RRULE until values must be specified in UTC tz (#1661)

When generating ical information for an event, the RRULE until value
must be specified in UTC.

Related to https://github.com/grafana/support-escalations/issues/5426.

CHANGELOG.md

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Addressed bug with iOS mobile push notifications always being set to critical by @imtoori and @joeyorlando ([#1646](https://github.com/grafana/oncall/pull/1646))
 - Fixed issue where Viewer was not able to view which people were oncall in a schedule ([#999](https://github.com/grafana/oncall/issues/999))
 - Fixed a bug with syncing teams from Grafana API by @vadimkerr ([#1652](https://github.com/grafana/oncall/pull/1652))
+- Fixed bug when web schedules/shifts use non-UTC timezone and shift is deleted by @matiasb ([#1661](https://github.com/grafana/oncall/pull/1661))
 
 ## v1.2.3 (2023-03-28)
 

engine/apps/schedules/models/custom_on_call_shift.py

@@ -584,8 +584,8 @@ class CustomOnCallShift(models.Model):
             if self.week_start is not None:
                 rules["wkst"] = CustomOnCallShift.ICAL_WEEKDAY_MAP[self.week_start]
             if self.until is not None:
-                time_zone = self.time_zone if self.time_zone is not None else "UTC"
-                rules["until"] = self.convert_dt_to_schedule_timezone(self.until, time_zone)
+                # RRULE UNTIL values must be specified in UTC when DTSTART is timezone-aware
+                rules["until"] = self.convert_dt_to_schedule_timezone(self.until, "UTC")
         return rules
 
     @cached_property

engine/apps/schedules/tests/test_custom_on_call_shift.py

@@ -1625,3 +1625,43 @@ def test_delete_override(
             if (starting_day + duration) < 0
             else on_call_shift.duration < original_duration
         )
+
+
+@pytest.mark.django_db
+def test_until_rrule_must_be_utc(
+    make_organization_and_user,
+    make_user_for_organization,
+    make_schedule,
+    make_on_call_shift,
+):
+    organization, user_1 = make_organization_and_user()
+    user_2 = make_user_for_organization(organization)
+    schedule = make_schedule(organization, schedule_class=OnCallScheduleWeb, time_zone="Europe/Warsaw")
+
+    date = timezone.now().replace(microsecond=0) - timezone.timedelta(days=7)
+    data = {
+        "priority_level": 1,
+        "start": date,
+        "rotation_start": date,
+        "duration": timezone.timedelta(seconds=10800),
+        "frequency": CustomOnCallShift.FREQUENCY_WEEKLY,
+        "interval": 2,
+        "time_zone": "Europe/Warsaw",
+        "schedule": schedule,
+    }
+    on_call_shift = make_on_call_shift(
+        organization=organization, shift_type=CustomOnCallShift.TYPE_ROLLING_USERS_EVENT, **data
+    )
+    rolling_users = [[user_1], [user_2]]
+    on_call_shift.add_rolling_users(rolling_users)
+
+    # finish the rotation, will set until value
+    on_call_shift.delete()
+
+    on_call_shift.refresh_from_db()
+    assert on_call_shift.until.tzname() == "UTC"
+    ical_data = on_call_shift.convert_to_ical()
+    ical_rrule_until = on_call_shift.until.strftime("%Y%m%dT%H%M%S")
+    expected_rrule = f"RRULE:FREQ=WEEKLY;UNTIL={ical_rrule_until}Z;INTERVAL=4;WKST=SU"
+
+    assert expected_rrule in ical_data