validate hinted attributes on subcontrollers

Author: James Souter

src/fastcs/util.py

@@ -37,7 +37,8 @@ def validate_hinted_attributes(controller: BaseController):
     For each type-hinted attribute, validate that a corresponding instance exists in the
     controller with the correct access mode and datatype.
     """
-
+    for subcontroller in controller.sub_controllers.values():
+        validate_hinted_attributes(subcontroller)
     hints = get_type_hints(type(controller))
     alias_hints = {k: v for k, v in hints.items() if isinstance(v, _GenericAlias)}
     for name, hint in alias_hints.items():

tests/test_util.py

@@ -6,6 +6,7 @@
 from pydantic import ValidationError
 
 from fastcs.attributes import AttrR, AttrRW
+from fastcs.backend import Backend
 from fastcs.controller import Controller
 from fastcs.datatypes import Bool, Enum, Float, Int, String
 from fastcs.util import (
@@ -136,3 +137,26 @@ class ControllerWrongEnumClass(Controller):
         "'hinted_enum' does not match defined datatype. "
         "Expected 'MyEnum', got 'MyEnum2'."
     )
+
+
+def test_hinted_attributes_verified_on_subcontrollers():
+    loop = asyncio.get_event_loop()
+
+    class ControllerWithWrongType(SubController):
+        hinted_missing: AttrR[int]
+
+        async def connect(self):
+            return
+
+    class TopController(Controller):
+        async def initialise(self):
+            subcontroller = ControllerWithWrongType()
+            self.register_sub_controller("MySubController", subcontroller)
+
+    with pytest.raises(RuntimeError) as excinfo:
+        Backend(TopController(), loop)
+
+    assert str(excinfo.value) == (
+        "Controller `ControllerWithWrongType` failed to introspect hinted attribute "
+        "`hinted_missing` during initialisation"
+    )