fix: Check plan outcome when calling Plan objects

src/blueapi/client/client.py

@@ -6,7 +6,7 @@
 from functools import cached_property
 from itertools import chain
 from pathlib import Path
-from typing import Self
+from typing import Any, Self
 
 from bluesky_stomp.messaging import MessageContext, StompClient
 from bluesky_stomp.models import Broker
@@ -38,7 +38,7 @@
 )
 from blueapi.utils import deprecated
 from blueapi.worker import WorkerEvent, WorkerState
-from blueapi.worker.event import ProgressEvent, TaskStatus
+from blueapi.worker.event import ProgressEvent, TaskError, TaskResult, TaskStatus
 from blueapi.worker.task_worker import TrackableTask
 
 from .event_bus import AnyEvent, EventBusClient, OnAnyEvent
@@ -141,13 +141,17 @@ def __init__(self, name, model: PlanModel, client: "BlueapiClient"):
         self._client = client
         self.__doc__ = model.description
 
-    def __call__(self, *args, **kwargs):
+    def __call__(self, *args, **kwargs) -> Any:
         req = TaskRequest(
             name=self.name,
             params=self._build_args(*args, **kwargs),
             instrument_session=self._client.instrument_session,
         )
-        self._client.run_task(req)
+        match self._client.run_task(req):
+            case TaskStatus(result=TaskResult(result=res)):
+                return res
+            case TaskStatus(result=TaskError(type=typ, message=msg)):
+                raise PlanFailedError(typ, msg)
 
     @property
     def help_text(self) -> str:
@@ -744,3 +748,9 @@ def login(self, token_path: Path | None = None):
                 auth.start_device_flow()
             else:
                 print("Server is not configured to use authentication!")
+
+
+class PlanFailedError(Exception):
+    def __init__(self, typ: str, message: str):
+        super().__init__(message)
+        self._type = typ

tests/unit_tests/client/test_client.py

@@ -17,6 +17,7 @@
     MissingInstrumentSessionError,
     Plan,
     PlanCache,
+    PlanFailedError,
 )
 from blueapi.client.event_bus import AnyEvent, EventBusClient
 from blueapi.client.rest import BlueapiRestClient, BlueskyRemoteControlError
@@ -512,6 +513,39 @@ def callback(on_event: Callable[[AnyEvent, MessageContext], None]):
     mock_on_event.assert_called_once_with(COMPLETE_EVENT)
 
 
+def test_scripting_interface_returns_result():
+    client = Mock(spec=BlueapiClient, instrument_session="cm12345-1")
+    client.run_task.return_value = TaskStatus(
+        task_id="foobar",
+        task_complete=True,
+        task_failed=False,
+        result=TaskResult(result=42, type="int"),
+    )
+    demo_plan = Plan(
+        "demo",
+        client=client,
+        model=PlanModel(name="demo", description="Demo plan", schema={}),
+    )
+    assert demo_plan() == 42
+
+
+def test_scripting_interface_raises_exceptions():
+    client = Mock(spec=BlueapiClient, instrument_session="cm12345-1")
+    client.run_task.return_value = TaskStatus(
+        task_id="foobar",
+        task_complete=True,
+        task_failed=True,
+        result=TaskError(type="ValueError", message="Plan failed"),
+    )
+    demo_plan = Plan(
+        "demo",
+        client=client,
+        model=PlanModel(name="demo", description="Demo plan", schema={}),
+    )
+    with pytest.raises(PlanFailedError, match="Plan failed"):
+        demo_plan()
+
+
 def test_oidc_config_property(client, mock_rest):
     assert client.oidc_config == mock_rest.get_oidc_config()