From c0305343bc9312333957362d124c906f2febd82b Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Mon, 7 Jun 2021 23:23:44 +0900
Subject: [PATCH] Fix `FindProvider` incorrectly returning
 `LegacySkinTransformer` itself

---
 osu.Game/Skinning/LegacySkinTransformer.cs  |  8 +++++++-
 osu.Game/Skinning/SkinProvidingContainer.cs | 12 ++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/osu.Game/Skinning/LegacySkinTransformer.cs b/osu.Game/Skinning/LegacySkinTransformer.cs
index cace4acf6c..651fdddb1b 100644
--- a/osu.Game/Skinning/LegacySkinTransformer.cs
+++ b/osu.Game/Skinning/LegacySkinTransformer.cs
@@ -16,7 +16,7 @@ namespace osu.Game.Skinning
     /// <summary>
     /// Transformer used to handle support of legacy features for individual rulesets.
     /// </summary>
-    public abstract class LegacySkinTransformer : ISkin
+    public abstract class LegacySkinTransformer : ISkinSource
     {
         /// <summary>
         /// Source of the <see cref="ISkin"/> which is being transformed.
@@ -50,5 +50,11 @@ namespace osu.Game.Skinning
         public abstract IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup);
 
         public ISkin FindProvider(Func<ISkin, bool> lookupFunction) => Source.FindProvider(lookupFunction);
+
+        public event Action SourceChanged
+        {
+            add { throw new NotSupportedException(); }
+            remove { }
+        }
     }
 }
diff --git a/osu.Game/Skinning/SkinProvidingContainer.cs b/osu.Game/Skinning/SkinProvidingContainer.cs
index 863b5f5a24..0e16cf43ee 100644
--- a/osu.Game/Skinning/SkinProvidingContainer.cs
+++ b/osu.Game/Skinning/SkinProvidingContainer.cs
@@ -46,8 +46,16 @@ namespace osu.Game.Skinning
 
         public ISkin FindProvider(Func<ISkin, bool> lookupFunction)
         {
-            if (skin != null && lookupFunction(skin))
-                return skin;
+            if (skin is ISkinSource source)
+            {
+                if (source.FindProvider(lookupFunction) is ISkin found)
+                    return found;
+            }
+            else if (skin != null)
+            {
+                if (lookupFunction(skin))
+                    return skin;
+            }
 
             return fallbackSource?.FindProvider(lookupFunction);
         }