Behaviour change in DRF 3.15.0

[martinlehoux]

I have a very simple test that passes with version 3.14.0, but not with version 3.15.0.

def test_journey_to_suggested_station_has_correct_creation_reason(self) -> None:
        advert = AdvertFactory.create()
        closest_station = self.create_station()

        serializer = AdvertMutationSerializer(
            advert,
            data={"suggested_transportation_station": closest_station.pk},
        )
        serializer.is_valid(raise_exception=True)
        serializer.save()

The test fails because of a database constraint at the serializer.save() line, but this only shows the weird behaviour: after serializer.is_valid(raise_exception=True), I have

serializer.validated_data = {
	'has_filled_rules': False,
	'suggested_transportation_station': <TransportationStation: Marseilles Saint-Charles - FR>,
	'is_nearest_station_displayable': True
}

I don't understand why there is validated data that was not provided as input. For instance, even the advert.has_filled_rules value is True during the whole test.

• Did I miss the behaviour change that explains that?
• Or did I have a bug in my code that was fixed?

Thanks!

[martinlehoux]

I may have a hint: has_filled_rules = models.BooleanField(default=False, blank=True)

Maybe the default is now used as serializer default when not passed in initial data?

[tomchristie]

Yes... gnarly unexpected side-effect of #9030.

Resolved in master... we're looking at getting a patch release out ASAP, and working on improving the maintenance plans for the future.

[martinlehoux]

Thanks a lot!