Merge pull request #27 from MaxDude132/26

26 - Fix lookup for ManyToMany reverse relation

Author: MaxDude132

serializer_prefetch/utils.py

@@ -14,6 +14,9 @@ def is_model_field(model, source):
             if not isinstance(model_field, DjangoModelField | ForeignObjectRel):
                 return False
         except FieldDoesNotExist:
+            if source.endswith("_set"):
+                return is_model_field(model, source[:-4])
+
             return False
 
     return True

tests/test_serializers.py

@@ -8,7 +8,12 @@
 # drf-serializer-prefetch
 from serializer_prefetch import PrefetchingSerializerMixin
 from tests.models import Continent, Country, Pizza, Topping
-from tests.serializers import CountrySerializer, PizzaSerializer, ToppingSerializer
+from tests.serializers import (
+    ContinentSerializer,
+    CountrySerializer,
+    PizzaSerializer,
+    ToppingSerializer,
+)
 
 
 class SerializersTestCase(TestCase):
@@ -944,3 +949,19 @@ class Meta:
 
         with self.assertNumQueries(2):
             serializer.data
+
+    def test_reverse_many_to_many_relation(self):
+        class ContinentSerializer(
+            PrefetchingSerializerMixin, serializers.ModelSerializer
+        ):
+            country_set = CountrySerializer(many=True)
+
+            class Meta:
+                model = Continent
+                fields = ("label", "country_set")
+
+        continents = Continent.objects.all()
+        serializer = ContinentSerializer(continents, many=True)
+
+        with self.assertNumQueries(2):
+            serializer.data