From d4251271d87b1244ac31a5ac04f75db669d739c0 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Wed, 9 Nov 2022 13:50:39 +0900
Subject: [PATCH] Apply nullability to `SkinnableDrawable`

---
 osu.Game/Skinning/SkinnableDrawable.cs | 44 ++++++++++++--------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/osu.Game/Skinning/SkinnableDrawable.cs b/osu.Game/Skinning/SkinnableDrawable.cs
index 480d66c557..c6321553c7 100644
--- a/osu.Game/Skinning/SkinnableDrawable.cs
+++ b/osu.Game/Skinning/SkinnableDrawable.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 osu.Framework.Caching;
 using osu.Framework.Graphics;
@@ -19,7 +17,7 @@ namespace osu.Game.Skinning
         /// <summary>
         /// The displayed component.
         /// </summary>
-        public Drawable Drawable { get; private set; }
+        public Drawable Drawable { get; private set; } = null!;
 
         /// <summary>
         /// Whether the drawable component should be centered in available space.
@@ -43,7 +41,7 @@ namespace osu.Game.Skinning
         /// <param name="component">The namespace-complete resource name for this skinnable element.</param>
         /// <param name="defaultImplementation">A function to create the default skin implementation of this element.</param>
         /// <param name="confineMode">How (if at all) the <see cref="Drawable"/> should be resize to fit within our own bounds.</param>
-        public SkinnableDrawable(ISkinComponent component, Func<ISkinComponent, Drawable> defaultImplementation = null, ConfineMode confineMode = ConfineMode.NoScaling)
+        public SkinnableDrawable(ISkinComponent component, Func<ISkinComponent, Drawable>? defaultImplementation = null, ConfineMode confineMode = ConfineMode.NoScaling)
             : this(component, confineMode)
         {
             createDefault = defaultImplementation;
@@ -62,7 +60,7 @@ namespace osu.Game.Skinning
         /// </summary>
         public void ResetAnimation() => (Drawable as IFramedAnimation)?.GotoFrame(0);
 
-        private readonly Func<ISkinComponent, Drawable> createDefault;
+        private readonly Func<ISkinComponent, Drawable>? createDefault;
 
         private readonly Cached scaling = new Cached();
 
@@ -77,30 +75,28 @@ namespace osu.Game.Skinning
 
         protected override void SkinChanged(ISkinSource skin)
         {
-            Drawable = skin.GetDrawableComponent(Component);
+            var retrieved = skin.GetDrawableComponent(Component);
 
-            isDefault = false;
-
-            if (Drawable == null)
+            if (retrieved == null)
             {
                 Drawable = CreateDefault(Component);
                 isDefault = true;
             }
-
-            if (Drawable != null)
-            {
-                scaling.Invalidate();
-
-                if (CentreComponent)
-                {
-                    Drawable.Origin = Anchor.Centre;
-                    Drawable.Anchor = Anchor.Centre;
-                }
-
-                InternalChild = Drawable;
-            }
             else
-                ClearInternal();
+            {
+                Drawable = retrieved;
+                isDefault = false;
+            }
+
+            scaling.Invalidate();
+
+            if (CentreComponent)
+            {
+                Drawable.Origin = Anchor.Centre;
+                Drawable.Anchor = Anchor.Centre;
+            }
+
+            InternalChild = Drawable;
         }
 
         protected override void Update()
@@ -111,7 +107,7 @@ namespace osu.Game.Skinning
             {
                 try
                 {
-                    if (Drawable == null || (isDefault && !ApplySizeRestrictionsToDefault)) return;
+                    if (isDefault && !ApplySizeRestrictionsToDefault) return;
 
                     switch (confineMode)
                     {