Fix silence for paused escalations or alert groups with empty escalation chain

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fix issue with helm chart when specifying `broker.type=rabbitmq` where Redis environment variables
   were not longer being injected @joeyorlando ([#2927](https://github.com/grafana/oncall/pull/2927))
+- Fix silence for alert groups with empty escalation chain @Ferril ([#2929](https://github.com/grafana/oncall/pull/2929))
 - Fixed NPE when migrating legacy Grafana Alerting integrations
   ([#2908](https://github.com/grafana/oncall/issues/2908))
 

engine/apps/alerts/escalation_snapshot/escalation_snapshot_mixin.py

@@ -231,6 +231,9 @@ def update_next_step_eta(self, increase_by_timedelta: datetime.timedelta) -> typ
             return None
 
         raw_next_step_eta = self.raw_escalation_snapshot.get("next_step_eta")
+        if not raw_next_step_eta:  # empty escalation chain or paused escalations
+            return self.raw_escalation_snapshot
+
         next_step_eta = parse(raw_next_step_eta).replace(tzinfo=pytz.UTC)
         updated_next_step_eta = next_step_eta + increase_by_timedelta
         self.raw_escalation_snapshot["next_step_eta"] = updated_next_step_eta.strftime("%Y-%m-%dT%H:%M:%S.%fZ")

engine/apps/alerts/tests/test_escalation_snapshot_mixin.py

@@ -684,3 +684,24 @@ def test_update_next_step_eta(
     alert_group.refresh_from_db()
 
     assert alert_group.raw_escalation_snapshot["next_step_eta"] == updated_raw_next_step_eta
+
+
+@pytest.mark.django_db
+def test_update_next_step_eta_none(
+    make_organization_and_user,
+    make_alert_receive_channel,
+    make_alert_group,
+):
+    increase_by_timedelta = datetime.timedelta(minutes=120)
+
+    organization, _ = make_organization_and_user()
+    alert_receive_channel = make_alert_receive_channel(organization)
+    alert_group = make_alert_group(alert_receive_channel)
+    alert_group.raw_escalation_snapshot = alert_group.build_raw_escalation_snapshot()
+
+    assert alert_group.raw_escalation_snapshot is not None
+    assert alert_group.raw_escalation_snapshot.get("next_step_eta") is None
+
+    updated_snapshot = alert_group.update_next_step_eta(increase_by_timedelta)
+    assert updated_snapshot == alert_group.build_raw_escalation_snapshot()
+    assert updated_snapshot.get("next_step_eta") is None