fix bug where implicit prefetch and explicit prefetch behaviors were … (

#286)

* fix bug where implicit prefetch and explicit prefetch behaviors were inconsistent

dynamic_rest/filters.py

@@ -518,6 +518,18 @@ def _build_queryset(
             requirements
         )
 
+        # Implicit requirements (i.e. via `requires`) can potentially
+        # include fields that haven't been explicitly included.
+        # Such fields would not be in `fields`, so they need to be added.
+        implicitly_included = set(requirements.keys()) - set(fields.keys())
+        if implicitly_included:
+            all_fields = serializer.get_all_fields()
+            fields.update({
+                field: all_fields[field]
+                for field in implicitly_included
+                if field in all_fields
+            })
+
         if filters is None:
             filters = self._get_requested_filters()
 

tests/serializers.py

@@ -63,7 +63,8 @@ class Meta:
         'UserSerializer',
         source='user_set',
         many=True,
-        deferred=True)
+        deferred=True
+    )
     user_count = CountField('users', required=False, deferred=True)
     address = DynamicField(source='blob', required=False, deferred=True)
     cats = DynamicRelationField(
@@ -73,6 +74,9 @@ class Meta:
     bad_cats = DynamicRelationField(
         'CatSerializer', source='annoying_cats', many=True, deferred=True)
 
+    def filter_queryset(self, query):
+        return query.exclude(name='Atlantis')
+
 
 class PermissionSerializer(DynamicModelSerializer):
 

tests/test_api.py

@@ -827,6 +827,51 @@ def test_get_with_request_filters_and_requires(self):
                 }]
             }, json.loads(response.content.decode('utf-8')))
 
+    def test_implicit_vs_explicit_prefetch(self):
+        """
+        LocationSerializer has a built-in filter to hide Atlantis.
+        UserSerializer can explicitly include Location, and it can also
+        implicitly require Location through the `number_of_cats` field.
+        This test ensures that LocationSerializer.filter_queryset() is
+        being respected regardless of whether `User.location` is being
+        included implicitly or explicitly.
+        """
+        atlantis = Location.objects.create(name='Atlantis')
+        atlantian = User.objects.create(
+            name='Atlantian',
+            last_name='Human',
+            location=atlantis
+        )
+        Cat.objects.create(
+            name='Gato',
+            home=atlantis,
+            backup_home=self.fixture.locations[0],
+        )
+
+        url = (
+            '/users/%s/?'
+            'include[]=number_of_cats&'
+            'include[]=location.'
+        ) % atlantian.pk
+        response1 = self._get_json(url)
+
+        url = (
+            '/users/%s/?'
+            'include[]=number_of_cats&'
+            'exclude[]=location'
+        ) % atlantian.pk
+        response2 = self._get_json(url)
+
+        # Atlantis is hidden, therefore its cats are also hidden
+        self.assertEqual(
+            response1['user']['number_of_cats'],
+            0
+        )
+        self.assertEqual(
+            response1['user']['number_of_cats'],
+            response2['user']['number_of_cats']
+        )
+
     def test_boolean_filters_on_boolean_field(self):
         # create one dead user
         User.objects.create(name='Dead', last_name='Mort', is_dead=True)