fix(aci): Drop metric_alert_fire detectors (#89924)

We're renaming `MetricAlertFire` to `MetricIssue`
([PR](#89896)). To do so, we
need to drop existing detectors that use the `metric_alert_fire` slug.
There's ~230 rows that match that filter and the table has ~3k rows. All
the rows in the table were written during a test of the dual write and
are safe to drop as they'll be rewritten again once the flag is on. I've
marked this as post-deploy but it probably doesn't need to be.

Author: snigdhas

migrations_lockfile.txt

@@ -29,4 +29,4 @@ tempest: 0002_make_message_type_nullable
 
 uptime: 0033_uptime_backfill_to_detectors
 
-workflow_engine: 0045_add_unique_constraint_alert_rule_detector
+workflow_engine: 0046_drop_metric_alert_fire_detectors

src/sentry/workflow_engine/migrations/0046_drop_metric_alert_fire_detectors.py

@@ -0,0 +1,52 @@
+# Generated by Django 5.1.7 on 2025-04-18 01:22
+
+from django.db import migrations
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+from django.db.migrations.state import StateApps
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+def delete_metric_alert_fire_detectors(
+    apps: StateApps, schema_editor: BaseDatabaseSchemaEditor
+) -> None:
+    Detector = apps.get_model("workflow_engine", "Detector")
+    DetectorWorkflow = apps.get_model("workflow_engine", "DetectorWorkflow")
+    Workflow = apps.get_model("workflow_engine", "Workflow")
+
+    detectors = Detector.objects.filter(type="metric_alert_fire")
+    workflow_ids = DetectorWorkflow.objects.filter(detector__in=detectors).values_list(
+        "workflow__id", flat=True
+    )
+    workflows = Workflow.objects.filter(id__in=workflow_ids)
+
+    workflows.delete()
+    detectors.delete()
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = True
+
+    dependencies = [
+        ("workflow_engine", "0045_add_unique_constraint_alert_rule_detector"),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            code=delete_metric_alert_fire_detectors,
+            reverse_code=migrations.RunPython.noop,
+            hints={"tables": ["workflow_engine.Detector"]},
+        ),
+    ]

tests/sentry/workflow_engine/migrations/test_0046_drop_metric_alert_fire_detectors.py

@@ -0,0 +1,39 @@
+from sentry.models.organization import Organization
+from sentry.testutils.cases import TestMigrations
+from sentry.workflow_engine.models.detector import Detector
+
+
+class DropMetricAlertFireDetectors(TestMigrations):
+    app = "workflow_engine"
+    migrate_from = "0045_add_unique_constraint_alert_rule_detector"
+    migrate_to = "0046_drop_metric_alert_fire_detectors"
+
+    def setup_before_migration(self, app):
+        self.organization = Organization.objects.create(name="test", slug="test")
+        self.project = self.create_project(organization=self.organization)
+
+        detector_field_values = {
+            "project_id": self.project.id,
+            "name": "test",
+            "description": "test",
+            "workflow_condition_group": None,
+            "owner_user_id": None,
+            "owner_team": None,
+            "config": {
+                "threshold_period": 1,
+                "comparison_delta": 300,
+                "detection_type": "static",
+            },
+            "enabled": True,
+            "created_by_id": None,
+            "type": "metric_alert_fire",
+        }
+
+        Detector.objects.create(**detector_field_values)
+        detector_field_values["type"] = "monitor_check_in_failure"
+        Detector.objects.create(**detector_field_values)
+
+        assert Detector.objects.filter(type="metric_alert_fire").count() == 1
+
+    def test(self):
+        assert Detector.objects.filter(type="metric_alert_fire").count() == 0