Fix nested model serializer base class

rest_framework/serializers.py

@@ -368,6 +368,7 @@ class ModelSerializer(Serializer):
         models.TimeField: TimeField,
         models.URLField: URLField,
     }
+    nested_class = None  # We fill this in at the end of this module.
 
     _options_class = ModelSerializerOptions
 
@@ -454,7 +455,7 @@ class ModelSerializer(Serializer):
 
         Note that model_field will be `None` for reverse relationships.
         """
-        class NestedModelSerializer(ModelSerializer):
+        class NestedModelSerializer(self.nested_class):
             class Meta:
                 model = related_model
                 depth = self.opts.depth - 1
@@ -694,3 +695,7 @@ class HyperlinkedModelSerializer(ModelSerializer):
             'app_label': model._meta.app_label,
             'model_name': model._meta.object_name.lower()
         }
+
+
+ModelSerializer.nested_class = ModelSerializer
+HyperlinkedModelSerializer.nested_class = HyperlinkedModelSerializer

tests/test_model_field_mappings.py

@@ -150,13 +150,13 @@ class TestRelationalFieldMappings(TestCase):
             TestSerializer():
                 url = HyperlinkedIdentityField(view_name='relationalmodel-detail')
                 foreign_key = NestedModelSerializer(read_only=True):
-                    id = IntegerField(label='ID', read_only=True)
+                    url = HyperlinkedIdentityField(view_name='foreignkeytargetmodel-detail')
                     name = CharField(max_length=100)
                 one_to_one = NestedModelSerializer(read_only=True):
-                    id = IntegerField(label='ID', read_only=True)
+                    url = HyperlinkedIdentityField(view_name='onetoonetargetmodel-detail')
                     name = CharField(max_length=100)
                 many_to_many = NestedModelSerializer(many=True, read_only=True):
-                    id = IntegerField(label='ID', read_only=True)
+                    url = HyperlinkedIdentityField(view_name='manytomanytargetmodel-detail')
                     name = CharField(max_length=100)
         """)
         self.assertEqual(repr(TestSerializer()), expected)