Give ruleset settings a ruleset-specific config manager

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -130,7 +130,7 @@ namespace osu.Game.Rulesets.Osu
 
         public override string ShortName => "osu";
 
-        public override SettingsSubsection CreateSettings() => new OsuSettings();
+        public override RulesetSettingsSubsection CreateSettings() => new OsuSettings(this);
 
         public override int? LegacyID => 0;
 

osu.Game.Rulesets.Osu/UI/OsuSettings.cs

@@ -8,10 +8,15 @@ using osu.Game.Overlays.Settings;
 
 namespace osu.Game.Rulesets.Osu.UI
 {
-    public class OsuSettings : SettingsSubsection
+    public class OsuSettings : RulesetSettingsSubsection
     {
         protected override string Header => "osu!";
 
+        public OsuSettings(Ruleset ruleset)
+            : base(ruleset)
+        {
+        }
+
         [BackgroundDependencyLoader]
         private void load(OsuConfigManager config)
         {

osu.Game/Overlays/Settings/RulesetSettingsSubsection.cs

@@ -0,0 +1,36 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Game.Configuration;
+using osu.Game.Rulesets;
+
+namespace osu.Game.Overlays.Settings
+{
+    /// <summary>
+    /// A <see cref="SettingsSubsection"/> which provides subclasses with the <see cref="IRulesetConfigManager"/>
+    /// from the <see cref="Ruleset"/>'s <see cref="Ruleset.CreateConfig()"/>.
+    /// </summary>
+    public abstract class RulesetSettingsSubsection : SettingsSubsection
+    {
+        private readonly Ruleset ruleset;
+
+        protected RulesetSettingsSubsection(Ruleset ruleset)
+        {
+            this.ruleset = ruleset;
+        }
+
+        private DependencyContainer dependencies;
+
+        protected override IReadOnlyDependencyContainer CreateLocalDependencies(IReadOnlyDependencyContainer parent)
+        {
+            dependencies = new DependencyContainer(base.CreateLocalDependencies(parent));
+
+            var config = ruleset.CreateConfig(dependencies.Get<SettingsStore>());
+            if (config != null)
+                dependencies.Cache(config);
+
+            return dependencies;
+        }
+    }
+}

osu.Game/Rulesets/Ruleset.cs

@@ -71,7 +71,7 @@ namespace osu.Game.Rulesets
 
         public abstract string Description { get; }
 
-        public virtual SettingsSubsection CreateSettings() => null;
+        public virtual RulesetSettingsSubsection CreateSettings() => null;
 
         /// <summary>
         /// Creates the <see cref="IRulesetConfigManager"/> for this <see cref="Ruleset"/>.