Merge pull request #21 from MaxDude132/bugfix/20

Fix non-model serializer fields being inclided in the prefetching

Author: MaxDude132

serializer_prefetch/base.py

@@ -253,16 +253,23 @@ def _get_serializer_field_relations(
             if current_relation:
                 source = self._get_joined_prefetch(current_relation, source)
 
-            append_to.append(source)
-
             add_to_select, add_to_prefetch = self.get_prefetch(
                 field,
                 current_relation=source,
                 should_prefetch=future_should_prefetch,
             )
 
-            select_items.extend(add_to_select)
-            prefetch_items.extend(add_to_prefetch)
+            meta = (
+                getattr(field.child, "Meta", None)
+                if isinstance(field, serializers.ListSerializer)
+                else getattr(field, "Meta", None)
+            )
+            if meta:
+                model = getattr(meta, "model", None)
+            if meta and model:
+                append_to.append(source)
+                select_items.extend(add_to_select)
+                prefetch_items.extend(add_to_prefetch)
 
         return select_items, prefetch_items
 

setup.py

@@ -4,7 +4,7 @@
 # drf-serializer-prefetch
 from setuptools import find_packages, setup
 
-VERSION = "1.1.4"
+VERSION = "1.1.5"
 DESCRIPTION = "An automatic prefetcher for django-rest-framework."
 this_directory = Path(__file__).parent
 LONG_DESCRIPTION = (this_directory / "README.md").read_text()

tests/models.py

@@ -15,6 +15,8 @@ class Pizza(models.Model):
     label = models.CharField(max_length=50)
     provenance = models.ForeignKey(Country, on_delete=models.CASCADE)
 
+    extra_data = models.JSONField(null=True)
+
 
 class Topping(models.Model):
     pizza = models.ForeignKey(Pizza, on_delete=models.CASCADE, related_name="toppings")

tests/test_serializers.py

@@ -896,3 +896,30 @@ class Meta:
                 },
             ],
         )
+
+    def test_non_model_serializer_not_prefetched(self):
+        class ExtraDataSerializer(serializers.Serializer):
+            label = serializers.CharField()
+
+        class PizzaSerializer(PrefetchingSerializerMixin, serializers.ModelSerializer):
+            extra_data = ExtraDataSerializer()
+
+            class Meta:
+                model = Pizza
+                fields = ("label", "extra_data")
+
+        Pizza.objects.create(
+            label="Margherita",
+            extra_data={"label": "Margherita"},
+            provenance=self.canada,
+        )
+        pizzas = Pizza.objects.filter(label="Margherita")
+        serializer = PizzaSerializer(pizzas, many=True)
+
+        with self.assertNumQueries(1):
+            data = serializer.data
+
+        self.assertEqual(
+            data,
+            [{"label": "Margherita", "extra_data": {"label": "Margherita"}}],
+        )