chore: add exception handler for non-dict input to declarative hook

tackle/parser.py

@@ -1196,16 +1196,24 @@ def create_function_model(
     context: 'Context', func_name: str, func_dict: dict
 ) -> Type[BaseFunction]:
     """Create a model from the function input dict."""
+    if func_name.endswith(('<-', '<_')):
+        func_name = func_name[:-2]
+
     if func_dict is None:
         raise exceptions.EmptyFunctionException(
             "Can't have an empty function", context=context, function_name=func_name
         )
+    if not isinstance(func_dict, dict):
+        raise exceptions.MalformedFunctionFieldException(
+            "Input to a declarative hook must be a map. This could change in future"
+            " versions.",
+            context=context,
+            function_name=func_name,
+        ) from None
+
     # Macro to expand all keys properly so that a field's default can be parsed
     func_dict = function_field_to_parseable_macro(func_dict, context, func_name)
 
-    if func_name.endswith(('<-', '<_')):
-        func_name = func_name[:-2]
-
     # Implement inheritance
     if 'extends' in func_dict and func_dict['extends'] is not None:
         base_hook = get_hook(func_dict['extends'], context)

tests/parser/functions/exceptions/str-value.yaml

@@ -0,0 +1,2 @@
+
+s<-: stuff

tests/parser/functions/test_functions_exceptions.py

@@ -1,6 +1,7 @@
 import pytest
 
 from tackle import tackle
+from tackle.cli import main
 from tackle import exceptions
 
 
@@ -57,8 +58,12 @@ def test_parser_functions_raises_hook_kwarg_missing_default(chdir):
 
 
 def test_parser_functions_raises_validation_missing_field(chdir):
-    from tackle.cli import main
-
     chdir('exceptions')
     with pytest.raises(exceptions.MalformedFunctionFieldException):
         main(["missing-field.yaml", "stuff"])
+
+
+def test_parser_functions_raises_(chdir):
+    chdir('exceptions')
+    with pytest.raises(exceptions.MalformedFunctionFieldException):
+        main(["str-value.yaml", "stuff"])