Avoid exception in AutoPrefetchMixin when including a reverse one to one relation

CHANGELOG.md

@@ -29,6 +29,7 @@ any parts of the framework not mentioned in the documentation should generally b
 * Do not skip empty one-to-one relationships
 * Allow `HyperlinkRelatedField` to be used with [related urls](https://django-rest-framework-json-api.readthedocs.io/en/stable/usage.html?highlight=related%20links#related-urls)
 * Fixed hardcoded year 2018 in tests ([#539](https://github.com/django-json-api/django-rest-framework-json-api/issues/539))
+* Avoid exception in `AutoPrefetchMixin` when including a reverse one to one relation ([#537](https://github.com/django-json-api/django-rest-framework-json-api/issues/537))
 
 ## [2.6.0] - 2018-09-20
 

example/factories.py

@@ -14,8 +14,8 @@
     Entry,
     ProjectType,
     ResearchProject,
-    TaggedItem
-)
+    TaggedItem,
+    AuthorBioMetadata)
 
 faker = FakerFactory.create()
 faker.seed(983843)
@@ -53,6 +53,16 @@ class Meta:
     author = factory.SubFactory(AuthorFactory)
     body = factory.LazyAttribute(lambda x: faker.text())
 
+    metadata = factory.RelatedFactory('example.factories.AuthorBioMetadataFactory', 'bio')
+
+
+class AuthorBioMetadataFactory(factory.django.DjangoModelFactory):
+    class Meta:
+        model = AuthorBioMetadata
+
+    bio = factory.SubFactory(AuthorBioFactory)
+    body = factory.LazyAttribute(lambda x: faker.text())
+
 
 class EntryFactory(factory.django.DjangoModelFactory):
     class Meta:

example/migrations/0006_auto_20181228_0752.py

@@ -0,0 +1,32 @@
+# Generated by Django 2.1.4 on 2018-12-28 07:52
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('example', '0005_auto_20180922_1508'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='AuthorBioMetadata',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('modified_at', models.DateTimeField(auto_now=True)),
+                ('body', models.TextField()),
+                ('bio', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, related_name='metadata', to='example.AuthorBio')),
+            ],
+            options={
+                'ordering': ('id',),
+            },
+        ),
+        migrations.AlterField(
+            model_name='comment',
+            name='author',
+            field=models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, related_name='comments', to='example.Author'),
+        ),
+    ]

example/models.py

@@ -81,6 +81,21 @@ class Meta:
         ordering = ('id',)
 
 
+@python_2_unicode_compatible
+class AuthorBioMetadata(BaseModel):
+    """
+    Just a class to have a relation with author bio
+    """
+    bio = models.OneToOneField(AuthorBio, related_name='metadata', on_delete=models.CASCADE)
+    body = models.TextField()
+
+    def __str__(self):
+        return self.bio.author.name
+
+    class Meta:
+        ordering = ('id',)
+
+
 @python_2_unicode_compatible
 class Entry(BaseModel):
     blog = models.ForeignKey(Blog, on_delete=models.CASCADE)

example/serializers.py

@@ -16,8 +16,8 @@
     Project,
     ProjectType,
     ResearchProject,
-    TaggedItem
-)
+    TaggedItem,
+    AuthorBioMetadata)
 
 
 class TaggedItemSerializer(serializers.ModelSerializer):
@@ -197,7 +197,17 @@ class Meta:
 class AuthorBioSerializer(serializers.ModelSerializer):
     class Meta:
         model = AuthorBio
-        fields = ('author', 'body')
+        fields = ('author', 'body', 'metadata')
+
+    included_serializers = {
+        'metadata': 'example.serializers.AuthorBioMetadataSerializer',
+    }
+
+
+class AuthorBioMetadataSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = AuthorBioMetadata
+        fields = ('body',)
 
 
 class AuthorSerializer(serializers.ModelSerializer):

example/tests/conftest.py

@@ -6,6 +6,7 @@
     ArtProjectFactory,
     AuthorBioFactory,
     AuthorFactory,
+    AuthorBioMetadataFactory,
     AuthorTypeFactory,
     BlogFactory,
     CommentFactory,
@@ -18,6 +19,7 @@
 register(BlogFactory)
 register(AuthorFactory)
 register(AuthorBioFactory)
+register(AuthorBioMetadataFactory)
 register(AuthorTypeFactory)
 register(EntryFactory)
 register(CommentFactory)

example/tests/integration/test_includes.py

@@ -20,6 +20,25 @@ def test_included_data_on_list(multiple_entries, client):
     assert comment_count == expected_comment_count, 'List comment count is incorrect'
 
 
+def test_included_data_on_list_with_one_to_one_relations(multiple_entries, client):
+    response = client.get(reverse("entry-list"),
+                          data={'include': 'authors.bio.metadata', 'page[size]': 5})
+    included = response.json().get('included')
+
+    assert len(response.json()['data']) == len(multiple_entries), (
+        'Incorrect entry count'
+    )
+    expected_include_types = [
+        'authorBioMetadata', 'authorBioMetadata',
+        'authorBios', 'authorBios',
+        'authors', 'authors'
+    ]
+    include_types = [x.get('type') for x in included]
+    assert include_types == expected_include_types, (
+        'List included types are incorrect'
+    )
+
+
 def test_default_included_data_on_detail(single_entry, client):
     return test_included_data_on_detail(single_entry=single_entry, client=client, query='')
 

example/tests/test_views.py

@@ -1,6 +1,6 @@
 import json
-
 from datetime import datetime
+
 from django.test import RequestFactory
 from django.utils import timezone
 from rest_framework.exceptions import NotFound
@@ -337,7 +337,10 @@ def test_retrieve_related_single_reverse_lookup(self):
             'data': {
                 'type': 'authorBios', 'id': str(self.author.bio.id),
                 'relationships': {
-                    'author': {'data': {'type': 'authors', 'id': str(self.author.id)}}},
+                    'author': {'data': {'type': 'authors', 'id': str(self.author.id)}},
+                    'metadata': {'data': {'id': str(self.author.bio.metadata.id),
+                                          'type': 'authorBioMetadata'}}
+                },
                 'attributes': {
                     'body': str(self.author.bio.body)
                 },

rest_framework_json_api/views.py

@@ -92,7 +92,11 @@ def get_queryset(self, *args, **kwargs):
                 if level == levels[-1]:
                     included_model = field
                 else:
-                    model_field = field.field
+
+                    if issubclass(field_class, ReverseOneToOneDescriptor):
+                        model_field = field.related.field
+                    else:
+                        model_field = field.field
 
                     if is_forward_relation:
                         level_model = model_field.related_model