Merge pull request #15480 from frenzibyte/fix-more-null

Fix more occurring "possible null reference exception" inspections

osu.Game.Tests/Mods/ModDifficultyAdjustTest.cs

@@ -105,6 +105,9 @@ namespace osu.Game.Tests.Mods
             testMod.ResetSettingsToDefaults();
 
             Assert.That(testMod.DrainRate.Value, Is.Null);
+
+            // ReSharper disable once HeuristicUnreachableCode
+            // see https://youtrack.jetbrains.com/issue/RIDER-70159.
             Assert.That(testMod.OverallDifficulty.Value, Is.Null);
 
             var applied = applyDifficulty(new BeatmapDifficulty

osu.Game.Tests/NonVisual/FirstAvailableHitWindowsTest.cs

@@ -79,8 +79,17 @@ namespace osu.Game.Tests.NonVisual
             public List<HitObject> HitObjects;
             public override IEnumerable<HitObject> Objects => HitObjects;
 
-            public override event Action<JudgementResult> NewResult;
+            public override event Action<JudgementResult> NewResult
-            public override event Action<JudgementResult> RevertResult;
+            {
+                add => throw new InvalidOperationException();
+                remove => throw new InvalidOperationException();
+            }
+
+            public override event Action<JudgementResult> RevertResult
+            {
+                add => throw new InvalidOperationException();
+                remove => throw new InvalidOperationException();
+            }
 
             public override Playfield Playfield { get; }
             public override Container Overlays { get; }
@@ -95,9 +104,6 @@ namespace osu.Game.Tests.NonVisual
             public TestDrawableRuleset()
                 : base(new OsuRuleset())
             {
-                // won't compile without this.
-                NewResult?.Invoke(null);
-                RevertResult?.Invoke(null);
             }
 
             public override void SetReplayScore(Score replayScore) => throw new NotImplementedException();

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

@@ -235,8 +235,17 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public override IEnumerable<HitObject> Objects => new[] { new HitCircle { HitWindows = HitWindows } };
 
-            public override event Action<JudgementResult> NewResult;
+            public override event Action<JudgementResult> NewResult
-            public override event Action<JudgementResult> RevertResult;
+            {
+                add => throw new InvalidOperationException();
+                remove => throw new InvalidOperationException();
+            }
+
+            public override event Action<JudgementResult> RevertResult
+            {
+                add => throw new InvalidOperationException();
+                remove => throw new InvalidOperationException();
+            }
 
             public override Playfield Playfield { get; }
             public override Container Overlays { get; }
@@ -251,9 +260,6 @@ namespace osu.Game.Tests.Visual.Gameplay
             public TestDrawableRuleset()
                 : base(new OsuRuleset())
             {
-                // won't compile without this.
-                NewResult?.Invoke(null);
-                RevertResult?.Invoke(null);
             }
 
             public override void SetReplayScore(Score replayScore) => throw new NotImplementedException();

osu.Game/Graphics/UserInterface/LoadingButton.cs

@@ -1,7 +1,9 @@
 // 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.Input.Events;
 using osu.Game.Graphics.Containers;
 using osuTK;
@@ -22,15 +24,9 @@ namespace osu.Game.Graphics.UserInterface
                 Enabled.Value = !isLoading;
 
                 if (value)
-                {
                     loading.Show();
-                    OnLoadStarted();
-                }
                 else
-                {
                     loading.Hide();
-                    OnLoadFinished();
-                }
             }
         }
 
@@ -44,18 +40,34 @@ namespace osu.Game.Graphics.UserInterface
 
         protected LoadingButton()
         {
-            AddRange(new[]
+            Add(loading = new LoadingSpinner
             {
-                CreateContent(),
+                Anchor = Anchor.Centre,
-                loading = new LoadingSpinner
+                Origin = Anchor.Centre,
-                {
+                Size = new Vector2(12),
-                    Anchor = Anchor.Centre,
+                Depth = -1,
-                    Origin = Anchor.Centre,
-                    Size = new Vector2(12)
-                }
             });
         }
 
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Add(CreateContent());
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            loading.State.BindValueChanged(s =>
+            {
+                if (s.NewValue == Visibility.Visible)
+                    OnLoadStarted();
+                else
+                    OnLoadFinished();
+            }, true);
+        }
+
         protected override bool OnClick(ClickEvent e)
         {
             if (!Enabled.Value)

osu.Game/Overlays/BeatmapListing/BeatmapSearchMultipleSelectionFilterRow.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -22,6 +23,11 @@ namespace osu.Game.Overlays.BeatmapListing
 
         public BeatmapSearchMultipleSelectionFilterRow(LocalisableString header)
             : base(header)
+        {
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
         {
             Current.BindTo(filter.Current);
         }
@@ -31,6 +37,7 @@ namespace osu.Game.Overlays.BeatmapListing
         /// <summary>
         /// Creates a filter control that can be used to simultaneously select multiple values of type <typeparamref name="T"/>.
         /// </summary>
+        [NotNull]
         protected virtual MultipleSelectionFilter CreateMultipleSelectionFilter() => new MultipleSelectionFilter();
 
         protected class MultipleSelectionFilter : FillFlowContainer<MultipleSelectionFilterTabItem>

osu.Game/Overlays/Changelog/ChangelogHeader.cs

@@ -26,6 +26,8 @@ namespace osu.Game.Overlays.Changelog
 
         public static LocalisableString ListingString => LayoutStrings.HeaderChangelogIndex;
 
+        private readonly Bindable<APIUpdateStream> currentStream = new Bindable<APIUpdateStream>();
+
         private Box streamsBackground;
 
         public ChangelogHeader()
@@ -39,7 +41,7 @@ namespace osu.Game.Overlays.Changelog
 
             Build.ValueChanged += showBuild;
 
-            Streams.Current.ValueChanged += e =>
+            currentStream.ValueChanged += e =>
             {
                 if (e.NewValue?.LatestBuild != null && !e.NewValue.Equals(Build.Value?.UpdateStream))
                     Build.Value = e.NewValue.LatestBuild;
@@ -67,7 +69,7 @@ namespace osu.Game.Overlays.Changelog
             else
             {
                 Current.Value = ListingString;
-                Streams.Current.Value = null;
+                currentStream.Value = null;
             }
         }
 
@@ -92,7 +94,7 @@ namespace osu.Game.Overlays.Changelog
                         Horizontal = 65,
                         Vertical = 20
                     },
-                    Child = Streams = new ChangelogUpdateStreamControl()
+                    Child = Streams = new ChangelogUpdateStreamControl { Current = currentStream },
                 }
             }
         };
@@ -110,7 +112,7 @@ namespace osu.Game.Overlays.Changelog
             if (Build.Value == null)
                 return;
 
-            Streams.Current.Value = Streams.Items.FirstOrDefault(s => s.Name == Build.Value.UpdateStream.Name);
+            currentStream.Value = Streams.Items.FirstOrDefault(s => s.Name == Build.Value.UpdateStream.Name);
         }
 
         private class ChangelogHeaderTitle : OverlayTitle

osu.Game/Overlays/Comments/CommentEditor.cs

@@ -175,6 +175,8 @@ namespace osu.Game.Overlays.Comments
 
             protected override IEnumerable<Drawable> EffectTargets => new[] { background };
 
+            private readonly string text;
+
             [Resolved]
             private OverlayColourProvider colourProvider { get; set; }
 
@@ -184,10 +186,10 @@ namespace osu.Game.Overlays.Comments
 
             public CommitButton(string text)
             {
+                this.text = text;
+
                 AutoSizeAxes = Axes.Both;
                 LoadingAnimationSize = new Vector2(10);
-
-                drawableText.Text = text;
             }
 
             [BackgroundDependencyLoader]
@@ -232,7 +234,8 @@ namespace osu.Game.Overlays.Comments
                         Anchor = Anchor.Centre,
                         Origin = Anchor.Centre,
                         Font = OsuFont.GetFont(size: 12, weight: FontWeight.Bold),
-                        Margin = new MarginPadding { Horizontal = 20 }
+                        Margin = new MarginPadding { Horizontal = 20 },
+                        Text = text,
                     }
                 }
             };

osu.Game/Overlays/OverlayScrollContainer.cs

@@ -37,11 +37,7 @@ namespace osu.Game.Overlays
                 Anchor = Anchor.BottomRight,
                 Origin = Anchor.BottomRight,
                 Margin = new MarginPadding(20),
-                Action = () =>
+                Action = scrollToTop
-                {
-                    ScrollToStart();
-                    Button.State = Visibility.Hidden;
-                }
             });
         }
 
@@ -58,6 +54,12 @@ namespace osu.Game.Overlays
             Button.State = Target > button_scroll_position ? Visibility.Visible : Visibility.Hidden;
         }
 
+        private void scrollToTop()
+        {
+            ScrollToStart();
+            Button.State = Visibility.Hidden;
+        }
+
         public class ScrollToTopButton : OsuHoverContainer
         {
             private const int fade_duration = 500;