Only transform the user's skin, not all fallbacks

osu.Game.Rulesets.Catch.Tests/TestSceneCatchPlayerLegacySkin.cs

@@ -28,7 +28,7 @@ namespace osu.Game.Rulesets.Catch.Tests
                 CreateTest();
             }
 
-            AddAssert("legacy HUD combo counter not added", () => !Player.ChildrenOfType<LegacyDefaultComboCounter>().Any());
+            AddAssert("legacy HUD combo counter not added", () => Player.ChildrenOfType<LegacyDefaultComboCounter>(), () => Is.Empty);
         }
     }
 }

osu.Game/Skinning/RulesetSkinProvidingContainer.cs

@@ -4,7 +4,6 @@
 #nullable disable
 
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.Linq;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
@@ -67,28 +66,13 @@ namespace osu.Game.Skinning
             // Populate a local list first so we can adjust the returned order as we go.
             var sources = new List<ISkin>();
 
-            Debug.Assert(ParentSource != null);
-
-            foreach (var source in ParentSource.AllSources)
-            {
-                switch (source)
-                {
-                    case Skin skin:
-                        sources.Add(GetRulesetTransformedSkin(skin));
-                        break;
-                }
-            }
-
-            // TODO: check
-            int lastDefaultSkinIndex = sources.IndexOf(sources.OfType<TrianglesSkin>().LastOrDefault());
+            // We want to transform the current user's skin for the current ruleset.
+            // Assume it's the first skin provided by the parent source (generally the case for both SkinManager and tests).
+            if (ParentSource?.AllSources.FirstOrDefault() is ISkin skin)
+                sources.Add(GetRulesetTransformedSkin(skin));
 
             // Ruleset resources should be given the ability to override game-wide defaults
-            // This is achieved by placing them before the last instance of DefaultSkin.
-            // Note that DefaultSkin may not be present in some test scenes.
-            if (lastDefaultSkinIndex >= 0)
-                sources.Insert(lastDefaultSkinIndex, rulesetResourcesSkin);
-            else
-                sources.Add(rulesetResourcesSkin);
+            sources.Add(rulesetResourcesSkin);
 
             SetSources(sources);
         }

osu.Game/Skinning/SkinManager.cs

@@ -256,7 +256,7 @@ namespace osu.Game.Skinning
                 // This handles cases where a user skin doesn't have the required resources for complete display of
                 // certain elements.
 
-                if (CurrentSkin.Value is LegacySkin && CurrentSkin.Value != DefaultClassicSkin)
+                if (CurrentSkin.Value != DefaultClassicSkin)
                     yield return DefaultClassicSkin;
 
                 if (CurrentSkin.Value != trianglesSkin)