fix(anomaly detection): surface validation error to user on trigger create/update

src/sentry/incidents/serializers/alert_rule_trigger.py

@@ -1,3 +1,4 @@
+from django import forms
 from rest_framework import serializers
 
 from sentry.api.serializers.rest_framework.base import CamelSnakeModelSerializer
@@ -45,6 +46,9 @@ def create(self, validated_data):
             self._handle_actions(alert_rule_trigger, actions)
 
             return alert_rule_trigger
+        except forms.ValidationError as e:
+            # if we fail in create_alert_rule_trigger, then only one message is ever returned
+            raise serializers.ValidationError(e.error_list[0].message)
         except AlertRuleTriggerLabelAlreadyUsedError:
             raise serializers.ValidationError("This label is already in use for this alert rule")
 
@@ -56,6 +60,9 @@ def update(self, instance, validated_data):
             alert_rule_trigger = update_alert_rule_trigger(instance, **validated_data)
             self._handle_actions(alert_rule_trigger, actions)
             return alert_rule_trigger
+        except forms.ValidationError as e:
+            # if we fail in update_alert_rule_trigger, then only one message is ever returned
+            raise serializers.ValidationError(e.error_list[0].message)
         except AlertRuleTriggerLabelAlreadyUsedError:
             raise serializers.ValidationError("This label is already in use for this alert rule")
 

tests/sentry/incidents/endpoints/test_serializers.py

@@ -21,6 +21,8 @@
 from sentry.incidents.models.alert_rule import (
     AlertRule,
     AlertRuleDetectionType,
+    AlertRuleSeasonality,
+    AlertRuleSensitivity,
     AlertRuleThresholdType,
     AlertRuleTriggerAction,
 )
@@ -43,6 +45,7 @@
 from sentry.snuba.dataset import Dataset
 from sentry.snuba.models import SnubaQuery, SnubaQueryEventType
 from sentry.testutils.cases import TestCase
+from sentry.testutils.helpers.features import with_feature
 from sentry.testutils.silo import assume_test_silo_mode
 from sentry.testutils.skips import requires_snuba
 from sentry.users.models.user import User
@@ -464,6 +467,22 @@ def test_boundary_off_by_one(self):
             },
         )
 
+    @with_feature("organizations:anomaly-detection-alerts")
+    def test_invalid_alert_threshold(self):
+        """
+        Anomaly detection alerts cannot have a nonzero alert rule threshold
+        """
+        params = self.valid_params.copy()
+        params["detection_type"] = AlertRuleDetectionType.DYNAMIC
+        params["seasonality"] = AlertRuleSeasonality.AUTO
+        params["sensitivity"] = AlertRuleSensitivity.MEDIUM
+        params["time_window"] = 15
+        serializer = AlertRuleSerializer(context=self.context, data=params)
+        assert serializer.is_valid()
+
+        with pytest.raises(serializers.ValidationError):
+            serializer.save()
+
     def test_invalid_slack_channel(self):
         # We had an error where an invalid slack channel was spitting out unclear
         # error for the user, and CREATING THE RULE. So the next save (after fixing slack action)