PATCH with partial update sets all booleans fields to False

[davidfischer-ch]

I want to partially update a preferences model through a dedicated preferences API endpoint.

When using the PATCH method of the API I remarked that all boolean fields of the instance not present on the request DATA are updated to False!

DRF at commit 5b671cb
Django at commit 5b26a014

Preliminary analysis : PreferencesSerializerTestCase shows that partial update works, but the test is using a dict as data. The view is actually using a QueryDict and I think this is the only major difference. PreferencesViewTestCase works with the hack'ish implementation but not with the one using DRF.

Here an extract of my code:

class Preferences(dj_models.Model):
    user = dj_models.OneToOneField(settings.AUTH_USER_MODEL, related_name='preferences')
    language = dj_models.CharField(choices=settings.LANGUAGES, ...)
    edit = dj_models.BooleanField(default=True, verbose_name=_('Edit'))
    only_favorites = dj_models.BooleanField(default=False, verbose_name=_('Only favorites'))
    show_controls = dj_models.BooleanField(default=True, verbose_name=_('Show controls'))
    show_details = dj_models.BooleanField(default=True, verbose_name=_('Show details'))


class PreferencesSerializer(serializers.ModelSerializer):

    class Meta:
        model = models.Preferences
        fields = ('language', 'edit', 'only_favorites', 'show_controls', 'show_details')


class PreferencesView(APIView):

    permission_classes = [permissions.IsAuthenticated]

    def get(self, request):
        preferences = models.Preferences.objects.get_or_create(user=request.user)[0]
        return Response(serializers.PreferencesSerializer(preferences).data)

    def patch(self, request):
        """The temporary hack that works well."""
        preferences = models.Preferences.objects.get_or_create(user=request.user)[0]
        for name in ('edit', 'only_favorites', 'show_controls', 'show_details'):
            value = request.DATA.get(name, None)
            if value is not None:
                setattr(preferences, name, value == 'true')
        preferences.save()
        return Response(serializers.PreferencesSerializer(preferences).data)

    def patch_(self, request):
        """The buggy implementation using DRF that sets booleans to False."""
        preferences = models.Preferences.objects.get_or_create(user=request.user)[0]
        serializer = serializers.PreferencesSerializer(preferences, data=request.DATA, partial=True)
        if serializer.is_valid():
            serializer.save()
            return Response(serializer.data)
        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)


class PreferencesSerializerTestCase(mixins.BaseMixin, TestCase):

    def test_partial_update(self):
        user = G(self.User)
        preferences = models.Preferences.objects.get_or_create(user=user)[0]
        preferences.language = 'fr'
        preferences.edit = False
        preferences.only_favorites = True
        preferences.show_controls = False
        preferences.show_details = False
        serializer = serializers.PreferencesSerializer(preferences, data={'show_controls': True}, partial=True)
        self.assertTrue(serializer.is_valid())
        serializer.save()
        self.assertEqual(serializer.data['language'], 'fr')
        self.assertFalse(serializer.data['edit'])
        self.assertTrue(serializer.data['only_favorites'])
        self.assertTrue(serializer.data['show_controls'])
        self.assertFalse(serializer.data['show_details'])


class PreferencesViewTestCase(mixins.BaseMixin, APITestCase):

    def test_partial_update(self):
        self.login()
        a = self.get('preferences').data
        a['show_details'] = not a['show_details']
        b = self.patch('preferences', {'show_details': a['show_details']}).data
        self.assertDictEqual(a, b)

[tomchristie]

Which version of REST framework does this refer to?

[davidfischer-ch]

3.0-beta (5b671cb)