added option to not search controller for attributes

Use a method instead.

Author: evvaaaa

src/fastcs/controller.py

@@ -6,17 +6,22 @@
 
 
 class BaseController:
-    def __init__(self, path: list[str] | None = None) -> None:
+    def __init__(
+        self, path: list[str] | None = None, search_device_for_attributes: bool = True
+    ) -> None:
         self._path: list[str] = path or []
-        self.__sub_controller_tree: dict[str, BaseController] = {}
+        # If this is set to `False`, FastCS will only use attributes defined in
+        # `additional_attributes`.
+        self.search_device_for_attributes = search_device_for_attributes
 
+        self.__sub_controller_tree: dict[str, BaseController] = {}
         self._bind_attrs()
 
     @property
-    def additional_attributes(self) -> dict[str, Attribute] | None:
-        """FastCS will look for attributes on the controller, but additional attribtues
-        be provided here."""
-        return None
+    def additional_attributes(self) -> dict[str, Attribute]:
+        """FastCS will look for attributes on the controller, but additional attributes
+        are provided by this method."""
+        return {}
 
     @property
     def path(self) -> list[str]:
@@ -58,8 +63,8 @@ class Controller(BaseController):
     generating a UI or creating parameters for a control system.
     """
 
-    def __init__(self) -> None:
-        super().__init__()
+    def __init__(self, search_device_for_attributes: bool = True) -> None:
+        super().__init__(search_device_for_attributes=search_device_for_attributes)
 
     async def initialise(self) -> None:
         pass
@@ -75,5 +80,5 @@ class SubController(BaseController):
     it as part of a larger device.
     """
 
-    def __init__(self) -> None:
-        super().__init__()
+    def __init__(self, search_device_for_attributes: bool = True) -> None:
+        super().__init__(search_device_for_attributes=search_device_for_attributes)

src/fastcs/mapping.py

@@ -52,9 +52,17 @@ def _get_single_mapping(controller: BaseController) -> SingleMapping:
             case WrappedMethod(fastcs_method=Command(enabled=True) as command_method):
                 command_methods[attr_name] = command_method
             case Attribute(enabled=True):
-                attributes[attr_name] = attr
+                if controller.search_device_for_attributes:
+                    attributes[attr_name] = attr
 
-    attributes.update(controller.additional_attributes or {})
+    additional_attributes = controller.additional_attributes
+    if common_attributes := additional_attributes.keys() ^ attributes.keys():
+        raise RuntimeError(
+            f"Received additional attributes {common_attributes} "
+            "already present in the controller."
+        )
+
+    attributes.update(additional_attributes)
 
     return SingleMapping(
         controller, scan_methods, put_methods, command_methods, attributes