Handle non-UTC UNTIL datetime value when repeating ical events (#2241)

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Update notification text for "You're going on call" push notifications to include information about the shift start
   and end times by @joeyorlando ([#2131](https://github.com/grafana/oncall/pull/2131))
 
+### Fixed
+
+- Handle non-UTC UNTIL datetime value when repeating ical events [#2241](https://github.com/grafana/oncall/pull/2241)
+
 ## v1.2.44 (2023-06-14)
 
 ### Added

engine/apps/schedules/ical_events/adapter/amixr_recurring_ical_events_adapter.py

@@ -1,4 +1,5 @@
 import datetime
+import re
 import typing
 from collections import defaultdict
 
@@ -30,6 +31,8 @@ class AmixrUnfoldableCalendar(UnfoldableCalendar):
     """
 
     class RepeatedEvent(UnfoldableCalendar.RepeatedEvent):
+        RE_DATETIME_VALUE = re.compile(r"\d+T\d+")
+
         class Repetition(UnfoldableCalendar.RepeatedEvent.Repetition):
             """
             A repetition of an event. Overridden version of
@@ -40,6 +43,26 @@ class AmixrUnfoldableCalendar(UnfoldableCalendar):
 
             ATTRIBUTES_TO_DELETE_ON_COPY = ["RDATE", "EXDATE"]
 
+        def create_rule_with_start(self, rule_string, start):
+            """Override to handle issue with non-UTC UNTIL value including time information."""
+            try:
+                return super().create_rule_with_start(rule_string, start)
+            except ValueError:
+                # string: FREQ=WEEKLY;UNTIL=20191023T100000;BYDAY=TH;WKST=SU
+                # ValueError: RRULE UNTIL values must be specified in UTC when DTSTART is timezone-aware
+                # https://stackoverflow.com/a/49991809
+                rule_list = rule_string.split(";UNTIL=")
+                assert len(rule_list) == 2
+                date_end_index = rule_list[1].find(";")
+                if date_end_index == -1:
+                    date_end_index = len(rule_list[1])
+                until_string = rule_list[1][:date_end_index]
+                if self.RE_DATETIME_VALUE.match(until_string):
+                    rule_string = rule_list[0] + rule_list[1][date_end_index:] + ";UNTIL=" + until_string + "Z"
+                    return super().create_rule_with_start(rule_string, self.start)
+                # otherwise, keep raising
+                raise
+
     def between(self, start, stop):
         """Return events at a time between start (inclusive) and end (inclusive)"""
         span_start = self.to_datetime(start)

engine/apps/schedules/tests/test_on_call_schedule.py

@@ -1744,3 +1744,39 @@ def test_refresh_ical_final_schedule_all_day_date_event(
     calendar = icalendar.Calendar.from_ical(schedule.cached_ical_final_schedule)
     events = [component for component in calendar.walk() if component.name == ICAL_COMPONENT_VEVENT]
     assert len(events) == 0
+
+
+@pytest.mark.django_db
+def test_event_until_non_utc(make_organization, make_schedule):
+    organization = make_organization()
+    cached_ical_primary_schedule = textwrap.dedent(
+        """
+        BEGIN:VCALENDAR
+        VERSION:2.0
+        PRODID:testing
+        CALSCALE:GREGORIAN
+        BEGIN:VEVENT
+        CREATED:20220316T121102Z
+        LAST-MODIFIED:20230127T151619Z
+        DTSTAMP:20230127T151619Z
+        UID:something
+        SUMMARY:testing
+        RRULE:FREQ=WEEKLY;UNTIL=20221231T010101
+        DTSTART;TZID=Europe/Madrid:20220309T130000
+        DTEND;TZID=Europe/Madrid:20220309T133000
+        SEQUENCE:4
+        END:VEVENT
+        END:VCALENDAR
+    """
+    )
+
+    schedule = make_schedule(
+        organization,
+        schedule_class=OnCallScheduleICal,
+        cached_ical_file_primary=cached_ical_primary_schedule,
+    )
+
+    now = timezone.now().replace(hour=0, minute=0, second=0, microsecond=0)
+
+    # check this works without raising exception
+    schedule.final_events("UTC", now, days=7)