fix(aci): use singular preferred detector in workflow processing round 2

src/sentry/workflow_engine/models/action.py

@@ -124,9 +124,9 @@ def get_handler(self) -> builtins.type[ActionHandler]:
         return action_handler_registry.get(action_type)
 
     def trigger(self, event_data: WorkflowEventData, notification_uuid: str) -> None:
-        from sentry.workflow_engine.processors.detector import get_detector_from_event_data
+        from sentry.workflow_engine.processors.detector import get_preferred_detector
 
-        detector = get_detector_from_event_data(event_data)
+        detector = get_preferred_detector(event_data)
 
         with metrics.timer(
             "workflow_engine.action.trigger.execution_time",

src/sentry/workflow_engine/processors/detector.py

@@ -226,6 +226,10 @@ def ensure_default_detectors(project: Project) -> tuple[Detector, Detector]:
     )
 
 
+class SpecificDetectorNotFound(Exception):
+    pass
+
+
 @dataclass(frozen=True)
 class EventDetectors:
     issue_stream_detector: Detector | None = None
@@ -258,17 +262,17 @@ def detectors(self) -> set[Detector]:
         return {d for d in [self.issue_stream_detector, self.event_detector] if d is not None}
 
 
-def get_detectors_for_event(
-    event_data: WorkflowEventData, detector: Detector | None = None
+def get_detectors_for_event_data(
+    event_data: WorkflowEventData,
+    detector: Detector | None = None,
 ) -> EventDetectors | None:
     """
     Returns a list of detectors for the event to process workflows for.
 
     We always return at least the issue stream detector, unless excluded via option.
     If the event has an associated detector, we return it too.
 
-    If the detector is passed in, use that instead of searching for a detector.
-    This is used for Activity updates.
+    We expect a detector to be passed in for Activity updates.
     """
     issue_stream_detector: Detector | None = None
     exclude_issue_stream = options.get("workflow_engine.exclude_issue_stream_detector")
@@ -288,10 +292,10 @@ def get_detectors_for_event(
                 },
             )
 
-    if detector is None:
+    if detector is None and isinstance(event_data.event, GroupEvent):
         try:
-            detector = get_detector_by_event(event_data)
-        except Detector.DoesNotExist:
+            detector = _get_detector_for_event(event_data.event)
+        except (Detector.DoesNotExist, SpecificDetectorNotFound):
             pass
 
     try:
@@ -300,24 +304,21 @@ def get_detectors_for_event(
         return None
 
 
-def get_detector_by_event(event_data: WorkflowEventData) -> Detector:
-    evt = event_data.event
-
-    if not isinstance(evt, GroupEvent):
-        raise TypeError(
-            "Can only use `get_detector_by_event` for a new event, Activity updates are not supported"
-        )
+def _get_detector_for_event(event: GroupEvent) -> Detector:
+    """
+    Returns the detector from the GroupEvent in event_data.
+    """
 
-    issue_occurrence = evt.occurrence
+    issue_occurrence = event.occurrence
 
     try:
-        if issue_occurrence is None or evt.group.issue_type.detector_settings is None:
-            # if there are no detector settings, default to the error detector
-            detector = Detector.get_error_detector_for_project(evt.project_id)
+        if issue_occurrence is not None:
+            detector_id = issue_occurrence.evidence_data.get("detector_id")
+            if detector_id is None:
+                raise SpecificDetectorNotFound
+            detector = Detector.objects.get(id=detector_id)
         else:
-            detector = Detector.objects.get(
-                id=issue_occurrence.evidence_data.get("detector_id", None)
-            )
+            detector = Detector.get_error_detector_for_project(event.group.project_id)
     except Detector.DoesNotExist:
         metrics.incr("workflow_engine.detectors.error")
         detector_id = (
@@ -327,8 +328,8 @@ def get_detector_by_event(event_data: WorkflowEventData) -> Detector:
         logger.exception(
             "Detector not found for event",
             extra={
-                "event_id": evt.event_id,
-                "group_id": evt.group_id,
+                "event_id": event.event_id,
+                "group_id": event.group_id,
                 "detector_id": detector_id,
             },
         )
@@ -337,7 +338,7 @@ def get_detector_by_event(event_data: WorkflowEventData) -> Detector:
     return detector
 
 
-def get_detector_by_group(group: Group) -> Detector:
+def _get_detector_for_group(group: Group) -> Detector:
     """
     Returns Detector associated with this group, either based on DetectorGroup,
     (project, type), or if those fail, returns the Issue Stream detector.
@@ -360,12 +361,18 @@ def get_detector_by_group(group: Group) -> Detector:
         return Detector.objects.get(project_id=group.project_id, type=IssueStreamGroupType.slug)
 
 
-def get_detector_from_event_data(event_data: WorkflowEventData) -> Detector:
+def get_preferred_detector(event_data: WorkflowEventData) -> Detector:
+    """
+    Attempts to fetch the specific detector based on the GroupEvent or Activity in event_data
+    """
     try:
         if isinstance(event_data.event, GroupEvent):
-            return get_detector_by_event(event_data)
+            event_detectors = get_detectors_for_event_data(event_data)
+            if event_detectors is None:
+                raise Detector.DoesNotExist("No detectors found for event")
+            return event_detectors.preferred_detector
         elif isinstance(event_data.event, Activity):
-            return get_detector_by_group(event_data.group)
+            return _get_detector_for_group(event_data.group)
         else:
             raise TypeError(f"Cannot determine the detector from {type(event_data.event)}.")
     except Detector.DoesNotExist:

src/sentry/workflow_engine/processors/workflow.py

@@ -1,4 +1,4 @@
-from collections.abc import Collection, Sequence
+from collections.abc import Sequence
 from dataclasses import asdict, replace
 from datetime import datetime
 from enum import StrEnum
@@ -30,7 +30,7 @@
     get_data_conditions_for_group,
     process_data_condition_group,
 )
-from sentry.workflow_engine.processors.detector import get_detectors_for_event
+from sentry.workflow_engine.processors.detector import get_detectors_for_event_data
 from sentry.workflow_engine.processors.workflow_fire_history import create_workflow_fire_histories
 from sentry.workflow_engine.types import (
     WorkflowEvaluation,
@@ -380,7 +380,7 @@ def get_environment_by_event(event_data: WorkflowEventData) -> Environment | Non
 
 @scopedstats.timer()
 def _get_associated_workflows(
-    detectors: Collection[Detector], environment: Environment | None, event_data: WorkflowEventData
+    detector: Detector, environment: Environment | None, event_data: WorkflowEventData
 ) -> set[Workflow]:
     """
     This is a wrapper method to get the workflows associated with a detector and environment.
@@ -394,7 +394,7 @@ def _get_associated_workflows(
     workflows = set(
         Workflow.objects.filter(
             environment_filter,
-            detectorworkflow__detector_id__in=[detector.id for detector in detectors],
+            detectorworkflow__detector_id=detector.id,
             enabled=True,
         )
         .select_related("environment")
@@ -421,7 +421,7 @@ def _get_associated_workflows(
                 "event_data": asdict(event_data),
                 "event_environment_id": environment.id if environment else None,
                 "workflows": [workflow.id for workflow in workflows],
-                "detector_types": [detector.type for detector in detectors],
+                "detector_type": detector.type,
             },
         )
 
@@ -454,7 +454,7 @@ def process_workflows(
     )
 
     try:
-        event_detectors = get_detectors_for_event(event_data, detector)
+        event_detectors = get_detectors_for_event_data(event_data, detector)
 
         if not event_detectors:
             raise Detector.DoesNotExist("No Detectors associated with the issue were found")
@@ -500,7 +500,9 @@ def process_workflows(
     if features.has("organizations:workflow-engine-process-workflows-logs", organization):
         log_context.set_verbose(True)
 
-    workflows = _get_associated_workflows(event_detectors.detectors, environment, event_data)
+    workflows = _get_associated_workflows(
+        event_detectors.preferred_detector, environment, event_data
+    )
     workflow_evaluation_data.workflows = workflows
 
     if not workflows:

src/sentry/workflow_engine/tasks/actions.py

@@ -91,7 +91,7 @@ def trigger_action(
     import uuid
 
     from sentry.notifications.notification_action.utils import should_fire_workflow_actions
-    from sentry.workflow_engine.processors.detector import get_detector_from_event_data
+    from sentry.workflow_engine.processors.detector import get_preferred_detector
 
     # Generate UUID if not provided (handles version skew at task boundary)
     if notification_uuid is None:
@@ -129,7 +129,7 @@ def trigger_action(
         )
         raise ValueError("Exactly one of event_id or activity_id must be provided")
 
-    detector = get_detector_from_event_data(event_data)
+    detector = get_preferred_detector(event_data)
 
     metrics.incr(
         "workflow_engine.tasks.trigger_action_task_started",

tests/sentry/workflow_engine/models/test_action.py

@@ -71,7 +71,7 @@ def test_get_handler_unregistered_type(self) -> None:
             # Verify the registry was queried with the correct action type
             mock_get.assert_called_once_with(Action.Type.SLACK)
 
-    @patch("sentry.workflow_engine.processors.detector.get_detector_from_event_data")
+    @patch("sentry.workflow_engine.processors.detector.get_preferred_detector")
     def test_trigger_calls_handler_execute(self, mock_get_detector: MagicMock) -> None:
         mock_handler = Mock(spec=ActionHandler)
         mock_detector = Mock(spec=Detector, type="error")
@@ -88,7 +88,7 @@ def test_trigger_calls_handler_execute(self, mock_get_detector: MagicMock) -> No
             assert invocation.action == self.action
             assert invocation.detector == mock_detector
 
-    @patch("sentry.workflow_engine.processors.detector.get_detector_from_event_data")
+    @patch("sentry.workflow_engine.processors.detector.get_preferred_detector")
     def test_trigger_with_failing_handler(self, mock_get_detector: MagicMock) -> None:
         mock_handler = Mock(spec=ActionHandler)
         mock_handler.execute.side_effect = Exception("Handler failed")
@@ -99,7 +99,7 @@ def test_trigger_with_failing_handler(self, mock_get_detector: MagicMock) -> Non
                 self.action.trigger(self.mock_event, notification_uuid=str(uuid.uuid4()))
 
     @patch("sentry.utils.metrics.incr")
-    @patch("sentry.workflow_engine.processors.detector.get_detector_from_event_data")
+    @patch("sentry.workflow_engine.processors.detector.get_preferred_detector")
     def test_trigger_metrics(self, mock_get_detector: MagicMock, mock_incr: MagicMock) -> None:
         mock_handler = Mock(spec=ActionHandler)
         mock_get_detector.return_value = Mock(spec=Detector, type="error")