Defer implementation of MsgGenerator to prevent strange behaviour (#832)

src/dodal/common/types.py

@@ -1,16 +1,11 @@
 from abc import ABC, abstractmethod
-from collections.abc import Callable, Generator
-from typing import (
-    Any,
-)
+from collections.abc import Callable
 
-from bluesky.utils import Msg
+from bluesky.utils import MsgGenerator
 from ophyd_async.core import PathProvider
 
 # String identifier used by 'wait' or stubs that await
 Group = str
-# A true 'plan', usually the output of a generator function
-MsgGenerator = Generator[Msg, Any, None]
 # A function that generates a plan
 PlanGenerator = Callable[..., MsgGenerator]
 

src/dodal/plans/data_session_metadata.py

@@ -1,9 +1,9 @@
 from bluesky import plan_stubs as bps
 from bluesky import preprocessors as bpp
-from bluesky.utils import make_decorator
+from bluesky.utils import MsgGenerator, make_decorator
 
 from dodal.common.beamlines import beamline_utils
-from dodal.common.types import MsgGenerator, UpdatingPathProvider
+from dodal.common.types import UpdatingPathProvider
 
 DATA_SESSION = "data_session"
 DATA_GROUPS = "data_groups"

src/dodal/plans/motor_util_plans.py

@@ -4,11 +4,10 @@
 
 from bluesky import plan_stubs as bps
 from bluesky.preprocessors import finalize_wrapper, pchain
-from bluesky.utils import Msg, make_decorator
+from bluesky.utils import Msg, MsgGenerator, make_decorator
 from ophyd_async.core import Device
 from ophyd_async.epics.motor import Motor
 
-from dodal.common import MsgGenerator
 from dodal.utils import MovableReadable
 
 MovableReadableDevice = TypeVar("MovableReadableDevice", bound=MovableReadable)

tests/common/test_coordination.py

@@ -2,9 +2,9 @@
 
 import pytest
 from bluesky.protocols import Movable
+from bluesky.utils import MsgGenerator
 
 from dodal.common.coordination import group_uuid, inject
-from dodal.common.types import MsgGenerator
 
 static_uuid = "51aef931-33b4-4b33-b7ad-a8287f541202"
 

tests/preprocessors/test_filesystem_metadata.py

@@ -14,11 +14,12 @@
 )
 from bluesky.protocols import HasName, Readable, Reading, Triggerable
 from bluesky.run_engine import RunEngine
+from bluesky.utils import MsgGenerator
 from event_model.documents.event_descriptor import DataKey
 from ophyd_async.core import AsyncStatus, DeviceCollector, PathProvider
 from pydantic import BaseModel
 
-from dodal.common.types import MsgGenerator, UpdatingPathProvider
+from dodal.common.types import UpdatingPathProvider
 from dodal.common.visit import (
     DataCollectionIdentifier,
     DirectoryServiceClient,