Merge branch 'master' into results-clean

.config/dotnet-tools.json

@@ -3,13 +3,13 @@
   "isRoot": true,
   "tools": {
     "jetbrains.resharper.globaltools": {
-      "version": "2022.2.3",
+      "version": "2023.3.3",
       "commands": [
         "jb"
       ]
     },
     "nvika": {
-      "version": "2.2.0",
+      "version": "3.0.0",
       "commands": [
         "nvika"
       ]

.globalconfig

@@ -1,5 +1,3 @@
-is_global = true
-
 # .NET Code Style
 # IDE styles reference: https://docs.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/
 
@@ -56,4 +54,4 @@ dotnet_diagnostic.RS0030.severity = error
 
 # Temporarily disable analysing CanBeNull = true in NRT contexts due to mobile issues.
 # See: https://github.com/ppy/osu/pull/19677
-dotnet_diagnostic.OSUF001.severity = none
+dotnet_diagnostic.OSUF001.severity = none

osu.Android.props

@@ -10,7 +10,7 @@
     <EmbedAssembliesIntoApk>true</EmbedAssembliesIntoApk>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2024.127.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2024.131.0" />
   </ItemGroup>
   <PropertyGroup>
     <!-- Fody does not handle Android build well, and warns when unchanged.

osu.Desktop/osu.nuspec

@@ -20,5 +20,6 @@
       <file src="**.dll" target="lib\net45\"/>
       <file src="**.config" target="lib\net45\"/>
       <file src="**.json" target="lib\net45\"/>
+      <file src="icon.png" target=""/>
     </files>
 </package>

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

@@ -91,7 +91,7 @@ namespace osu.Game.Rulesets.Mania.Tests
         {
             foreach (var stage in stages)
             {
-                for (int i = 0; i < stage.Columns.Count; i++)
+                for (int i = 0; i < stage.Columns.Length; i++)
                 {
                     var obj = new Note { Column = i, StartTime = Time.Current + 2000 };
                     obj.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
@@ -105,7 +105,7 @@ namespace osu.Game.Rulesets.Mania.Tests
         {
             foreach (var stage in stages)
             {
-                for (int i = 0; i < stage.Columns.Count; i++)
+                for (int i = 0; i < stage.Columns.Length; i++)
                 {
                     var obj = new HoldNote { Column = i, StartTime = Time.Current + 2000, Duration = 500 };
                     obj.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());

osu.Game.Rulesets.Mania/Skinning/Argon/ArgonJudgementPiece.cs

@@ -17,7 +17,7 @@ using osuTK.Graphics;
 
 namespace osu.Game.Rulesets.Mania.Skinning.Argon
 {
-    public partial class ArgonJudgementPiece : JudgementPiece, IAnimatableJudgement
+    public partial class ArgonJudgementPiece : TextJudgementPiece, IAnimatableJudgement
     {
         private const float judgement_y_position = 160;
 

osu.Game.Rulesets.Mania/UI/ColumnFlow.cs

@@ -4,8 +4,6 @@
 #nullable disable
 
 using System;
-using System.Collections.Generic;
-using System.Linq;
 using osu.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -28,20 +26,21 @@ namespace osu.Game.Rulesets.Mania.UI
         /// <summary>
         /// All contents added to this <see cref="ColumnFlow{TContent}"/>.
         /// </summary>
-        public IReadOnlyList<TContent> Content => columns.Children.Select(c => c.Count == 0 ? null : (TContent)c.Child).ToList();
+        public TContent[] Content { get; }
 
-        private readonly FillFlowContainer<Container> columns;
+        private readonly FillFlowContainer<Container<TContent>> columns;
         private readonly StageDefinition stageDefinition;
 
         public ColumnFlow(StageDefinition stageDefinition)
         {
             this.stageDefinition = stageDefinition;
+            Content = new TContent[stageDefinition.Columns];
 
             AutoSizeAxes = Axes.X;
 
             Masking = true;
 
-            InternalChild = columns = new FillFlowContainer<Container>
+            InternalChild = columns = new FillFlowContainer<Container<TContent>>
             {
                 RelativeSizeAxes = Axes.Y,
                 AutoSizeAxes = Axes.X,
@@ -49,7 +48,7 @@ namespace osu.Game.Rulesets.Mania.UI
             };
 
             for (int i = 0; i < stageDefinition.Columns; i++)
-                columns.Add(new Container { RelativeSizeAxes = Axes.Y });
+                columns.Add(new Container<TContent> { RelativeSizeAxes = Axes.Y });
         }
 
         private ISkinSource currentSkin;
@@ -102,7 +101,10 @@ namespace osu.Game.Rulesets.Mania.UI
         /// </summary>
         /// <param name="column">The index of the column to set the content of.</param>
         /// <param name="content">The content.</param>
-        public void SetContentForColumn(int column, TContent content) => columns[column].Child = content;
+        public void SetContentForColumn(int column, TContent content)
+        {
+            Content[column] = columns[column].Child = content;
+        }
 
         private void updateMobileSizing()
         {

osu.Game.Rulesets.Mania/UI/ManiaPlayfield.cs

@@ -42,7 +42,16 @@ namespace osu.Game.Rulesets.Mania.UI
             }
         }
 
-        public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => stages.Any(s => s.ReceivePositionalInputAt(screenSpacePos));
+        public override bool ReceivePositionalInputAt(Vector2 screenSpacePos)
+        {
+            foreach (var s in stages)
+            {
+                if (s.ReceivePositionalInputAt(screenSpacePos))
+                    return true;
+            }
+
+            return false;
+        }
 
         public ManiaPlayfield(List<StageDefinition> stageDefinitions)
         {
@@ -71,7 +80,7 @@ namespace osu.Game.Rulesets.Mania.UI
                 stages.Add(newStage);
                 AddNested(newStage);
 
-                firstColumnIndex += newStage.Columns.Count;
+                firstColumnIndex += newStage.Columns.Length;
             }
         }
 
@@ -125,9 +134,9 @@ namespace osu.Game.Rulesets.Mania.UI
 
             foreach (var stage in stages)
             {
-                if (index >= stage.Columns.Count)
+                if (index >= stage.Columns.Length)
                 {
-                    index -= stage.Columns.Count;
+                    index -= stage.Columns.Length;
                     continue;
                 }
 
@@ -140,7 +149,7 @@ namespace osu.Game.Rulesets.Mania.UI
         /// <summary>
         /// Retrieves the total amount of columns across all stages in this playfield.
         /// </summary>
-        public int TotalColumns => stages.Sum(s => s.Columns.Count);
+        public int TotalColumns => stages.Sum(s => s.Columns.Length);
 
         private Stage getStageByColumn(int column)
         {
@@ -148,7 +157,7 @@ namespace osu.Game.Rulesets.Mania.UI
 
             foreach (var stage in stages)
             {
-                sum += stage.Columns.Count;
+                sum += stage.Columns.Length;
                 if (sum > column)
                     return stage;
             }

osu.Game.Rulesets.Mania/UI/Stage.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions.ObjectExtensions;
@@ -37,7 +36,7 @@ namespace osu.Game.Rulesets.Mania.UI
 
         public const float HIT_TARGET_POSITION = 110;
 
-        public IReadOnlyList<Column> Columns => columnFlow.Content;
+        public Column[] Columns => columnFlow.Content;
         private readonly ColumnFlow<Column> columnFlow;
 
         private readonly JudgementContainer<DrawableManiaJudgement> judgements;
@@ -45,7 +44,16 @@ namespace osu.Game.Rulesets.Mania.UI
 
         private readonly Drawable barLineContainer;
 
-        public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => Columns.Any(c => c.ReceivePositionalInputAt(screenSpacePos));
+        public override bool ReceivePositionalInputAt(Vector2 screenSpacePos)
+        {
+            foreach (var c in Columns)
+            {
+                if (c.ReceivePositionalInputAt(screenSpacePos))
+                    return true;
+            }
+
+            return false;
+        }
 
         private readonly int firstColumnIndex;
 
@@ -184,13 +192,13 @@ namespace osu.Game.Rulesets.Mania.UI
             NewResult += OnNewResult;
         }
 
-        public override void Add(HitObject hitObject) => Columns.ElementAt(((ManiaHitObject)hitObject).Column - firstColumnIndex).Add(hitObject);
+        public override void Add(HitObject hitObject) => Columns[((ManiaHitObject)hitObject).Column - firstColumnIndex].Add(hitObject);
 
-        public override bool Remove(HitObject hitObject) => Columns.ElementAt(((ManiaHitObject)hitObject).Column - firstColumnIndex).Remove(hitObject);
+        public override bool Remove(HitObject hitObject) => Columns[((ManiaHitObject)hitObject).Column - firstColumnIndex].Remove(hitObject);
 
-        public override void Add(DrawableHitObject h) => Columns.ElementAt(((ManiaHitObject)h.HitObject).Column - firstColumnIndex).Add(h);
+        public override void Add(DrawableHitObject h) => Columns[((ManiaHitObject)h.HitObject).Column - firstColumnIndex].Add(h);
 
-        public override bool Remove(DrawableHitObject h) => Columns.ElementAt(((ManiaHitObject)h.HitObject).Column - firstColumnIndex).Remove(h);
+        public override bool Remove(DrawableHitObject h) => Columns[((ManiaHitObject)h.HitObject).Column - firstColumnIndex].Remove(h);
 
         public void Add(BarLine barLine) => base.Add(barLine);
 

osu.Game.Rulesets.Osu.Tests/Editor/TestScenePathControlPointVisualiser.cs

@@ -206,7 +206,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
         {
             AddStep($"click context menu item \"{contextMenuText}\"", () =>
             {
-                MenuItem item = visualiser.ContextMenuItems.FirstOrDefault(menuItem => menuItem.Text.Value == "Curve type")?.Items.FirstOrDefault(menuItem => menuItem.Text.Value == contextMenuText);
+                MenuItem item = visualiser.ContextMenuItems!.FirstOrDefault(menuItem => menuItem.Text.Value == "Curve type")?.Items.FirstOrDefault(menuItem => menuItem.Text.Value == contextMenuText);
 
                 item?.Action.Value?.Invoke();
             });

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

@@ -31,7 +31,7 @@ namespace osu.Game.Rulesets.Osu.Tests
                         new PathControlPoint(new Vector2(-128, 0), PathType.LINEAR) // absolute position: (0, 128)
                     }
                 },
-                RepeatCount = 1
+                RepeatCount = 2
             };
             slider.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
             return slider;
@@ -45,7 +45,9 @@ namespace osu.Game.Rulesets.Osu.Tests
             OsuHitObjectGenerationUtils.ReflectHorizontallyAlongPlayfield(slider);
 
             Assert.That(slider.Position, Is.EqualTo(new Vector2(OsuPlayfield.BASE_SIZE.X - 128, 128)));
-            Assert.That(slider.NestedHitObjects.OfType<SliderRepeat>().Single().Position, Is.EqualTo(new Vector2(OsuPlayfield.BASE_SIZE.X - 0, 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderHeadCircle>().Single().Position, Is.EqualTo(new Vector2(OsuPlayfield.BASE_SIZE.X - 128, 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderRepeat>().First().Position, Is.EqualTo(new Vector2(OsuPlayfield.BASE_SIZE.X - 0, 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderTailCircle>().Single().Position, Is.EqualTo(new Vector2(OsuPlayfield.BASE_SIZE.X, 128)));
             Assert.That(slider.Path.ControlPoints.Select(point => point.Position), Is.EquivalentTo(new[]
             {
                 new Vector2(),
@@ -62,7 +64,9 @@ namespace osu.Game.Rulesets.Osu.Tests
             OsuHitObjectGenerationUtils.ReflectVerticallyAlongPlayfield(slider);
 
             Assert.That(slider.Position, Is.EqualTo(new Vector2(128, OsuPlayfield.BASE_SIZE.Y - 128)));
-            Assert.That(slider.NestedHitObjects.OfType<SliderRepeat>().Single().Position, Is.EqualTo(new Vector2(0, OsuPlayfield.BASE_SIZE.Y - 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderHeadCircle>().Single().Position, Is.EqualTo(new Vector2(128, OsuPlayfield.BASE_SIZE.Y - 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderRepeat>().First().Position, Is.EqualTo(new Vector2(0, OsuPlayfield.BASE_SIZE.Y - 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderTailCircle>().Single().Position, Is.EqualTo(new Vector2(0, OsuPlayfield.BASE_SIZE.Y - 128)));
             Assert.That(slider.Path.ControlPoints.Select(point => point.Position), Is.EquivalentTo(new[]
             {
                 new Vector2(),
@@ -79,7 +83,9 @@ namespace osu.Game.Rulesets.Osu.Tests
             OsuHitObjectGenerationUtils.FlipSliderInPlaceHorizontally(slider);
 
             Assert.That(slider.Position, Is.EqualTo(new Vector2(128, 128)));
-            Assert.That(slider.NestedHitObjects.OfType<SliderRepeat>().Single().Position, Is.EqualTo(new Vector2(256, 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderHeadCircle>().Single().Position, Is.EqualTo(new Vector2(128, 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderRepeat>().First().Position, Is.EqualTo(new Vector2(256, 128)));
+            Assert.That(slider.NestedHitObjects.OfType<SliderTailCircle>().Single().Position, Is.EqualTo(new Vector2(256, 128)));
             Assert.That(slider.Path.ControlPoints.Select(point => point.Position), Is.EquivalentTo(new[]
             {
                 new Vector2(),

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

@@ -183,7 +183,7 @@ namespace osu.Game.Rulesets.Osu.Tests
                             break;
                     }
 
-                    hitObjectContainer.Add(drawableObject);
+                    hitObjectContainer.Add(drawableObject!);
                     followPointRenderer.AddFollowPoints(objects[i]);
                 }
             });

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

@@ -6,6 +6,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using JetBrains.Annotations;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
@@ -173,6 +174,7 @@ namespace osu.Game.Rulesets.Osu.Tests
 
             public IEnumerable<ISkin> AllSources => new[] { this };
 
+            [CanBeNull]
             public event Action SourceChanged;
 
             private bool enabled = true;

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs

@@ -239,11 +239,11 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
                 if (Tracking.Value && Time.Current >= HitObject.StartTime)
                 {
                     // keep the sliding sample playing at the current tracking position
-                    if (!slidingSample.IsPlaying)
+                    if (!slidingSample.RequestedPlaying)
                         slidingSample.Play();
                     slidingSample.Balance.Value = CalculateSamplePlaybackBalance(CalculateDrawableRelativePosition(Ball));
                 }
-                else if (slidingSample.IsPlaying)
+                else if (slidingSample.IsPlaying || slidingSample.RequestedPlaying)
                     slidingSample.Stop();
             }
         }

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSliderTick.cs

@@ -18,7 +18,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
     {
         public const double ANIM_DURATION = 150;
 
-        private const float default_tick_size = 16;
+        public const float DEFAULT_TICK_SIZE = 16;
 
         protected DrawableSlider DrawableSlider => (DrawableSlider)ParentHitObject;
 
@@ -44,8 +44,8 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
             {
                 Masking = true,
                 Origin = Anchor.Centre,
-                Size = new Vector2(default_tick_size),
+                Size = new Vector2(DEFAULT_TICK_SIZE),
-                BorderThickness = default_tick_size / 4,
+                BorderThickness = DEFAULT_TICK_SIZE / 4,
                 BorderColour = Color4.White,
                 Child = new Box
                 {
@@ -88,8 +88,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
                     break;
 
                 case ArmedState.Miss:
-                    this.FadeOut(ANIM_DURATION);
+                    this.FadeOut(ANIM_DURATION, Easing.OutQuint);
-                    this.TransformBindableTo(AccentColour, Color4.Red, 0);
                     break;
 
                 case ArmedState.Hit:

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSpinner.cs

@@ -153,7 +153,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         {
             if (tracking.NewValue)
             {
-                if (!spinningSample.IsPlaying)
+                if (!spinningSample.RequestedPlaying)
                     spinningSample.Play();
 
                 spinningSample.VolumeTo(1, 300);

osu.Game.Rulesets.Osu/Objects/Slider.cs

@@ -98,7 +98,7 @@ namespace osu.Game.Rulesets.Osu.Objects
             set
             {
                 repeatCount = value;
-                endPositionCache.Invalidate();
+                updateNestedPositions();
             }
         }
 
@@ -165,7 +165,7 @@ namespace osu.Game.Rulesets.Osu.Objects
         public Slider()
         {
             SamplesBindable.CollectionChanged += (_, _) => UpdateNestedSamples();
-            Path.Version.ValueChanged += _ => endPositionCache.Invalidate();
+            Path.Version.ValueChanged += _ => updateNestedPositions();
         }
 
         protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)

osu.Game.Rulesets.Osu/OsuInputManager.cs

@@ -98,7 +98,7 @@ namespace osu.Game.Rulesets.Osu
                 base.ReloadMappings(realmKeyBindings);
 
                 if (!AllowGameplayInputs)
-                    KeyBindings = KeyBindings.Where(b => b.GetAction<OsuAction>() == OsuAction.Smoke).ToList();
+                    KeyBindings = KeyBindings.Where(static b => b.GetAction<OsuAction>() == OsuAction.Smoke).ToList();
             }
         }
     }

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -28,6 +28,7 @@ using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Osu.Replays;
 using osu.Game.Rulesets.Osu.Scoring;
 using osu.Game.Rulesets.Osu.Skinning.Argon;
+using osu.Game.Rulesets.Osu.Skinning.Default;
 using osu.Game.Rulesets.Osu.Skinning.Legacy;
 using osu.Game.Rulesets.Osu.Statistics;
 using osu.Game.Rulesets.Osu.UI;
@@ -254,6 +255,9 @@ namespace osu.Game.Rulesets.Osu
 
                 case ArgonSkin:
                     return new OsuArgonSkinTransformer(skin);
+
+                case TrianglesSkin:
+                    return new OsuTrianglesSkinTransformer(skin);
             }
 
             return null;

osu.Game.Rulesets.Osu/Skinning/Argon/ArgonJudgementPiece.cs

@@ -16,7 +16,7 @@ using osuTK;
 
 namespace osu.Game.Rulesets.Osu.Skinning.Argon
 {
-    public partial class ArgonJudgementPiece : JudgementPiece, IAnimatableJudgement
+    public partial class ArgonJudgementPiece : TextJudgementPiece, IAnimatableJudgement
     {
         private RingExplosion? ringExplosion;
 

osu.Game.Rulesets.Osu/Skinning/Argon/ArgonJudgementPieceSliderTickMiss.cs

@@ -0,0 +1,51 @@
+// 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.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using osu.Game.Rulesets.Judgements;
+using osu.Game.Rulesets.Scoring;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Skinning.Argon
+{
+    public partial class ArgonJudgementPieceSliderTickMiss : CompositeDrawable, IAnimatableJudgement
+    {
+        private readonly HitResult result;
+        private Circle piece = null!;
+
+        [Resolved]
+        private OsuColour colours { get; set; } = null!;
+
+        public ArgonJudgementPieceSliderTickMiss(HitResult result)
+        {
+            this.result = result;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            AddInternal(piece = new Circle
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                Blending = BlendingParameters.Additive,
+                Colour = colours.ForHitResult(result),
+                Size = new Vector2(ArgonSliderScorePoint.SIZE)
+            });
+        }
+
+        public void PlayAnimation()
+        {
+            this.ScaleTo(1.4f);
+            this.ScaleTo(1f, 150, Easing.Out);
+
+            this.FadeOutFromOne(600);
+        }
+
+        public Drawable? GetAboveHitObjectsProxiedContent() => piece.CreateProxy();
+    }
+}

osu.Game.Rulesets.Osu/Skinning/Argon/ArgonSliderScorePoint.cs

@@ -16,14 +16,14 @@ namespace osu.Game.Rulesets.Osu.Skinning.Argon
     {
         private Bindable<Color4> accentColour = null!;
 
-        private const float size = 12;
+        public const float SIZE = 12;
 
         [BackgroundDependencyLoader]
         private void load(DrawableHitObject hitObject)
         {
             Masking = true;
             Origin = Anchor.Centre;
-            Size = new Vector2(size);
+            Size = new Vector2(SIZE);
             BorderThickness = 3;
             BorderColour = Color4.White;
             Child = new Box

osu.Game.Rulesets.Osu/Skinning/Argon/OsuArgonSkinTransformer.cs

@@ -19,11 +19,21 @@ namespace osu.Game.Rulesets.Osu.Skinning.Argon
             switch (lookup)
             {
                 case GameplaySkinComponentLookup<HitResult> resultComponent:
+                    HitResult result = resultComponent.Component;
+
                     // This should eventually be moved to a skin setting, when supported.
-                    if (Skin is ArgonProSkin && (resultComponent.Component == HitResult.Great || resultComponent.Component == HitResult.Perfect))
+                    if (Skin is ArgonProSkin && (result == HitResult.Great || result == HitResult.Perfect))
                         return Drawable.Empty();
 
-                    return new ArgonJudgementPiece(resultComponent.Component);
+                    switch (result)
+                    {
+                        case HitResult.IgnoreMiss:
+                        case HitResult.LargeTickMiss:
+                            return new ArgonJudgementPieceSliderTickMiss(result);
+
+                        default:
+                            return new ArgonJudgementPiece(result);
+                    }
 
                 case OsuSkinComponentLookup osuComponent:
                     // TODO: Once everything is finalised, consider throwing UnsupportedSkinComponentException on missing entries.

osu.Game.Rulesets.Osu/Skinning/Default/DefaultJudgementPieceSliderTickMiss.cs

@@ -0,0 +1,52 @@
+// 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.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using osu.Game.Rulesets.Judgements;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
+using osu.Game.Rulesets.Scoring;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Skinning.Default
+{
+    public partial class DefaultJudgementPieceSliderTickMiss : CompositeDrawable, IAnimatableJudgement
+    {
+        private readonly HitResult result;
+        private Circle piece = null!;
+
+        [Resolved]
+        private OsuColour colours { get; set; } = null!;
+
+        public DefaultJudgementPieceSliderTickMiss(HitResult result)
+        {
+            this.result = result;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            AddInternal(piece = new Circle
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                Blending = BlendingParameters.Additive,
+                Colour = colours.ForHitResult(result),
+                Size = new Vector2(DrawableSliderTick.DEFAULT_TICK_SIZE)
+            });
+        }
+
+        public void PlayAnimation()
+        {
+            this.ScaleTo(1.4f);
+            this.ScaleTo(1f, 150, Easing.Out);
+
+            this.FadeOutFromOne(600);
+        }
+
+        public Drawable? GetAboveHitObjectsProxiedContent() => piece.CreateProxy();
+    }
+}

osu.Game.Rulesets.Osu/Skinning/Default/OsuTrianglesSkinTransformer.cs

@@ -0,0 +1,38 @@
+// 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.Rulesets.Scoring;
+using osu.Game.Skinning;
+
+namespace osu.Game.Rulesets.Osu.Skinning.Default
+{
+    public class OsuTrianglesSkinTransformer : SkinTransformer
+    {
+        public OsuTrianglesSkinTransformer(ISkin skin)
+            : base(skin)
+        {
+        }
+
+        public override Drawable? GetDrawableComponent(ISkinComponentLookup lookup)
+        {
+            switch (lookup)
+            {
+                case GameplaySkinComponentLookup<HitResult> resultComponent:
+                    HitResult result = resultComponent.Component;
+
+                    switch (result)
+                    {
+                        case HitResult.IgnoreMiss:
+                        case HitResult.LargeTickMiss:
+                            // use argon judgement piece for new tick misses because i don't want to design another one for triangles.
+                            return new DefaultJudgementPieceSliderTickMiss(result);
+                    }
+
+                    break;
+            }
+
+            return base.GetDrawableComponent(lookup);
+        }
+    }
+}

osu.Game.Rulesets.Taiko/Skinning/Argon/ArgonJudgementPiece.cs

@@ -17,7 +17,7 @@ using osuTK.Graphics;
 
 namespace osu.Game.Rulesets.Taiko.Skinning.Argon
 {
-    public partial class ArgonJudgementPiece : JudgementPiece, IAnimatableJudgement
+    public partial class ArgonJudgementPiece : TextJudgementPiece, IAnimatableJudgement
     {
         private RingExplosion? ringExplosion;
 

osu.Game.Rulesets.Taiko/UI/DrawableTaikoRuleset.cs

@@ -16,7 +16,6 @@ using osu.Game.Replays;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
-using osu.Game.Rulesets.Taiko.Beatmaps;
 using osu.Game.Rulesets.Taiko.Objects;
 using osu.Game.Rulesets.Taiko.Replays;
 using osu.Game.Rulesets.Timing;
@@ -36,6 +35,8 @@ namespace osu.Game.Rulesets.Taiko.UI
 
         public new TaikoInputManager KeyBindingInputManager => (TaikoInputManager)base.KeyBindingInputManager;
 
+        protected new TaikoPlayfieldAdjustmentContainer PlayfieldAdjustmentContainer => (TaikoPlayfieldAdjustmentContainer)base.PlayfieldAdjustmentContainer;
+
         protected override bool UserScrollSpeedAdjustment => false;
 
         private SkinnableDrawable scroller;
@@ -68,22 +69,7 @@ namespace osu.Game.Rulesets.Taiko.UI
             TimeRange.Value = ComputeTimeRange();
         }
 
-        protected virtual double ComputeTimeRange()
+        protected virtual double ComputeTimeRange() => PlayfieldAdjustmentContainer.ComputeTimeRange();
-        {
-            // Taiko scrolls at a constant 100px per 1000ms. More notes become visible as the playfield is lengthened.
-            const float scroll_rate = 10;
-
-            // Since the time range will depend on a positional value, it is referenced to the x480 pixel space.
-            // Width is used because it defines how many notes fit on the playfield.
-            // We clamp the ratio to the maximum aspect ratio to keep scroll speed consistent on widths lower than the default.
-            float ratio = Math.Max(DrawSize.X / 768f, TaikoPlayfieldAdjustmentContainer.MAXIMUM_ASPECT);
-
-            // Stable internally increased the slider velocity of objects by a factor of `VELOCITY_MULTIPLIER`.
-            // To simulate this, we shrink the time range by that factor here.
-            // This, when combined with the rest of the scrolling ruleset machinery (see `MultiplierControlPoint` et al.),
-            // has the effect of increasing each multiplier control point's multiplier by `VELOCITY_MULTIPLIER`, ensuring parity with stable.
-            return (Playfield.HitObjectContainer.DrawWidth / ratio) * scroll_rate / TaikoBeatmapConverter.VELOCITY_MULTIPLIER;
-        }
 
         protected override void UpdateAfterChildren()
         {

osu.Game.Rulesets.Taiko/UI/DrumTouchInputArea.cs

@@ -179,10 +179,9 @@ namespace osu.Game.Rulesets.Taiko.UI
             TaikoAction taikoAction = getTaikoActionFromPosition(position);
 
             // Not too sure how this can happen, but let's avoid throwing.
-            if (trackedActions.ContainsKey(source))
+            if (!trackedActions.TryAdd(source, taikoAction))
                 return;
 
-            trackedActions.Add(source, taikoAction);
             keyBindingContainer.TriggerPressed(taikoAction);
         }
 

osu.Game.Rulesets.Taiko/UI/TaikoPlayfieldAdjustmentContainer.cs

@@ -4,6 +4,7 @@
 using System;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Game.Rulesets.Taiko.Beatmaps;
 using osu.Game.Rulesets.UI;
 using osuTK;
 
@@ -14,6 +15,8 @@ namespace osu.Game.Rulesets.Taiko.UI
         public const float MAXIMUM_ASPECT = 16f / 9f;
         public const float MINIMUM_ASPECT = 5f / 4f;
 
+        private const float stable_gamefield_height = 480f;
+
         public readonly IBindable<bool> LockPlayfieldAspectRange = new BindableBool(true);
 
         public TaikoPlayfieldAdjustmentContainer()
@@ -21,6 +24,9 @@ namespace osu.Game.Rulesets.Taiko.UI
             RelativeSizeAxes = Axes.X;
             RelativePositionAxes = Axes.Y;
             Height = TaikoPlayfield.BASE_HEIGHT;
+
+            // Matches stable, see https://github.com/peppy/osu-stable-reference/blob/7519cafd1823f1879c0d9c991ba0e5c7fd3bfa02/osu!/GameModes/Play/Rulesets/Taiko/RulesetTaiko.cs#L514
+            Y = 135f / stable_gamefield_height;
         }
 
         protected override void Update()
@@ -28,8 +34,6 @@ namespace osu.Game.Rulesets.Taiko.UI
             base.Update();
 
             const float base_relative_height = TaikoPlayfield.BASE_HEIGHT / 768;
-            // Matches stable, see https://github.com/peppy/osu-stable-reference/blob/7519cafd1823f1879c0d9c991ba0e5c7fd3bfa02/osu!/GameModes/Play/Rulesets/Taiko/RulesetTaiko.cs#L514
-            const float base_position = 135f / 480f;
 
             float relativeHeight = base_relative_height;
 
@@ -51,10 +55,38 @@ namespace osu.Game.Rulesets.Taiko.UI
             // Limit the maximum relative height of the playfield to one-third of available area to avoid it masking out on extreme resolutions.
             relativeHeight = Math.Min(relativeHeight, 1f / 3f);
 
-            Y = base_position;
-
             Scale = new Vector2(Math.Max((Parent!.ChildSize.Y / 768f) * (relativeHeight / base_relative_height), 1f));
             Width = 1 / Scale.X;
         }
+
+        public double ComputeTimeRange()
+        {
+            float currentAspect = Parent!.ChildSize.X / Parent!.ChildSize.Y;
+
+            if (LockPlayfieldAspectRange.Value)
+                currentAspect = Math.Clamp(currentAspect, MINIMUM_ASPECT, MAXIMUM_ASPECT);
+
+            // in a game resolution of 1024x768, stable's scrolling system consists of objects being placed 600px (widthScaled - 40) away from their hit location.
+            // however, the point at which the object renders at the end of the screen is exactly x=640, but stable makes the object start moving from beyond the screen instead of the boundary point.
+            // therefore, in lazer we have to adjust the "in length" so that it's in a 640px->160px fashion before passing it down as a "time range".
+            // see stable's "in length": https://github.com/peppy/osu-stable-reference/blob/013c3010a9d495e3471a9c59518de17006f9ad89/osu!/GameplayElements/HitObjectManagerTaiko.cs#L168
+            const float stable_hit_location = 160f;
+            float widthScaled = currentAspect * stable_gamefield_height;
+            float inLength = widthScaled - stable_hit_location;
+
+            // also in a game resolution of 1024x768, stable makes hit objects scroll from 760px->160px at a duration of 6000ms, divided by slider velocity (i.e. at a rate of 0.1px/ms)
+            // compare: https://github.com/peppy/osu-stable-reference/blob/013c3010a9d495e3471a9c59518de17006f9ad89/osu!/GameplayElements/HitObjectManagerTaiko.cs#L218
+            // note: the variable "sv", in the linked reference, is equivalent to MultiplierControlPoint.Multiplier * 100, but since time range is agnostic of velocity, we replace "sv" with 100 below.
+            float inMsLength = inLength / 100 * 1000;
+
+            // stable multiplies the slider velocity by 1.4x for certain reasons, divide the time range by that factor to achieve similar result.
+            // for references on how the factor is applied to the time range, see:
+            //  1. https://github.com/peppy/osu-stable-reference/blob/013c3010a9d495e3471a9c59518de17006f9ad89/osu!/GameplayElements/HitObjectManagerTaiko.cs#L79 (DifficultySliderMultiplier multiplied by 1.4x)
+            //  2. https://github.com/peppy/osu-stable-reference/blob/013c3010a9d495e3471a9c59518de17006f9ad89/osu!/GameplayElements/HitObjectManager.cs#L468-L470 (DifficultySliderMultiplier used to calculate SliderScoringPointDistance)
+            //  3. https://github.com/peppy/osu-stable-reference/blob/013c3010a9d495e3471a9c59518de17006f9ad89/osu!/GameplayElements/HitObjectManager.cs#L248-L250 (SliderScoringPointDistance used to calculate slider velocity, i.e. the "sv" variable from above)
+            inMsLength /= TaikoBeatmapConverter.VELOCITY_MULTIPLIER;
+
+            return inMsLength;
+        }
     }
 }

osu.Game.Tests/Beatmaps/WorkingBeatmapTest.cs

@@ -7,6 +7,7 @@ using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
+using JetBrains.Annotations;
 using Moq;
 using NUnit.Framework;
 using osu.Game.Beatmaps;
@@ -98,9 +99,10 @@ namespace osu.Game.Tests.Beatmaps
                     Beatmap = beatmap;
                 }
 
+#pragma warning disable CS0067
+                [CanBeNull]
                 public event Action<HitObject, IEnumerable<HitObject>> ObjectConverted;
-
+#pragma warning restore CS0067
-                protected virtual void OnObjectConverted(HitObject arg1, IEnumerable<HitObject> arg2) => ObjectConverted?.Invoke(arg1, arg2);
 
                 public IBeatmap Beatmap { get; }
 

osu.Game.Tests/Chat/TestSceneChannelManager.cs

@@ -75,8 +75,6 @@ namespace osu.Game.Tests.Chat
                     return false;
                 };
             });
-
-            AddUntilStep("wait for notifications client", () => channelManager.NotificationsConnected);
         }
 
         [Test]

osu.Game.Tests/Database/RulesetStoreTests.cs

@@ -79,7 +79,7 @@ namespace osu.Game.Tests.Database
                 Assert.That(realm.Run(r => r.Find<RulesetInfo>(rulesetShortName)!.Available), Is.True);
 
                 // Availability is updated on construction of a RealmRulesetStore
-                var _ = new RealmRulesetStore(realm, storage);
+                _ = new RealmRulesetStore(realm, storage);
 
                 Assert.That(realm.Run(r => r.Find<RulesetInfo>(rulesetShortName)!.Available), Is.False);
             });
@@ -104,13 +104,13 @@ namespace osu.Game.Tests.Database
                 Assert.That(realm.Run(r => r.Find<RulesetInfo>(rulesetShortName)!.Available), Is.True);
 
                 // Availability is updated on construction of a RealmRulesetStore
-                var _ = new RealmRulesetStore(realm, storage);
+                _ = new RealmRulesetStore(realm, storage);
 
                 Assert.That(realm.Run(r => r.Find<RulesetInfo>(rulesetShortName)!.Available), Is.False);
 
                 // Simulate the ruleset getting updated
                 LoadTestRuleset.Version = Ruleset.CURRENT_RULESET_API_VERSION;
-                var __ = new RealmRulesetStore(realm, storage);
+                _ = new RealmRulesetStore(realm, storage);
 
                 Assert.That(realm.Run(r => r.Find<RulesetInfo>(rulesetShortName)!.Available), Is.True);
             });

osu.Game.Tests/Gameplay/TestSceneStoryboardSamples.cs

@@ -203,9 +203,9 @@ namespace osu.Game.Tests.Gameplay
 
         public IRenderer Renderer => host.Renderer;
         public AudioManager AudioManager => Audio;
-        public IResourceStore<byte[]> Files => null;
+        public IResourceStore<byte[]> Files => null!;
         public new IResourceStore<byte[]> Resources => base.Resources;
-        public RealmAccess RealmAccess => null;
+        public RealmAccess RealmAccess => null!;
         public IResourceStore<TextureUpload> CreateTextureLoaderStore(IResourceStore<byte[]> underlyingStore) => null;
 
         #endregion

osu.Game.Tests/NonVisual/Skinning/LegacySkinTextureFallbackTest.cs

@@ -169,9 +169,9 @@ namespace osu.Game.Tests.NonVisual.Skinning
 
                 public IRenderer Renderer => new DummyRenderer();
                 public AudioManager AudioManager => null;
-                public IResourceStore<byte[]> Files => null;
+                public IResourceStore<byte[]> Files => null!;
-                public IResourceStore<byte[]> Resources => null;
+                public IResourceStore<byte[]> Resources => null!;
-                public RealmAccess RealmAccess => null;
+                public RealmAccess RealmAccess => null!;
                 public IResourceStore<TextureUpload> CreateTextureLoaderStore(IResourceStore<byte[]> underlyingStore) => textureStore;
             }
         }

osu.Game.Tests/Rulesets/TestSceneBrokenRulesetHandling.cs

@@ -56,9 +56,9 @@ namespace osu.Game.Tests.Rulesets
 
             public override IEnumerable<Mod> GetModsFor(ModType type) => new Mod[] { null };
 
-            public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => null;
+            public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => null!;
-            public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => null;
+            public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => null!;
-            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => null;
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => null!;
         }
 
         private class TestAPIIncompatibleRuleset : Ruleset
@@ -69,9 +69,9 @@ namespace osu.Game.Tests.Rulesets
             // simulate API incompatibility by throwing similar exceptions.
             public override IEnumerable<Mod> GetModsFor(ModType type) => throw new MissingMethodException();
 
-            public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => null;
+            public override DrawableRuleset CreateDrawableRulesetWith(IBeatmap beatmap, IReadOnlyList<Mod> mods = null) => null!;
-            public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => null;
+            public override IBeatmapConverter CreateBeatmapConverter(IBeatmap beatmap) => null!;
-            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => null;
+            public override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => null!;
         }
     }
 }

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

@@ -142,7 +142,7 @@ namespace osu.Game.Tests.Visual.Editing
 
             AddStep("dismiss prompt", () =>
             {
-                var button = DialogOverlay.CurrentDialog.Buttons.Last();
+                var button = DialogOverlay.CurrentDialog!.Buttons.Last();
                 InputManager.MoveMouseTo(button);
                 InputManager.Click(MouseButton.Left);
             });
@@ -167,7 +167,7 @@ namespace osu.Game.Tests.Visual.Editing
             });
             AddUntilStep("save prompt shown", () => DialogOverlay.CurrentDialog is SaveRequiredPopupDialog);
 
-            AddStep("save changes", () => DialogOverlay.CurrentDialog.PerformOkAction());
+            AddStep("save changes", () => DialogOverlay.CurrentDialog!.PerformOkAction());
 
             EditorPlayer editorPlayer = null;
             AddUntilStep("player pushed", () => (editorPlayer = Stack.CurrentScreen as EditorPlayer) != null);

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

@@ -47,8 +47,8 @@ namespace osu.Game.Tests.Visual.Gameplay
             seekTo(referenceBeatmap.HitObjects[^1].GetEndTime());
             AddUntilStep("results displayed", () => getResultsScreen()?.IsLoaded == true);
 
-            AddAssert("score has combo", () => getResultsScreen().Score.Combo > 100);
+            AddAssert("score has combo", () => getResultsScreen().Score!.Combo > 100);
-            AddAssert("score has no misses", () => getResultsScreen().Score.Statistics[HitResult.Miss] == 0);
+            AddAssert("score has no misses", () => getResultsScreen().Score!.Statistics[HitResult.Miss] == 0);
 
             AddUntilStep("avatar displayed", () => getAvatar() != null);
             AddAssert("avatar not clickable", () => getAvatar().ChildrenOfType<OsuClickableContainer>().First().Action == null);

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

@@ -138,8 +138,8 @@ namespace osu.Game.Tests.Visual.Gameplay
             AddUntilStep("results displayed", () => Player.GetChildScreen() is ResultsScreen);
 
             // Player creates new instance of mods after gameplay to ensure any runtime references to drawables etc. are not retained.
-            AddAssert("results screen score has copied mods", () => (Player.GetChildScreen() as ResultsScreen)?.Score.Mods.First(), () => Is.Not.SameAs(playerMods.First()));
+            AddAssert("results screen score has copied mods", () => (Player.GetChildScreen() as ResultsScreen)?.Score?.Mods.First(), () => Is.Not.SameAs(playerMods.First()));
-            AddAssert("results screen score has matching", () => (Player.GetChildScreen() as ResultsScreen)?.Score.Mods.First(), () => Is.EqualTo(playerMods.First()));
+            AddAssert("results screen score has matching", () => (Player.GetChildScreen() as ResultsScreen)?.Score?.Mods.First(), () => Is.EqualTo(playerMods.First()));
 
             AddUntilStep("score in database", () => Realm.Run(r => r.Find<ScoreInfo>(Player.Score.ScoreInfo.ID) != null));
             AddUntilStep("databased score has correct mods", () => Realm.Run(r => r.Find<ScoreInfo>(Player.Score.ScoreInfo.ID))!.Mods.First(), () => Is.EqualTo(playerMods.First()));
@@ -184,7 +184,11 @@ namespace osu.Game.Tests.Visual.Gameplay
             CreateTest();
 
             AddUntilStep("wait for track to start running", () => Beatmap.Value.Track.IsRunning);
-            AddStep("log back in", () => API.Login("username", "password"));
+            AddStep("log back in", () =>
+            {
+                API.Login("username", "password");
+                ((DummyAPIAccess)API).AuthenticateSecondFactor("abcdefgh");
+            });
 
             AddStep("seek to completion", () => Player.GameplayClockContainer.Seek(Player.DrawableRuleset.Objects.Last().GetEndTime()));
 

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

@@ -120,7 +120,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         protected override void Update()
         {
             base.Update();
-            playbackManager?.ReplayInputHandler.SetFrameFromTime(Time.Current - 100);
+            playbackManager?.ReplayInputHandler?.SetFrameFromTime(Time.Current - 100);
         }
 
         [TearDownSteps]

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

@@ -198,7 +198,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             foreach (var legacyFrame in frames.Frames)
             {
                 var frame = new TestReplayFrame();
-                frame.FromLegacy(legacyFrame, null);
+                frame.FromLegacy(legacyFrame, null!);
                 playbackReplay.Frames.Add(frame);
             }
 

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

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Linq;
+using System.Net;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -9,7 +10,9 @@ using osu.Framework.Graphics.Containers;
 using osu.Framework.Testing;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
 using osu.Game.Overlays;
+using osu.Game.Overlays.Login;
 using osu.Game.Users.Drawables;
 using osuTK.Input;
 
@@ -18,6 +21,8 @@ namespace osu.Game.Tests.Visual.Menus
     [TestFixture]
     public partial class TestSceneLoginOverlay : OsuManualInputManagerTestScene
     {
+        private DummyAPIAccess dummyAPI => (DummyAPIAccess)API;
+
         private LoginOverlay loginOverlay = null!;
 
         [BackgroundDependencyLoader]
@@ -40,9 +45,69 @@ namespace osu.Game.Tests.Visual.Menus
         public void TestLoginSuccess()
         {
             AddStep("logout", () => API.Logout());
+            assertAPIState(APIState.Offline);
 
             AddStep("enter password", () => loginOverlay.ChildrenOfType<OsuPasswordTextBox>().First().Text = "password");
             AddStep("submit", () => loginOverlay.ChildrenOfType<OsuButton>().First(b => b.Text.ToString() == "Sign in").TriggerClick());
+
+            assertAPIState(APIState.RequiresSecondFactorAuth);
+            AddUntilStep("wait for second factor auth form", () => loginOverlay.ChildrenOfType<SecondFactorAuthForm>().SingleOrDefault(), () => Is.Not.Null);
+
+            AddStep("set up verification handling", () => dummyAPI.HandleRequest = req =>
+            {
+                switch (req)
+                {
+                    case VerifySessionRequest verifySessionRequest:
+                        if (verifySessionRequest.VerificationKey == "88800088")
+                            verifySessionRequest.TriggerSuccess();
+                        else
+                            verifySessionRequest.TriggerFailure(new WebException());
+                        return true;
+                }
+
+                return false;
+            });
+            AddStep("enter code", () => loginOverlay.ChildrenOfType<OsuTextBox>().First().Text = "88800088");
+            assertAPIState(APIState.Online);
+            AddStep("clear handler", () => dummyAPI.HandleRequest = null);
+        }
+
+        private void assertAPIState(APIState expected) =>
+            AddUntilStep($"login state is {expected}", () => API.State.Value, () => Is.EqualTo(expected));
+
+        [Test]
+        public void TestVerificationFailure()
+        {
+            bool verificationHandled = false;
+            AddStep("reset flag", () => verificationHandled = false);
+            AddStep("logout", () => API.Logout());
+            assertAPIState(APIState.Offline);
+
+            AddStep("enter password", () => loginOverlay.ChildrenOfType<OsuPasswordTextBox>().First().Text = "password");
+            AddStep("submit", () => loginOverlay.ChildrenOfType<OsuButton>().First(b => b.Text.ToString() == "Sign in").TriggerClick());
+
+            assertAPIState(APIState.RequiresSecondFactorAuth);
+            AddUntilStep("wait for second factor auth form", () => loginOverlay.ChildrenOfType<SecondFactorAuthForm>().SingleOrDefault(), () => Is.Not.Null);
+
+            AddStep("set up verification handling", () => dummyAPI.HandleRequest = req =>
+            {
+                switch (req)
+                {
+                    case VerifySessionRequest verifySessionRequest:
+                        if (verifySessionRequest.VerificationKey == "88800088")
+                            verifySessionRequest.TriggerSuccess();
+                        else
+                            verifySessionRequest.TriggerFailure(new WebException());
+                        verificationHandled = true;
+                        return true;
+                }
+
+                return false;
+            });
+            AddStep("enter code", () => loginOverlay.ChildrenOfType<OsuTextBox>().First().Text = "abcdefgh");
+            AddUntilStep("wait for verification handled", () => verificationHandled);
+            assertAPIState(APIState.RequiresSecondFactorAuth);
+            AddStep("clear handler", () => dummyAPI.HandleRequest = null);
         }
 
         [Test]
@@ -78,6 +143,12 @@ namespace osu.Game.Tests.Visual.Menus
             AddStep("enter password", () => loginOverlay.ChildrenOfType<OsuPasswordTextBox>().First().Text = "password");
             AddStep("submit", () => loginOverlay.ChildrenOfType<OsuButton>().First(b => b.Text.ToString() == "Sign in").TriggerClick());
 
+            assertAPIState(APIState.RequiresSecondFactorAuth);
+            AddUntilStep("wait for second factor auth form", () => loginOverlay.ChildrenOfType<SecondFactorAuthForm>().SingleOrDefault(), () => Is.Not.Null);
+
+            AddStep("enter code", () => loginOverlay.ChildrenOfType<OsuTextBox>().First().Text = "88800088");
+            assertAPIState(APIState.Online);
+
             AddStep("click on flag", () =>
             {
                 InputManager.MoveMouseTo(loginOverlay.ChildrenOfType<UpdateableFlag>().First());

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

@@ -250,7 +250,7 @@ namespace osu.Game.Tests.Visual.Menus
             {
             }
 
-            public virtual IBindable<int> UnreadCount => null;
+            public virtual IBindable<int> UnreadCount { get; } = new Bindable<int>();
 
             public IEnumerable<Notification> AllNotifications => Enumerable.Empty<Notification>();
         }

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

@@ -16,6 +16,8 @@ namespace osu.Game.Tests.Visual.Menus
     [TestFixture]
     public partial class TestSceneToolbarUserButton : OsuManualInputManagerTestScene
     {
+        private DummyAPIAccess dummyAPI => (DummyAPIAccess)API;
+
         public TestSceneToolbarUserButton()
         {
             Container mainContainer;
@@ -69,18 +71,20 @@ namespace osu.Game.Tests.Visual.Menus
         [Test]
         public void TestLoginLogout()
         {
-            AddStep("Log out", () => ((DummyAPIAccess)API).Logout());
+            AddStep("Log out", () => dummyAPI.Logout());
-            AddStep("Log in", () => ((DummyAPIAccess)API).Login("wang", "jang"));
+            AddStep("Log in", () => dummyAPI.Login("wang", "jang"));
+            AddStep("Authenticate via second factor", () => dummyAPI.AuthenticateSecondFactor("abcdefgh"));
         }
 
         [Test]
         public void TestStates()
         {
-            AddStep("Log in", () => ((DummyAPIAccess)API).Login("wang", "jang"));
+            AddStep("Log in", () => dummyAPI.Login("wang", "jang"));
+            AddStep("Authenticate via second factor", () => dummyAPI.AuthenticateSecondFactor("abcdefgh"));
 
             foreach (var state in Enum.GetValues<APIState>())
             {
-                AddStep($"Change state to {state}", () => ((DummyAPIAccess)API).SetState(state));
+                AddStep($"Change state to {state}", () => dummyAPI.SetState(state));
             }
         }
     }

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

@@ -58,7 +58,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                                                               .SkipWhile(r => r.Room.Category.Value == RoomCategory.Spotlight)
                                                               .All(r => r.Room.Category.Value == RoomCategory.Normal));
 
-            AddStep("remove first room", () => RoomManager.RemoveRoom(RoomManager.Rooms.FirstOrDefault(r => r.RoomID.Value == 0)));
+            AddStep("remove first room", () => RoomManager.RemoveRoom(RoomManager.Rooms.First(r => r.RoomID.Value == 0)));
             AddAssert("has 4 rooms", () => container.Rooms.Count == 4);
             AddAssert("first room removed", () => container.Rooms.All(r => r.Room.RoomID.Value != 0));
 

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

@@ -698,7 +698,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 var scoreInfo = ((ResultsScreen)multiplayerComponents.CurrentScreen).Score;
 
-                return !scoreInfo.Passed && scoreInfo.Rank == ScoreRank.F;
+                return scoreInfo?.Passed == false && scoreInfo.Rank == ScoreRank.F;
             });
         }
 

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

@@ -3,13 +3,18 @@
 
 #nullable disable
 
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Screens;
 using osu.Framework.Testing;
 using osu.Game.Online.Multiplayer;
 using osu.Game.Online.Rooms;
+using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu;
+using osu.Game.Rulesets.Osu.Mods;
+using osu.Game.Rulesets.Scoring;
 using osu.Game.Screens.OnlinePlay.Multiplayer;
 using osu.Game.Screens.Play;
 
@@ -19,14 +24,37 @@ namespace osu.Game.Tests.Visual.Multiplayer
     {
         private MultiplayerPlayer player;
 
-        [SetUpSteps]
+        [Test]
-        public override void SetUpSteps()
+        public void TestGameplay()
         {
-            base.SetUpSteps();
+            setup();
 
+            AddUntilStep("wait for gameplay start", () => player.LocalUserPlaying.Value);
+        }
+
+        [Test]
+        public void TestFail()
+        {
+            setup(() => new[] { new OsuModAutopilot() });
+
+            AddUntilStep("wait for gameplay start", () => player.LocalUserPlaying.Value);
+            AddStep("set health zero", () => player.ChildrenOfType<HealthProcessor>().Single().Health.Value = 0);
+            AddUntilStep("wait for fail", () => player.ChildrenOfType<HealthProcessor>().Single().HasFailed);
+            AddAssert("fail animation not shown", () => !player.GameplayState.HasFailed);
+
+            // ensure that even after reaching a failed state, score processor keeps accounting for new hit results.
+            // the testing method used here (autopilot + hold key) is sort-of dodgy, but works enough.
+            AddAssert("score is zero", () => player.GameplayState.ScoreProcessor.TotalScore.Value == 0);
+            AddStep("hold key", () => player.ChildrenOfType<OsuInputManager.RulesetKeyBindingContainer>().First().TriggerPressed(OsuAction.LeftButton));
+            AddUntilStep("score changed", () => player.GameplayState.ScoreProcessor.TotalScore.Value > 0);
+        }
+
+        private void setup(Func<IReadOnlyList<Mod>> mods = null)
+        {
             AddStep("set beatmap", () =>
             {
                 Beatmap.Value = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
+                SelectedMods.Value = mods?.Invoke() ?? Array.Empty<Mod>();
             });
 
             AddStep("Start track playing", () =>
@@ -52,11 +80,5 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("gameplay clock is not paused", () => !player.ChildrenOfType<GameplayClockContainer>().Single().IsPaused.Value);
             AddAssert("gameplay clock is running", () => player.ChildrenOfType<GameplayClockContainer>().Single().IsRunning);
         }
-
-        [Test]
-        public void TestGameplay()
-        {
-            AddUntilStep("wait for gameplay start", () => player.LocalUserPlaying.Value);
-        }
     }
 }

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

@@ -193,7 +193,7 @@ namespace osu.Game.Tests.Visual.Navigation
                 case ScorePresentType.Results:
                     AddUntilStep("wait for results", () => lastWaitedScreen != Game.ScreenStack.CurrentScreen && Game.ScreenStack.CurrentScreen is ResultsScreen);
                     AddStep("store last waited screen", () => lastWaitedScreen = Game.ScreenStack.CurrentScreen);
-                    AddUntilStep("correct score displayed", () => ((ResultsScreen)Game.ScreenStack.CurrentScreen).Score.Equals(getImport()));
+                    AddUntilStep("correct score displayed", () => ((ResultsScreen)Game.ScreenStack.CurrentScreen).Score!.Equals(getImport()));
                     AddAssert("correct ruleset selected", () => Game.Ruleset.Value.Equals(getImport().Ruleset));
                     break;
 

osu.Game.Tests/Visual/Online/TestSceneAccountCreationOverlay.cs

@@ -10,6 +10,8 @@ using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Testing;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Overlays;
 using osu.Game.Overlays.AccountCreation;
@@ -59,7 +61,40 @@ namespace osu.Game.Tests.Visual.Online
             AddStep("click button", () => accountCreation.ChildrenOfType<SettingsButton>().Single().TriggerClick());
             AddUntilStep("warning screen is present", () => accountCreation.ChildrenOfType<ScreenWarning>().SingleOrDefault()?.IsPresent == true);
 
-            AddStep("log back in", () => API.Login("dummy", "password"));
+            AddStep("log back in", () =>
+            {
+                API.Login("dummy", "password");
+                ((DummyAPIAccess)API).AuthenticateSecondFactor("abcdefgh");
+            });
+            AddUntilStep("overlay is hidden", () => accountCreation.State.Value == Visibility.Hidden);
+        }
+
+        [Test]
+        public void TestFullFlow()
+        {
+            AddStep("log out", () => API.Logout());
+
+            AddStep("show manually", () => accountCreation.Show());
+            AddUntilStep("overlay is visible", () => accountCreation.State.Value == Visibility.Visible);
+
+            AddStep("click button", () => accountCreation.ChildrenOfType<SettingsButton>().Single().TriggerClick());
+            AddUntilStep("warning screen is present", () => accountCreation.ChildrenOfType<ScreenWarning>().SingleOrDefault()?.IsPresent == true);
+
+            AddStep("proceed", () => accountCreation.ChildrenOfType<DangerousSettingsButton>().Single().TriggerClick());
+            AddUntilStep("entry screen is present", () => accountCreation.ChildrenOfType<ScreenEntry>().SingleOrDefault()?.IsPresent == true);
+
+            AddStep("input details", () =>
+            {
+                var entryScreen = accountCreation.ChildrenOfType<ScreenEntry>().Single();
+                entryScreen.ChildrenOfType<OsuTextBox>().ElementAt(0).Text = "new_user";
+                entryScreen.ChildrenOfType<OsuTextBox>().ElementAt(1).Text = "new.user@fake.mail";
+                entryScreen.ChildrenOfType<OsuTextBox>().ElementAt(2).Text = "password";
+            });
+            AddStep("click button", () => accountCreation.ChildrenOfType<ScreenEntry>().Single()
+                                                         .ChildrenOfType<SettingsButton>().Single().TriggerClick());
+            AddUntilStep("verification screen is present", () => accountCreation.ChildrenOfType<ScreenEmailVerification>().SingleOrDefault()?.IsPresent == true);
+
+            AddStep("verify", () => ((DummyAPIAccess)API).AuthenticateSecondFactor("abcdefgh"));
             AddUntilStep("overlay is hidden", () => accountCreation.State.Value == Visibility.Hidden);
         }
     }

osu.Game.Tests/Visual/Online/TestSceneCommentActions.cs

@@ -67,6 +67,7 @@ namespace osu.Game.Tests.Visual.Online
             Schedule(() =>
             {
                 API.Login("test", "test");
+                dummyAPI.AuthenticateSecondFactor("abcdefgh");
                 Child = commentsContainer = new CommentsContainer();
             });
         }

osu.Game.Tests/Visual/Online/TestSceneFavouriteButton.cs

@@ -6,6 +6,7 @@
 using NUnit.Framework;
 using osu.Framework.Graphics;
 using osu.Framework.Testing;
+using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Overlays.BeatmapSet.Buttons;
 using osuTK;
@@ -34,14 +35,22 @@ namespace osu.Game.Tests.Visual.Online
             AddStep("set valid beatmap", () => favourite.BeatmapSet.Value = new APIBeatmapSet { OnlineID = 88 });
             AddStep("log out", () => API.Logout());
             checkEnabled(false);
-            AddStep("log in", () => API.Login("test", "test"));
+            AddStep("log in", () =>
+            {
+                API.Login("test", "test");
+                ((DummyAPIAccess)API).AuthenticateSecondFactor("abcdefgh");
+            });
             checkEnabled(true);
         }
 
         [Test]
         public void TestBeatmapChange()
         {
-            AddStep("log in", () => API.Login("test", "test"));
+            AddStep("log in", () =>
+            {
+                API.Login("test", "test");
+                ((DummyAPIAccess)API).AuthenticateSecondFactor("abcdefgh");
+            });
             AddStep("set valid beatmap", () => favourite.BeatmapSet.Value = new APIBeatmapSet { OnlineID = 88 });
             checkEnabled(true);
             AddStep("set invalid beatmap", () => favourite.BeatmapSet.Value = new APIBeatmapSet());

osu.Game.Tests/Visual/Online/TestSceneSoloStatisticsWatcher.cs

@@ -90,7 +90,7 @@ namespace osu.Game.Tests.Visual.Online
                             else
                             {
                                 int userId = int.Parse(getUserRequest.Lookup);
-                                string rulesetName = getUserRequest.Ruleset.ShortName;
+                                string rulesetName = getUserRequest.Ruleset!.ShortName;
                                 var response = new APIUser
                                 {
                                     Id = userId,
@@ -177,7 +177,11 @@ namespace osu.Game.Tests.Visual.Online
             AddWaitStep("wait a bit", 5);
             AddAssert("update not received", () => update == null);
 
-            AddStep("log in user", () => dummyAPI.Login("user", "password"));
+            AddStep("log in user", () =>
+            {
+                dummyAPI.Login("user", "password");
+                dummyAPI.AuthenticateSecondFactor("abcdefgh");
+            });
         }
 
         [Test]

osu.Game.Tests/Visual/Online/TestSceneUserProfileOverlay.cs

@@ -52,7 +52,11 @@ namespace osu.Game.Tests.Visual.Online
             AddStep("show user", () => profile.ShowUser(new APIUser { Id = 1 }));
             AddToggleStep("toggle visibility", visible => profile.State.Value = visible ? Visibility.Visible : Visibility.Hidden);
             AddStep("log out", () => dummyAPI.Logout());
-            AddStep("log back in", () => dummyAPI.Login("username", "password"));
+            AddStep("log back in", () =>
+            {
+                dummyAPI.Login("username", "password");
+                dummyAPI.AuthenticateSecondFactor("abcdefgh");
+            });
         }
 
         [Test]
@@ -98,7 +102,11 @@ namespace osu.Game.Tests.Visual.Online
             });
             AddStep("logout", () => dummyAPI.Logout());
             AddStep("show user", () => profile.ShowUser(new APIUser { Id = 1 }));
-            AddStep("login", () => dummyAPI.Login("username", "password"));
+            AddStep("login", () =>
+            {
+                dummyAPI.Login("username", "password");
+                dummyAPI.AuthenticateSecondFactor("abcdefgh");
+            });
             AddWaitStep("wait some", 3);
             AddStep("complete request", () => pendingRequest.TriggerSuccess(TEST_USER));
         }

osu.Game.Tests/Visual/Online/TestSceneVotePill.cs

@@ -11,6 +11,7 @@ using osu.Framework.Allocation;
 using osu.Game.Overlays;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Containers;
+using osu.Game.Online.API;
 
 namespace osu.Game.Tests.Visual.Online
 {
@@ -72,7 +73,11 @@ namespace osu.Game.Tests.Visual.Online
             AddAssert("Login overlay is visible", () => login.State.Value == Visibility.Visible);
         }
 
-        private void logIn() => API.Login("localUser", "password");
+        private void logIn()
+        {
+            API.Login("localUser", "password");
+            ((DummyAPIAccess)API).AuthenticateSecondFactor("abcdefgh");
+        }
 
         private Comment getUserComment() => new Comment
         {

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsMatchSettingsOverlay.cs

@@ -179,7 +179,7 @@ namespace osu.Game.Tests.Visual.Playlists
 
             public IBindable<bool> InitialRoomsReceived { get; } = new Bindable<bool>(true);
 
-            public IBindableList<Room> Rooms => null;
+            public IBindableList<Room> Rooms => null!;
 
             public void AddOrUpdateRoom(Room room) => throw new NotImplementedException();
 

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsResultsScreen.cs

@@ -420,7 +420,7 @@ namespace osu.Game.Tests.Visual.Playlists
             public new LoadingSpinner RightSpinner => base.RightSpinner;
             public new ScorePanelList ScorePanelList => base.ScorePanelList;
 
-            public TestResultsScreen(ScoreInfo score, int roomId, PlaylistItem playlistItem, bool allowRetry = true)
+            public TestResultsScreen([CanBeNull] ScoreInfo score, int roomId, PlaylistItem playlistItem, bool allowRetry = true)
                 : base(score, roomId, playlistItem, allowRetry)
             {
             }

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsRoomCreation.cs

@@ -52,11 +52,11 @@ namespace osu.Game.Tests.Visual.Playlists
         [SetUpSteps]
         public void SetupSteps()
         {
-            AddStep("set room", () => SelectedRoom.Value = new Room());
+            AddStep("set room", () => SelectedRoom!.Value = new Room());
 
             importBeatmap();
 
-            AddStep("load match", () => LoadScreen(match = new TestPlaylistsRoomSubScreen(SelectedRoom.Value)));
+            AddStep("load match", () => LoadScreen(match = new TestPlaylistsRoomSubScreen(SelectedRoom!.Value)));
             AddUntilStep("wait for load", () => match.IsCurrentScreen());
         }
 
@@ -115,7 +115,7 @@ namespace osu.Game.Tests.Visual.Playlists
                 });
             });
 
-            AddAssert("first playlist item selected", () => match.SelectedItem.Value == SelectedRoom.Value.Playlist[0]);
+            AddAssert("first playlist item selected", () => match.SelectedItem.Value == SelectedRoom!.Value.Playlist[0]);
         }
 
         [Test]
@@ -201,7 +201,7 @@ namespace osu.Game.Tests.Visual.Playlists
 
         private void setupAndCreateRoom(Action<Room> room)
         {
-            AddStep("setup room", () => room(SelectedRoom.Value));
+            AddStep("setup room", () => room(SelectedRoom!.Value));
 
             AddStep("click create button", () =>
             {

osu.Game.Tests/Visual/Ranking/TestSceneResultsScreen.cs

@@ -418,7 +418,7 @@ namespace osu.Game.Tests.Visual.Ranking
             public UnrankedSoloResultsScreen(ScoreInfo score)
                 : base(score, true)
             {
-                Score.BeatmapInfo!.OnlineID = 0;
+                Score!.BeatmapInfo!.OnlineID = 0;
                 Score.BeatmapInfo.Status = BeatmapOnlineStatus.Pending;
             }
 
@@ -432,7 +432,7 @@ namespace osu.Game.Tests.Visual.Ranking
 
         private class RulesetWithNoPerformanceCalculator : OsuRuleset
         {
-            public override PerformanceCalculator CreatePerformanceCalculator() => null;
+            public override PerformanceCalculator CreatePerformanceCalculator() => null!;
         }
     }
 }

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

@@ -125,7 +125,11 @@ namespace osu.Game.Tests.Visual.UserInterface
             assertLoggedOutState();
 
             // moving from logged out -> logged in
-            AddStep("log back in", () => dummyAPI.Login("username", "password"));
+            AddStep("log back in", () =>
+            {
+                dummyAPI.Login("username", "password");
+                dummyAPI.AuthenticateSecondFactor("abcdefgh");
+            });
             assertLoggedInState();
         }
 

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

@@ -213,7 +213,7 @@ namespace osu.Game.Tests.Visual.UserInterface
             {
             }
 
-            public virtual IBindable<int> UnreadCount => null;
+            public virtual IBindable<int> UnreadCount { get; } = new Bindable<int>();
 
             public IEnumerable<Notification> AllNotifications => Enumerable.Empty<Notification>();
         }

osu.Game/Beatmaps/ControlPoints/EffectControlPoint.cs

@@ -21,7 +21,6 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         public readonly BindableDouble ScrollSpeedBindable = new BindableDouble(1)
         {
-            Precision = 0.01,
             MinValue = 0.01,
             MaxValue = 10
         };

osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs

@@ -567,10 +567,9 @@ namespace osu.Game.Beatmaps.Formats
             for (int i = pendingControlPoints.Count - 1; i >= 0; i--)
             {
                 var type = pendingControlPoints[i].GetType();
-                if (pendingControlPointTypes.Contains(type))
+                if (!pendingControlPointTypes.Add(type))
                     continue;
 
-                pendingControlPointTypes.Add(type);
                 beatmap.ControlPointInfo.Add(pendingControlPointsTime, pendingControlPoints[i]);
             }
 

osu.Game/Beatmaps/WorkingBeatmapCache.cs

@@ -116,7 +116,7 @@ namespace osu.Game.Beatmaps
         ITrackStore IBeatmapResourceProvider.Tracks => trackStore;
         IRenderer IStorageResourceProvider.Renderer => host?.Renderer ?? new DummyRenderer();
         AudioManager IStorageResourceProvider.AudioManager => audioManager;
-        RealmAccess IStorageResourceProvider.RealmAccess => null;
+        RealmAccess IStorageResourceProvider.RealmAccess => null!;
         IResourceStore<byte[]> IStorageResourceProvider.Files => files;
         IResourceStore<byte[]> IStorageResourceProvider.Resources => resources;
         IResourceStore<TextureUpload> IStorageResourceProvider.CreateTextureLoaderStore(IResourceStore<byte[]> underlyingStore) => host?.CreateTextureLoaderStore(underlyingStore);

osu.Game/Graphics/Containers/SelectionCycleFillFlowContainer.cs

@@ -52,10 +52,10 @@ namespace osu.Game.Graphics.Containers
 
         public override void Add(T drawable)
         {
-            base.Add(drawable);
-
             Debug.Assert(drawable != null);
 
+            base.Add(drawable);
+
             drawable.StateChanged += state => selectionChanged(drawable, state);
         }
 

osu.Game/Graphics/OsuColour.cs

@@ -77,7 +77,7 @@ namespace osu.Game.Graphics
             {
                 case HitResult.IgnoreMiss:
                 case HitResult.SmallTickMiss:
-                    return Orange1;
+                    return Color4.Gray;
 
                 case HitResult.Miss:
                 case HitResult.LargeTickMiss:

osu.Game/Graphics/UserInterface/BreadcrumbControl.cs

@@ -10,6 +10,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.UserInterface;
 using System.Linq;
+using JetBrains.Annotations;
 using osu.Framework.Graphics.Sprites;
 
 namespace osu.Game.Graphics.UserInterface
@@ -48,6 +49,7 @@ namespace osu.Game.Graphics.UserInterface
         {
             protected virtual float ChevronSize => 10;
 
+            [CanBeNull]
             public event Action<Visibility> StateChanged;
 
             public readonly SpriteIcon Chevron;

osu.Game/IO/IStorageResourceProvider.cs

@@ -41,6 +41,6 @@ namespace osu.Game.IO
         /// </summary>
         /// <param name="underlyingStore">The underlying provider of texture data (in arbitrary image formats).</param>
         /// <returns>A texture loader store.</returns>
-        IResourceStore<TextureUpload> CreateTextureLoaderStore(IResourceStore<byte[]> underlyingStore);
+        IResourceStore<TextureUpload>? CreateTextureLoaderStore(IResourceStore<byte[]> underlyingStore);
     }
 }

osu.Game/Localisation/ToolbarStrings.cs

@@ -19,6 +19,11 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString Connecting => new TranslatableString(getKey(@"connecting"), @"Connecting...");
 
+        /// <summary>
+        /// "Verification required"
+        /// </summary>
+        public static LocalisableString VerificationRequired => new TranslatableString(getKey(@"verification_required"), @"Verification required");
+
         /// <summary>
         /// "home"
         /// </summary>

osu.Game/Online/API/APIAccess.cs

@@ -21,7 +21,7 @@ using osu.Game.Configuration;
 using osu.Game.Localisation;
 using osu.Game.Online.API.Requests;
 using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Notifications;
+using osu.Game.Online.Chat;
 using osu.Game.Online.Notifications.WebSocket;
 using osu.Game.Users;
 
@@ -48,6 +48,8 @@ namespace osu.Game.Online.API
 
         public string ProvidedUsername { get; private set; }
 
+        public string SecondFactorCode { get; private set; }
+
         private string password;
 
         public IBindable<APIUser> LocalUser => localUser;
@@ -55,6 +57,8 @@ namespace osu.Game.Online.API
         public IBindable<UserActivity> Activity => activity;
         public IBindable<UserStatistics> Statistics => statistics;
 
+        public INotificationsClient NotificationsClient { get; }
+
         public Language Language => game.CurrentLanguage.Value;
 
         private Bindable<APIUser> localUser { get; } = new Bindable<APIUser>(createGuestUser());
@@ -82,6 +86,7 @@ namespace osu.Game.Online.API
 
             APIEndpointUrl = endpointConfiguration.APIEndpointUrl;
             WebsiteRootUrl = endpointConfiguration.WebsiteRootUrl;
+            NotificationsClient = setUpNotificationsClient();
 
             authentication = new OAuth(endpointConfiguration.APIClientID, endpointConfiguration.APIClientSecret, APIEndpointUrl);
             log = Logger.GetLogger(LoggingTarget.Network);
@@ -114,6 +119,30 @@ namespace osu.Game.Online.API
             thread.Start();
         }
 
+        private WebSocketNotificationsClientConnector setUpNotificationsClient()
+        {
+            var connector = new WebSocketNotificationsClientConnector(this);
+
+            connector.MessageReceived += msg =>
+            {
+                switch (msg.Event)
+                {
+                    case @"verified":
+                        if (state.Value == APIState.RequiresSecondFactorAuth)
+                            state.Value = APIState.Online;
+                        break;
+
+                    case @"logout":
+                        if (state.Value == APIState.Online)
+                            Logout();
+
+                        break;
+                }
+            };
+
+            return connector;
+        }
+
         private void onTokenChanged(ValueChangedEvent<OAuthToken> e) => config.SetValue(OsuSetting.Token, config.Get<bool>(OsuSetting.SavePassword) ? authentication.TokenString : string.Empty);
 
         internal new void Schedule(Action action) => base.Schedule(action);
@@ -197,6 +226,7 @@ namespace osu.Game.Online.API
         /// </summary>
         /// <remarks>
         /// This method takes control of <see cref="state"/> and transitions from <see cref="APIState.Connecting"/> to either
+        /// - <see cref="APIState.RequiresSecondFactorAuth"/> (pending 2fa)
         /// - <see cref="APIState.Online"/>  (successful connection)
         /// - <see cref="APIState.Failing"/> (failed connection but retrying)
         /// - <see cref="APIState.Offline"/> (failed and can't retry, clear credentials and require user interaction)
@@ -204,8 +234,6 @@ namespace osu.Game.Online.API
         /// <returns>Whether the connection attempt was successful.</returns>
         private void attemptConnect()
         {
-            state.Value = APIState.Connecting;
-
             if (localUser.IsDefault)
             {
                 // Show a placeholder user if saved credentials are available.
@@ -223,6 +251,7 @@ namespace osu.Game.Online.API
 
             if (!authentication.HasValidAccessToken)
             {
+                state.Value = APIState.Connecting;
                 LastLoginError = null;
 
                 try
@@ -240,40 +269,79 @@ namespace osu.Game.Online.API
                 }
             }
 
-            var userReq = new GetUserRequest();
+            switch (state.Value)
-            userReq.Failure += ex =>
             {
-                if (ex is APIException)
+                case APIState.RequiresSecondFactorAuth:
                 {
-                    LastLoginError = ex;
+                    if (string.IsNullOrEmpty(SecondFactorCode))
-                    log.Add($@"Login failed for username {ProvidedUsername} on user retrieval ({LastLoginError.Message})!");
+                        return;
-                    Logout();
+
+                    state.Value = APIState.Connecting;
+                    LastLoginError = null;
+
+                    var verificationRequest = new VerifySessionRequest(SecondFactorCode);
+
+                    verificationRequest.Success += () => state.Value = APIState.Online;
+                    verificationRequest.Failure += ex =>
+                    {
+                        state.Value = APIState.RequiresSecondFactorAuth;
+                        LastLoginError = ex;
+                        SecondFactorCode = null;
+                    };
+
+                    if (!handleRequest(verificationRequest))
+                    {
+                        state.Value = APIState.Failing;
+                        return;
+                    }
+
+                    if (state.Value != APIState.Online)
+                        return;
+
+                    break;
                 }
-                else if (ex is WebException webException && webException.Message == @"Unauthorized")
+
+                default:
                 {
-                    log.Add(@"Login no longer valid");
+                    var userReq = new GetMeRequest();
-                    Logout();
+
+                    userReq.Failure += ex =>
+                    {
+                        if (ex is APIException)
+                        {
+                            LastLoginError = ex;
+                            log.Add($@"Login failed for username {ProvidedUsername} on user retrieval ({LastLoginError.Message})!");
+                            Logout();
+                        }
+                        else if (ex is WebException webException && webException.Message == @"Unauthorized")
+                        {
+                            log.Add(@"Login no longer valid");
+                            Logout();
+                        }
+                        else
+                        {
+                            state.Value = APIState.Failing;
+                        }
+                    };
+
+                    userReq.Success += me =>
+                    {
+                        me.Status.Value = configStatus.Value ?? UserStatus.Online;
+
+                        setLocalUser(me);
+
+                        state.Value = me.SessionVerified ? APIState.Online : APIState.RequiresSecondFactorAuth;
+                        failureCount = 0;
+                    };
+
+                    if (!handleRequest(userReq))
+                    {
+                        state.Value = APIState.Failing;
+                        return;
+                    }
+
+                    break;
                 }
-                else
-                {
-                    state.Value = APIState.Failing;
-                }
-            };
-            userReq.Success += user =>
-            {
-                user.Status.Value = configStatus.Value ?? UserStatus.Online;
-
-                setLocalUser(user);
-
-                // we're connected!
-                state.Value = APIState.Online;
-                failureCount = 0;
-            };
-
-            if (!handleRequest(userReq))
-            {
-                state.Value = APIState.Failing;
-                return;
             }
 
             var friendsReq = new GetFriendsRequest();
@@ -321,11 +389,17 @@ namespace osu.Game.Online.API
             this.password = password;
         }
 
+        public void AuthenticateSecondFactor(string code)
+        {
+            Debug.Assert(State.Value == APIState.RequiresSecondFactorAuth);
+
+            SecondFactorCode = code;
+        }
+
         public IHubClientConnector GetHubConnector(string clientName, string endpoint, bool preferMessagePack) =>
             new HubClientConnector(clientName, endpoint, this, versionHash, preferMessagePack);
 
-        public NotificationsClientConnector GetNotificationsConnector() =>
+        public IChatClient GetChatClient() => new WebSocketChatClient(this);
-            new WebSocketNotificationsClientConnector(this);
 
         public RegistrationRequest.RegistrationRequestErrors CreateAccount(string email, string username, string password)
         {
@@ -507,6 +581,7 @@ namespace osu.Game.Online.API
         public void Logout()
         {
             password = null;
+            SecondFactorCode = null;
             authentication.Clear();
 
             // Scheduled prior to state change such that the state changed event is invoked with the correct user and their friends present
@@ -566,6 +641,11 @@ namespace osu.Game.Online.API
         /// </summary>
         Failing,
 
+        /// <summary>
+        /// Waiting on second factor authentication.
+        /// </summary>
+        RequiresSecondFactorAuth,
+
         /// <summary>
         /// We are in the process of (re-)connecting.
         /// </summary>

osu.Game/Online/API/DummyAPIAccess.cs

@@ -7,8 +7,10 @@ using System.Threading.Tasks;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Game.Localisation;
+using osu.Game.Online.API.Requests;
 using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Notifications;
+using osu.Game.Online.Chat;
+using osu.Game.Online.Notifications.WebSocket;
 using osu.Game.Tests;
 using osu.Game.Users;
 
@@ -30,6 +32,9 @@ namespace osu.Game.Online.API
 
         public Bindable<UserStatistics?> Statistics { get; } = new Bindable<UserStatistics?>();
 
+        public DummyNotificationsClient NotificationsClient { get; } = new DummyNotificationsClient();
+        INotificationsClient IAPIProvider.NotificationsClient => NotificationsClient;
+
         public Language Language => Language.en;
 
         public string AccessToken => "token";
@@ -57,6 +62,7 @@ namespace osu.Game.Online.API
 
         private bool shouldFailNextLogin;
         private bool stayConnectingNextLogin;
+        private bool requiredSecondFactorAuth = true;
 
         /// <summary>
         /// The current connectivity state of the API.
@@ -117,13 +123,46 @@ namespace osu.Game.Online.API
                 Id = DUMMY_USER_ID,
             };
 
+            if (requiredSecondFactorAuth)
+            {
+                state.Value = APIState.RequiresSecondFactorAuth;
+            }
+            else
+            {
+                onSuccessfulLogin();
+                requiredSecondFactorAuth = true;
+            }
+        }
+
+        public void AuthenticateSecondFactor(string code)
+        {
+            var request = new VerifySessionRequest(code);
+            request.Failure += e =>
+            {
+                state.Value = APIState.RequiresSecondFactorAuth;
+                LastLoginError = e;
+            };
+
+            state.Value = APIState.Connecting;
+            LastLoginError = null;
+
+            // if no handler installed / handler can't handle verification, just assume that the server would verify for simplicity.
+            if (HandleRequest?.Invoke(request) != true)
+                onSuccessfulLogin();
+
+            // if a handler did handle this, make sure the verification actually passed.
+            if (request.CompletionState == APIRequestCompletionState.Completed)
+                onSuccessfulLogin();
+        }
+
+        private void onSuccessfulLogin()
+        {
+            state.Value = APIState.Online;
             Statistics.Value = new UserStatistics
             {
                 GlobalRank = 1,
                 CountryRank = 1
             };
-
-            state.Value = APIState.Online;
         }
 
         public void Logout()
@@ -144,7 +183,7 @@ namespace osu.Game.Online.API
 
         public IHubClientConnector? GetHubConnector(string clientName, string endpoint, bool preferMessagePack) => null;
 
-        public NotificationsClientConnector GetNotificationsConnector() => new PollingNotificationsClientConnector(this);
+        public IChatClient GetChatClient() => new TestChatClientConnector(this);
 
         public RegistrationRequest.RegistrationRequestErrors? CreateAccount(string email, string username, string password)
         {
@@ -159,6 +198,11 @@ namespace osu.Game.Online.API
         IBindable<UserActivity> IAPIProvider.Activity => Activity;
         IBindable<UserStatistics?> IAPIProvider.Statistics => Statistics;
 
+        /// <summary>
+        /// Skip 2FA requirement for next login.
+        /// </summary>
+        public void SkipSecondFactor() => requiredSecondFactorAuth = false;
+
         /// <summary>
         /// During the next simulated login, the process will fail immediately.
         /// </summary>

osu.Game/Online/API/IAPIProvider.cs

@@ -6,7 +6,8 @@ using System.Threading.Tasks;
 using osu.Framework.Bindables;
 using osu.Game.Localisation;
 using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Notifications;
+using osu.Game.Online.Chat;
+using osu.Game.Online.Notifications.WebSocket;
 using osu.Game.Users;
 
 namespace osu.Game.Online.API
@@ -111,6 +112,12 @@ namespace osu.Game.Online.API
         /// <param name="password">The user's password.</param>
         void Login(string username, string password);
 
+        /// <summary>
+        /// Provide a second-factor authentication code for authentication.
+        /// </summary>
+        /// <param name="code">The 2FA code.</param>
+        void AuthenticateSecondFactor(string code);
+
         /// <summary>
         /// Log out the current user.
         /// </summary>
@@ -130,9 +137,14 @@ namespace osu.Game.Online.API
         IHubClientConnector? GetHubConnector(string clientName, string endpoint, bool preferMessagePack = true);
 
         /// <summary>
-        /// Constructs a new <see cref="NotificationsClientConnector"/>.
+        /// Accesses the <see cref="INotificationsClient"/> used to receive asynchronous notifications from web.
         /// </summary>
-        NotificationsClientConnector GetNotificationsConnector();
+        INotificationsClient NotificationsClient { get; }
+
+        /// <summary>
+        /// Creates a <see cref="IChatClient"/> instance to use in order to chat.
+        /// </summary>
+        IChatClient GetChatClient();
 
         /// <summary>
         /// Create a new user account. This is a blocking operation.

osu.Game/Online/API/OAuth.cs

@@ -128,19 +128,12 @@ namespace osu.Game.Online.API
             // if we already have a valid access token, let's use it.
             if (accessTokenValid) return true;
 
-            // we want to ensure only a single authentication update is happening at once.
+            // if not, let's try using our refresh token to request a new access token.
-            lock (access_token_retrieval_lock)
+            if (!string.IsNullOrEmpty(Token.Value?.RefreshToken))
-            {
+                // ReSharper disable once PossibleNullReferenceException
-                // re-check if valid, in case another request completed and revalidated our access.
+                AuthenticateWithRefresh(Token.Value.RefreshToken);
-                if (accessTokenValid) return true;
 
-                // if not, let's try using our refresh token to request a new access token.
+            return accessTokenValid;
-                if (!string.IsNullOrEmpty(Token.Value?.RefreshToken))
-                    // ReSharper disable once PossibleNullReferenceException
-                    AuthenticateWithRefresh(Token.Value.RefreshToken);
-
-                return accessTokenValid;
-            }
         }
 
         private bool accessTokenValid => Token.Value?.IsValid ?? false;
@@ -149,14 +142,18 @@ namespace osu.Game.Online.API
 
         internal string RequestAccessToken()
         {
-            if (!ensureAccessToken()) return null;
+            lock (access_token_retrieval_lock)
+            {
+                if (!ensureAccessToken()) return null;
 
-            return Token.Value.AccessToken;
+                return Token.Value.AccessToken;
+            }
         }
 
         internal void Clear()
         {
-            Token.Value = null;
+            lock (access_token_retrieval_lock)
+                Token.Value = null;
         }
 
         private class AccessTokenRequestRefresh : AccessTokenRequest

osu.Game/Online/API/Requests/GetMeRequest.cs

@@ -0,0 +1,24 @@
+// 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.Game.Online.API.Requests.Responses;
+using osu.Game.Rulesets;
+
+namespace osu.Game.Online.API.Requests
+{
+    public class GetMeRequest : APIRequest<APIMe>
+    {
+        public readonly IRulesetInfo? Ruleset;
+
+        /// <summary>
+        /// Gets the currently logged-in user.
+        /// </summary>
+        /// <param name="ruleset">The ruleset to get the user's info for.</param>
+        public GetMeRequest(IRulesetInfo? ruleset = null)
+        {
+            Ruleset = ruleset;
+        }
+
+        protected override string Target => $@"me/{Ruleset?.ShortName}";
+    }
+}

osu.Game/Online/API/Requests/GetSystemTitleRequest.cs

@@ -1,7 +1,6 @@
 // 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.Game.Online.API.Requests.Responses;
 
 namespace osu.Game.Online.API.Requests
@@ -9,7 +8,7 @@ namespace osu.Game.Online.API.Requests
     public class GetSystemTitleRequest : OsuJsonWebRequest<APISystemTitle>
     {
         public GetSystemTitleRequest()
-            : base($@"https://assets.ppy.sh/lazer-status.json?{DateTimeOffset.UtcNow.ToUnixTimeSeconds() / 1800}")
+            : base(@"https://assets.ppy.sh/lazer-status.json")
         {
         }
     }

osu.Game/Online/API/Requests/GetUserRequest.cs

@@ -1,8 +1,6 @@
 // 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.
 
-#nullable disable
-
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Rulesets;
 
@@ -11,24 +9,17 @@ namespace osu.Game.Online.API.Requests
     public class GetUserRequest : APIRequest<APIUser>
     {
         public readonly string Lookup;
-        public readonly IRulesetInfo Ruleset;
+        public readonly IRulesetInfo? Ruleset;
         private readonly LookupType lookupType;
 
-        /// <summary>
-        /// Gets the currently logged-in user.
-        /// </summary>
-        public GetUserRequest()
-        {
-        }
-
         /// <summary>
         /// Gets a user from their ID.
         /// </summary>
         /// <param name="userId">The user to get.</param>
         /// <param name="ruleset">The ruleset to get the user's info for.</param>
-        public GetUserRequest(long? userId = null, IRulesetInfo ruleset = null)
+        public GetUserRequest(long? userId = null, IRulesetInfo? ruleset = null)
         {
-            Lookup = userId.ToString();
+            Lookup = userId.ToString()!;
             lookupType = LookupType.Id;
             Ruleset = ruleset;
         }
@@ -38,14 +29,14 @@ namespace osu.Game.Online.API.Requests
         /// </summary>
         /// <param name="username">The user to get.</param>
         /// <param name="ruleset">The ruleset to get the user's info for.</param>
-        public GetUserRequest(string username = null, IRulesetInfo ruleset = null)
+        public GetUserRequest(string username, IRulesetInfo? ruleset = null)
         {
             Lookup = username;
             lookupType = LookupType.Username;
             Ruleset = ruleset;
         }
 
-        protected override string Target => Lookup != null ? $@"users/{Lookup}/{Ruleset?.ShortName}?key={lookupType.ToString().ToLowerInvariant()}" : $@"me/{Ruleset?.ShortName}";
+        protected override string Target => $@"users/{Lookup}/{Ruleset?.ShortName}?key={lookupType.ToString().ToLowerInvariant()}";
 
         private enum LookupType
         {

osu.Game/Online/API/Requests/ReissueVerificationCodeRequest.cs

@@ -0,0 +1,22 @@
+// 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.Net.Http;
+using osu.Framework.IO.Network;
+
+namespace osu.Game.Online.API.Requests
+{
+    public class ReissueVerificationCodeRequest : APIRequest
+    {
+        protected override WebRequest CreateWebRequest()
+        {
+            var req = base.CreateWebRequest();
+
+            req.Method = HttpMethod.Post;
+
+            return req;
+        }
+
+        protected override string Target => @"session/verify/reissue";
+    }
+}

osu.Game/Online/API/Requests/Responses/APIMe.cs

@@ -0,0 +1,13 @@
+// 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 Newtonsoft.Json;
+
+namespace osu.Game.Online.API.Requests.Responses
+{
+    public class APIMe : APIUser
+    {
+        [JsonProperty("session_verified")]
+        public bool SessionVerified { get; set; }
+    }
+}

osu.Game/Online/API/Requests/VerifySessionRequest.cs

@@ -0,0 +1,30 @@
+// 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.Net.Http;
+using osu.Framework.IO.Network;
+
+namespace osu.Game.Online.API.Requests
+{
+    public class VerifySessionRequest : APIRequest
+    {
+        public readonly string VerificationKey;
+
+        public VerifySessionRequest(string verificationKey)
+        {
+            VerificationKey = verificationKey;
+        }
+
+        protected override WebRequest CreateWebRequest()
+        {
+            var req = base.CreateWebRequest();
+
+            req.Method = HttpMethod.Post;
+            req.AddParameter(@"verification_key", VerificationKey);
+
+            return req;
+        }
+
+        protected override string Target => @"session/verify";
+    }
+}

osu.Game/Online/Chat/ChannelManager.cs

@@ -16,7 +16,6 @@ using osu.Game.Database;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests;
 using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Notifications;
 using osu.Game.Overlays.Chat.Listing;
 
 namespace osu.Game.Online.Chat
@@ -64,13 +63,8 @@ namespace osu.Game.Online.Chat
         /// </summary>
         public IBindableList<Channel> AvailableChannels => availableChannels;
 
-        /// <summary>
-        /// Whether the client responsible for channel notifications is connected.
-        /// </summary>
-        public bool NotificationsConnected => connector.IsConnected.Value;
-
         private readonly IAPIProvider api;
-        private readonly NotificationsClientConnector connector;
+        private readonly IChatClient chatClient;
 
         [Resolved]
         private UserLookupCache users { get; set; }
@@ -85,7 +79,7 @@ namespace osu.Game.Online.Chat
         {
             this.api = api;
 
-            connector = api.GetNotificationsConnector();
+            chatClient = api.GetChatClient();
 
             CurrentChannel.ValueChanged += currentChannelChanged;
         }
@@ -93,15 +87,11 @@ namespace osu.Game.Online.Chat
         [BackgroundDependencyLoader]
         private void load()
         {
-            connector.ChannelJoined += ch => Schedule(() => joinChannel(ch));
+            chatClient.ChannelJoined += ch => Schedule(() => joinChannel(ch));
-
+            chatClient.ChannelParted += ch => Schedule(() => leaveChannel(getChannel(ch), false));
-            connector.ChannelParted += ch => Schedule(() => leaveChannel(getChannel(ch), false));
+            chatClient.NewMessages += msgs => Schedule(() => addMessages(msgs));
-
+            chatClient.PresenceReceived += () => Schedule(initializeChannels);
-            connector.NewMessages += msgs => Schedule(() => addMessages(msgs));
+            chatClient.RequestPresence();
-
-            connector.PresenceReceived += () => Schedule(initializeChannels);
-
-            connector.Start();
 
             apiState.BindTo(api.State);
             apiState.BindValueChanged(_ => SendAck(), true);
@@ -655,7 +645,7 @@ namespace osu.Game.Online.Chat
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);
-            connector?.Dispose();
+            chatClient?.Dispose();
         }
     }
 

osu.Game/Online/Chat/IChatClient.cs

@@ -0,0 +1,39 @@
+// 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;
+
+namespace osu.Game.Online.Chat
+{
+    /// <summary>
+    /// Interface for consuming online chat.
+    /// </summary>
+    public interface IChatClient : IDisposable
+    {
+        /// <summary>
+        /// Fired when a <see cref="Channel"/> has been joined.
+        /// </summary>
+        event Action<Channel>? ChannelJoined;
+
+        /// <summary>
+        /// Fired when a <see cref="Channel"/> has been parted.
+        /// </summary>
+        event Action<Channel>? ChannelParted;
+
+        /// <summary>
+        /// Fired when new <see cref="Message"/>s have arrived from the server.
+        /// </summary>
+        event Action<List<Message>>? NewMessages;
+
+        /// <summary>
+        /// Requests presence information from the server.
+        /// </summary>
+        void RequestPresence();
+
+        /// <summary>
+        /// Fired when the initial user presence information has been received.
+        /// </summary>
+        event Action? PresenceReceived;
+    }
+}

osu.Game/Online/Chat/WebSocketChatClient.cs

@@ -0,0 +1,173 @@
+// 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.Concurrent;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Threading;
+using System.Threading.Tasks;
+using Newtonsoft.Json;
+using osu.Framework.Bindables;
+using osu.Framework.Logging;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Online.Notifications.WebSocket;
+
+namespace osu.Game.Online.Chat
+{
+    public class WebSocketChatClient : IChatClient
+    {
+        public event Action<Channel>? ChannelJoined;
+        public event Action<Channel>? ChannelParted;
+        public event Action<List<Message>>? NewMessages;
+        public event Action? PresenceReceived;
+
+        private readonly IAPIProvider api;
+        private readonly INotificationsClient client;
+        private readonly ConcurrentDictionary<long, Channel> channelsMap = new ConcurrentDictionary<long, Channel>();
+
+        private CancellationTokenSource? chatStartCancellationSource;
+
+        public WebSocketChatClient(IAPIProvider api)
+        {
+            this.api = api;
+            client = api.NotificationsClient;
+            client.IsConnected.BindValueChanged(onConnectedChanged, true);
+        }
+
+        private void onConnectedChanged(ValueChangedEvent<bool> connected)
+        {
+            if (connected.NewValue)
+            {
+                client.MessageReceived += onMessageReceived;
+                attemptToStartChat();
+                RequestPresence();
+            }
+            else
+                chatStartCancellationSource?.Cancel();
+        }
+
+        private void attemptToStartChat()
+        {
+            chatStartCancellationSource?.Cancel();
+            chatStartCancellationSource = new CancellationTokenSource();
+
+            Task.Factory.StartNew(async () =>
+            {
+                while (!chatStartCancellationSource.IsCancellationRequested)
+                {
+                    try
+                    {
+                        await client.SendAsync(new StartChatRequest()).ConfigureAwait(false);
+                        Logger.Log(@"Now listening to websocket chat messages.", LoggingTarget.Network);
+                        chatStartCancellationSource.Cancel();
+                    }
+                    catch (Exception ex)
+                    {
+                        Logger.Log($@"Could not start listening to websocket chat messages: {ex}", LoggingTarget.Network);
+                        await Task.Delay(5000).ConfigureAwait(false);
+                    }
+                }
+            }, chatStartCancellationSource.Token);
+        }
+
+        public void RequestPresence()
+        {
+            var fetchReq = new GetUpdatesRequest(0);
+
+            fetchReq.Success += updates =>
+            {
+                if (updates?.Presence != null)
+                {
+                    foreach (var channel in updates.Presence)
+                        joinChannel(channel);
+
+                    handleMessages(updates.Messages);
+                }
+
+                PresenceReceived?.Invoke();
+            };
+
+            api.Queue(fetchReq);
+        }
+
+        private void onMessageReceived(SocketMessage message)
+        {
+            switch (message.Event)
+            {
+                case @"chat.channel.join":
+                    Debug.Assert(message.Data != null);
+
+                    Channel? joinedChannel = JsonConvert.DeserializeObject<Channel>(message.Data.ToString());
+                    Debug.Assert(joinedChannel != null);
+
+                    joinChannel(joinedChannel);
+                    break;
+
+                case @"chat.channel.part":
+                    Debug.Assert(message.Data != null);
+
+                    Channel? partedChannel = JsonConvert.DeserializeObject<Channel>(message.Data.ToString());
+                    Debug.Assert(partedChannel != null);
+
+                    partChannel(partedChannel);
+                    break;
+
+                case @"chat.message.new":
+                    Debug.Assert(message.Data != null);
+
+                    NewChatMessageData? messageData = JsonConvert.DeserializeObject<NewChatMessageData>(message.Data.ToString());
+                    Debug.Assert(messageData != null);
+
+                    foreach (var msg in messageData.Messages)
+                        postToChannel(msg);
+
+                    break;
+            }
+        }
+
+        private void postToChannel(Message message)
+        {
+            if (channelsMap.TryGetValue(message.ChannelId, out Channel? channel))
+            {
+                joinChannel(channel);
+                NewMessages?.Invoke(new List<Message> { message });
+                return;
+            }
+
+            var req = new GetChannelRequest(message.ChannelId);
+
+            req.Success += response =>
+            {
+                joinChannel(channelsMap[message.ChannelId] = response.Channel);
+                NewMessages?.Invoke(new List<Message> { message });
+            };
+            req.Failure += ex => Logger.Error(ex, "Failed to join channel");
+
+            api.Queue(req);
+        }
+
+        private void joinChannel(Channel ch)
+        {
+            ch.Joined.Value = true;
+            ChannelJoined?.Invoke(ch);
+        }
+
+        private void partChannel(Channel channel) => ChannelParted?.Invoke(channel);
+
+        private void handleMessages(List<Message>? messages)
+        {
+            if (messages == null)
+                return;
+
+            NewMessages?.Invoke(messages);
+        }
+
+        public void Dispose()
+        {
+            client.IsConnected.ValueChanged -= onConnectedChanged;
+            client.MessageReceived -= onMessageReceived;
+        }
+    }
+}

osu.Game/Online/EndpointConfiguration.cs

@@ -1,8 +1,6 @@
 // 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.
 
-#nullable disable
-
 namespace osu.Game.Online
 {
     /// <summary>
@@ -13,36 +11,36 @@ namespace osu.Game.Online
         /// <summary>
         /// The base URL for the website.
         /// </summary>
-        public string WebsiteRootUrl { get; set; }
+        public string WebsiteRootUrl { get; set; } = string.Empty;
 
         /// <summary>
         /// The endpoint for the main (osu-web) API.
         /// </summary>
-        public string APIEndpointUrl { get; set; }
+        public string APIEndpointUrl { get; set; } = string.Empty;
 
         /// <summary>
         /// The OAuth client secret.
         /// </summary>
-        public string APIClientSecret { get; set; }
+        public string APIClientSecret { get; set; } = string.Empty;
 
         /// <summary>
         /// The OAuth client ID.
         /// </summary>
-        public string APIClientID { get; set; }
+        public string APIClientID { get; set; } = string.Empty;
 
         /// <summary>
         /// The endpoint for the SignalR spectator server.
         /// </summary>
-        public string SpectatorEndpointUrl { get; set; }
+        public string SpectatorEndpointUrl { get; set; } = string.Empty;
 
         /// <summary>
         /// The endpoint for the SignalR multiplayer server.
         /// </summary>
-        public string MultiplayerEndpointUrl { get; set; }
+        public string MultiplayerEndpointUrl { get; set; } = string.Empty;
 
         /// <summary>
         /// The endpoint for the SignalR metadata server.
         /// </summary>
-        public string MetadataEndpointUrl { get; set; }
+        public string MetadataEndpointUrl { get; set; } = string.Empty;
     }
 }

osu.Game/Online/ExperimentalEndpointConfiguration.cs

@@ -1,19 +0,0 @@
-// 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.
-
-namespace osu.Game.Online
-{
-    public class ExperimentalEndpointConfiguration : EndpointConfiguration
-    {
-        public ExperimentalEndpointConfiguration()
-        {
-            WebsiteRootUrl = @"https://osu.ppy.sh";
-            APIEndpointUrl = @"https://lazer.ppy.sh";
-            APIClientSecret = @"FGc9GAtyHzeQDshWP5Ah7dega8hJACAJpQtw6OXk";
-            APIClientID = "5";
-            SpectatorEndpointUrl = "https://spectator.ppy.sh/spectator";
-            MultiplayerEndpointUrl = "https://spectator.ppy.sh/multiplayer";
-            MetadataEndpointUrl = "https://spectator.ppy.sh/metadata";
-        }
-    }
-}

osu.Game/Online/Notifications/NotificationsClientConnector.cs

@@ -1,42 +0,0 @@
-// 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.Threading;
-using System.Threading.Tasks;
-using osu.Game.Online.API;
-using osu.Game.Online.Chat;
-
-namespace osu.Game.Online.Notifications
-{
-    /// <summary>
-    /// An abstract connector or <see cref="NotificationsClient"/>s.
-    /// </summary>
-    public abstract class NotificationsClientConnector : PersistentEndpointClientConnector
-    {
-        public event Action<Channel>? ChannelJoined;
-        public event Action<Channel>? ChannelParted;
-        public event Action<List<Message>>? NewMessages;
-        public event Action? PresenceReceived;
-
-        protected NotificationsClientConnector(IAPIProvider api)
-            : base(api)
-        {
-        }
-
-        protected sealed override async Task<PersistentEndpointClient> BuildConnectionAsync(CancellationToken cancellationToken)
-        {
-            var client = await BuildNotificationClientAsync(cancellationToken).ConfigureAwait(false);
-
-            client.ChannelJoined = c => ChannelJoined?.Invoke(c);
-            client.ChannelParted = c => ChannelParted?.Invoke(c);
-            client.NewMessages = m => NewMessages?.Invoke(m);
-            client.PresenceReceived = () => PresenceReceived?.Invoke();
-
-            return client;
-        }
-
-        protected abstract Task<NotificationsClient> BuildNotificationClientAsync(CancellationToken cancellationToken);
-    }
-}

osu.Game/Online/Notifications/WebSocket/DummyNotificationsClient.cs

@@ -0,0 +1,29 @@
+// 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.Threading;
+using System.Threading.Tasks;
+using osu.Framework.Bindables;
+
+namespace osu.Game.Online.Notifications.WebSocket
+{
+    public class DummyNotificationsClient : INotificationsClient
+    {
+        public IBindable<bool> IsConnected => new BindableBool(true);
+
+        public event Action<SocketMessage>? MessageReceived;
+
+        public Func<SocketMessage, bool>? HandleMessage;
+
+        public Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = default)
+        {
+            if (HandleMessage?.Invoke(message) != true)
+                throw new InvalidOperationException($@"{nameof(DummyNotificationsClient)} cannot process this message.");
+
+            return Task.CompletedTask;
+        }
+
+        public void Receive(SocketMessage message) => MessageReceived?.Invoke(message);
+    }
+}

osu.Game/Online/Notifications/WebSocket/INotificationsClient.cs

@@ -0,0 +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 System.Threading;
+using System.Threading.Tasks;
+using osu.Framework.Bindables;
+
+namespace osu.Game.Online.Notifications.WebSocket
+{
+    /// <summary>
+    /// A client for asynchronous notifications sent by osu-web.
+    /// </summary>
+    public interface INotificationsClient
+    {
+        /// <summary>
+        /// Whether this <see cref="INotificationsClient"/> is currently connected to a server.
+        /// </summary>
+        IBindable<bool> IsConnected { get; }
+
+        /// <summary>
+        /// Invoked when a new <see cref="SocketMessage"/> arrives for this client.
+        /// </summary>
+        event Action<SocketMessage>? MessageReceived;
+
+        /// <summary>
+        /// Sends a <see cref="SocketMessage"/> to the notification server.
+        /// </summary>
+        Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = default);
+    }
+}

osu.Game/Online/Notifications/WebSocket/WebSocketNotificationsClient.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Net;
 using System.Net.WebSockets;
@@ -12,23 +11,20 @@ using System.Threading.Tasks;
 using Newtonsoft.Json;
 using osu.Framework.Extensions.TypeExtensions;
 using osu.Framework.Logging;
-using osu.Game.Online.API;
-using osu.Game.Online.API.Requests;
-using osu.Game.Online.Chat;
 
 namespace osu.Game.Online.Notifications.WebSocket
 {
     /// <summary>
     /// A notifications client which receives events via a websocket.
     /// </summary>
-    public class WebSocketNotificationsClient : NotificationsClient
+    public class WebSocketNotificationsClient : PersistentEndpointClient
     {
+        public event Action<SocketMessage>? MessageReceived;
+
         private readonly ClientWebSocket socket;
         private readonly string endpoint;
-        private readonly ConcurrentDictionary<long, Channel> channelsMap = new ConcurrentDictionary<long, Channel>();
 
-        public WebSocketNotificationsClient(ClientWebSocket socket, string endpoint, IAPIProvider api)
+        public WebSocketNotificationsClient(ClientWebSocket socket, string endpoint)
-            : base(api)
         {
             this.socket = socket;
             this.endpoint = endpoint;
@@ -37,11 +33,7 @@ namespace osu.Game.Online.Notifications.WebSocket
         public override async Task ConnectAsync(CancellationToken cancellationToken)
         {
             await socket.ConnectAsync(new Uri(endpoint), cancellationToken).ConfigureAwait(false);
-            await sendMessage(new StartChatRequest(), CancellationToken.None).ConfigureAwait(false);
-
             runReadLoop(cancellationToken);
-
-            await base.ConnectAsync(cancellationToken).ConfigureAwait(false);
         }
 
         private void runReadLoop(CancellationToken cancellationToken) => Task.Run(async () =>
@@ -73,7 +65,7 @@ namespace osu.Game.Online.Notifications.WebSocket
                                     break;
                                 }
 
-                                await onMessageReceivedAsync(message).ConfigureAwait(false);
+                                MessageReceived?.Invoke(message);
                             }
 
                             break;
@@ -105,69 +97,12 @@ namespace osu.Game.Online.Notifications.WebSocket
             }
         }
 
-        private async Task sendMessage(SocketMessage message, CancellationToken cancellationToken)
+        public async Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = default)
         {
             if (socket.State != WebSocketState.Open)
                 return;
 
-            await socket.SendAsync(Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(message)), WebSocketMessageType.Text, true, cancellationToken).ConfigureAwait(false);
+            await socket.SendAsync(Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(message)), WebSocketMessageType.Text, true, cancellationToken ?? CancellationToken.None).ConfigureAwait(false);
-        }
-
-        private async Task onMessageReceivedAsync(SocketMessage message)
-        {
-            switch (message.Event)
-            {
-                case @"chat.channel.join":
-                    Debug.Assert(message.Data != null);
-
-                    Channel? joinedChannel = JsonConvert.DeserializeObject<Channel>(message.Data.ToString());
-                    Debug.Assert(joinedChannel != null);
-
-                    HandleChannelJoined(joinedChannel);
-                    break;
-
-                case @"chat.channel.part":
-                    Debug.Assert(message.Data != null);
-
-                    Channel? partedChannel = JsonConvert.DeserializeObject<Channel>(message.Data.ToString());
-                    Debug.Assert(partedChannel != null);
-
-                    HandleChannelParted(partedChannel);
-                    break;
-
-                case @"chat.message.new":
-                    Debug.Assert(message.Data != null);
-
-                    NewChatMessageData? messageData = JsonConvert.DeserializeObject<NewChatMessageData>(message.Data.ToString());
-                    Debug.Assert(messageData != null);
-
-                    foreach (var msg in messageData.Messages)
-                        HandleChannelJoined(await getChannel(msg.ChannelId).ConfigureAwait(false));
-
-                    HandleMessages(messageData.Messages);
-                    break;
-            }
-        }
-
-        private async Task<Channel> getChannel(long channelId)
-        {
-            if (channelsMap.TryGetValue(channelId, out Channel? channel))
-                return channel;
-
-            var tsc = new TaskCompletionSource<Channel>();
-            var req = new GetChannelRequest(channelId);
-
-            req.Success += response =>
-            {
-                channelsMap[channelId] = response.Channel;
-                tsc.SetResult(response.Channel);
-            };
-
-            req.Failure += ex => tsc.SetException(ex);
-
-            API.Queue(req);
-
-            return await tsc.Task.ConfigureAwait(false);
         }
 
         public override async ValueTask DisposeAsync()

osu.Game/Online/Notifications/WebSocket/WebSocketNotificationsClientConnector.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 System;
 using System.Net;
 using System.Net.WebSockets;
 using System.Threading;
@@ -13,26 +14,26 @@ namespace osu.Game.Online.Notifications.WebSocket
     /// <summary>
     /// A connector for <see cref="WebSocketNotificationsClient"/>s that receive events via a websocket.
     /// </summary>
-    public class WebSocketNotificationsClientConnector : NotificationsClientConnector
+    public class WebSocketNotificationsClientConnector : PersistentEndpointClientConnector, INotificationsClient
     {
+        public event Action<SocketMessage>? MessageReceived;
+
         private readonly IAPIProvider api;
 
         public WebSocketNotificationsClientConnector(IAPIProvider api)
             : base(api)
         {
             this.api = api;
+            Start();
         }
 
-        protected override async Task<NotificationsClient> BuildNotificationClientAsync(CancellationToken cancellationToken)
+        protected override async Task<PersistentEndpointClient> BuildConnectionAsync(CancellationToken cancellationToken)
         {
-            var tcs = new TaskCompletionSource<string>();
-
             var req = new GetNotificationsRequest();
-            req.Success += bundle => tcs.SetResult(bundle.Endpoint);
+            // must use `PerformAsync()`, since we may not be fully online yet
-            req.Failure += ex => tcs.SetException(ex);
+            // (see `APIState.RequiresSecondFactorAuth` - in this state queued requests will not execute).
-            api.Queue(req);
+            await api.PerformAsync(req).ConfigureAwait(false);
-
+            string endpoint = req.Response!.Endpoint;
-            string endpoint = await tcs.Task.ConfigureAwait(false);
 
             ClientWebSocket socket = new ClientWebSocket();
             socket.Options.SetRequestHeader(@"Authorization", @$"Bearer {api.AccessToken}");
@@ -40,7 +41,17 @@ namespace osu.Game.Online.Notifications.WebSocket
             if (socket.Options.Proxy != null)
                 socket.Options.Proxy.Credentials = CredentialCache.DefaultCredentials;
 
-            return new WebSocketNotificationsClient(socket, endpoint, api);
+            var client = new WebSocketNotificationsClient(socket, endpoint);
+            client.MessageReceived += msg => MessageReceived?.Invoke(msg);
+            return client;
+        }
+
+        public Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = default)
+        {
+            if (CurrentConnection is not WebSocketNotificationsClient webSocketClient)
+                return Task.CompletedTask;
+
+            return webSocketClient.SendAsync(message, cancellationToken);
         }
     }
 }

osu.Game/Online/OnlineStatusNotifier.cs

@@ -11,6 +11,7 @@ using osu.Framework.Screens;
 using osu.Game.Online.API;
 using osu.Game.Online.Metadata;
 using osu.Game.Online.Multiplayer;
+using osu.Game.Online.Notifications.WebSocket;
 using osu.Game.Online.Spectator;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Notifications;
@@ -25,6 +26,8 @@ namespace osu.Game.Online
     {
         private readonly Func<IScreen> getCurrentScreen;
 
+        private INotificationsClient notificationsClient = null!;
+
         [Resolved]
         private MultiplayerClient multiplayerClient { get; set; } = null!;
 
@@ -55,9 +58,11 @@ namespace osu.Game.Online
         private void load(IAPIProvider api)
         {
             apiState = api.State.GetBoundCopy();
+            notificationsClient = api.NotificationsClient;
             multiplayerState = multiplayerClient.IsConnected.GetBoundCopy();
             spectatorState = spectatorClient.IsConnected.GetBoundCopy();
 
+            notificationsClient.MessageReceived += notifyAboutForcedDisconnection;
             multiplayerClient.Disconnecting += notifyAboutForcedDisconnection;
             spectatorClient.Disconnecting += notifyAboutForcedDisconnection;
             metadataClient.Disconnecting += notifyAboutForcedDisconnection;
@@ -127,10 +132,27 @@ namespace osu.Game.Online
             });
         }
 
+        private void notifyAboutForcedDisconnection(SocketMessage obj)
+        {
+            if (obj.Event != @"logout") return;
+
+            if (userNotified) return;
+
+            userNotified = true;
+            notificationOverlay?.Post(new SimpleErrorNotification
+            {
+                Icon = FontAwesome.Solid.ExclamationCircle,
+                Text = "You have been logged out due to a change to your account. Please log in again."
+            });
+        }
+
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);
 
+            if (notificationsClient.IsNotNull())
+                notificationsClient.MessageReceived += notifyAboutForcedDisconnection;
+
             if (spectatorClient.IsNotNull())
                 spectatorClient.Disconnecting -= notifyAboutForcedDisconnection;
 

osu.Game/Online/OnlineViewContainer.cs

@@ -3,6 +3,7 @@
 
 #nullable disable
 
+using System;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -79,10 +80,14 @@ namespace osu.Game.Online
 
                 case APIState.Failing:
                 case APIState.Connecting:
+                case APIState.RequiresSecondFactorAuth:
                     PopContentOut(Content);
                     LoadingSpinner.Show();
                     placeholder.FadeOut(transform_duration / 2, Easing.OutQuint);
                     break;
+
+                default:
+                    throw new ArgumentOutOfRangeException();
             }
         });
 

osu.Game/Online/PersistentEndpointClientConnector.cs

@@ -69,6 +69,7 @@ namespace osu.Game.Online
                     break;
 
                 case APIState.Online:
+                case APIState.RequiresSecondFactorAuth:
                     await connect().ConfigureAwait(true);
                     break;
             }
@@ -83,7 +84,7 @@ namespace osu.Game.Online
 
             try
             {
-                while (apiState.Value == APIState.Online)
+                while (apiState.Value == APIState.RequiresSecondFactorAuth || apiState.Value == APIState.Online)
                 {
                     // ensure any previous connection was disposed.
                     // this will also create a new cancellation token source.

osu.Game/Online/Spectator/SpectatorClient.cs

@@ -264,13 +264,12 @@ namespace osu.Game.Online.Spectator
         {
             Debug.Assert(ThreadSafety.IsUpdateThread);
 
-            if (watchedUsersRefCounts.ContainsKey(userId))
+            if (!watchedUsersRefCounts.TryAdd(userId, 1))
             {
                 watchedUsersRefCounts[userId]++;
                 return;
             }
 
-            watchedUsersRefCounts.Add(userId, 1);
             WatchUserInternal(userId);
         }
 

osu.Game/OsuGameBase.cs

@@ -102,7 +102,7 @@ namespace osu.Game
         public virtual bool UseDevelopmentServer => DebugUtils.IsDebugBuild;
 
         public virtual EndpointConfiguration CreateEndpoints() =>
-            UseDevelopmentServer ? new DevelopmentEndpointConfiguration() : new ExperimentalEndpointConfiguration();
+            UseDevelopmentServer ? new DevelopmentEndpointConfiguration() : new ProductionEndpointConfiguration();
 
         public virtual Version AssemblyVersion => Assembly.GetEntryAssembly()?.GetName().Version ?? new Version();
 
@@ -340,10 +340,6 @@ namespace osu.Game
             dependencies.Cache(beatmapCache = new BeatmapLookupCache());
             base.Content.Add(beatmapCache);
 
-            var scorePerformanceManager = new ScorePerformanceCache();
-            dependencies.Cache(scorePerformanceManager);
-            base.Content.Add(scorePerformanceManager);
-
             dependencies.CacheAs<IRulesetConfigCache>(rulesetConfigCache = new RulesetConfigCache(realm, RulesetStore));
 
             var powerStatus = CreateBatteryInfo();

osu.Game/Overlays/AccountCreation/ScreenEmailVerification.cs

@@ -0,0 +1,24 @@
+// 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.Graphics;
+using osu.Game.Overlays.Login;
+
+namespace osu.Game.Overlays.AccountCreation
+{
+    public partial class ScreenEmailVerification : AccountCreationScreen
+    {
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            InternalChild = new SecondFactorAuthForm
+            {
+                RelativeSizeAxes = Axes.Both,
+                Padding = new MarginPadding(20),
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+            };
+        }
+    }
+}

osu.Game/Overlays/AccountCreation/ScreenEntry.cs

@@ -1,12 +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.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Extensions.LocalisationExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -28,28 +27,30 @@ namespace osu.Game.Overlays.AccountCreation
 {
     public partial class ScreenEntry : AccountCreationScreen
     {
-        private ErrorTextFlowContainer usernameDescription;
+        private ErrorTextFlowContainer usernameDescription = null!;
-        private ErrorTextFlowContainer emailAddressDescription;
+        private ErrorTextFlowContainer emailAddressDescription = null!;
-        private ErrorTextFlowContainer passwordDescription;
+        private ErrorTextFlowContainer passwordDescription = null!;
 
-        private OsuTextBox usernameTextBox;
+        private OsuTextBox usernameTextBox = null!;
-        private OsuTextBox emailTextBox;
+        private OsuTextBox emailTextBox = null!;
-        private OsuPasswordTextBox passwordTextBox;
+        private OsuPasswordTextBox passwordTextBox = null!;
 
         [Resolved]
-        private IAPIProvider api { get; set; }
+        private IAPIProvider api { get; set; } = null!;
 
-        private ShakeContainer registerShake;
+        private IBindable<APIState> apiState = null!;
-        private ITextPart characterCheckText;
 
-        private OsuTextBox[] textboxes;
+        private ShakeContainer registerShake = null!;
-        private LoadingLayer loadingLayer;
+        private ITextPart characterCheckText = null!;
+
+        private OsuTextBox[] textboxes = null!;
+        private LoadingLayer loadingLayer = null!;
 
         [Resolved]
-        private GameHost host { get; set; }
+        private GameHost? host { get; set; }
 
         [Resolved]
-        private OsuGame game { get; set; }
+        private OsuGame? game { get; set; }
 
         [BackgroundDependencyLoader]
         private void load()
@@ -144,6 +145,8 @@ namespace osu.Game.Overlays.AccountCreation
 
             passwordTextBox.Current.BindValueChanged(_ => updateCharacterCheckTextColour(), true);
             characterCheckText.DrawablePartsRecreated += _ => updateCharacterCheckTextColour();
+
+            apiState = api.State.GetBoundCopy();
         }
 
         private void updateCharacterCheckTextColour()
@@ -180,7 +183,7 @@ namespace osu.Game.Overlays.AccountCreation
             Task.Run(() =>
             {
                 bool success;
-                RegistrationRequest.RegistrationRequestErrors errors = null;
+                RegistrationRequest.RegistrationRequestErrors? errors = null;
 
                 try
                 {
@@ -210,7 +213,7 @@ namespace osu.Game.Overlays.AccountCreation
                                 if (!string.IsNullOrEmpty(errors.Message))
                                     passwordDescription.AddErrors(new[] { errors.Message });
 
-                                game.OpenUrlExternally($"{errors.Redirect}?username={usernameTextBox.Text}&email={emailTextBox.Text}", true);
+                                game?.OpenUrlExternally($"{errors.Redirect}?username={usernameTextBox.Text}&email={emailTextBox.Text}", true);
                             }
                         }
                         else
@@ -223,6 +226,12 @@ namespace osu.Game.Overlays.AccountCreation
                         return;
                     }
 
+                    apiState.BindValueChanged(state =>
+                    {
+                        if (state.NewValue == APIState.RequiresSecondFactorAuth)
+                            this.Push(new ScreenEmailVerification());
+                    });
+
                     api.Login(usernameTextBox.Text, passwordTextBox.Text);
                 });
             });
@@ -241,6 +250,6 @@ namespace osu.Game.Overlays.AccountCreation
             return false;
         }
 
-        private OsuTextBox nextUnfilledTextBox() => textboxes.FirstOrDefault(t => string.IsNullOrEmpty(t.Text));
+        private OsuTextBox? nextUnfilledTextBox() => textboxes.FirstOrDefault(t => string.IsNullOrEmpty(t.Text));
     }
 }

osu.Game/Overlays/AccountCreation/ScreenWarning.cs

@@ -1,8 +1,6 @@
 // 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.
 
-#nullable disable
-
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -23,14 +21,14 @@ namespace osu.Game.Overlays.AccountCreation
 {
     public partial class ScreenWarning : AccountCreationScreen
     {
-        private OsuTextFlowContainer multiAccountExplanationText;
+        private OsuTextFlowContainer multiAccountExplanationText = null!;
-        private LinkFlowContainer furtherAssistance;
+        private LinkFlowContainer furtherAssistance = null!;
 
-        [Resolved(canBeNull: true)]
+        [Resolved]
-        private IAPIProvider api { get; set; }
+        private IAPIProvider? api { get; set; }
 
-        [Resolved(canBeNull: true)]
+        [Resolved]
-        private OsuGame game { get; set; }
+        private OsuGame? game { get; set; }
 
         private const string help_centre_url = "/help/wiki/Help_Centre#login";
 

osu.Game/Overlays/AccountCreationOverlay.cs

@@ -1,8 +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.
 
-#nullable disable
+using System;
-
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.Color4Extensions;
@@ -24,7 +23,9 @@ namespace osu.Game.Overlays
     {
         private const float transition_time = 400;
 
-        private ScreenWelcome welcomeScreen;
+        private ScreenWelcome welcomeScreen = null!;
+
+        private ScheduledDelegate? scheduledHide;
 
         public AccountCreationOverlay()
         {
@@ -107,8 +108,6 @@ namespace osu.Game.Overlays
             this.FadeOut(100);
         }
 
-        private ScheduledDelegate scheduledHide;
-
         private void apiStateChanged(ValueChangedEvent<APIState> state)
         {
             switch (state.NewValue)
@@ -118,12 +117,16 @@ namespace osu.Game.Overlays
                     break;
 
                 case APIState.Connecting:
+                case APIState.RequiresSecondFactorAuth:
                     break;
 
                 case APIState.Online:
                     scheduledHide?.Cancel();
                     scheduledHide = Schedule(Hide);
                     break;
+
+                default:
+                    throw new ArgumentOutOfRangeException();
             }
         }
     }

osu.Game/Overlays/Comments/VotePill.cs

@@ -30,7 +30,7 @@ namespace osu.Game.Overlays.Comments
 
         public Color4 AccentColour { get; set; }
 
-        protected override IEnumerable<Drawable> EffectTargets => null;
+        protected override IEnumerable<Drawable> EffectTargets => Enumerable.Empty<Drawable>();
 
         [Resolved]
         private IAPIProvider api { get; set; }

osu.Game/Overlays/Login/LoginForm.cs

@@ -32,13 +32,7 @@ namespace osu.Game.Overlays.Login
 
         public Action? RequestHide;
 
-        private void performLogin()
+        public override bool AcceptsFocus => true;
-        {
-            if (!string.IsNullOrEmpty(username.Text) && !string.IsNullOrEmpty(password.Text))
-                api.Login(username.Text, password.Text);
-            else
-                shakeSignIn.Shake();
-        }
 
         [BackgroundDependencyLoader(permitNulls: true)]
         private void load(OsuConfigManager config, AccountCreationOverlay accountCreation)
@@ -144,7 +138,13 @@ namespace osu.Game.Overlays.Login
             }
         }
 
-        public override bool AcceptsFocus => true;
+        private void performLogin()
+        {
+            if (!string.IsNullOrEmpty(username.Text) && !string.IsNullOrEmpty(password.Text))
+                api.Login(username.Text, password.Text);
+            else
+                shakeSignIn.Shake();
+        }
 
         protected override bool OnClick(ClickEvent e) => true;
 

osu.Game/Overlays/Login/LoginPanel.cs

@@ -25,7 +25,7 @@ namespace osu.Game.Overlays.Login
     {
         private bool bounding = true;
 
-        private LoginForm? form;
+        private Drawable? form;
 
         [Resolved]
         private OsuColour colours { get; set; } = null!;
@@ -81,6 +81,10 @@ namespace osu.Game.Overlays.Login
                     };
                     break;
 
+                case APIState.RequiresSecondFactorAuth:
+                    Child = form = new SecondFactorAuthForm();
+                    break;
+
                 case APIState.Failing:
                 case APIState.Connecting:
                     LinkFlowContainer linkFlow;

osu.Game/Overlays/Login/SecondFactorAuthForm.cs

@@ -0,0 +1,147 @@
+// 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.Threading.Tasks;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input.Events;
+using osu.Framework.Logging;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Overlays.Settings;
+using osu.Game.Resources.Localisation.Web;
+using osuTK;
+
+namespace osu.Game.Overlays.Login
+{
+    public partial class SecondFactorAuthForm : Container
+    {
+        private OsuTextBox codeTextBox = null!;
+        private LinkFlowContainer explainText = null!;
+        private ErrorTextFlowContainer errorText = null!;
+
+        private LoadingLayer loading = null!;
+
+        [Resolved]
+        private IAPIProvider api { get; set; } = null!;
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            RelativeSizeAxes = Axes.X;
+            AutoSizeAxes = Axes.Y;
+
+            Children = new Drawable[]
+            {
+                new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.X,
+                    AutoSizeAxes = Axes.Y,
+                    Direction = FillDirection.Vertical,
+                    Spacing = new Vector2(0, SettingsSection.ITEM_SPACING),
+                    Children = new Drawable[]
+                    {
+                        new FillFlowContainer
+                        {
+                            RelativeSizeAxes = Axes.X,
+                            AutoSizeAxes = Axes.Y,
+                            Padding = new MarginPadding { Horizontal = SettingsPanel.CONTENT_MARGINS },
+                            Direction = FillDirection.Vertical,
+                            Spacing = new Vector2(0f, SettingsSection.ITEM_SPACING),
+                            Children = new Drawable[]
+                            {
+                                new OsuTextFlowContainer(s => s.Font = OsuFont.GetFont(weight: FontWeight.Regular))
+                                {
+                                    RelativeSizeAxes = Axes.X,
+                                    AutoSizeAxes = Axes.Y,
+                                    Text = "An email has been sent to you with a verification code. Enter the code.",
+                                },
+                                codeTextBox = new OsuTextBox
+                                {
+                                    PlaceholderText = "Enter code",
+                                    RelativeSizeAxes = Axes.X,
+                                    TabbableContentContainer = this,
+                                },
+                                explainText = new LinkFlowContainer(s => s.Font = OsuFont.GetFont(weight: FontWeight.Regular))
+                                {
+                                    RelativeSizeAxes = Axes.X,
+                                    AutoSizeAxes = Axes.Y,
+                                },
+                                errorText = new ErrorTextFlowContainer
+                                {
+                                    RelativeSizeAxes = Axes.X,
+                                    AutoSizeAxes = Axes.Y,
+                                    Alpha = 0,
+                                },
+                            },
+                        },
+                        new LinkFlowContainer
+                        {
+                            Padding = new MarginPadding { Horizontal = SettingsPanel.CONTENT_MARGINS },
+                            RelativeSizeAxes = Axes.X,
+                            AutoSizeAxes = Axes.Y,
+                        },
+                    }
+                },
+                loading = new LoadingLayer(true)
+                {
+                    Padding = new MarginPadding { Vertical = -SettingsSection.ITEM_SPACING },
+                }
+            };
+
+            explainText.AddParagraph(UserVerificationStrings.BoxInfoCheckSpam);
+            // We can't support localisable strings with nested links yet. Not sure if we even can (probably need to allow markdown link formatting or something).
+            explainText.AddParagraph("If you can't access your email or have forgotten what you used, please follow the ");
+            explainText.AddLink(UserVerificationStrings.BoxInfoRecoverLink, $"{api.WebsiteRootUrl}/home/password-reset");
+            explainText.AddText(". You can also ");
+            explainText.AddLink(UserVerificationStrings.BoxInfoReissueLink, () =>
+            {
+                loading.Show();
+
+                var reissueRequest = new ReissueVerificationCodeRequest();
+                reissueRequest.Failure += ex =>
+                {
+                    Logger.Error(ex, @"Failed to retrieve new verification code.");
+                    loading.Hide();
+                };
+                reissueRequest.Success += () =>
+                {
+                    loading.Hide();
+                };
+
+                Task.Run(() => api.Perform(reissueRequest));
+            });
+            explainText.AddText(" or ");
+            explainText.AddLink(UserVerificationStrings.BoxInfoLogoutLink, () => { api.Logout(); });
+            explainText.AddText(".");
+
+            codeTextBox.Current.BindValueChanged(code =>
+            {
+                if (code.NewValue.Length == 8)
+                {
+                    api.AuthenticateSecondFactor(code.NewValue);
+                    codeTextBox.Current.Disabled = true;
+                }
+            });
+
+            if (api.LastLoginError?.Message is string error)
+            {
+                errorText.Alpha = 1;
+                errorText.AddErrors(new[] { error });
+            }
+        }
+
+        public override bool AcceptsFocus => true;
+
+        protected override bool OnClick(ClickEvent e) => true;
+
+        protected override void OnFocus(FocusEvent e)
+        {
+            Schedule(() => { GetContainingInputManager().ChangeFocus(codeTextBox); });
+        }
+    }
+}