[Resolve #1468] Cast parameters to strings

sceptre/stack.py

@@ -263,7 +263,7 @@ def __init__(
         )
 
         self.s3_details = s3_details
-        self.parameters = self._ensure_parameters(parameters or {})
+        self.parameters = self._cast_parameters(parameters or {})
         self.sceptre_user_data = sceptre_user_data or {}
         self.notifications = notifications or []
 
@@ -276,10 +276,21 @@ def _ensure_boolean(self, config_name: str, value: Any) -> bool:
             )
         return value
 
-    def _ensure_parameters(
+    def _cast_parameters(
         self, parameters: Dict[str, Any]
     ) -> Dict[str, Union[str, List[Union[str, Resolver]], Resolver]]:
-        """Ensure CloudFormation parameters are of valid types"""
+        """Cast CloudFormation parameters to valid types"""
+
+        def cast_value(value: Any) -> Union[str, List[Union[str, Resolver]], Resolver]:
+            if isinstance(value, bool):
+                return "true" if value else "false"
+            elif isinstance(value, (int, float)):
+                return str(value)
+            elif isinstance(value, list):
+                return [cast_value(item) for item in value]
+            elif isinstance(value, Resolver):
+                return value
+            return value
 
         def is_valid(value: Any) -> bool:
             return (
@@ -294,11 +305,14 @@ def is_valid(value: Any) -> bool:
                 or isinstance(value, Resolver)
             )
 
-        if not all(is_valid(value) for value in parameters.values()):
+        casted_parameters = {k: cast_value(v) for k, v in parameters.items()}
+
+        if not all(is_valid(value) for value in casted_parameters.values()):
             raise InvalidConfigFileError(
-                f"{self.name}: Values for parameters must be strings, lists or resolvers, got {parameters}"
+                f"{self.name}: Values for parameters must be strings, lists or resolvers, got {casted_parameters}"
             )
-        return parameters
+
+        return casted_parameters
 
     def __repr__(self):
         return (

tests/test_stack.py

@@ -190,12 +190,7 @@ def test_init__non_boolean_obsolete_value__raises_invalid_config_file_error(self
 
     @pytest.mark.parametrize(
         "parameters",
-        [
-            {"someNum": 1},
-            {"someBool": True},
-            {"aBadList": [1, 2, 3]},
-            {"aDict": {"foo": "bar"}},
-        ],
+        [{"Dict": {"foo": "bar"}}, {"List": ["of", "stuff", {"including": "aDict"}]}],
     )
     def test_init__invalid_parameters_raise_invalid_config_file_error(self, parameters):
         with pytest.raises(InvalidConfigFileError):
@@ -210,10 +205,13 @@ def test_init__invalid_parameters_raise_invalid_config_file_error(self, paramete
     @pytest.mark.parametrize(
         "parameters",
         [
-            {"someNum": "1"},
-            {"someBool": "true"},
-            {"aList": ["aString", FakeResolver()]},
-            {"aResolver": FakeResolver()},
+            {"IntAsString": "1"},
+            {"Int": 1},
+            {"BoolAsString": "true"},
+            {"Bool": True},
+            {"List": ["aStringAndA", FakeResolver()]},
+            {"ListOfInts": [1, 2, 3]},
+            {"Resolver": FakeResolver()},
         ],
     )
     def test_init__valid_parameters_do_not_raise_invalid_config_file_error(