Problems when Serializing instance of a derived class that is also the target of a OneToOneField

rest_framework/serializers.py

@@ -1157,9 +1157,29 @@ def build_relational_field(self, field_name, relation_info):
         field_kwargs = get_relation_kwargs(field_name, relation_info)
 
         to_field = field_kwargs.pop('to_field', None)
-        if to_field and not relation_info.related_model._meta.get_field(to_field).primary_key:
-            field_kwargs['slug_field'] = to_field
-            field_class = self.serializer_related_to_field
+        if to_field:
+            def get_related_field(related_model, to_field):
+                '''Returns the primary key of the field defined by to_field
+                on the model passed in'''
+                from django.core.exceptions import FieldDoesNotExist
+                try:
+                    return related_model._meta.get_field(to_field)
+                except FieldDoesNotExist:
+                    for field in related_model._meta.fields:
+                        if field.related_model:
+                            try:
+                                new_field = get_related_field(
+                                    field.related_model, to_field)
+                                return new_field
+                            except FieldDoesNotExist:
+                                continue
+                raise FieldDoesNotExist(
+                    '%s has not field named %r' % (related_model, to_field))
+            pk = (get_related_field(relation_info.related_model, to_field)
+                  .primary_key)
+            if not pk:
+                field_kwargs['slug_field'] = to_field
+                field_class = self.serializer_related_to_field
 
         # `view_name` is only valid for hyperlinked relationships.
         if not issubclass(field_class, HyperlinkedRelatedField):

tests/test_onetoone_with_inheritance.py

@@ -0,0 +1,44 @@
+from __future__ import unicode_literals
+
+from django.db import models
+from django.test import TestCase
+
+from rest_framework import serializers
+from tests.models import RESTFrameworkModel
+
+
+# Models
+from tests.test_multitable_inheritance import ChildModel
+
+
+class ChildAssociatedModel(RESTFrameworkModel):
+    child_model = models.OneToOneField(ChildModel)
+    child_name = models.CharField(max_length=100)
+
+
+# Serializers
+class DerivedModelSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ChildModel
+        fields = ['id', 'name1', 'name2', 'childassociatedmodel']
+
+
+class ChildAssociatedModelSerializer(serializers.ModelSerializer):
+
+    class Meta:
+        model = ChildAssociatedModel
+        fields = ['id', 'child_name']
+
+
+# Tests
+class InheritedModelSerializationTests(TestCase):
+
+    def test_multitable_inherited_model_fields_as_expected(self):
+        """
+        Assert that the parent pointer field is not included in the fields
+        serialized fields
+        """
+        child = ChildModel(name1='parent name', name2='child name')
+        serializer = DerivedModelSerializer(child)
+        self.assertEqual(set(serializer.data.keys()),
+                         set(['name1', 'name2', 'id', 'childassociatedmodel']))