[Resolve #1451] Stop suppressing ClientError in describe_outputs

integration-tests/steps/stack_groups.py

@@ -204,13 +204,6 @@ def step_impl(context, stack_group_name, status):
         assert response in expected_response
 
 
-@then("no resources are described")
-def step_impl(context):
-    for stack_resources in context.response:
-        stack_name = next(iter(stack_resources))
-        assert stack_resources == {stack_name: []}
-
-
 @then('stack "{stack_name}" is described as "{status}"')
 def step_impl(context, stack_name, status):
     response = next(

sceptre/diffing/stack_differ.py

@@ -23,6 +23,8 @@
 from sceptre.plan.actions import StackActions
 from sceptre.stack import Stack
 
+from botocore.exceptions import ClientError
+
 DiffType = TypeVar("DiffType")
 
 logger = logging.getLogger(__name__)
@@ -192,10 +194,12 @@ def _extract_parameters_from_generated_stack(self, stack: Stack) -> dict:
     def _create_deployed_stack_config(
         self, stack_actions: StackActions
     ) -> Optional[StackConfiguration]:
-        description = stack_actions.describe()
-        if description is None:
+        try:
+            description = stack_actions.describe()
+        except ClientError as err:
             # This means the stack has not been deployed yet
-            return None
+            if err.response["Error"]["Message"].endswith("does not exist"):
+                return None
 
         stacks = description["Stacks"]
         for stack in stacks:

sceptre/plan/actions.py

@@ -303,16 +303,11 @@ def describe(self):
         :returns: A Stack description.
         :rtype: dict
         """
-        try:
-            return self.connection_manager.call(
-                service="cloudformation",
-                command="describe_stacks",
-                kwargs={"StackName": self.stack.external_name},
-            )
-        except botocore.exceptions.ClientError as e:
-            if e.response["Error"]["Message"].endswith("does not exist"):
-                return
-            raise
+        return self.connection_manager.call(
+            service="cloudformation",
+            command="describe_stacks",
+            kwargs={"StackName": self.stack.external_name},
+        )
 
     def describe_events(self):
         """
@@ -364,15 +359,11 @@ def describe_outputs(self):
         """
         Returns the Stack's outputs.
 
-        :returns: The Stack's outputs.
+        :returns: The stack's outputs.
         :rtype: list
         """
         self.logger.debug("%s - Describing stack outputs", self.stack.name)
-
-        try:
-            response = self._describe()
-        except botocore.exceptions.ClientError:
-            return []
+        response = self.describe()
 
         return {self.stack.name: response["Stacks"][0].get("Outputs", [])}
 
@@ -784,16 +775,9 @@ def timed_out(elapsed):
 
         return status
 
-    def _describe(self):
-        return self.connection_manager.call(
-            service="cloudformation",
-            command="describe_stacks",
-            kwargs={"StackName": self.stack.external_name},
-        )
-
     def _get_status(self):
         try:
-            status = self._describe()["Stacks"][0]["StackStatus"]
+            status = self.describe()["Stacks"][0]["StackStatus"]
         except botocore.exceptions.ClientError as exp:
             if exp.response["Error"]["Message"].endswith("does not exist"):
                 raise StackDoesNotExistError(exp.response["Error"]["Message"])

tests/test_actions.py

@@ -556,14 +556,15 @@ def test_describe_resources_sends_correct_request(self):
             ]
         }
 
-    @patch("sceptre.plan.actions.StackActions._describe")
+    @patch("sceptre.plan.actions.StackActions.describe")
     def test_describe_outputs_sends_correct_request(self, mock_describe):
         mock_describe.return_value = {"Stacks": [{"Outputs": sentinel.outputs}]}
         response = self.actions.describe_outputs()
+
         mock_describe.assert_called_once_with()
         assert response == {self.stack.name: sentinel.outputs}
 
-    @patch("sceptre.plan.actions.StackActions._describe")
+    @patch("sceptre.plan.actions.StackActions.describe")
     def test_describe_outputs_handles_stack_with_no_outputs(self, mock_describe):
         mock_describe.return_value = {"Stacks": [{}]}
         response = self.actions.describe_outputs()
@@ -892,13 +893,13 @@ def test_format_parameters_with_none_list_and_string_values(self):
             {"ParameterKey": "key2", "ParameterValue": "value4"},
         ]
 
-    @patch("sceptre.plan.actions.StackActions._describe")
+    @patch("sceptre.plan.actions.StackActions.describe")
     def test_get_status_with_created_stack(self, mock_describe):
         mock_describe.return_value = {"Stacks": [{"StackStatus": "CREATE_COMPLETE"}]}
         status = self.actions.get_status()
         assert status == "CREATE_COMPLETE"
 
-    @patch("sceptre.plan.actions.StackActions._describe")
+    @patch("sceptre.plan.actions.StackActions.describe")
     def test_get_status_with_non_existent_stack(self, mock_describe):
         mock_describe.side_effect = ClientError(
             {
@@ -911,7 +912,7 @@ def test_get_status_with_non_existent_stack(self, mock_describe):
         )
         assert self.actions.get_status() == "PENDING"
 
-    @patch("sceptre.plan.actions.StackActions._describe")
+    @patch("sceptre.plan.actions.StackActions.describe")
     def test_get_status_with_unknown_clinet_error(self, mock_describe):
         mock_describe.side_effect = ClientError(
             {"Error": {"Code": "DoesNotExistException", "Message": "Boom!"}},

tests/test_diffing/test_stack_differ.py

@@ -20,6 +20,8 @@
 from sceptre.plan.actions import StackActions
 from sceptre.stack import Stack
 
+from botocore.exceptions import ClientError
+
 
 class ImplementedStackDiffer(StackDiffer):
     def __init__(self, command_capturer: Mock):
@@ -224,14 +226,22 @@ def test_diff__deployed_stack_exists__returns_is_deployed_as_true(self):
         assert diff.is_deployed is True
 
     def test_diff__deployed_stack_does_not_exist__returns_is_deployed_as_false(self):
-        self.actions.describe.return_value = self.actions.describe.side_effect = None
+        self.actions.describe.side_effect = ClientError(
+            {"Error": {"Code": "Whatevs", "Message": "Stack does not exist"}},
+            "DescribeStacks",
+        )
+        self.actions.describe.return_value = None
         diff = self.differ.diff(self.actions)
         assert diff.is_deployed is False
 
     def test_diff__deployed_stack_does_not_exist__compares_none_to_generated_config(
         self,
     ):
-        self.actions.describe.return_value = self.actions.describe.side_effect = None
+        self.actions.describe.side_effect = ClientError(
+            {"Error": {"Code": "Whatevs", "Message": "Stack does not exist"}},
+            "DescribeStacks",
+        )
+        self.actions.describe.return_value = None
         self.differ.diff(self.actions)
 
         self.command_capturer.compare_stack_configurations.assert_called_with(