From 938428d2641705fbb2f7cba5861c2b5d36a49907 Mon Sep 17 00:00:00 2001
From: Huo Yaoyuan <huoyaoyuan@hotmail.com>
Date: Wed, 27 Nov 2024 21:37:25 +0800
Subject: [PATCH] Resolve new nullability warnings

---
 osu.Game/Graphics/UserInterface/DrawableStatefulMenuItem.cs | 4 ++--
 osu.Game/Graphics/UserInterface/StatefulMenuItem.cs         | 4 ++--
 osu.Game/Screens/Edit/Setup/ColoursSection.cs               | 2 +-
 osu.Game/Screens/OnlinePlay/Match/DrawableMatchRoom.cs      | 5 +++++
 osu.Game/Screens/Select/SongSelect.cs                       | 2 +-
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/osu.Game/Graphics/UserInterface/DrawableStatefulMenuItem.cs b/osu.Game/Graphics/UserInterface/DrawableStatefulMenuItem.cs
index 4206f77c9865..f917203b6b0f 100644
--- a/osu.Game/Graphics/UserInterface/DrawableStatefulMenuItem.cs
+++ b/osu.Game/Graphics/UserInterface/DrawableStatefulMenuItem.cs
@@ -37,7 +37,7 @@ protected override bool OnMouseDown(MouseDownEvent e)
         private partial class ToggleTextContainer : TextContainer
         {
             private readonly StatefulMenuItem menuItem;
-            private readonly Bindable<object> state;
+            private readonly Bindable<object?> state;
             private readonly SpriteIcon stateIcon;
 
             public ToggleTextContainer(StatefulMenuItem menuItem)
@@ -61,7 +61,7 @@ protected override void LoadComplete()
                 state.BindValueChanged(updateState, true);
             }
 
-            private void updateState(ValueChangedEvent<object> state)
+            private void updateState(ValueChangedEvent<object?> state)
             {
                 var icon = menuItem.GetIconForState(state.NewValue);
 
diff --git a/osu.Game/Graphics/UserInterface/StatefulMenuItem.cs b/osu.Game/Graphics/UserInterface/StatefulMenuItem.cs
index 9111cfb3aada..c3d8877ede53 100644
--- a/osu.Game/Graphics/UserInterface/StatefulMenuItem.cs
+++ b/osu.Game/Graphics/UserInterface/StatefulMenuItem.cs
@@ -53,7 +53,7 @@ protected StatefulMenuItem(LocalisableString text, Func<object?, object?>? chang
         /// </summary>
         /// <param name="state">The state to retrieve the relevant icon for.</param>
         /// <returns>The icon to be displayed for <paramref name="state"/>.</returns>
-        public abstract IconUsage? GetIconForState(object state);
+        public abstract IconUsage? GetIconForState(object? state);
     }
 
     public abstract class StatefulMenuItem<T> : StatefulMenuItem
@@ -97,7 +97,7 @@ protected StatefulMenuItem(LocalisableString text, Func<T, T>? changeStateFunc,
             State.BindValueChanged(state => base.State.Value = state.NewValue);
         }
 
-        public sealed override IconUsage? GetIconForState(object state) => GetIconForState((T)state);
+        public sealed override IconUsage? GetIconForState(object? state) => GetIconForState((T)state!);
 
         /// <summary>
         /// Retrieves the icon to be displayed for a state.
diff --git a/osu.Game/Screens/Edit/Setup/ColoursSection.cs b/osu.Game/Screens/Edit/Setup/ColoursSection.cs
index 8de7f86523a7..f6c61daa69b4 100644
--- a/osu.Game/Screens/Edit/Setup/ColoursSection.cs
+++ b/osu.Game/Screens/Edit/Setup/ColoursSection.cs
@@ -66,7 +66,7 @@ protected override void LoadComplete()
                 syncingColours = true;
 
                 comboColours.Colours.Clear();
-                comboColours.Colours.AddRange(Beatmap.BeatmapSkin?.ComboColours);
+                comboColours.Colours.AddRange(Beatmap.BeatmapSkin?.ComboColours ?? []);
 
                 syncingColours = false;
             });
diff --git a/osu.Game/Screens/OnlinePlay/Match/DrawableMatchRoom.cs b/osu.Game/Screens/OnlinePlay/Match/DrawableMatchRoom.cs
index 0c993f4abf32..3ceaf187e26d 100644
--- a/osu.Game/Screens/OnlinePlay/Match/DrawableMatchRoom.cs
+++ b/osu.Game/Screens/OnlinePlay/Match/DrawableMatchRoom.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.ComponentModel;
+using System.Diagnostics;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -38,6 +39,10 @@ public DrawableMatchRoom(Room room, bool allowEdit = true)
         {
             this.allowEdit = allowEdit;
 
+            // Roslyn sees required non-nullable property as nullable in constructor,
+            // as it can't see the implementation provides a fallback.
+            Debug.Assert(SelectedItem != null);
+
             base.SelectedItem.BindTo(SelectedItem);
         }
 
diff --git a/osu.Game/Screens/Select/SongSelect.cs b/osu.Game/Screens/Select/SongSelect.cs
index 1c431b1cd484..e30ef761cde9 100644
--- a/osu.Game/Screens/Select/SongSelect.cs
+++ b/osu.Game/Screens/Select/SongSelect.cs
@@ -994,7 +994,7 @@ private void bindBindables()
 
             selectedMods.BindValueChanged(_ =>
             {
-                if (decoupledRuleset.Value.Equals(rulesetNoDebounce))
+                if (decoupledRuleset.Value?.Equals(rulesetNoDebounce) ?? false)
                     advancedStats.Mods.Value = selectedMods.Value;
             }, true);