ref(crons): Set null for owner_user_id when a user is deleted (#69034)

Co-authored-by: getsantry[bot] <66042841+getsantry[bot]@users.noreply.github.com>

migrations_lockfile.txt

@@ -9,5 +9,5 @@ feedback: 0004_index_together
 hybridcloud: 0016_add_control_cacheversion
 nodestore: 0002_nodestore_no_dictfield
 replays: 0004_index_together
-sentry: 0698_remove_file_id_from_control_avatars
+sentry: 0699_update_monitor_owner_team_id_cascsade
 social_auth: 0002_default_auto_field

src/sentry/migrations/0699_update_monitor_owner_team_id_cascsade.py

@@ -0,0 +1,36 @@
+# Generated by Django 5.0.3 on 2024-04-16 20:35
+
+from django.db import migrations
+
+import sentry.db.models.fields.hybrid_cloud_foreign_key
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+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 = False
+
+    dependencies = [
+        ("sentry", "0698_remove_file_id_from_control_avatars"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="monitor",
+            name="owner_user_id",
+            field=sentry.db.models.fields.hybrid_cloud_foreign_key.HybridCloudForeignKey(
+                "sentry.User", db_index=True, null=True, on_delete="SET_NULL"
+            ),
+        ),
+    ]

src/sentry/monitors/models.py

@@ -251,7 +251,7 @@ class Monitor(Model):
     Type of monitor. Currently there are only CRON_JOB monitors.
     """
 
-    owner_user_id = HybridCloudForeignKey(settings.AUTH_USER_MODEL, null=True, on_delete="CASCADE")
+    owner_user_id = HybridCloudForeignKey(settings.AUTH_USER_MODEL, null=True, on_delete="SET_NULL")
     """
     The user assigned as the owner of this model.
     """