Value = CreateWorkingBeatmap(editorBeatmap.PlayableBeatmap);
+            Child = new SetupScreen();
+        }
+    }
+}

osu.Game.Tests/Visual/Gameplay/TestSceneOverlayActivation.cs

@@ -0,0 +1,54 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using NUnit.Framework;
+using osu.Game.Overlays;
+using osu.Game.Rulesets;
+
+namespace osu.Game.Tests.Visual.Gameplay
+{
+    public class TestSceneOverlayActivation : OsuPlayerTestScene
+    {
+        protected new OverlayTestPlayer Player => base.Player as OverlayTestPlayer;
+
+        [Test]
+        public void TestGameplayOverlayActivation()
+        {
+            AddAssert("activation mode is disabled", () => Player.OverlayActivationMode == OverlayActivation.Disabled);
+        }
+
+        [Test]
+        public void TestGameplayOverlayActivationPaused()
+        {
+            AddUntilStep("activation mode is disabled", () => Player.OverlayActivationMode == OverlayActivation.Disabled);
+            AddStep("pause gameplay", () => Player.Pause());
+            AddUntilStep("activation mode is user triggered", () => Player.OverlayActivationMode == OverlayActivation.UserTriggered);
+        }
+
+        [Test]
+        public void TestGameplayOverlayActivationReplayLoaded()
+        {
+            AddAssert("activation mode is disabled", () => Player.OverlayActivationMode == OverlayActivation.Disabled);
+            AddStep("load a replay", () => Player.DrawableRuleset.HasReplayLoaded.Value = true);
+            AddAssert("activation mode is user triggered", () => Player.OverlayActivationMode == OverlayActivation.UserTriggered);
+        }
+
+        [Test]
+        public void TestGameplayOverlayActivationBreaks()
+        {
+            AddAssert("activation mode is disabled", () => Player.OverlayActivationMode == OverlayActivation.Disabled);
+            AddStep("seek to break", () => Player.GameplayClockContainer.Seek(Beatmap.Value.Beatmap.Breaks.First().StartTime));
+            AddUntilStep("activation mode is user triggered", () => Player.OverlayActivationMode == OverlayActivation.UserTriggered);
+            AddStep("seek to break end", () => Player.GameplayClockContainer.Seek(Beatmap.Value.Beatmap.Breaks.First().EndTime));
+            AddUntilStep("activation mode is disabled", () => Player.OverlayActivationMode == OverlayActivation.Disabled);
+        }
+
+        protected override TestPlayer CreatePlayer(Ruleset ruleset) => new OverlayTestPlayer();
+
+        protected class OverlayTestPlayer : TestPlayer
+        {
+            public new OverlayActivation OverlayActivationMode => base.OverlayActivationMode.Value;
+        }
+    }
+}

osu.Game.Tests/Visual/Gameplay/TestSceneReplaySettingsOverlay.cs

@@ -48,7 +48,10 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         private class ExampleContainer : PlayerSettingsGroup
         {
-            protected override string Title => @"example";
+            public ExampleContainer()
+                : base("example")
+            {
+            }
         }
     }
 }

osu.Game.Tests/Visual/Menus/TestSceneMusicActionHandling.cs

@@ -0,0 +1,83 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Input.Bindings;
+using osu.Game.Overlays;
+using osu.Game.Tests.Resources;
+using osu.Game.Tests.Visual.Navigation;
+
+namespace osu.Game.Tests.Visual.Menus
+{
+    public class TestSceneMusicActionHandling : OsuGameTestScene
+    {
+        private GlobalActionContainer globalActionContainer => Game.ChildrenOfType<GlobalActionContainer>().First();
+
+        [Test]
+        public void TestMusicPlayAction()
+        {
+            AddStep("ensure playing something", () => Game.MusicController.EnsurePlayingSomething());
+            AddStep("toggle playback", () => globalActionContainer.TriggerPressed(GlobalAction.MusicPlay));
+            AddAssert("music paused", () => !Game.MusicController.IsPlaying && Game.MusicController.IsUserPaused);
+            AddStep("toggle playback", () => globalActionContainer.TriggerPressed(GlobalAction.MusicPlay));
+            AddAssert("music resumed", () => Game.MusicController.IsPlaying && !Game.MusicController.IsUserPaused);
+        }
+
+        [Test]
+        public void TestMusicNavigationActions()
+        {
+            int importId = 0;
+            Queue<(WorkingBeatmap working, TrackChangeDirection changeDirection)> trackChangeQueue = null;
+
+            // ensure we have at least two beatmaps available to identify the direction the music controller navigated to.
+            AddRepeatStep("import beatmap", () => Game.BeatmapManager.Import(new BeatmapSetInfo
+            {
+                Beatmaps = new List<BeatmapInfo>
+                {
+                    new BeatmapInfo
+                    {
+                        BaseDifficulty = new BeatmapDifficulty(),
+                    }
+                },
+                Metadata = new BeatmapMetadata
+                {
+                    Artist = $"a test map {importId++}",
+                    Title = "title",
+                }
+            }).Wait(), 5);
+
+            AddStep("import beatmap with track", () =>
+            {
+                var setWithTrack = Game.BeatmapManager.Import(TestResources.GetTestBeatmapForImport()).Result;
+                Beatmap.Value = Game.BeatmapManager.GetWorkingBeatmap(setWithTrack.Beatmaps.First());
+            });
+
+            AddStep("bind to track change", () =>
+            {
+                trackChangeQueue = new Queue<(WorkingBeatmap, TrackChangeDirection)>();
+                Game.MusicController.TrackChanged += (working, changeDirection) => trackChangeQueue.Enqueue((working, changeDirection));
+            });
+
+            AddStep("seek track to 6 second", () => Game.MusicController.SeekTo(6000));
+            AddUntilStep("wait for current time to update", () => Game.MusicController.CurrentTrack.CurrentTime > 5000);
+
+            AddStep("press previous", () => globalActionContainer.TriggerPressed(GlobalAction.MusicPrev));
+            AddAssert("no track change", () => trackChangeQueue.Count == 0);
+            AddUntilStep("track restarted", () => Game.MusicController.CurrentTrack.CurrentTime < 5000);
+
+            AddStep("press previous", () => globalActionContainer.TriggerPressed(GlobalAction.MusicPrev));
+            AddAssert("track changed to previous", () =>
+                trackChangeQueue.Count == 1 &&
+                trackChangeQueue.Dequeue().changeDirection == TrackChangeDirection.Prev);
+
+            AddStep("press next", () => globalActionContainer.TriggerPressed(GlobalAction.MusicNext));
+            AddAssert("track changed to next", () =>
+                trackChangeQueue.Count == 1 &&
+                trackChangeQueue.Dequeue().changeDirection == TrackChangeDirection.Next);
+        }
+    }
+}

osu.Game.Tests/Visual/Multiplayer/TestSceneMatchSongSelect.cs

@@ -162,6 +162,28 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddAssert("item 2 has rate 2", () => Precision.AlmostEquals(2, ((OsuModDoubleTime)Room.Playlist.Last().RequiredMods[0]).SpeedChange.Value));
         }
 
+        /// <summary>
+        /// Tests that the global mod instances are not retained by the rooms, as global mod instances are retained and re-used by the mod select overlay.
+        /// </summary>
+        [Test]
+        public void TestGlobalModInstancesNotRetained()
+        {
+            OsuModDoubleTime mod = null;
+
+            AddStep("set dt mod and store", () =>
+            {
+                SelectedMods.Value = new[] { new OsuModDoubleTime() };
+
+                // Mod select overlay replaces our mod.
+                mod = (OsuModDoubleTime)SelectedMods.Value[0];
+            });
+
+            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem());
+
+            AddStep("change stored mod rate", () => mod.SpeedChange.Value = 2);
+            AddAssert("item has rate 1.5", () => Precision.AlmostEquals(1.5, ((OsuModDoubleTime)Room.Playlist.First().RequiredMods[0]).SpeedChange.Value));
+        }
+
         private class TestMatchSongSelect : MatchSongSelect
         {
             public new MatchBeatmapDetailArea BeatmapDetails => (MatchBeatmapDetailArea)base.BeatmapDetails;

osu.Game.Tests/Visual/Navigation/TestScenePresentScore.cs

@@ -12,6 +12,7 @@ using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mania;
 using osu.Game.Rulesets.Osu;
 using osu.Game.Scoring;
+using osu.Game.Screens;
 using osu.Game.Screens.Menu;
 using osu.Game.Screens.Play;
 using osu.Game.Screens.Ranking;

osu.Game.Tests/Visual/SongSelect/TestSceneFilterControl.cs

@@ -0,0 +1,237 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Platform;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Collections;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Rulesets;
+using osu.Game.Screens.Select;
+using osu.Game.Tests.Resources;
+using osuTK.Input;
+
+namespace osu.Game.Tests.Visual.SongSelect
+{
+    public class TestSceneFilterControl : OsuManualInputManagerTestScene
+    {
+        protected override Container<Drawable> Content => content;
+        private readonly Container content;
+
+        private readonly CollectionManager collectionManager;
+
+        private RulesetStore rulesets;
+        private BeatmapManager beatmapManager;
+
+        private FilterControl control;
+
+        public TestSceneFilterControl()
+        {
+            base.Content.AddRange(new Drawable[]
+            {
+                collectionManager = new CollectionManager(LocalStorage),
+                content = new Container { RelativeSizeAxes = Axes.Both }
+            });
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(GameHost host)
+        {
+            Dependencies.Cache(rulesets = new RulesetStore(ContextFactory));
+            Dependencies.Cache(beatmapManager = new BeatmapManager(LocalStorage, ContextFactory, rulesets, null, Audio, host, Beatmap.Default));
+
+            beatmapManager.Import(TestResources.GetTestBeatmapForImport()).Wait();
+        }
+
+        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
+        {
+            var dependencies = new DependencyContainer(base.CreateChildDependencies(parent));
+            dependencies.Cache(collectionManager);
+            return dependencies;
+        }
+
+        [SetUp]
+        public void SetUp() => Schedule(() =>
+        {
+            collectionManager.Collections.Clear();
+
+            Child = control = new FilterControl
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                RelativeSizeAxes = Axes.X,
+                Height = FilterControl.HEIGHT,
+            };
+        });
+
+        [Test]
+        public void TestEmptyCollectionFilterContainsAllBeatmaps()
+        {
+            assertCollectionDropdownContains("All beatmaps");
+            assertCollectionHeaderDisplays("All beatmaps");
+        }
+
+        [Test]
+        public void TestCollectionAddedToDropdown()
+        {
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "2" } }));
+            assertCollectionDropdownContains("1");
+            assertCollectionDropdownContains("2");
+        }
+
+        [Test]
+        public void TestCollectionRemovedFromDropdown()
+        {
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "2" } }));
+            AddStep("remove collection", () => collectionManager.Collections.RemoveAt(0));
+
+            assertCollectionDropdownContains("1", false);
+            assertCollectionDropdownContains("2");
+        }
+
+        [Test]
+        public void TestCollectionRenamed()
+        {
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddStep("select collection", () =>
+            {
+                var dropdown = control.ChildrenOfType<CollectionFilterDropdown>().Single();
+                dropdown.Current.Value = dropdown.ItemSource.ElementAt(1);
+            });
+
+            addExpandHeaderStep();
+
+            AddStep("change name", () => collectionManager.Collections[0].Name.Value = "First");
+
+            assertCollectionDropdownContains("First");
+            assertCollectionHeaderDisplays("First");
+        }
+
+        [Test]
+        public void TestAllBeatmapFilterDoesNotHaveAddButton()
+        {
+            addExpandHeaderStep();
+            AddStep("hover all beatmaps", () => InputManager.MoveMouseTo(getAddOrRemoveButton(0)));
+            AddAssert("'All beatmaps' filter does not have add button", () => !getAddOrRemoveButton(0).IsPresent);
+        }
+
+        [Test]
+        public void TestCollectionFilterHasAddButton()
+        {
+            addExpandHeaderStep();
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddStep("hover collection", () => InputManager.MoveMouseTo(getAddOrRemoveButton(1)));
+            AddAssert("collection has add button", () => getAddOrRemoveButton(1).IsPresent);
+        }
+
+        [Test]
+        public void TestButtonDisabledAndEnabledWithBeatmapChanges()
+        {
+            addExpandHeaderStep();
+
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+
+            AddStep("select available beatmap", () => Beatmap.Value = beatmapManager.GetWorkingBeatmap(beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0]));
+            AddAssert("button enabled", () => getAddOrRemoveButton(1).Enabled.Value);
+
+            AddStep("set dummy beatmap", () => Beatmap.SetDefault());
+            AddAssert("button disabled", () => !getAddOrRemoveButton(1).Enabled.Value);
+        }
+
+        [Test]
+        public void TestButtonChangesWhenAddedAndRemovedFromCollection()
+        {
+            addExpandHeaderStep();
+
+            AddStep("select available beatmap", () => Beatmap.Value = beatmapManager.GetWorkingBeatmap(beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0]));
+
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddAssert("button is plus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.PlusSquare));
+
+            AddStep("add beatmap to collection", () => collectionManager.Collections[0].Beatmaps.Add(Beatmap.Value.BeatmapInfo));
+            AddAssert("button is minus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.MinusSquare));
+
+            AddStep("remove beatmap from collection", () => collectionManager.Collections[0].Beatmaps.Clear());
+            AddAssert("button is plus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.PlusSquare));
+        }
+
+        [Test]
+        public void TestButtonAddsAndRemovesBeatmap()
+        {
+            addExpandHeaderStep();
+
+            AddStep("select available beatmap", () => Beatmap.Value = beatmapManager.GetWorkingBeatmap(beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0]));
+
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddAssert("button is plus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.PlusSquare));
+
+            addClickAddOrRemoveButtonStep(1);
+            AddAssert("collection contains beatmap", () => collectionManager.Collections[0].Beatmaps.Contains(Beatmap.Value.BeatmapInfo));
+            AddAssert("button is minus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.MinusSquare));
+
+            addClickAddOrRemoveButtonStep(1);
+            AddAssert("collection does not contain beatmap", () => !collectionManager.Collections[0].Beatmaps.Contains(Beatmap.Value.BeatmapInfo));
+            AddAssert("button is plus", () => getAddOrRemoveButton(1).Icon.Equals(FontAwesome.Solid.PlusSquare));
+        }
+
+        [Test]
+        public void TestManageCollectionsFilterIsNotSelected()
+        {
+            addExpandHeaderStep();
+
+            AddStep("add collection", () => collectionManager.Collections.Add(new BeatmapCollection { Name = { Value = "1" } }));
+            AddStep("select collection", () =>
+            {
+                InputManager.MoveMouseTo(getCollectionDropdownItems().ElementAt(1));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            addExpandHeaderStep();
+
+            AddStep("click manage collections filter", () =>
+            {
+                InputManager.MoveMouseTo(getCollectionDropdownItems().Last());
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("collection filter still selected", () => control.CreateCriteria().Collection?.Name.Value == "1");
+        }
+
+        private void assertCollectionHeaderDisplays(string collectionName, bool shouldDisplay = true)
+            => AddAssert($"collection dropdown header displays '{collectionName}'",
+                () => shouldDisplay == (control.ChildrenOfType<CollectionFilterDropdown.CollectionDropdownHeader>().Single().ChildrenOfType<SpriteText>().First().Text == collectionName));
+
+        private void assertCollectionDropdownContains(string collectionName, bool shouldContain = true) =>
+            AddAssert($"collection dropdown {(shouldContain ? "contains" : "does not contain")} '{collectionName}'",
+                // A bit of a roundabout way of going about this, see: https://github.com/ppy/osu-framework/issues/3871 + https://github.com/ppy/osu-framework/issues/3872
+                () => shouldContain == (getCollectionDropdownItems().Any(i => i.ChildrenOfType<FillFlowContainer>().OfType<IHasText>().First().Text == collectionName)));
+
+        private IconButton getAddOrRemoveButton(int index)
+            => getCollectionDropdownItems().ElementAt(index).ChildrenOfType<IconButton>().Single();
+
+        private void addExpandHeaderStep() => AddStep("expand header", () =>
+        {
+            InputManager.MoveMouseTo(control.ChildrenOfType<CollectionFilterDropdown.CollectionDropdownHeader>().Single());
+            InputManager.Click(MouseButton.Left);
+        });
+
+        private void addClickAddOrRemoveButtonStep(int index) => AddStep("click add or remove button", () =>
+        {
+            InputManager.MoveMouseTo(getAddOrRemoveButton(index));
+            InputManager.Click(MouseButton.Left);
+        });
+
+        private IEnumerable<Dropdown<CollectionMenuItem>.DropdownMenu.DrawableDropdownMenuItem> getCollectionDropdownItems()
+            => control.ChildrenOfType<CollectionFilterDropdown>().Single().ChildrenOfType<Dropdown<CollectionMenuItem>.DropdownMenu.DrawableDropdownMenuItem>();
+    }
+}

osu.Game.Tests/Visual/UserInterface/TestSceneNowPlayingOverlay.cs

@@ -1,18 +1,11 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System.Collections.Generic;
-using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
-using osu.Framework.Audio;
 using osu.Framework.Graphics;
-using osu.Framework.Platform;
-using osu.Game.Beatmaps;
 using osu.Game.Overlays;
-using osu.Game.Rulesets;
 using osu.Game.Rulesets.Osu;
-using osu.Game.Tests.Resources;
 
 namespace osu.Game.Tests.Visual.UserInterface
 {
@@ -24,14 +17,9 @@ namespace osu.Game.Tests.Visual.UserInterface
 
         private NowPlayingOverlay nowPlayingOverlay;
 
-        private RulesetStore rulesets;
-
         [BackgroundDependencyLoader]
-        private void load(AudioManager audio, GameHost host)
+        private void load()
         {
-            Dependencies.Cache(rulesets = new RulesetStore(ContextFactory));
-            Dependencies.Cache(manager = new BeatmapManager(LocalStorage, ContextFactory, rulesets, null, audio, host, Beatmap.Default));
-
             Beatmap.Value = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
 
             nowPlayingOverlay = new NowPlayingOverlay
@@ -51,49 +39,5 @@ namespace osu.Game.Tests.Visual.UserInterface
             AddToggleStep(@"toggle beatmap lock", state => Beatmap.Disabled = state);
             AddStep(@"hide", () => nowPlayingOverlay.Hide());
         }
-
-        private BeatmapManager manager { get; set; }
-
-        private int importId;
-
-        [Test]
-        public void TestPrevTrackBehavior()
-        {
-            // ensure we have at least two beatmaps available.
-            AddRepeatStep("import beatmap", () => manager.Import(new BeatmapSetInfo
-            {
-                Beatmaps = new List<BeatmapInfo>
-                {
-                    new BeatmapInfo
-                    {
-                        BaseDifficulty = new BeatmapDifficulty(),
-                    }
-                },
-                Metadata = new BeatmapMetadata
-                {
-                    Artist = $"a test map {importId++}",
-                    Title = "title",
-                }
-            }).Wait(), 5);
-
-            WorkingBeatmap currentBeatmap = null;
-
-            AddStep("import beatmap with track", () =>
-            {
-                var setWithTrack = manager.Import(TestResources.GetTestBeatmapForImport()).Result;
-                Beatmap.Value = currentBeatmap = manager.GetWorkingBeatmap(setWithTrack.Beatmaps.First());
-            });
-
-            AddStep(@"Seek track to 6 second", () => musicController.SeekTo(6000));
-            AddUntilStep(@"Wait for current time to update", () => musicController.CurrentTrack.CurrentTime > 5000);
-
-            AddStep(@"Set previous", () => musicController.PreviousTrack());
-
-            AddAssert(@"Check beatmap didn't change", () => currentBeatmap == Beatmap.Value);
-            AddUntilStep("Wait for current time to update", () => musicController.CurrentTrack.CurrentTime < 5000);
-
-            AddStep(@"Set previous", () => musicController.PreviousTrack());
-            AddAssert(@"Check beatmap did change", () => currentBeatmap != Beatmap.Value);
-        }
     }
 }

osu.Game.Tournament/Screens/Ladder/Components/LadderEditorSettings.cs

@@ -20,8 +20,6 @@ namespace osu.Game.Tournament.Screens.Ladder.Components
     {
         private const int padding = 10;
 
-        protected override string Title => @"ladder";
-
         private SettingsDropdown<TournamentRound> roundDropdown;
         private PlayerCheckbox losersCheckbox;
         private DateTextBox dateTimeBox;
@@ -34,6 +32,11 @@ namespace osu.Game.Tournament.Screens.Ladder.Components
         [Resolved]
         private LadderInfo ladderInfo { get; set; }
 
+        public LadderEditorSettings()
+            : base("ladder")
+        {
+        }
+
         [BackgroundDependencyLoader]
         private void load()
         {

osu.Game/Beatmaps/BeatmapDifficultyManager.cs

@@ -207,11 +207,11 @@ namespace osu.Game.Beatmaps
                 var calculator = ruleset.CreateDifficultyCalculator(beatmapManager.GetWorkingBeatmap(beatmapInfo));
                 var attributes = calculator.Calculate(key.Mods);
 
-                return difficultyCache[key] = new StarDifficulty(attributes.StarRating);
+                return difficultyCache[key] = new StarDifficulty(attributes.StarRating, attributes.MaxCombo);
             }
             catch
             {
-                return difficultyCache[key] = new StarDifficulty(0);
+                return difficultyCache[key] = new StarDifficulty();
             }
         }
 
@@ -233,7 +233,7 @@ namespace osu.Game.Beatmaps
             if (beatmapInfo.ID == 0 || rulesetInfo.ID == null)
             {
                 // If not, fall back to the existing star difficulty (e.g. from an online source).
-                existingDifficulty = new StarDifficulty(beatmapInfo.StarDifficulty);
+                existingDifficulty = new StarDifficulty(beatmapInfo.StarDifficulty, beatmapInfo.MaxCombo ?? 0);
                 key = default;
 
                 return true;
@@ -298,10 +298,12 @@ namespace osu.Game.Beatmaps
     public readonly struct StarDifficulty
     {
         public readonly double Stars;
+        public readonly int MaxCombo;
 
-        public StarDifficulty(double stars)
+        public StarDifficulty(double stars, int maxCombo)
         {
             Stars = stars;
+            MaxCombo = maxCombo;
 
             // Todo: Add more members (BeatmapInfo.DifficultyRating? Attributes? Etc...)
         }

osu.Game/Beatmaps/BeatmapInfo.cs

@@ -7,6 +7,7 @@ using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
 using Newtonsoft.Json;
+using osu.Framework.Testing;
 using osu.Game.Database;
 using osu.Game.IO.Serialization;
 using osu.Game.Rulesets;
@@ -14,6 +15,7 @@ using osu.Game.Scoring;
 
 namespace osu.Game.Beatmaps
 {
+    [ExcludeFromDynamicCompile]
     [Serializable]
     public class BeatmapInfo : IEquatable<BeatmapInfo>, IJsonSerializable, IHasPrimaryKey
     {

osu.Game/Beatmaps/BeatmapManager.cs

@@ -27,6 +27,8 @@ using osu.Game.Online.API;
 using osu.Game.Online.API.Requests;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Objects;
+using osu.Game.Users;
+using osu.Game.Skinning;
 using Decoder = osu.Game.Beatmaps.Formats.Decoder;
 
 namespace osu.Game.Beatmaps
@@ -64,12 +66,14 @@ namespace osu.Game.Beatmaps
         private readonly RulesetStore rulesets;
         private readonly BeatmapStore beatmaps;
         private readonly AudioManager audioManager;
-        private readonly BeatmapOnlineLookupQueue onlineLookupQueue;
         private readonly TextureStore textureStore;
         private readonly ITrackStore trackStore;
 
+        [CanBeNull]
+        private readonly BeatmapOnlineLookupQueue onlineLookupQueue;
+
         public BeatmapManager(Storage storage, IDatabaseContextFactory contextFactory, RulesetStore rulesets, IAPIProvider api, [NotNull] AudioManager audioManager, GameHost host = null,
-                              WorkingBeatmap defaultBeatmap = null)
+                              WorkingBeatmap defaultBeatmap = null, bool performOnlineLookups = false)
             : base(storage, contextFactory, api, new BeatmapStore(contextFactory), host)
         {
             this.rulesets = rulesets;
@@ -83,7 +87,8 @@ namespace osu.Game.Beatmaps
             beatmaps.ItemRemoved += removeWorkingCache;
             beatmaps.ItemUpdated += removeWorkingCache;
 
-            onlineLookupQueue = new BeatmapOnlineLookupQueue(api, storage);
+            if (performOnlineLookups)
+                onlineLookupQueue = new BeatmapOnlineLookupQueue(api, storage);
 
             textureStore = new LargeTextureStore(host?.CreateTextureLoaderStore(Files.Store));
             trackStore = audioManager.GetTrackStore(Files.Store);
@@ -94,6 +99,34 @@ namespace osu.Game.Beatmaps
 
         protected override bool ShouldDeleteArchive(string path) => Path.GetExtension(path)?.ToLowerInvariant() == ".osz";
 
+        public WorkingBeatmap CreateNew(RulesetInfo ruleset, User user)
+        {
+            var metadata = new BeatmapMetadata
+            {
+                Artist = "artist",
+                Title = "title",
+                Author = user,
+            };
+
+            var set = new BeatmapSetInfo
+            {
+                Metadata = metadata,
+                Beatmaps = new List<BeatmapInfo>
+                {
+                    new BeatmapInfo
+                    {
+                        BaseDifficulty = new BeatmapDifficulty(),
+                        Ruleset = ruleset,
+                        Metadata = metadata,
+                        Version = "difficulty"
+                    }
+                }
+            };
+
+            var working = Import(set).Result;
+            return GetWorkingBeatmap(working.Beatmaps.First());
+        }
+
         protected override async Task Populate(BeatmapSetInfo beatmapSet, ArchiveReader archive, CancellationToken cancellationToken = default)
         {
             if (archive != null)
@@ -112,7 +145,8 @@ namespace osu.Game.Beatmaps
 
             bool hadOnlineBeatmapIDs = beatmapSet.Beatmaps.Any(b => b.OnlineBeatmapID > 0);
 
-            await onlineLookupQueue.UpdateAsync(beatmapSet, cancellationToken);
+            if (onlineLookupQueue != null)
+                await onlineLookupQueue.UpdateAsync(beatmapSet, cancellationToken);
 
             // ensure at least one beatmap was able to retrieve or keep an online ID, else drop the set ID.
             if (hadOnlineBeatmapIDs && !beatmapSet.Beatmaps.Any(b => b.OnlineBeatmapID > 0))
@@ -198,24 +232,35 @@ namespace osu.Game.Beatmaps
         /// </summary>
         /// <param name="info">The <see cref="BeatmapInfo"/> to save the content against. The file referenced by <see cref="BeatmapInfo.Path"/> will be replaced.</param>
         /// <param name="beatmapContent">The <see cref="IBeatmap"/> content to write.</param>
-        public void Save(BeatmapInfo info, IBeatmap beatmapContent)
+        /// <param name="beatmapSkin">The beatmap <see cref="ISkin"/> content to write, null if to be omitted.</param>
+        public void Save(BeatmapInfo info, IBeatmap beatmapContent, ISkin beatmapSkin = null)
         {
-            var setInfo = QueryBeatmapSet(s => s.Beatmaps.Any(b => b.ID == info.ID));
+            var setInfo = info.BeatmapSet;
 
             using (var stream = new MemoryStream())
             {
                 using (var sw = new StreamWriter(stream, Encoding.UTF8, 1024, true))
-                    new LegacyBeatmapEncoder(beatmapContent).Encode(sw);
+                    new LegacyBeatmapEncoder(beatmapContent, beatmapSkin).Encode(sw);
 
                 stream.Seek(0, SeekOrigin.Begin);
 
                 using (ContextFactory.GetForWrite())
                 {
                     var beatmapInfo = setInfo.Beatmaps.Single(b => b.ID == info.ID);
+                    var metadata = beatmapInfo.Metadata ?? setInfo.Metadata;
+
+                    // grab the original file (or create a new one if not found).
+                    var fileInfo = setInfo.Files.SingleOrDefault(f => string.Equals(f.Filename, beatmapInfo.Path, StringComparison.OrdinalIgnoreCase)) ?? new BeatmapSetFileInfo();
+
+                    // metadata may have changed; update the path with the standard format.
+                    beatmapInfo.Path = $"{metadata.Artist} - {metadata.Title} ({metadata.Author}) [{beatmapInfo.Version}].osu";
                     beatmapInfo.MD5Hash = stream.ComputeMD5Hash();
 
+                    // update existing or populate new file's filename.
+                    fileInfo.Filename = beatmapInfo.Path;
+
                     stream.Seek(0, SeekOrigin.Begin);
-                    UpdateFile(setInfo, setInfo.Files.Single(f => string.Equals(f.Filename, info.Path, StringComparison.OrdinalIgnoreCase)), stream);
+                    UpdateFile(setInfo, fileInfo, stream);
                 }
             }
 

osu.Game/Beatmaps/BeatmapManager_WorkingBeatmap.cs

@@ -33,6 +33,9 @@ namespace osu.Game.Beatmaps
 
             protected override IBeatmap GetBeatmap()
             {
+                if (BeatmapInfo.Path == null)
+                    return new Beatmap { BeatmapInfo = BeatmapInfo };
+
                 try
                 {
                     using (var stream = new LineBufferedReader(store.GetStream(getPathForFile(BeatmapInfo.Path))))
@@ -67,6 +70,9 @@ namespace osu.Game.Beatmaps
 
             protected override Track GetBeatmapTrack()
             {
+                if (Metadata?.AudioFile == null)
+                    return null;
+
                 try
                 {
                     return trackStore.Get(getPathForFile(Metadata.AudioFile));
@@ -80,6 +86,9 @@ namespace osu.Game.Beatmaps
 
             protected override Waveform GetWaveform()
             {
+                if (Metadata?.AudioFile == null)
+                    return null;
+
                 try
                 {
                     var trackData = store.GetStream(getPathForFile(Metadata.AudioFile));

osu.Game/Beatmaps/BeatmapMetadata.cs

@@ -6,11 +6,13 @@ using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
 using Newtonsoft.Json;
+using osu.Framework.Testing;
 using osu.Game.Database;
 using osu.Game.Users;
 
 namespace osu.Game.Beatmaps
 {
+    [ExcludeFromDynamicCompile]
     [Serializable]
     public class BeatmapMetadata : IEquatable<BeatmapMetadata>, IHasPrimaryKey
     {

osu.Game/Beatmaps/BeatmapSetInfo.cs

@@ -5,10 +5,12 @@ using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
+using osu.Framework.Testing;
 using osu.Game.Database;
 
 namespace osu.Game.Beatmaps
 {
+    [ExcludeFromDynamicCompile]
     public class BeatmapSetInfo : IHasPrimaryKey, IHasFiles<BeatmapSetFileInfo>, ISoftDelete, IEquatable<BeatmapSetInfo>
     {
         public int ID { get; set; }

osu.Game/Beatmaps/BeatmapStatistic.cs

@@ -1,14 +1,31 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
+using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
+using osuTK;
 
 namespace osu.Game.Beatmaps
 {
     public class BeatmapStatistic
     {
-        public IconUsage Icon;
+        [Obsolete("Use CreateIcon instead")] // can be removed 20210203
+        public IconUsage Icon = FontAwesome.Regular.QuestionCircle;
+
+        /// <summary>
+        /// A function to create the icon for display purposes. Use default icons available via <see cref="BeatmapStatisticIcon"/> whenever possible for conformity.
+        /// </summary>
+        public Func<Drawable> CreateIcon;
+
         public string Content;
         public string Name;
+
+        public BeatmapStatistic()
+        {
+#pragma warning disable 618
+            CreateIcon = () => new SpriteIcon { Icon = Icon, Scale = new Vector2(0.7f) };
+#pragma warning restore 618
+        }
     }
 }

osu.Game/Beatmaps/BeatmapStatisticIcon.cs

@@ -0,0 +1,43 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using Humanizer;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Textures;
+
+namespace osu.Game.Beatmaps
+{
+    /// <summary>
+    /// A default implementation of an icon used to represent beatmap statistics.
+    /// </summary>
+    public class BeatmapStatisticIcon : Sprite
+    {
+        private readonly BeatmapStatisticsIconType iconType;
+
+        public BeatmapStatisticIcon(BeatmapStatisticsIconType iconType)
+        {
+            this.iconType = iconType;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(TextureStore textures)
+        {
+            Texture = textures.Get($"Icons/BeatmapDetails/{iconType.ToString().Kebaberize()}");
+        }
+    }
+
+    public enum BeatmapStatisticsIconType
+    {
+        Accuracy,
+        ApproachRate,
+        Bpm,
+        Circles,
+        HpDrain,
+        Length,
+        OverallDifficulty,
+        Size,
+        Sliders,
+        Spinners,
+    }
+}

osu.Game/Beatmaps/Formats/IHasCustomColours.cs

@@ -8,6 +8,6 @@ namespace osu.Game.Beatmaps.Formats
 {
     public interface IHasCustomColours
     {
-        Dictionary<string, Color4> CustomColours { get; set; }
+        Dictionary<string, Color4> CustomColours { get; }
     }
 }

osu.Game/Beatmaps/Formats/LegacyBeatmapEncoder.cs

@@ -7,13 +7,16 @@ using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Text;
+using JetBrains.Annotations;
 using osu.Game.Audio;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Beatmaps.Legacy;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Legacy;
 using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Skinning;
 using osuTK;
+using osuTK.Graphics;
 
 namespace osu.Game.Beatmaps.Formats
 {
@@ -23,9 +26,18 @@ namespace osu.Game.Beatmaps.Formats
 
         private readonly IBeatmap beatmap;
 
-        public LegacyBeatmapEncoder(IBeatmap beatmap)
+        [CanBeNull]
+        private readonly ISkin skin;
+
+        /// <summary>
+        /// Creates a new <see cref="LegacyBeatmapEncoder"/>.
+        /// </summary>
+        /// <param name="beatmap">The beatmap to encode.</param>
+        /// <param name="skin">The beatmap's skin, used for encoding combo colours.</param>
+        public LegacyBeatmapEncoder(IBeatmap beatmap, [CanBeNull] ISkin skin)
         {
             this.beatmap = beatmap;
+            this.skin = skin;
 
             if (beatmap.BeatmapInfo.RulesetID < 0 || beatmap.BeatmapInfo.RulesetID > 3)
                 throw new ArgumentException("Only beatmaps in the osu, taiko, catch, or mania rulesets can be encoded to the legacy beatmap format.", nameof(beatmap));
@@ -53,6 +65,9 @@ namespace osu.Game.Beatmaps.Formats
             writer.WriteLine();
             handleControlPoints(writer);
 
+            writer.WriteLine();
+            handleColours(writer);
+
             writer.WriteLine();
             handleHitObjects(writer);
         }
@@ -196,6 +211,28 @@ namespace osu.Game.Beatmaps.Formats
             }
         }
 
+        private void handleColours(TextWriter writer)
+        {
+            var colours = skin?.GetConfig<GlobalSkinColours, IReadOnlyList<Color4>>(GlobalSkinColours.ComboColours)?.Value;
+
+            if (colours == null || colours.Count == 0)
+                return;
+
+            writer.WriteLine("[Colours]");
+
+            for (var i = 0; i < colours.Count; i++)
+            {
+                var comboColour = colours[i];
+
+                writer.Write(FormattableString.Invariant($"Combo{i}: "));
+                writer.Write(FormattableString.Invariant($"{(byte)(comboColour.R * byte.MaxValue)},"));
+                writer.Write(FormattableString.Invariant($"{(byte)(comboColour.G * byte.MaxValue)},"));
+                writer.Write(FormattableString.Invariant($"{(byte)(comboColour.B * byte.MaxValue)},"));
+                writer.Write(FormattableString.Invariant($"{(byte)(comboColour.A * byte.MaxValue)}"));
+                writer.WriteLine();
+            }
+        }
+
         private void handleHitObjects(TextWriter writer)
         {
             if (beatmap.HitObjects.Count == 0)

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -13,6 +13,7 @@ using osu.Framework.Audio.Track;
 using osu.Framework.Graphics.Textures;
 using osu.Framework.Logging;
 using osu.Framework.Statistics;
+using osu.Framework.Testing;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects.Types;
@@ -22,6 +23,7 @@ using osu.Game.Storyboards;
 
 namespace osu.Game.Beatmaps
 {
+    [ExcludeFromDynamicCompile]
     public abstract class WorkingBeatmap : IWorkingBeatmap
     {
         public readonly BeatmapInfo BeatmapInfo;
@@ -53,7 +55,7 @@ namespace osu.Game.Beatmaps
         {
             const double excess_length = 1000;
 
-            var lastObject = Beatmap.HitObjects.LastOrDefault();
+            var lastObject = Beatmap?.HitObjects.LastOrDefault();
 
             double length;
 

osu.Game/Collections/BeatmapCollection.cs

@@ -0,0 +1,47 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Bindables;
+using osu.Game.Beatmaps;
+
+namespace osu.Game.Collections
+{
+    /// <summary>
+    /// A collection of beatmaps grouped by a name.
+    /// </summary>
+    public class BeatmapCollection
+    {
+        /// <summary>
+        /// Invoked whenever any change occurs on this <see cref="BeatmapCollection"/>.
+        /// </summary>
+        public event Action Changed;
+
+        /// <summary>
+        /// The collection's name.
+        /// </summary>
+        public readonly Bindable<string> Name = new Bindable<string>();
+
+        /// <summary>
+        /// The beatmaps contained by the collection.
+        /// </summary>
+        public readonly BindableList<BeatmapInfo> Beatmaps = new BindableList<BeatmapInfo>();
+
+        /// <summary>
+        /// The date when this collection was last modified.
+        /// </summary>
+        public DateTimeOffset LastModifyDate { get; private set; } = DateTimeOffset.UtcNow;
+
+        public BeatmapCollection()
+        {
+            Beatmaps.CollectionChanged += (_, __) => onChange();
+            Name.ValueChanged += _ => onChange();
+        }
+
+        private void onChange()
+        {
+            LastModifyDate = DateTimeOffset.Now;
+            Changed?.Invoke();
+        }
+    }
+}

osu.Game/Collections/CollectionManager.cs

@@ -0,0 +1,303 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Specialized;
+using System.IO;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using osu.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Logging;
+using osu.Framework.Platform;
+using osu.Game.Beatmaps;
+using osu.Game.IO.Legacy;
+using osu.Game.Overlays.Notifications;
+
+namespace osu.Game.Collections
+{
+    /// <summary>
+    /// Handles user-defined collections of beatmaps.
+    /// </summary>
+    /// <remarks>
+    /// This is currently reading and writing from the osu-stable file format. This is a temporary arrangement until we refactor the
+    /// database backing the game. Going forward writing should be done in a similar way to other model stores.
+    /// </remarks>
+    public class CollectionManager : Component
+    {
+        /// <summary>
+        /// Database version in stable-compatible YYYYMMDD format.
+        /// </summary>
+        private const int database_version = 30000000;
+
+        private const string database_name = "collection.db";
+
+        public readonly BindableList<BeatmapCollection> Collections = new BindableList<BeatmapCollection>();
+
+        public bool SupportsImportFromStable => RuntimeInfo.IsDesktop;
+
+        [Resolved]
+        private GameHost host { get; set; }
+
+        [Resolved]
+        private BeatmapManager beatmaps { get; set; }
+
+        private readonly Storage storage;
+
+        public CollectionManager(Storage storage)
+        {
+            this.storage = storage;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Collections.CollectionChanged += collectionsChanged;
+
+            if (storage.Exists(database_name))
+            {
+                using (var stream = storage.GetStream(database_name))
+                    importCollections(readCollections(stream));
+            }
+        }
+
+        private void collectionsChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            switch (e.Action)
+            {
+                case NotifyCollectionChangedAction.Add:
+                    foreach (var c in e.NewItems.Cast<BeatmapCollection>())
+                        c.Changed += backgroundSave;
+                    break;
+
+                case NotifyCollectionChangedAction.Remove:
+                    foreach (var c in e.OldItems.Cast<BeatmapCollection>())
+                        c.Changed -= backgroundSave;
+                    break;
+
+                case NotifyCollectionChangedAction.Replace:
+                    foreach (var c in e.OldItems.Cast<BeatmapCollection>())
+                        c.Changed -= backgroundSave;
+
+                    foreach (var c in e.NewItems.Cast<BeatmapCollection>())
+                        c.Changed += backgroundSave;
+                    break;
+            }
+
+            backgroundSave();
+        }
+
+        /// <summary>
+        /// Set an endpoint for notifications to be posted to.
+        /// </summary>
+        public Action<Notification> PostNotification { protected get; set; }
+
+        /// <summary>
+        /// Set a storage with access to an osu-stable install for import purposes.
+        /// </summary>
+        public Func<Storage> GetStableStorage { private get; set; }
+
+        /// <summary>
+        /// This is a temporary method and will likely be replaced by a full-fledged (and more correctly placed) migration process in the future.
+        /// </summary>
+        public Task ImportFromStableAsync()
+        {
+            var stable = GetStableStorage?.Invoke();
+
+            if (stable == null)
+            {
+                Logger.Log("No osu!stable installation available!", LoggingTarget.Information, LogLevel.Error);
+                return Task.CompletedTask;
+            }
+
+            if (!stable.Exists(database_name))
+            {
+                // This handles situations like when the user does not have a collections.db file
+                Logger.Log($"No {database_name} available in osu!stable installation", LoggingTarget.Information, LogLevel.Error);
+                return Task.CompletedTask;
+            }
+
+            return Task.Run(async () =>
+            {
+                using (var stream = stable.GetStream(database_name))
+                    await Import(stream);
+            });
+        }
+
+        public async Task Import(Stream stream)
+        {
+            var notification = new ProgressNotification
+            {
+                State = ProgressNotificationState.Active,
+                Text = "Collections import is initialising..."
+            };
+
+            PostNotification?.Invoke(notification);
+
+            var collection = readCollections(stream, notification);
+            bool importCompleted = false;
+
+            Schedule(() =>
+            {
+                importCollections(collection);
+                importCompleted = true;
+            });
+
+            while (!IsDisposed && !importCompleted)
+                await Task.Delay(10);
+
+            notification.CompletionText = $"Imported {collection.Count} collections";
+            notification.State = ProgressNotificationState.Completed;
+        }
+
+        private void importCollections(List<BeatmapCollection> newCollections)
+        {
+            foreach (var newCol in newCollections)
+            {
+                var existing = Collections.FirstOrDefault(c => c.Name == newCol.Name);
+                if (existing == null)
+                    Collections.Add(existing = new BeatmapCollection { Name = { Value = newCol.Name.Value } });
+
+                foreach (var newBeatmap in newCol.Beatmaps)
+                {
+                    if (!existing.Beatmaps.Contains(newBeatmap))
+                        existing.Beatmaps.Add(newBeatmap);
+                }
+            }
+        }
+
+        private List<BeatmapCollection> readCollections(Stream stream, ProgressNotification notification = null)
+        {
+            if (notification != null)
+            {
+                notification.Text = "Reading collections...";
+                notification.Progress = 0;
+            }
+
+            var result = new List<BeatmapCollection>();
+
+            try
+            {
+                using (var sr = new SerializationReader(stream))
+                {
+                    sr.ReadInt32(); // Version
+
+                    int collectionCount = sr.ReadInt32();
+                    result.Capacity = collectionCount;
+
+                    for (int i = 0; i < collectionCount; i++)
+                    {
+                        if (notification?.CancellationToken.IsCancellationRequested == true)
+                            return result;
+
+                        var collection = new BeatmapCollection { Name = { Value = sr.ReadString() } };
+                        int mapCount = sr.ReadInt32();
+
+                        for (int j = 0; j < mapCount; j++)
+                        {
+                            if (notification?.CancellationToken.IsCancellationRequested == true)
+                                return result;
+
+                            string checksum = sr.ReadString();
+
+                            var beatmap = beatmaps.QueryBeatmap(b => b.MD5Hash == checksum);
+                            if (beatmap != null)
+                                collection.Beatmaps.Add(beatmap);
+                        }
+
+                        if (notification != null)
+                        {
+                            notification.Text = $"Imported {i + 1} of {collectionCount} collections";
+                            notification.Progress = (float)(i + 1) / collectionCount;
+                        }
+
+                        result.Add(collection);
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                Logger.Error(e, "Failed to read collection database.");
+            }
+
+            return result;
+        }
+
+        public void DeleteAll()
+        {
+            Collections.Clear();
+            PostNotification?.Invoke(new SimpleNotification { Text = "Deleted all collections!" });
+        }
+
+        private readonly object saveLock = new object();
+        private int lastSave;
+        private int saveFailures;
+
+        /// <summary>
+        /// Perform a save with debounce.
+        /// </summary>
+        private void backgroundSave()
+        {
+            var current = Interlocked.Increment(ref lastSave);
+            Task.Delay(100).ContinueWith(task =>
+            {
+                if (current != lastSave)
+                    return;
+
+                if (!save())
+                    backgroundSave();
+            });
+        }
+
+        private bool save()
+        {
+            lock (saveLock)
+            {
+                Interlocked.Increment(ref lastSave);
+
+                try
+                {
+                    // This is NOT thread-safe!!
+
+                    using (var sw = new SerializationWriter(storage.GetStream(database_name, FileAccess.Write)))
+                    {
+                        sw.Write(database_version);
+                        sw.Write(Collections.Count);
+
+                        foreach (var c in Collections)
+                        {
+                            sw.Write(c.Name.Value);
+                            sw.Write(c.Beatmaps.Count);
+
+                            foreach (var b in c.Beatmaps)
+                                sw.Write(b.MD5Hash);
+                        }
+                    }
+
+                    if (saveFailures < 10)
+                        saveFailures = 0;
+                    return true;
+                }
+                catch (Exception e)
+                {
+                    // Since this code is not thread-safe, we may run into random exceptions (such as collection enumeration or out of range indexing).
+                    // Failures are thus only alerted if they exceed a threshold (once) to indicate "actual" errors having occurred.
+                    if (++saveFailures == 10)
+                        Logger.Error(e, "Failed to save collection database!");
+                }
+
+                return false;
+            }
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            save();
+        }
+    }
+}

osu.Game/Collections/DeleteCollectionDialog.cs

@@ -0,0 +1,34 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using Humanizer;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Overlays.Dialog;
+
+namespace osu.Game.Collections
+{
+    public class DeleteCollectionDialog : PopupDialog
+    {
+        public DeleteCollectionDialog(BeatmapCollection collection, Action deleteAction)
+        {
+            HeaderText = "Confirm deletion of";
+            BodyText = $"{collection.Name.Value} ({"beatmap".ToQuantity(collection.Beatmaps.Count)})";
+
+            Icon = FontAwesome.Regular.TrashAlt;
+
+            Buttons = new PopupDialogButton[]
+            {
+                new PopupDialogOkButton
+                {
+                    Text = @"Yes. Go for it.",
+                    Action = deleteAction
+                },
+                new PopupDialogCancelButton
+                {
+                    Text = @"No! Abort mission!",
+                },
+            };
+        }
+    }
+}

osu.Game/Collections/DrawableCollectionList.cs

@@ -0,0 +1,122 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Graphics.Containers;
+using osuTK;
+
+namespace osu.Game.Collections
+{
+    /// <summary>
+    /// Visualises a list of <see cref="BeatmapCollection"/>s.
+    /// </summary>
+    public class DrawableCollectionList : OsuRearrangeableListContainer<BeatmapCollection>
+    {
+        private Scroll scroll;
+
+        protected override ScrollContainer<Drawable> CreateScrollContainer() => scroll = new Scroll();
+
+        protected override FillFlowContainer<RearrangeableListItem<BeatmapCollection>> CreateListFillFlowContainer() => new Flow
+        {
+            DragActive = { BindTarget = DragActive }
+        };
+
+        protected override OsuRearrangeableListItem<BeatmapCollection> CreateOsuDrawable(BeatmapCollection item)
+        {
+            if (item == scroll.PlaceholderItem.Model)
+                return scroll.ReplacePlaceholder();
+
+            return new DrawableCollectionListItem(item, true);
+        }
+
+        /// <summary>
+        /// The scroll container for this <see cref="DrawableCollectionList"/>.
+        /// Contains the main flow of <see cref="DrawableCollectionListItem"/> and attaches a placeholder item to the end of the list.
+        /// </summary>
+        /// <remarks>
+        /// Use <see cref="ReplacePlaceholder"/> to transfer the placeholder into the main list.
+        /// </remarks>
+        private class Scroll : OsuScrollContainer
+        {
+            /// <summary>
+            /// The currently-displayed placeholder item.
+            /// </summary>
+            public DrawableCollectionListItem PlaceholderItem { get; private set; }
+
+            protected override Container<Drawable> Content => content;
+            private readonly Container content;
+
+            private readonly Container<DrawableCollectionListItem> placeholderContainer;
+
+            public Scroll()
+            {
+                ScrollbarVisible = false;
+                Padding = new MarginPadding(10);
+
+                base.Content.Add(new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    LayoutDuration = 200,
+                    LayoutEasing = Easing.OutQuint,
+                    Children = new Drawable[]
+                    {
+                        content = new Container { RelativeSizeAxes = Axes.X },
+                        placeholderContainer = new Container<DrawableCollectionListItem>
+                        {
+                            RelativeSizeAxes = Axes.X,
+                            AutoSizeAxes = Axes.Y
+                        }
+                    }
+                });
+
+                ReplacePlaceholder();
+            }
+
+            protected override void Update()
+            {
+                base.Update();
+
+                // AutoSizeAxes cannot be used as the height should represent the post-layout-transform height at all times, so that the placeholder doesn't bounce around.
+                content.Height = ((Flow)Child).Children.Sum(c => c.DrawHeight + 5);
+            }
+
+            /// <summary>
+            /// Replaces the current <see cref="PlaceholderItem"/> with a new one, and returns the previous.
+            /// </summary>
+            /// <returns>The current <see cref="PlaceholderItem"/>.</returns>
+            public DrawableCollectionListItem ReplacePlaceholder()
+            {
+                var previous = PlaceholderItem;
+
+                placeholderContainer.Clear(false);
+                placeholderContainer.Add(PlaceholderItem = new DrawableCollectionListItem(new BeatmapCollection(), false));
+
+                return previous;
+            }
+        }
+
+        /// <summary>
+        /// The flow of <see cref="DrawableCollectionListItem"/>. Disables layout easing unless a drag is in progress.
+        /// </summary>
+        private class Flow : FillFlowContainer<RearrangeableListItem<BeatmapCollection>>
+        {
+            public readonly IBindable<bool> DragActive = new Bindable<bool>();
+
+            public Flow()
+            {
+                Spacing = new Vector2(0, 5);
+                LayoutEasing = Easing.OutQuint;
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+                DragActive.BindValueChanged(active => LayoutDuration = active.NewValue ? 200 : 0);
+            }
+        }
+    }
+}

osu.Game/Collections/DrawableCollectionListItem.cs

@@ -0,0 +1,237 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Extensions.Color4Extensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Overlays;
+using osuTK;
+using osuTK.Graphics;
+
+namespace osu.Game.Collections
+{
+    /// <summary>
+    /// Visualises a <see cref="BeatmapCollection"/> inside a <see cref="DrawableCollectionList"/>.
+    /// </summary>
+    public class DrawableCollectionListItem : OsuRearrangeableListItem<BeatmapCollection>
+    {
+        private const float item_height = 35;
+        private const float button_width = item_height * 0.75f;
+
+        /// <summary>
+        /// Whether the <see cref="BeatmapCollection"/> currently exists inside the <see cref="CollectionManager"/>.
+        /// </summary>
+        public IBindable<bool> IsCreated => isCreated;
+
+        private readonly Bindable<bool> isCreated = new Bindable<bool>();
+
+        /// <summary>
+        /// Creates a new <see cref="DrawableCollectionListItem"/>.
+        /// </summary>
+        /// <param name="item">The <see cref="BeatmapCollection"/>.</param>
+        /// <param name="isCreated">Whether <paramref name="item"/> currently exists inside the <see cref="CollectionManager"/>.</param>
+        public DrawableCollectionListItem(BeatmapCollection item, bool isCreated)
+            : base(item)
+        {
+            this.isCreated.Value = isCreated;
+
+            ShowDragHandle.BindTo(this.isCreated);
+        }
+
+        protected override Drawable CreateContent() => new ItemContent(Model)
+        {
+            IsCreated = { BindTarget = isCreated }
+        };
+
+        /// <summary>
+        /// The main content of the <see cref="DrawableCollectionListItem"/>.
+        /// </summary>
+        private class ItemContent : CircularContainer
+        {
+            public readonly Bindable<bool> IsCreated = new Bindable<bool>();
+
+            private readonly IBindable<string> collectionName;
+            private readonly BeatmapCollection collection;
+
+            [Resolved(CanBeNull = true)]
+            private CollectionManager collectionManager { get; set; }
+
+            private Container textBoxPaddingContainer;
+            private ItemTextBox textBox;
+
+            public ItemContent(BeatmapCollection collection)
+            {
+                this.collection = collection;
+
+                RelativeSizeAxes = Axes.X;
+                Height = item_height;
+                Masking = true;
+
+                collectionName = collection.Name.GetBoundCopy();
+            }
+
+            [BackgroundDependencyLoader]
+            private void load(OsuColour colours)
+            {
+                Children = new Drawable[]
+                {
+                    new DeleteButton(collection)
+                    {
+                        Anchor = Anchor.CentreRight,
+                        Origin = Anchor.CentreRight,
+                        IsCreated = { BindTarget = IsCreated },
+                        IsTextBoxHovered = v => textBox.ReceivePositionalInputAt(v)
+                    },
+                    textBoxPaddingContainer = new Container
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Padding = new MarginPadding { Right = button_width },
+                        Children = new Drawable[]
+                        {
+                            textBox = new ItemTextBox
+                            {
+                                RelativeSizeAxes = Axes.Both,
+                                Size = Vector2.One,
+                                CornerRadius = item_height / 2,
+                                Current = collection.Name,
+                                PlaceholderText = IsCreated.Value ? string.Empty : "Create a new collection"
+                            },
+                        }
+                    },
+                };
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+
+                collectionName.BindValueChanged(_ => createNewCollection(), true);
+                IsCreated.BindValueChanged(created => textBoxPaddingContainer.Padding = new MarginPadding { Right = created.NewValue ? button_width : 0 }, true);
+            }
+
+            private void createNewCollection()
+            {
+                if (IsCreated.Value)
+                    return;
+
+                if (string.IsNullOrEmpty(collectionName.Value))
+                    return;
+
+                // Add the new collection and disable our placeholder. If all text is removed, the placeholder should not show back again.
+                collectionManager?.Collections.Add(collection);
+                textBox.PlaceholderText = string.Empty;
+
+                // When this item changes from placeholder to non-placeholder (via changing containers), its textbox will lose focus, so it needs to be re-focused.
+                Schedule(() => GetContainingInputManager().ChangeFocus(textBox));
+
+                IsCreated.Value = true;
+            }
+        }
+
+        private class ItemTextBox : OsuTextBox
+        {
+            protected override float LeftRightPadding => item_height / 2;
+
+            [BackgroundDependencyLoader]
+            private void load(OsuColour colours)
+            {
+                BackgroundUnfocused = colours.GreySeafoamDarker.Darken(0.5f);
+                BackgroundFocused = colours.GreySeafoam;
+            }
+        }
+
+        public class DeleteButton : CompositeDrawable
+        {
+            public readonly IBindable<bool> IsCreated = new Bindable<bool>();
+
+            public Func<Vector2, bool> IsTextBoxHovered;
+
+            [Resolved(CanBeNull = true)]
+            private DialogOverlay dialogOverlay { get; set; }
+
+            [Resolved(CanBeNull = true)]
+            private CollectionManager collectionManager { get; set; }
+
+            private readonly BeatmapCollection collection;
+
+            private Drawable fadeContainer;
+            private Drawable background;
+
+            public DeleteButton(BeatmapCollection collection)
+            {
+                this.collection = collection;
+                RelativeSizeAxes = Axes.Y;
+
+                Width = button_width + item_height / 2; // add corner radius to cover with fill
+            }
+
+            [BackgroundDependencyLoader]
+            private void load(OsuColour colours)
+            {
+                InternalChild = fadeContainer = new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Alpha = 0.1f,
+                    Children = new[]
+                    {
+                        background = new Box
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Colour = colours.Red
+                        },
+                        new SpriteIcon
+                        {
+                            Anchor = Anchor.CentreRight,
+                            Origin = Anchor.Centre,
+                            X = -button_width * 0.6f,
+                            Size = new Vector2(10),
+                            Icon = FontAwesome.Solid.Trash
+                        }
+                    }
+                };
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+                IsCreated.BindValueChanged(created => Alpha = created.NewValue ? 1 : 0, true);
+            }
+
+            public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => base.ReceivePositionalInputAt(screenSpacePos) && !IsTextBoxHovered(screenSpacePos);
+
+            protected override bool OnHover(HoverEvent e)
+            {
+                fadeContainer.FadeTo(1f, 100, Easing.Out);
+                return false;
+            }
+
+            protected override void OnHoverLost(HoverLostEvent e)
+            {
+                fadeContainer.FadeTo(0.1f, 100);
+            }
+
+            protected override bool OnClick(ClickEvent e)
+            {
+                background.FlashColour(Color4.White, 150);
+
+                if (collection.Beatmaps.Count == 0)
+                    deleteCollection();
+                else
+                    dialogOverlay?.Push(new DeleteCollectionDialog(collection, deleteCollection));
+
+                return true;
+            }
+
+            private void deleteCollection() => collectionManager?.Collections.Remove(collection);
+        }
+    }
+}

osu.Game/Collections/ManageCollectionsDialog.cs

@@ -0,0 +1,134 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Graphics.UserInterface;
+using osuTK;
+
+namespace osu.Game.Collections
+{
+    public class ManageCollectionsDialog : OsuFocusedOverlayContainer
+    {
+        private const double enter_duration = 500;
+        private const double exit_duration = 200;
+
+        [Resolved(CanBeNull = true)]
+        private CollectionManager collectionManager { get; set; }
+
+        public ManageCollectionsDialog()
+        {
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
+            RelativeSizeAxes = Axes.Both;
+            Size = new Vector2(0.5f, 0.8f);
+
+            Masking = true;
+            CornerRadius = 10;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(OsuColour colours)
+        {
+            Children = new Drawable[]
+            {
+                new Box
+                {
+                    Colour = colours.GreySeafoamDark,
+                    RelativeSizeAxes = Axes.Both,
+                },
+                new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Child = new GridContainer
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        RowDimensions = new[]
+                        {
+                            new Dimension(GridSizeMode.AutoSize),
+                        },
+                        Content = new[]
+                        {
+                            new Drawable[]
+                            {
+                                new Container
+                                {
+                                    RelativeSizeAxes = Axes.X,
+                                    AutoSizeAxes = Axes.Y,
+                                    Children = new Drawable[]
+                                    {
+                                        new OsuSpriteText
+                                        {
+                                            Anchor = Anchor.Centre,
+                                            Origin = Anchor.Centre,
+                                            Text = "Manage collections",
+                                            Font = OsuFont.GetFont(size: 30),
+                                            Padding = new MarginPadding { Vertical = 10 },
+                                        },
+                                        new IconButton
+                                        {
+                                            Anchor = Anchor.CentreRight,
+                                            Origin = Anchor.CentreRight,
+                                            Icon = FontAwesome.Solid.Times,
+                                            Colour = colours.GreySeafoamDarker,
+                                            Scale = new Vector2(0.8f),
+                                            X = -10,
+                                            Action = () => State.Value = Visibility.Hidden
+                                        }
+                                    }
+                                }
+                            },
+                            new Drawable[]
+                            {
+                                new Container
+                                {
+                                    RelativeSizeAxes = Axes.Both,
+                                    Children = new Drawable[]
+                                    {
+                                        new Box
+                                        {
+                                            RelativeSizeAxes = Axes.Both,
+                                            Colour = colours.GreySeafoamDarker
+                                        },
+                                        new DrawableCollectionList
+                                        {
+                                            RelativeSizeAxes = Axes.Both,
+                                            Items = { BindTarget = collectionManager?.Collections ?? new BindableList<BeatmapCollection>() }
+                                        }
+                                    }
+                                }
+                            },
+                        }
+                    }
+                }
+            };
+        }
+
+        protected override void PopIn()
+        {
+            base.PopIn();
+
+            this.FadeIn(enter_duration, Easing.OutQuint);
+            this.ScaleTo(0.9f).Then().ScaleTo(1f, enter_duration, Easing.OutQuint);
+        }
+
+        protected override void PopOut()
+        {
+            base.PopOut();
+
+            this.FadeOut(exit_duration, Easing.OutQuint);
+            this.ScaleTo(0.9f, exit_duration);
+
+            // Ensure that textboxes commit
+            GetContainingInputManager()?.TriggerFocusContention(this);
+        }
+    }
+}

osu.Game/Configuration/OsuConfigManager.cs

@@ -6,6 +6,7 @@ using osu.Framework.Configuration;
 using osu.Framework.Configuration.Tracking;
 using osu.Framework.Extensions;
 using osu.Framework.Platform;
+using osu.Framework.Testing;
 using osu.Game.Overlays;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Screens.Select;
@@ -13,6 +14,7 @@ using osu.Game.Screens.Select.Filter;
 
 namespace osu.Game.Configuration
 {
+    [ExcludeFromDynamicCompile]
     public class OsuConfigManager : IniConfigManager<OsuSetting>
     {
         protected override void InitialiseDefaults()
@@ -231,6 +233,6 @@ namespace osu.Game.Configuration
         UIHoldActivationDelay,
         HitLighting,
         MenuBackgroundSource,
-        GameplayDisableWinKey
+        GameplayDisableWinKey,
     }
 }

osu.Game/Database/ArchiveModelManager.cs

@@ -397,15 +397,24 @@ namespace osu.Game.Database
             }
         }
 
+        /// <summary>
+        /// Update an existing file, or create a new entry if not already part of the <paramref name="model"/>'s files.
+        /// </summary>
+        /// <param name="model">The item to operate on.</param>
+        /// <param name="file">The file model to be updated or added.</param>
+        /// <param name="contents">The new file contents.</param>
         public void UpdateFile(TModel model, TFileModel file, Stream contents)
         {
             using (var usage = ContextFactory.GetForWrite())
             {
                 // Dereference the existing file info, since the file model will be removed.
-                Files.Dereference(file.FileInfo);
+                if (file.FileInfo != null)
+                {
+                    Files.Dereference(file.FileInfo);
 
-                // Remove the file model.
-                usage.Context.Set<TFileModel>().Remove(file);
+                    // Remove the file model.
+                    usage.Context.Set<TFileModel>().Remove(file);
+                }
 
                 // Add the new file info and containing file model.
                 model.Files.Remove(file);

osu.Game/Graphics/Containers/OsuFocusedOverlayContainer.cs

@@ -103,6 +103,8 @@ namespace osu.Game.Graphics.Containers
         {
         }
 
+        private bool playedPopInSound;
+
         protected override void UpdateState(ValueChangedEvent<Visibility> state)
         {
             switch (state.NewValue)
@@ -110,16 +112,24 @@ namespace osu.Game.Graphics.Containers
                 case Visibility.Visible:
                     if (OverlayActivationMode.Value == OverlayActivation.Disabled)
                     {
+                        // todo: visual/audible feedback that this operation could not complete.
                         State.Value = Visibility.Hidden;
                         return;
                     }
 
                     samplePopIn?.Play();
+                    playedPopInSound = true;
+
                     if (BlockScreenWideMouse && DimMainContent) game?.AddBlockingOverlay(this);
                     break;
 
                 case Visibility.Hidden:
-                    samplePopOut?.Play();
+                    if (playedPopInSound)
+                    {
+                        samplePopOut?.Play();
+                        playedPopInSound = false;
+                    }
+
                     if (BlockScreenWideMouse) game?.RemoveBlockingOverlay(this);
                     break;
             }

osu.Game/Graphics/Containers/OsuRearrangeableListContainer.cs

@@ -12,13 +12,13 @@ namespace osu.Game.Graphics.Containers
         /// <summary>
         /// Whether any item is currently being dragged. Used to hide other items' drag handles.
         /// </summary>
-        private readonly BindableBool playlistDragActive = new BindableBool();
+        protected readonly BindableBool DragActive = new BindableBool();
 
         protected override ScrollContainer<Drawable> CreateScrollContainer() => new OsuScrollContainer();
 
         protected sealed override RearrangeableListItem<TModel> CreateDrawable(TModel item) => CreateOsuDrawable(item).With(d =>
         {
-            d.PlaylistDragActive.BindTo(playlistDragActive);
+            d.DragActive.BindTo(DragActive);
         });
 
         protected abstract OsuRearrangeableListItem<TModel> CreateOsuDrawable(TModel item);

osu.Game/Graphics/Containers/OsuRearrangeableListItem.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Graphics.Containers
         /// <summary>
         /// Whether any item is currently being dragged. Used to hide other items' drag handles.
         /// </summary>
-        public readonly BindableBool PlaylistDragActive = new BindableBool();
+        public readonly BindableBool DragActive = new BindableBool();
 
         private Color4 handleColour = Color4.White;
 
@@ -44,8 +44,9 @@ namespace osu.Game.Graphics.Containers
         /// <summary>
         /// Whether the drag handle should be shown.
         /// </summary>
-        protected virtual bool ShowDragHandle => true;
+        protected readonly Bindable<bool> ShowDragHandle = new Bindable<bool>();
 
+        private Container handleContainer;
         private PlaylistItemHandle handle;
 
         protected OsuRearrangeableListItem(TModel item)
@@ -58,8 +59,6 @@ namespace osu.Game.Graphics.Containers
         [BackgroundDependencyLoader]
         private void load()
         {
-            Container handleContainer;
-
             InternalChild = new GridContainer
             {
                 RelativeSizeAxes = Axes.X,
@@ -88,9 +87,12 @@ namespace osu.Game.Graphics.Containers
                 ColumnDimensions = new[] { new Dimension(GridSizeMode.AutoSize) },
                 RowDimensions = new[] { new Dimension(GridSizeMode.AutoSize) }
             };
+        }
 
-            if (!ShowDragHandle)
-                handleContainer.Alpha = 0;
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            ShowDragHandle.BindValueChanged(show => handleContainer.Alpha = show.NewValue ? 1 : 0, true);
         }
 
         protected override bool OnDragStart(DragStartEvent e)
@@ -98,13 +100,13 @@ namespace osu.Game.Graphics.Containers
             if (!base.OnDragStart(e))
                 return false;
 
-            PlaylistDragActive.Value = true;
+            DragActive.Value = true;
             return true;
         }
 
         protected override void OnDragEnd(DragEndEvent e)
         {
-            PlaylistDragActive.Value = false;
+            DragActive.Value = false;
             base.OnDragEnd(e);
         }
 
@@ -112,7 +114,7 @@ namespace osu.Game.Graphics.Containers
 
         protected override bool OnHover(HoverEvent e)
         {
-            handle.UpdateHoverState(IsDragged || !PlaylistDragActive.Value);
+            handle.UpdateHoverState(IsDragged || !DragActive.Value);
             return base.OnHover(e);
         }
 

osu.Game/Graphics/Cursor/MenuCursorContainer.cs

@@ -5,6 +5,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Cursor;
 using osu.Framework.Input;
+using osu.Framework.Input.StateChanges;
 
 namespace osu.Game.Graphics.Cursor
 {
@@ -47,7 +48,10 @@ namespace osu.Game.Graphics.Cursor
         {
             base.Update();
 
-            if (!CanShowCursor)
+            var lastMouseSource = inputManager.CurrentState.Mouse.LastSource;
+            bool hasValidInput = lastMouseSource != null && !(lastMouseSource is ISourcedFromTouch);
+
+            if (!hasValidInput || !CanShowCursor)
             {
                 currentTarget?.Cursor?.Hide();
                 currentTarget = null;

osu.Game/Graphics/Sprites/GlowingSpriteText.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Colour;
 using osu.Framework.Graphics.Containers;
@@ -55,6 +56,12 @@ namespace osu.Game.Graphics.Sprites
             set => spriteText.UseFullGlyphHeight = blurredText.UseFullGlyphHeight = value;
         }
 
+        public Bindable<string> Current
+        {
+            get => spriteText.Current;
+            set => spriteText.Current = value;
+        }
+
         public GlowingSpriteText()
         {
             AutoSizeAxes = Axes.Both;

osu.Game/Graphics/UserInterface/IconButton.cs

@@ -24,7 +24,7 @@ namespace osu.Game.Graphics.UserInterface
             set
             {
                 iconColour = value;
-                icon.Colour = value;
+                icon.FadeColour(value);
             }
         }
 

osu.Game/Graphics/UserInterface/OsuContextMenu.cs

@@ -26,6 +26,8 @@ namespace osu.Game.Graphics.UserInterface
             };
 
             ItemsContainer.Padding = new MarginPadding { Vertical = DrawableOsuMenuItem.MARGIN_VERTICAL };
+
+            MaxHeight = 250;
         }
 
         [BackgroundDependencyLoader]

osu.Game/Graphics/UserInterface/OsuDropdown.cs

@@ -17,6 +17,8 @@ namespace osu.Game.Graphics.UserInterface
 {
     public class OsuDropdown<T> : Dropdown<T>, IHasAccentColour
     {
+        private const float corner_radius = 4;
+
         private Color4 accentColour;
 
         public Color4 AccentColour
@@ -57,9 +59,11 @@ namespace osu.Game.Graphics.UserInterface
             // todo: this uses the same styling as OsuMenu. hopefully we can just use OsuMenu in the future with some refactoring
             public OsuDropdownMenu()
             {
-                CornerRadius = 4;
+                CornerRadius = corner_radius;
                 BackgroundColour = Color4.Black.Opacity(0.5f);
 
+                MaskingContainer.CornerRadius = corner_radius;
+
                 // todo: this uses the same styling as OsuMenu. hopefully we can just use OsuMenu in the future with some refactoring
                 ItemsContainer.Padding = new MarginPadding(5);
             }
@@ -138,7 +142,7 @@ namespace osu.Game.Graphics.UserInterface
                     Foreground.Padding = new MarginPadding(2);
 
                     Masking = true;
-                    CornerRadius = 6;
+                    CornerRadius = corner_radius;
                 }
 
                 [BackgroundDependencyLoader]
@@ -237,7 +241,7 @@ namespace osu.Game.Graphics.UserInterface
 
                 AutoSizeAxes = Axes.None;
                 Margin = new MarginPadding { Bottom = 4 };
-                CornerRadius = 4;
+                CornerRadius = corner_radius;
                 Height = 40;
 
                 Foreground.Children = new Drawable[]

osu.Game/Graphics/UserInterface/RollingCounter.cs

@@ -9,16 +9,20 @@ using System;
 using System.Collections.Generic;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Graphics.UserInterface;
 
 namespace osu.Game.Graphics.UserInterface
 {
-    public abstract class RollingCounter<T> : Container
+    public abstract class RollingCounter<T> : Container, IHasCurrentValue<T>
         where T : struct, IEquatable<T>
     {
-        /// <summary>
-        /// The current value.
-        /// </summary>
-        public Bindable<T> Current = new Bindable<T>();
+        private readonly BindableWithCurrent<T> current = new BindableWithCurrent<T>();
+
+        public Bindable<T> Current
+        {
+            get => current.Current;
+            set => current.Current = value;
+        }
 
         private SpriteText displayedCountSpriteText;
 

osu.Game/Graphics/UserInterfaceV2/LabelledTextBox.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.UserInterface;
 using osu.Game.Graphics.UserInterface;
 
@@ -32,6 +33,11 @@ namespace osu.Game.Graphics.UserInterfaceV2
             set => Component.Text = value;
         }
 
+        public Container TabbableContentContainer
+        {
+            set => Component.TabbableContentContainer = value;
+        }
+
         [BackgroundDependencyLoader]
         private void load(OsuColour colours)
         {

osu.Game/IO/WrappedStorage.cs

@@ -25,7 +25,13 @@ namespace osu.Game.IO
             this.subPath = subPath;
         }
 
-        protected virtual string MutatePath(string path) => !string.IsNullOrEmpty(subPath) ? Path.Combine(subPath, path) : path;
+        protected virtual string MutatePath(string path)
+        {
+            if (path == null)
+                return null;
+
+            return !string.IsNullOrEmpty(subPath) ? Path.Combine(subPath, path) : path;
+        }
 
         protected virtual void ChangeTargetStorage(Storage newStorage)
         {

osu.Game/Input/GameIdleTracker.cs

@@ -0,0 +1,25 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Input;
+
+namespace osu.Game.Input
+{
+    public class GameIdleTracker : IdleTracker
+    {
+        private InputManager inputManager;
+
+        public GameIdleTracker(int time)
+            : base(time)
+        {
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            inputManager = GetContainingInputManager();
+        }
+
+        protected override bool AllowIdle => inputManager.FocusedDrawable == null;
+    }
+}

osu.Game/Online/Leaderboards/Leaderboard.cs

@@ -56,13 +56,14 @@ namespace osu.Game.Online.Leaderboards
                 scrollFlow?.FadeOut(fade_duration, Easing.OutQuint).Expire();
                 scrollFlow = null;
 
-                loading.Hide();
-
                 showScoresDelegate?.Cancel();
                 showScoresCancellationSource?.Cancel();
 
                 if (scores == null || !scores.Any())
+                {
+                    loading.Hide();
                     return;
+                }
 
                 // ensure placeholder is hidden when displaying scores
                 PlaceholderState = PlaceholderState.Successful;
@@ -84,6 +85,7 @@ namespace osu.Game.Online.Leaderboards
                     }
 
                     scrollContainer.ScrollTo(0f, false);
+                    loading.Hide();
                 }, (showScoresCancellationSource = new CancellationTokenSource()).Token));
             }
         }

osu.Game/Online/Leaderboards/LeaderboardScore.cs

@@ -72,7 +72,7 @@ namespace osu.Game.Online.Leaderboards
         }
 
         [BackgroundDependencyLoader]
-        private void load(IAPIProvider api, OsuColour colour)
+        private void load(IAPIProvider api, OsuColour colour, ScoreManager scoreManager)
         {
             var user = score.User;
 
@@ -194,7 +194,7 @@ namespace osu.Game.Online.Leaderboards
                                         {
                                             TextColour = Color4.White,
                                             GlowColour = Color4Extensions.FromHex(@"83ccfa"),
-                                            Text = score.TotalScore.ToString(@"N0"),
+                                            Current = scoreManager.GetBindableTotalScoreString(score),
                                             Font = OsuFont.Numeric.With(size: 23),
                                         },
                                         RankContainer = new Container

osu.Game/OsuGame.cs

@@ -31,6 +31,7 @@ using osu.Framework.Input.Events;
 using osu.Framework.Platform;
 using osu.Framework.Threading;
 using osu.Game.Beatmaps;
+using osu.Game.Collections;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.UserInterface;
@@ -38,6 +39,7 @@ using osu.Game.Input;
 using osu.Game.Overlays.Notifications;
 using osu.Game.Input.Bindings;
 using osu.Game.Online.Chat;
+using osu.Game.Overlays.Music;
 using osu.Game.Skinning;
 using osuTK.Graphics;
 using osu.Game.Overlays.Volume;
@@ -609,12 +611,19 @@ namespace osu.Game
                 d.Origin = Anchor.TopRight;
             }), rightFloatingOverlayContent.Add, true);
 
+            loadComponentSingleFile(new CollectionManager(Storage)
+            {
+                PostNotification = n => notifications.Post(n),
+                GetStableStorage = GetStorageForStableInstall
+            }, Add, true);
+
             loadComponentSingleFile(screenshotManager, Add);
 
             // dependency on notification overlay, dependent by settings overlay
             loadComponentSingleFile(CreateUpdateManager(), Add, true);
 
             // overlay elements
+            loadComponentSingleFile(new ManageCollectionsDialog(), overlayContent.Add, true);
             loadComponentSingleFile(beatmapListing = new BeatmapListingOverlay(), overlayContent.Add, true);
             loadComponentSingleFile(dashboard = new DashboardOverlay(), overlayContent.Add, true);
             loadComponentSingleFile(news = new NewsOverlay(), overlayContent.Add, true);
@@ -647,6 +656,7 @@ namespace osu.Game
             chatOverlay.State.ValueChanged += state => channelManager.HighPollRate.Value = state.NewValue == Visibility.Visible;
 
             Add(externalLinkOpener = new ExternalLinkOpener());
+            Add(new MusicKeyBindingHandler());
 
             // side overlays which cancel each other.
             var singleDisplaySideOverlays = new OverlayContainer[] { Settings, notifications };
@@ -718,24 +728,6 @@ namespace osu.Game
                 overlayContent.ChangeChildDepth(overlay, (float)-Clock.CurrentTime);
         }
 
-        public class GameIdleTracker : IdleTracker
-        {
-            private InputManager inputManager;
-
-            public GameIdleTracker(int time)
-                : base(time)
-            {
-            }
-
-            protected override void LoadComplete()
-            {
-                base.LoadComplete();
-                inputManager = GetContainingInputManager();
-            }
-
-            protected override bool AllowIdle => inputManager.FocusedDrawable == null;
-        }
-
         private void forwardLoggedErrorsToNotifications()
         {
             int recentLogCount = 0;
@@ -991,10 +983,4 @@ namespace osu.Game
                 Exit();
         }
     }
-
-    public enum ScorePresentType
-    {
-        Results,
-        Gameplay
-    }
 }

osu.Game/OsuGameBase.cs

@@ -58,6 +58,8 @@ namespace osu.Game
 
         protected ScoreManager ScoreManager;
 
+        protected BeatmapDifficultyManager DifficultyManager;
+
         protected SkinManager SkinManager;
 
         protected RulesetStore RulesetStore;
@@ -197,8 +199,8 @@ namespace osu.Game
             dependencies.Cache(FileStore = new FileStore(contextFactory, Storage));
 
             // ordering is important here to ensure foreign keys rules are not broken in ModelStore.Cleanup()
-            dependencies.Cache(ScoreManager = new ScoreManager(RulesetStore, () => BeatmapManager, Storage, API, contextFactory, Host));
-            dependencies.Cache(BeatmapManager = new BeatmapManager(Storage, contextFactory, RulesetStore, API, Audio, Host, defaultBeatmap));
+            dependencies.Cache(ScoreManager = new ScoreManager(RulesetStore, () => BeatmapManager, Storage, API, contextFactory, Host, () => DifficultyManager, LocalConfig));
+            dependencies.Cache(BeatmapManager = new BeatmapManager(Storage, contextFactory, RulesetStore, API, Audio, Host, defaultBeatmap, true));
 
             // this should likely be moved to ArchiveModelManager when another case appers where it is necessary
             // to have inter-dependent model managers. this could be obtained with an IHasForeign<T> interface to
@@ -221,9 +223,8 @@ namespace osu.Game
                     ScoreManager.Undelete(getBeatmapScores(item), true);
             });
 
-            var difficultyManager = new BeatmapDifficultyManager();
-            dependencies.Cache(difficultyManager);
-            AddInternal(difficultyManager);
+            dependencies.Cache(DifficultyManager = new BeatmapDifficultyManager());
+            AddInternal(DifficultyManager);
 
             dependencies.Cache(KeyBindingStore = new KeyBindingStore(contextFactory, RulesetStore));
             dependencies.Cache(SettingsStore = new SettingsStore(contextFactory));
@@ -250,10 +251,11 @@ namespace osu.Game
                 AddInternal(apiAccess);
             AddInternal(RulesetConfigCache);
 
-            GlobalActionContainer globalBinding;
-
             MenuCursorContainer = new MenuCursorContainer { RelativeSizeAxes = Axes.Both };
-            MenuCursorContainer.Child = globalBinding = new GlobalActionContainer(this)
+
+            GlobalActionContainer globalBindings;
+
+            MenuCursorContainer.Child = globalBindings = new GlobalActionContainer(this)
             {
                 RelativeSizeAxes = Axes.Both,
                 Child = content = new OsuTooltipContainer(MenuCursorContainer.Cursor) { RelativeSizeAxes = Axes.Both }
@@ -261,8 +263,8 @@ namespace osu.Game
 
             base.Content.Add(CreateScalingContainer().WithChild(MenuCursorContainer));
 
-            KeyBindingStore.Register(globalBinding);
-            dependencies.Cache(globalBinding);
+            KeyBindingStore.Register(globalBindings);
+            dependencies.Cache(globalBindings);
 
             PreviewTrackManager previewTrackManager;
             dependencies.Cache(previewTrackManager = new PreviewTrackManager());

osu.Game/Overlays/BeatmapListing/BeatmapListingHeader.cs

@@ -12,7 +12,7 @@ namespace osu.Game.Overlays.BeatmapListing
             public BeatmapListingTitle()
             {
                 Title = "beatmap listing";
-                Description = "Browse for new beatmaps";
+                Description = "browse for new beatmaps";
                 IconTexture = "Icons/Hexacons/beatmap";
             }
         }

osu.Game/Overlays/BeatmapSet/Scores/ScoreTable.cs

@@ -25,6 +25,9 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
         private const float row_height = 22;
         private const int text_size = 12;
 
+        [Resolved]
+        private ScoreManager scoreManager { get; set; }
+
         private readonly FillFlowContainer backgroundFlow;
 
         private Color4 highAccuracyColour;
@@ -121,7 +124,7 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
                 new OsuSpriteText
                 {
                     Margin = new MarginPadding { Right = horizontal_inset },
-                    Text = $@"{score.TotalScore:N0}",
+                    Current = scoreManager.GetBindableTotalScoreString(score),
                     Font = OsuFont.GetFont(size: text_size, weight: index == 0 ? FontWeight.Bold : FontWeight.Medium)
                 },
                 new OsuSpriteText

osu.Game/Overlays/BeatmapSet/Scores/TopScoreStatisticsSection.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -38,6 +39,9 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
         private readonly FillFlowContainer<InfoColumn> statisticsColumns;
         private readonly ModsInfoColumn modsColumn;
 
+        [Resolved]
+        private ScoreManager scoreManager { get; set; }
+
         public TopScoreStatisticsSection()
         {
             RelativeSizeAxes = Axes.X;
@@ -87,6 +91,15 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
             };
         }
 
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            if (score != null)
+                totalScoreColumn.Current = scoreManager.GetBindableTotalScoreString(score);
+        }
+
+        private ScoreInfo score;
+
         /// <summary>
         /// Sets the score to be displayed.
         /// </summary>
@@ -94,7 +107,11 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
         {
             set
             {
-                totalScoreColumn.Text = $@"{value.TotalScore:N0}";
+                if (score == value)
+                    return;
+
+                score = value;
+
                 accuracyColumn.Text = value.DisplayAccuracy;
                 maxComboColumn.Text = $@"{value.MaxCombo:N0}x";
                 ppColumn.Alpha = value.Beatmap?.Status == BeatmapSetOnlineStatus.Ranked ? 1 : 0;
@@ -102,6 +119,9 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
 
                 statisticsColumns.ChildrenEnumerable = value.SortedStatistics.Select(kvp => createStatisticsColumn(kvp.Key, kvp.Value));
                 modsColumn.Mods = value.Mods;
+
+                if (scoreManager != null)
+                    totalScoreColumn.Current = scoreManager.GetBindableTotalScoreString(value);
             }
         }
 
@@ -190,6 +210,12 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
             {
                 set => text.Text = value;
             }
+
+            public Bindable<string> Current
+            {
+                get => text.Current;
+                set => text.Current = value;
+            }
         }
 
         private class ModsInfoColumn : InfoColumn

osu.Game/Overlays/Changelog/ChangelogHeader.cs

@@ -115,7 +115,7 @@ namespace osu.Game.Overlays.Changelog
             public ChangelogHeaderTitle()
             {
                 Title = "changelog";
-                Description = "Track recent dev updates in the osu! ecosystem";
+                Description = "track recent dev updates in the osu! ecosystem";
                 IconTexture = "Icons/Hexacons/devtools";
             }
         }

osu.Game/Overlays/ChatOverlay.cs

@@ -30,7 +30,7 @@ namespace osu.Game.Overlays
     {
         public string IconTexture => "Icons/Hexacons/messaging";
         public string Title => "chat";
-        public string Description => "Join the real-time discussion";
+        public string Description => "join the real-time discussion";
 
         private const float textbox_height = 60;
         private const float channel_selection_min_height = 0.3f;

osu.Game/Overlays/Dashboard/DashboardOverlayHeader.cs

@@ -12,7 +12,7 @@ namespace osu.Game.Overlays.Dashboard
             public DashboardTitle()
             {
                 Title = "dashboard";
-                Description = "View your friends and other information";
+                Description = "view your friends and other information";
                 IconTexture = "Icons/Hexacons/social";
             }
         }

osu.Game/Overlays/Music/MusicKeyBindingHandler.cs

@@ -0,0 +1,81 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Input.Bindings;
+using osu.Game.Beatmaps;
+using osu.Game.Input.Bindings;
+using osu.Game.Overlays.OSD;
+
+namespace osu.Game.Overlays.Music
+{
+    /// <summary>
+    /// Handles <see cref="GlobalAction"/>s related to music playback, and displays <see cref="Toast"/>s via the global <see cref="OnScreenDisplay"/> accordingly.
+    /// </summary>
+    public class MusicKeyBindingHandler : Component, IKeyBindingHandler<GlobalAction>
+    {
+        [Resolved]
+        private IBindable<WorkingBeatmap> beatmap { get; set; }
+
+        [Resolved]
+        private MusicController musicController { get; set; }
+
+        [Resolved(canBeNull: true)]
+        private OnScreenDisplay onScreenDisplay { get; set; }
+
+        public bool OnPressed(GlobalAction action)
+        {
+            if (beatmap.Disabled)
+                return false;
+
+            switch (action)
+            {
+                case GlobalAction.MusicPlay:
+                    // use previous state as TogglePause may not update the track's state immediately (state update is run on the audio thread see https://github.com/ppy/osu/issues/9880#issuecomment-674668842)
+                    bool wasPlaying = musicController.IsPlaying;
+
+                    if (musicController.TogglePause())
+                        onScreenDisplay?.Display(new MusicActionToast(wasPlaying ? "Pause track" : "Play track"));
+                    return true;
+
+                case GlobalAction.MusicNext:
+                    musicController.NextTrack(() => onScreenDisplay?.Display(new MusicActionToast("Next track")));
+
+                    return true;
+
+                case GlobalAction.MusicPrev:
+                    musicController.PreviousTrack(res =>
+                    {
+                        switch (res)
+                        {
+                            case PreviousTrackResult.Restart:
+                                onScreenDisplay?.Display(new MusicActionToast("Restart track"));
+                                break;
+
+                            case PreviousTrackResult.Previous:
+                                onScreenDisplay?.Display(new MusicActionToast("Previous track"));
+                                break;
+                        }
+                    });
+
+                    return true;
+            }
+
+            return false;
+        }
+
+        public void OnReleased(GlobalAction action)
+        {
+        }
+
+        private class MusicActionToast : Toast
+        {
+            public MusicActionToast(string action)
+                : base("Music Playback", action, string.Empty)
+            {
+            }
+        }
+    }
+}

osu.Game/Overlays/MusicController.cs

@@ -12,12 +12,9 @@ using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Audio;
 using osu.Framework.Graphics.Containers;
-using osu.Framework.Input.Bindings;
 using osu.Framework.Utils;
 using osu.Framework.Threading;
 using osu.Game.Beatmaps;
-using osu.Game.Input.Bindings;
-using osu.Game.Overlays.OSD;
 using osu.Game.Rulesets.Mods;
 
 namespace osu.Game.Overlays
@@ -25,7 +22,7 @@ namespace osu.Game.Overlays
     /// <summary>
     /// Handles playback of the global music track.
     /// </summary>
-    public class MusicController : CompositeDrawable, IKeyBindingHandler<GlobalAction>
+    public class MusicController : CompositeDrawable
     {
         [Resolved]
         private BeatmapManager beatmaps { get; set; }
@@ -62,9 +59,6 @@ namespace osu.Game.Overlays
         [Resolved]
         private IBindable<IReadOnlyList<Mod>> mods { get; set; }
 
-        [Resolved(canBeNull: true)]
-        private OnScreenDisplay onScreenDisplay { get; set; }
-
         [NotNull]
         public DrawableTrack CurrentTrack { get; private set; } = new DrawableTrack(new TrackVirtual(1000));
 
@@ -207,7 +201,13 @@ namespace osu.Game.Overlays
         /// <summary>
         /// Play the previous track or restart the current track if it's current time below <see cref="restart_cutoff_point"/>.
         /// </summary>
-        public void PreviousTrack() => Schedule(() => prev());
+        /// <param name="onSuccess">Invoked when the operation has been performed successfully.</param>
+        public void PreviousTrack(Action<PreviousTrackResult> onSuccess = null) => Schedule(() =>
+        {
+            PreviousTrackResult res = prev();
+            if (res != PreviousTrackResult.None)
+                onSuccess?.Invoke(res);
+        });
 
         /// <summary>
         /// Play the previous track or restart the current track if it's current time below <see cref="restart_cutoff_point"/>.
@@ -243,7 +243,14 @@ namespace osu.Game.Overlays
         /// <summary>
         /// Play the next random or playlist track.
         /// </summary>
-        public void NextTrack() => Schedule(() => next());
+        /// <param name="onSuccess">Invoked when the operation has been performed successfully.</param>
+        /// <returns>A <see cref="ScheduledDelegate"/> of the operation.</returns>
+        public void NextTrack(Action onSuccess = null) => Schedule(() =>
+        {
+            bool res = next();
+            if (res)
+                onSuccess?.Invoke();
+        });
 
         private bool next()
         {
@@ -279,6 +286,11 @@ namespace osu.Game.Overlays
 
         private void changeBeatmap(WorkingBeatmap newWorking)
         {
+            // This method can potentially be triggered multiple times as it is eagerly fired in next() / prev() to ensure correct execution order
+            // (changeBeatmap must be called before consumers receive the bindable changed event, which is not the case when the local beatmap bindable is updated directly).
+            if (newWorking == current)
+                return;
+
             var lastWorking = current;
 
             TrackChangeDirection direction = TrackChangeDirection.None;
@@ -402,54 +414,6 @@ namespace osu.Game.Overlays
                     mod.ApplyToTrack(CurrentTrack);
             }
         }
-
-        public bool OnPressed(GlobalAction action)
-        {
-            if (beatmap.Disabled)
-                return false;
-
-            switch (action)
-            {
-                case GlobalAction.MusicPlay:
-                    if (TogglePause())
-                        onScreenDisplay?.Display(new MusicControllerToast(IsPlaying ? "Play track" : "Pause track"));
-                    return true;
-
-                case GlobalAction.MusicNext:
-                    if (next())
-                        onScreenDisplay?.Display(new MusicControllerToast("Next track"));
-
-                    return true;
-
-                case GlobalAction.MusicPrev:
-                    switch (prev())
-                    {
-                        case PreviousTrackResult.Restart:
-                            onScreenDisplay?.Display(new MusicControllerToast("Restart track"));
-                            break;
-
-                        case PreviousTrackResult.Previous:
-                            onScreenDisplay?.Display(new MusicControllerToast("Previous track"));
-                            break;
-                    }
-
-                    return true;
-            }
-
-            return false;
-        }
-
-        public void OnReleased(GlobalAction action)
-        {
-        }
-
-        public class MusicControllerToast : Toast
-        {
-            public MusicControllerToast(string action)
-                : base("Music Playback", action, string.Empty)
-            {
-            }
-        }
     }
 
     public enum TrackChangeDirection

osu.Game/Overlays/News/NewsHeader.cs

@@ -57,7 +57,7 @@ namespace osu.Game.Overlays.News
             public NewsHeaderTitle()
             {
                 Title = "news";
-                Description = "Get up-to-date on community happenings";
+                Description = "get up-to-date on community happenings";
                 IconTexture = "Icons/Hexacons/news";
             }
         }

osu.Game/Overlays/NotificationOverlay.cs

@@ -19,8 +19,8 @@ namespace osu.Game.Overlays
     public class NotificationOverlay : OsuFocusedOverlayContainer, INamedOverlayComponent
     {
         public string IconTexture => "Icons/Hexacons/notification";
-        public string Title => "Notifications";
-        public string Description => "Waiting for 'ya";
+        public string Title => "notifications";
+        public string Description => "waiting for 'ya";
 
         private const float width = 320;
 

osu.Game/Overlays/NowPlayingOverlay.cs

@@ -29,7 +29,7 @@ namespace osu.Game.Overlays
     {
         public string IconTexture => "Icons/Hexacons/music";
         public string Title => "now playing";
-        public string Description => "Manage the currently playing track";
+        public string Description => "manage the currently playing track";
 
         private const float player_height = 130;
         private const float transition_length = 800;

osu.Game/Overlays/Rankings/RankingsOverlayHeader.cs

@@ -30,7 +30,7 @@ namespace osu.Game.Overlays.Rankings
             public RankingsTitle()
             {
                 Title = "ranking";
-                Description = "Find out who's the best right now";
+                Description = "find out who's the best right now";
                 IconTexture = "Icons/Hexacons/rankings";
             }
         }

osu.Game/Overlays/Settings/Sections/GameplaySection.cs

@@ -1,12 +1,14 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Game.Overlays.Settings.Sections.Gameplay;
 using osu.Game.Rulesets;
 using System.Linq;
 using osu.Framework.Graphics.Sprites;
+using osu.Framework.Logging;
 
 namespace osu.Game.Overlays.Settings.Sections
 {
@@ -34,9 +36,17 @@ namespace osu.Game.Overlays.Settings.Sections
         {
             foreach (Ruleset ruleset in rulesets.AvailableRulesets.Select(info => info.CreateInstance()))
             {
-                SettingsSubsection section = ruleset.CreateSettings();
-                if (section != null)
-                    Add(section);
+                try
+                {
+                    SettingsSubsection section = ruleset.CreateSettings();
+
+                    if (section != null)
+                        Add(section);
+                }
+                catch (Exception e)
+                {
+                    Logger.Error(e, "Failed to load ruleset settings");
+                }
             }
         }
     }

osu.Game/Overlays/Settings/Sections/Maintenance/GeneralSettings.cs

@@ -3,9 +3,11 @@
 
 using System.Linq;
 using System.Threading.Tasks;
+using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Game.Beatmaps;
+using osu.Game.Collections;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Scoring;
 using osu.Game.Skinning;
@@ -19,14 +21,15 @@ namespace osu.Game.Overlays.Settings.Sections.Maintenance
         private TriangleButton importBeatmapsButton;
         private TriangleButton importScoresButton;
         private TriangleButton importSkinsButton;
+        private TriangleButton importCollectionsButton;
         private TriangleButton deleteBeatmapsButton;
         private TriangleButton deleteScoresButton;
         private TriangleButton deleteSkinsButton;
         private TriangleButton restoreButton;
         private TriangleButton undeleteButton;
 
-        [BackgroundDependencyLoader]
-        private void load(BeatmapManager beatmaps, ScoreManager scores, SkinManager skins, DialogOverlay dialogOverlay)
+        [BackgroundDependencyLoader(permitNulls: true)]
+        private void load(BeatmapManager beatmaps, ScoreManager scores, SkinManager skins, [CanBeNull] CollectionManager collectionManager, DialogOverlay dialogOverlay)
         {
             if (beatmaps.SupportsImportFromStable)
             {
@@ -93,20 +96,46 @@ namespace osu.Game.Overlays.Settings.Sections.Maintenance
                 });
             }
 
-            AddRange(new Drawable[]
+            Add(deleteSkinsButton = new DangerousSettingsButton
             {
-                deleteSkinsButton = new DangerousSettingsButton
+                Text = "Delete ALL skins",
+                Action = () =>
                 {
-                    Text = "Delete ALL skins",
+                    dialogOverlay?.Push(new DeleteAllBeatmapsDialog(() =>
+                    {
+                        deleteSkinsButton.Enabled.Value = false;
+                        Task.Run(() => skins.Delete(skins.GetAllUserSkins())).ContinueWith(t => Schedule(() => deleteSkinsButton.Enabled.Value = true));
+                    }));
+                }
+            });
+
+            if (collectionManager != null)
+            {
+                if (collectionManager.SupportsImportFromStable)
+                {
+                    Add(importCollectionsButton = new SettingsButton
+                    {
+                        Text = "Import collections from stable",
+                        Action = () =>
+                        {
+                            importCollectionsButton.Enabled.Value = false;
+                            collectionManager.ImportFromStableAsync().ContinueWith(t => Schedule(() => importCollectionsButton.Enabled.Value = true));
+                        }
+                    });
+                }
+
+                Add(new DangerousSettingsButton
+                {
+                    Text = "Delete ALL collections",
                     Action = () =>
                     {
-                        dialogOverlay?.Push(new DeleteAllBeatmapsDialog(() =>
-                        {
-                            deleteSkinsButton.Enabled.Value = false;
-                            Task.Run(() => skins.Delete(skins.GetAllUserSkins())).ContinueWith(t => Schedule(() => deleteSkinsButton.Enabled.Value = true));
-                        }));
+                        dialogOverlay?.Push(new DeleteAllBeatmapsDialog(collectionManager.DeleteAll));
                     }
-                },
+                });
+            }
+
+            AddRange(new Drawable[]
+            {
                 restoreButton = new SettingsButton
                 {
                     Text = "Restore all hidden difficulties",

osu.Game/Overlays/SettingsOverlay.cs

@@ -17,7 +17,7 @@ namespace osu.Game.Overlays
     {
         public string IconTexture => "Icons/Hexacons/settings";
         public string Title => "settings";
-        public string Description => "Change the way osu! behaves";
+        public string Description => "change the way osu! behaves";
 
         protected override IEnumerable<SettingsSection> CreateSections() => new SettingsSection[]
         {