Fix interval validation when creating shift via public API (#3775)

Related to https://github.com/grafana/support-escalations/issues/9142.

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fix interval validation when creating shift via public API ([#3775](https://github.com/grafana/oncall/pull/3775))
 - Fix list user serializer logic refactoring ([3793](https://github.com/grafana/oncall/pull/3793))
 
 ## v1.3.94 (2024-01-30)

engine/apps/public_api/serializers/on_call_shifts.py

@@ -123,13 +123,13 @@ class CustomOnCallShiftSerializer(EagerLoadingMixin, serializers.ModelSerializer
     PREFETCH_RELATED = ["schedules", "users"]
 
     def create(self, validated_data):
+        validated_data = self._correct_validated_data(validated_data["type"], validated_data)
         self._validate_frequency_and_week_start(
             validated_data["type"],
             validated_data.get("frequency"),
-            validated_data.get("interval", 1),  # if field is missing, the default value will be used
+            validated_data.get("interval"),
             validated_data.get("week_start"),
         )
-        validated_data = self._correct_validated_data(validated_data["type"], validated_data)
         self._validate_start_rotation_from_user_index(
             validated_data["type"],
             validated_data.get("start_rotation_from_user_index"),
@@ -346,7 +346,7 @@ class CustomOnCallShiftSerializer(EagerLoadingMixin, serializers.ModelSerializer
                 validated_data[field] = None
         if validated_data.get("start") is not None:
             validated_data["start"] = validated_data["start"].replace(tzinfo=None)
-        if validated_data.get("frequency") and validated_data.get("interval") is None:
+        if validated_data.get("frequency") is not None and "interval" not in validated_data:
             # if there is frequency but no interval is given, default to 1
             validated_data["interval"] = 1
 
@@ -374,6 +374,7 @@ class CustomOnCallShiftUpdateSerializer(CustomOnCallShiftSerializer):
 
     def update(self, instance, validated_data):
         event_type = validated_data.get("type", instance.type)
+        validated_data = self._correct_validated_data(event_type, validated_data)
         frequency = validated_data.get("frequency", instance.frequency)
         start_rotation_from_user_index = validated_data.get(
             "start_rotation_from_user_index", instance.start_rotation_from_user_index
@@ -389,7 +390,6 @@ class CustomOnCallShiftUpdateSerializer(CustomOnCallShiftSerializer):
 
         if start_rotation_from_user_index != instance.start_rotation_from_user_index:
             self._validate_start_rotation_from_user_index(event_type, start_rotation_from_user_index)
-        validated_data = self._correct_validated_data(event_type, validated_data)
         result = super().update(instance, validated_data)
         for schedule in instance.schedules.all():
             instance.start_drop_ical_and_check_schedule_tasks(schedule)

engine/apps/public_api/tests/test_on_call_shifts.py

@@ -346,6 +346,53 @@ def test_create_on_call_shift_using_none_interval_fails(make_organization_and_us
     assert response.json() == {"detail": "Field 'interval' must be a positive integer"}
 
 
+@pytest.mark.django_db
+def test_create_on_call_shift_no_interval_fallback(make_organization_and_user_with_token):
+    _, user, token = make_organization_and_user_with_token()
+    client = APIClient()
+
+    url = reverse("api-public:on_call_shifts-list")
+
+    start = timezone.now()
+    until = start + timezone.timedelta(days=30)
+    data = {
+        "team_id": None,
+        "name": "test name",
+        "type": "recurrent_event",
+        "level": 1,
+        "start": start.strftime("%Y-%m-%dT%H:%M:%S"),
+        "rotation_start": start.strftime("%Y-%m-%dT%H:%M:%S"),
+        "duration": 10800,
+        "users": [user.public_primary_key],
+        "frequency": "daily",
+        "until": until.strftime("%Y-%m-%dT%H:%M:%S"),
+    }
+    response = client.post(url, data=data, format="json", HTTP_AUTHORIZATION=f"{token}")
+
+    on_call_shift = CustomOnCallShift.objects.get(public_primary_key=response.data["id"])
+    expected = {
+        "id": on_call_shift.public_primary_key,
+        "team_id": None,
+        "schedule": None,
+        "name": data["name"],
+        "type": "recurrent_event",
+        "time_zone": None,
+        "level": data["level"],
+        "start": data["start"],
+        "rotation_start": data["rotation_start"],
+        "duration": data["duration"],
+        "frequency": data["frequency"],
+        "interval": 1,
+        "until": data["until"],
+        "by_day": None,
+        "users": [user.public_primary_key],
+        "by_month": None,
+        "by_monthday": None,
+    }
+    assert response.status_code == status.HTTP_201_CREATED
+    assert response.data == expected
+
+
 @pytest.mark.django_db
 def test_create_override_on_call_shift(make_organization_and_user_with_token):
     _, user, token = make_organization_and_user_with_token()