Fix PUT/DELETE submodel-element-by-id-short-path not persisting changes (#80)

* Fix PUT/DELETE submodel-element-by-id-short-path not persisting changes

put_submodel_submodel_elements_id_short_path and
delete_submodel_submodel_elements_id_short_path each fetched the submodel
twice: once (indirectly) to locate/mutate the target element, and again
to pass to object_store.commit(). For object stores that deserialize a
fresh object graph on every get (e.g. Neo4jObjectStore), these are two
distinct instances, so the mutation made on the first instance was never
part of the object passed to commit() and the change was silently lost.

Fetch the submodel once, navigate to the nested element within that same
instance, mutate it, and commit that same submodel instance.

Author: tamasf1

server/app/interfaces/repository.py

@@ -830,23 +830,25 @@ def post_submodel_submodel_elements_id_short_path(
     def put_submodel_submodel_elements_id_short_path(
         self, request: Request, url_args: Dict, response_t: Type[APIResponse], **_kwargs
     ) -> Response:
-        submodel_element = self._get_submodel_submodel_elements_id_short_path(url_args)
+        submodel = self._get_submodel(url_args)
+        submodel_element = self._get_nested_submodel_element(submodel, url_args["id_shorts"])
         # TODO: remove the following type: ignore comment when mypy supports abstract types for Type[T]
         # see https://github.com/python/mypy/issues/5374
         new_submodel_element = HTTPApiDecoder.request_body(
             request, model.SubmodelElement, is_stripped_request(request)  # type: ignore[type-abstract]
         )
         submodel_element.update_from(new_submodel_element)
-        self.object_store.commit(self._get_submodel(url_args))
+        self.object_store.commit(submodel)
         return response_t()
 
     def delete_submodel_submodel_elements_id_short_path(
         self, request: Request, url_args: Dict, response_t: Type[APIResponse], **_kwargs
     ) -> Response:
-        sm_or_se = self._get_submodel_or_nested_submodel_element(url_args)
+        submodel = self._get_submodel(url_args)
+        sm_or_se = self._get_nested_submodel_element(submodel, url_args["id_shorts"])
         parent: model.UniqueIdShortNamespace = self._expect_namespace(sm_or_se.parent, sm_or_se.id_short)
         self._namespace_submodel_element_op(parent, parent.remove_referable, sm_or_se.id_short)
-        self.object_store.commit(self._get_submodel(url_args))
+        self.object_store.commit(submodel)
         return response_t()
 
     def get_submodel_submodel_element_attachment(self, request: Request, url_args: Dict, **_kwargs) -> Response: