fix: default value for SQS's receive message

kombu/transport/SQS.py

@@ -545,9 +545,10 @@ def _receive_message(
         client = self.sqs(queue=queue)
 
         message_system_attribute_names = self.get_message_attributes.get(
-            'MessageSystemAttributeNames')
+            'MessageSystemAttributeNames') or []
+
         message_attribute_names = self.get_message_attributes.get(
-            'MessageAttributeNames')
+            'MessageAttributeNames') or []
 
         params: dict[str, Any] = {
             'QueueUrl': q_url,
@@ -964,7 +965,7 @@ def get_message_attributes(self) -> dict[str, Any]:
 
         if fetch is None or isinstance(fetch, str):
             return {
-                'MessageAttributeNames': None,
+                'MessageAttributeNames': [],
                 'MessageSystemAttributeNames': [APPROXIMATE_RECEIVE_COUNT],
             }
 
@@ -988,7 +989,7 @@ def get_message_attributes(self) -> dict[str, Any]:
                 )
 
         return {
-            'MessageAttributeNames': sorted(message_attrs) if message_attrs else None,
+            'MessageAttributeNames': sorted(message_attrs) if message_attrs else [],
             'MessageSystemAttributeNames': (
                 sorted(message_system_attrs) if message_system_attrs else [APPROXIMATE_RECEIVE_COUNT]
             )

t/unit/transport/test_SQS.py

@@ -125,9 +125,11 @@ def receive_message(
         QueueUrl=None,
         MaxNumberOfMessages=1,
         WaitTimeSeconds=10,
-        MessageAttributeNames=None,
-        MessageSystemAttributeNames=None
+        MessageAttributeNames=[],
+        MessageSystemAttributeNames=[],
     ):
+        assert isinstance(MessageAttributeNames, (list, tuple))
+        assert isinstance(MessageSystemAttributeNames, (list, tuple))
         self._receive_messages_calls += 1
         for q in self._queues.values():
             if q.url == QueueUrl: