Handle error when updating ical cache from deleted web schedule

engine/apps/schedules/models/on_call_schedule.py

@@ -8,6 +8,7 @@
 from django.conf import settings
 from django.core.validators import MinLengthValidator
 from django.db import models
+from django.db.utils import DatabaseError
 from django.utils import timezone
 from django.utils.functional import cached_property
 from icalendar.cal import Calendar
@@ -637,7 +638,11 @@ def _ical_file_primary(self):
         """Return cached ical file with iCal events from custom on-call shifts."""
         if self.cached_ical_file_primary is None:
             self.cached_ical_file_primary = self._generate_ical_file_primary()
-            self.save(update_fields=["cached_ical_file_primary"])
+            try:
+                self.save(update_fields=["cached_ical_file_primary"])
+            except DatabaseError:
+                # schedule may have been deleted from db
+                return
         return self.cached_ical_file_primary
 
     def _refresh_primary_ical_file(self):
@@ -650,7 +655,11 @@ def _ical_file_overrides(self):
         """Return cached ical file with iCal events from custom on-call overrides shifts."""
         if self.cached_ical_file_overrides is None:
             self.cached_ical_file_overrides = self._generate_ical_file_overrides()
-            self.save(update_fields=["cached_ical_file_overrides"])
+            try:
+                self.save(update_fields=["cached_ical_file_overrides"])
+            except DatabaseError:
+                # schedule may have been deleted from db
+                return
         return self.cached_ical_file_overrides
 
     def _refresh_overrides_ical_file(self):

engine/apps/schedules/tests/test_on_call_schedule.py

@@ -924,3 +924,37 @@ def test_schedule_related_users(make_organization, make_user_for_organization, m
     schedule.refresh_from_db()
     users = schedule.related_users()
     assert users == set(u.public_primary_key for u in [user_a, user_d, user_e])
+
+
+@pytest.mark.django_db(transaction=True)
+def test_filter_events_none_cache_unchanged(
+    make_organization, make_user_for_organization, make_schedule, make_on_call_shift
+):
+    organization = make_organization()
+    user = make_user_for_organization(organization)
+    schedule = make_schedule(
+        organization,
+        schedule_class=OnCallScheduleWeb,
+        name="test_web_schedule",
+    )
+    start_date = timezone.now().replace(hour=0, minute=0, second=0, microsecond=0)
+
+    # add shift
+    data = {
+        "start": start_date + timezone.timedelta(hours=36),
+        "rotation_start": start_date + timezone.timedelta(hours=36),
+        "duration": timezone.timedelta(hours=2),
+        "frequency": CustomOnCallShift.FREQUENCY_DAILY,
+        "schedule": schedule,
+    }
+    on_call_shift = make_on_call_shift(
+        organization=organization, shift_type=CustomOnCallShift.TYPE_ROLLING_USERS_EVENT, **data
+    )
+    on_call_shift.add_rolling_users([[user]])
+
+    # schedule is removed from db
+    schedule.delete()
+
+    events = schedule.filter_events("UTC", start_date, days=5, filter_by=OnCallSchedule.TYPE_ICAL_PRIMARY)
+    expected = []
+    assert events == expected