aas.adapter.json: deserialize ModelReferences with last key type

Author: JGrothoff

sdk/basyx/aas/adapter/json/json_deserialization.py

@@ -340,10 +340,15 @@ def _construct_model_reference(cls, dct: Dict[str, object], type_: Type[T], obje
         if reference_type is not model.ModelReference:
             raise ValueError(f"Expected a reference of type {model.ModelReference}, got {reference_type}!")
         keys = [cls._construct_key(key_data) for key_data in _get_ts(dct, "keys", list)]
-        if keys and not issubclass(KEY_TYPES_CLASSES_INVERSE.get(keys[-1].type, type(None)), type_):
+        last_key_type = KEY_TYPES_CLASSES_INVERSE.get(keys[-1].type, type(None))
+        if keys and not issubclass(last_key_type, type_):
             logger.warning("type %s of last key of reference to %s does not match reference type %s",
                            keys[-1].type.name, " / ".join(str(k) for k in keys), type_.__name__)
-        return object_class(tuple(keys), type_, cls._construct_reference(_get_ts(dct, 'referredSemanticId', dict))
+        # Infer type the model refence points to using `last_key_type` instead of `type_`.
+        # `type_` is often a `model.Referable`, which is more abstract than e.g. a `model.ConceptDescription`,
+        # leading to information loss while deserializing.
+        return object_class(tuple(keys), last_key_type,
+                            cls._construct_reference(_get_ts(dct, 'referredSemanticId', dict))
                             if 'referredSemanticId' in dct else None)
 
     @classmethod