Restore #5243 AOT fix lost in #5246 merge resolution

Terminal.Gui/Configuration/ConfigurationManager.cs

@@ -204,7 +204,7 @@ internal static void Initialize ()
                 // Some getters (notably ThemeManager.Themes while uninitialized) synthesize composite
                 // objects from other configuration properties, so a single populate-and-clone pass can
                 // observe half-initialized cache entries and persist null/default values into the clone.
-                hardCodedProperty.Value.PropertyValue = CloneHardCodedPropertyValue (hardCodedProperty.Value.PropertyValue);
+                hardCodedProperty.Value.PropertyValue = DeepCloner.DeepClone (hardCodedProperty.Value.PropertyValue);
                 hardCodedProperty.Value.Immutable = true;
             }
         }
@@ -222,58 +222,6 @@ internal static void Initialize ()
         ThemeManager.Themes? [ThemeManager.Theme].Apply ();
     }
 
-    // AOT trimming removes the reflective Dictionary<,> constructor that DeepCloner relies on.
-    // Each non-trivially-cloneable config property type needs a typed clone path here to stay AOT-safe.
-    private static object? CloneHardCodedPropertyValue (object? propertyValue)
-    {
-        if (propertyValue is Dictionary<Command, PlatformKeyBinding> keyBindings)
-        {
-            return CloneKeyBindings (keyBindings);
-        }
-
-        return DeepCloner.DeepClone (propertyValue);
-    }
-
-    private static Dictionary<Command, PlatformKeyBinding> CloneKeyBindings (Dictionary<Command, PlatformKeyBinding> source)
-    {
-        Dictionary<Command, PlatformKeyBinding> clone = new (source.Comparer);
-
-        foreach (KeyValuePair<Command, PlatformKeyBinding> kvp in source)
-        {
-            clone [kvp.Key] = ClonePlatformKeyBinding (kvp.Value);
-        }
-
-        return clone;
-    }
-
-    private static PlatformKeyBinding ClonePlatformKeyBinding (PlatformKeyBinding binding)
-    {
-        return binding with
-        {
-            All = CloneKeyArray (binding.All),
-            Windows = CloneKeyArray (binding.Windows),
-            Linux = CloneKeyArray (binding.Linux),
-            Macos = CloneKeyArray (binding.Macos)
-        };
-    }
-
-    private static Key []? CloneKeyArray (Key []? keys)
-    {
-        if (keys is null)
-        {
-            return null;
-        }
-
-        Key [] clonedKeys = new Key [keys.Length];
-
-        for (int i = 0; i < keys.Length; i++)
-        {
-            clonedKeys [i] = new (keys [i]);
-        }
-
-        return clonedKeys;
-    }
-
     #endregion Initialization
 
     #region Enable/Disable

Terminal.Gui/Configuration/DeepCloner.cs

@@ -369,6 +369,7 @@ private static object CloneDictionary (object source, ConcurrentDictionary<objec
     [UnconditionalSuppressMessage ("Trimming", "IL2067", Justification = "Dictionary cloning only instantiates supported dictionary runtime types and falls back safely when comparer constructors are unavailable.")]
     private static IDictionary CreateDictionaryInstance (Type dictType, object? comparer)
     {
+        // Typed paths for dictionary types that require custom comparers.
         if (dictType == typeof (ConcurrentDictionary<string, ThemeScope>))
         {
             if (comparer is IEqualityComparer<string> stringComparer)
@@ -389,6 +390,32 @@ private static IDictionary CreateDictionaryInstance (Type dictType, object? comp
             return new Dictionary<string, Scheme?> ();
         }
 
+        // AOT-safe: use the source-generated JSON serializer to create empty dictionary instances.
+        // This avoids Activator.CreateInstance, whose target constructors are trimmed by the AOT linker
+        // for closed generic dictionary types not otherwise statically reachable.
+        // Only used when no comparer is needed — Deserialize("{}") always creates a default-comparer instance.
+        if (comparer is null)
+        {
+            try
+            {
+                JsonTypeInfo? jsonTypeInfo = ConfigurationManager.SerializerContext.GetTypeInfo (dictType);
+
+                if (jsonTypeInfo is not null)
+                {
+                    IDictionary? result = JsonSerializer.Deserialize ("{}", jsonTypeInfo) as IDictionary;
+
+                    if (result is not null)
+                    {
+                        return result;
+                    }
+                }
+            }
+            catch (InvalidOperationException)
+            {
+                // JSON serializer context may not be initialized — fall through to reflective construction.
+            }
+        }
+
         try
         {
             // Try to create the dictionary with the comparer