make pr

Author: aradyaron

aws_lambda_powertools/utilities/idempotency/base.py

@@ -182,7 +182,7 @@ def _get_idempotency_record(self) -> Optional[DataRecord]:
 
         return data_record
 
-    def _handle_for_status(self, data_record: DataRecord) -> Optional[Dict[Any, Any]]:
+    def _handle_for_status(self, data_record: DataRecord) -> Optional[Any]:
         """
         Take appropriate action based on data_record's status
 
@@ -192,8 +192,9 @@ def _handle_for_status(self, data_record: DataRecord) -> Optional[Dict[Any, Any]
 
         Returns
         -------
-        Optional[Dict[Any, Any]
+        Optional[Any]
             Function's response previously used for this idempotency key, if it has successfully executed already.
+            In case an output serializer is configured, the response is deserialized.
 
         Raises
         ------
@@ -219,7 +220,7 @@ def _handle_for_status(self, data_record: DataRecord) -> Optional[Dict[Any, Any]
                 f"{self.persistence_store.event_key_jmespath}={data_record.idempotency_key}",
             )
         response_dict: Optional[dict] = data_record.response_json_as_dict()
-        return self.output_serializer.from_dict(response_dict)
+        return self.output_serializer.from_dict(response_dict) if response_dict else None
 
     def _get_function_response(self):
         try:
@@ -238,7 +239,7 @@ def _get_function_response(self):
 
         else:
             try:
-                serialized_response: dict = self.output_serializer.to_dict(response)
+                serialized_response: dict = self.output_serializer.to_dict(response) if response else None
                 self.persistence_store.save_success(data=self.data, result=serialized_response)
             except Exception as save_exception:
                 raise IdempotencyPersistenceLayerError(

tests/functional/idempotency/test_idempotency.py

@@ -1237,6 +1237,47 @@ def record_handler(record):
     assert from_dict_called
 
 
+def test_idempotent_function_serialization_no_response():
+    # GIVEN
+    config = IdempotencyConfig(use_local_cache=True)
+    mock_event = {"customer_id": "fake", "transaction_id": "fake-id"}
+    idempotency_key = f"{TESTS_MODULE_PREFIX}.test_idempotent_function_serialization_no_response.<locals>.record_handler#{hash_idempotency_key(mock_event)}"  # noqa E501
+    persistence_layer = MockPersistenceLayer(expected_idempotency_key=idempotency_key)
+
+    to_dict_called = False
+    from_dict_called = False
+
+    def to_dict(data):
+        nonlocal to_dict_called
+        to_dict_called = True
+        return data
+
+    def from_dict(data):
+        nonlocal from_dict_called
+        from_dict_called = True
+        return data
+
+    output_serializer = CustomDictSerializer(
+        to_dict=to_dict,
+        from_dict=from_dict,
+    )
+
+    @idempotent_function(
+        persistence_store=persistence_layer,
+        data_keyword_argument="record",
+        config=config,
+        output_serializer=output_serializer,
+    )
+    def record_handler(record):
+        return None
+
+    record_handler(record=mock_event)
+    assert to_dict_called is False, "in case response is None, to_dict should not be called"
+    response = record_handler(record=mock_event)
+    assert response is None
+    assert from_dict_called is False, "in case response is None, from_dict should not be called"
+
+
 def test_idempotent_function_serialization_pydantic():
     # GIVEN
     config = IdempotencyConfig(use_local_cache=True)