Fix issue with deepMerge() caused by handling maps incorrectly, causing an unhandleable crash.

source/funkin/util/StructureUtil.hx

@@ -1,5 +1,6 @@
 package funkin.util;
 
+import funkin.util.tools.MapTools;
 import haxe.DynamicAccess;
 
 /**
@@ -26,6 +27,57 @@ class StructureUtil
     return result;
   }
 
+  public static function toMap(a:Dynamic):haxe.ds.Map<String, Dynamic>
+  {
+    var result:haxe.ds.Map<String, Dynamic> = [];
+
+    for (field in Reflect.fields(a))
+    {
+      result.set(field, Reflect.field(a, field));
+    }
+
+    return result;
+  }
+
+  public static function isMap(a:Dynamic):Bool
+  {
+    return Std.isOfType(a, haxe.Constraints.IMap);
+  }
+
+  public static function isObject(a:Dynamic):Bool
+  {
+    switch (Type.typeof(a))
+    {
+      case TObject:
+        return true;
+      default:
+        return false;
+    }
+  }
+
+  public static function isPrimitive(a:Dynamic):Bool
+  {
+    switch (Type.typeof(a))
+    {
+      case TInt | TFloat | TBool:
+        return true;
+      case TClass(c):
+        return false;
+      case TEnum(e):
+        return false;
+      case TObject:
+        return false;
+      case TFunction:
+        return false;
+      case TNull:
+        return true;
+      case TUnknown:
+        return false;
+      default:
+        return false;
+    }
+  }
+
   /**
    * Merge two structures, with the second overwriting the first.
    * Performs a DEEP clone, where child structures are also merged recursively.
@@ -37,6 +89,18 @@ class StructureUtil
   {
     if (a == null) return b;
     if (b == null) return null;
+    if (isPrimitive(a) && isPrimitive(b)) return b;
+    if (isMap(b))
+    {
+      if (isMap(a))
+      {
+        return MapTools.merge(a, b);
+      }
+      else
+      {
+        return StructureUtil.toMap(a).merge(b);
+      }
+    }
     if (!Reflect.isObject(a) || !Reflect.isObject(b)) return b;
 
     var result:DynamicAccess<Dynamic> = Reflect.copy(a);