Don't Reset next_occurrence For Cloned Objects

ambition_utils/rrule/models.py

@@ -351,9 +351,11 @@ def set_date_objects(self):
         """
         Ensure that all the date keys are properly set on all rrule params
         """
+        # A cloned object will not have a primary key but does have a next_occurrence that should not be reset
+        # to the first date in a series.
+        is_new = self.pk is None and self.last_occurrence is None
 
         # Convert the rrule and exclusion rrule params to properly set date keys
-        is_new = self.pk is None
         self.set_date_objects_for_params(self.rrule_params, is_new=is_new)
         self.set_date_objects_for_params(self.rrule_exclusion_params, is_new=is_new)
 
@@ -470,11 +472,13 @@ def clone_with_day_offset(self, day_offset: int) -> RRule:
         """
         Creates a clone of a passed RRule object with day_offset set.
         clone() is not called to ensure .id is not set before .save() so offset is applied.
+        The clone's next_occurrence is set to the offset of this object.
         :param day_offset: The number of days to offset the clone's start date. Can be negative.
         """
         clone = copy.deepcopy(self)
         clone.id = None
         clone.day_offset = day_offset
+        clone.next_occurrence = clone.offset(clone.next_occurrence)
         clone.save()
         return clone
 

ambition_utils/rrule/tests/model_tests.py

@@ -1614,6 +1614,37 @@ def test_next_occurrences_day_offset(self):
             self.assertEqual(rrule1.next_occurrence, datetime.datetime(2017, 1, 10))
             self.assertEqual(rrule2.next_occurrence, datetime.datetime(2017, 1, 15))
 
+    def test_next_occurrence_clone_with_offset(self):
+        """
+        Cloning an established object with an offset should yield a next_occurrence of the object's with the offset.
+        """
+        # A daily recurrence with a multi-day offset to highlight differences clearly.
+        rrule1 = G(
+            RRule,
+            rrule_params={
+                'freq': rrule.DAILY,
+                'interval': 1,
+                'dtstart': datetime.datetime(2023, 1, 1),
+            },
+            occurrence_handler_path='ambition_utils.rrule.tests.model_tests.HandlerOne',
+        )
+
+        # Many days into the future
+        with freeze_time('1-10-2023'):
+            # Catch the recurrence object up.
+            while rrule1.next_occurrence <= datetime.datetime.now():
+                RRule.objects.handle_overdue()
+                rrule1.refresh_from_db()
+            self.assertEqual(rrule1.next_occurrence, datetime.datetime(2023, 1, 11))
+
+            # Create a clone with an offset and assert that the clone's next occurrence is 1/11 -5 = 1/6.
+            rrule2 = rrule1.clone_with_day_offset(day_offset=-5)
+            self.assertEqual(rrule2.next_occurrence, datetime.datetime(2023, 1, 6))
+
+            # First object is unchanged
+            rrule1.refresh_from_db()
+            self.assertEqual(rrule1.next_occurrence, datetime.datetime(2023, 1, 11))
+
 
 class RRuleWithExclusionTest(TestCase):
     def test_exclusion(self):