From b733f46c6fed49d930da4e0cf20d5949c5914ddd Mon Sep 17 00:00:00 2001
From: Joseph Madamba <madamba.joehu@outlook.com>
Date: Sun, 15 Jan 2023 14:15:36 -0800
Subject: [PATCH] Apply NRT to `BeatmapPicker`

---
 .../TestSceneStartupBeatmapDisplay.cs         |  4 +---
 osu.Game/Overlays/BeatmapSet/BeatmapPicker.cs | 22 +++++++++----------
 2 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/osu.Game.Tests/Visual/Navigation/TestSceneStartupBeatmapDisplay.cs b/osu.Game.Tests/Visual/Navigation/TestSceneStartupBeatmapDisplay.cs
index 0c165bc40e..25cef8440a 100644
--- a/osu.Game.Tests/Visual/Navigation/TestSceneStartupBeatmapDisplay.cs
+++ b/osu.Game.Tests/Visual/Navigation/TestSceneStartupBeatmapDisplay.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 System.Linq;
 using NUnit.Framework;
 using osu.Framework.Graphics.Containers;
@@ -50,7 +48,7 @@ namespace osu.Game.Tests.Visual.Navigation
         public void TestBeatmapLink()
         {
             AddUntilStep("Beatmap overlay displayed", () => Game.ChildrenOfType<BeatmapSetOverlay>().FirstOrDefault()?.State.Value == Visibility.Visible);
-            AddUntilStep("Beatmap overlay showing content", () => Game.ChildrenOfType<BeatmapPicker>().FirstOrDefault()?.Beatmap.Value.OnlineID == requested_beatmap_id);
+            AddUntilStep("Beatmap overlay showing content", () => Game.ChildrenOfType<BeatmapPicker>().FirstOrDefault()?.Beatmap.Value?.OnlineID == requested_beatmap_id);
         }
     }
 }
diff --git a/osu.Game/Overlays/BeatmapSet/BeatmapPicker.cs b/osu.Game/Overlays/BeatmapSet/BeatmapPicker.cs
index 0ee7dfc9bd..76fc1bbf53 100644
--- a/osu.Game/Overlays/BeatmapSet/BeatmapPicker.cs
+++ b/osu.Game/Overlays/BeatmapSet/BeatmapPicker.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 System;
 using System.Linq;
 using osu.Framework;
@@ -38,10 +36,10 @@ namespace osu.Game.Overlays.BeatmapSet
 
         public readonly DifficultiesContainer Difficulties;
 
-        public readonly Bindable<APIBeatmap> Beatmap = new Bindable<APIBeatmap>();
-        private APIBeatmapSet beatmapSet;
+        public readonly Bindable<APIBeatmap?> Beatmap = new Bindable<APIBeatmap?>();
+        private APIBeatmapSet? beatmapSet;
 
-        public APIBeatmapSet BeatmapSet
+        public APIBeatmapSet? BeatmapSet
         {
             get => beatmapSet;
             set
@@ -142,7 +140,7 @@ namespace osu.Game.Overlays.BeatmapSet
         }
 
         [Resolved]
-        private IBindable<RulesetInfo> ruleset { get; set; }
+        private IBindable<RulesetInfo> ruleset { get; set; } = null!;
 
         [BackgroundDependencyLoader]
         private void load(OsuColour colours)
@@ -200,9 +198,9 @@ namespace osu.Game.Overlays.BeatmapSet
             updateDifficultyButtons();
         }
 
-        private void showBeatmap(IBeatmapInfo beatmapInfo)
+        private void showBeatmap(IBeatmapInfo? beatmapInfo)
         {
-            version.Text = beatmapInfo?.DifficultyName;
+            version.Text = beatmapInfo?.DifficultyName ?? string.Empty;
         }
 
         private void updateDifficultyButtons()
@@ -212,7 +210,7 @@ namespace osu.Game.Overlays.BeatmapSet
 
         public partial class DifficultiesContainer : FillFlowContainer<DifficultySelectorButton>
         {
-            public Action OnLostHover;
+            public Action? OnLostHover;
 
             protected override void OnHoverLost(HoverLostEvent e)
             {
@@ -233,9 +231,9 @@ namespace osu.Game.Overlays.BeatmapSet
 
             public readonly APIBeatmap Beatmap;
 
-            public Action<APIBeatmap> OnHovered;
-            public Action<APIBeatmap> OnClicked;
-            public event Action<DifficultySelectorState> StateChanged;
+            public Action<APIBeatmap>? OnHovered;
+            public Action<APIBeatmap>? OnClicked;
+            public event Action<DifficultySelectorState>? StateChanged;
 
             private DifficultySelectorState state;