- ArrayOf errors now catched in EntityTrait (event soon to be attached to it)

- Fixed some non-nullable defaulted to null vars in functions
- Added a new diff method for entities which skips nullable values if they are not defined.

src/Ulmus.php

@@ -108,7 +108,7 @@ abstract class Ulmus
         return static::$resolved[$entityClass] ?? static::$resolved[$entityClass] = new Common\EntityResolver($entityClass, static::$cache);
     }
 
-    public static function repository(string $entityClass, string $alias = Repository::DEFAULT_ALIAS, ConnectionAdapter $adapter = null) : Repository
+    public static function repository(string $entityClass, string $alias = Repository::DEFAULT_ALIAS, ?ConnectionAdapter $adapter = null) : Repository
     {
         $adapter ??= $entityClass::resolveEntity()->sqlAdapter();
         $cls = $adapter->adapter()->repositoryClass();