Fix ModelViewSet Nested bug (#65)

* Add todo repro app
* Add explicit test against model named "Nested"
* Force serializers named NestedSerializer to be output as inline models
* Allow ref_name to rescue a NestedSerializer
* Add tests and documentation

docs/changelog.rst

@@ -2,6 +2,15 @@
 Changelog
 #########
 
+*********
+**1.4.2**
+*********
+
+- **FIXED:** fixed a bug that causes a ``ModelViewSet`` generated from models with nested ``ForeignKey`` to output
+  models named ``Nested`` into the ``definitions`` section (:issue:`59`, :pr:`65`)
+- **FIXED:** ``Response`` objects without a ``schema`` are now properly handled when passed through
+  ``swagger_auto_schema`` (:issue:`66`)
+
 *********
 **1.4.1**
 *********

docs/custom_spec.rst

@@ -172,7 +172,11 @@ You can define some per-serializer options by adding a ``Meta`` class to your se
 Currently, the only option you can add here is
 
    * ``ref_name`` - a string which will be used as the model definition name for this serializer class; setting it to
-     ``None`` will force the serializer to be generated as an inline model everywhere it is used
+     ``None`` will force the serializer to be generated as an inline model everywhere it is used. If two serializers
+     have the same ``ref_name``, both their usages will be replaced with a reference to the same definition.
+     If this option is not specified, all serializers have an implicit name derived from their class name, minus any
+     ``Serializer`` suffix (e.g. ``UserSerializer`` -> ``User``, ``SerializerWithSuffix`` -> ``SerializerWithSuffix``)
+
 
 *************************
 Subclassing and extending
@@ -301,3 +305,25 @@ A second example, of a :class:`~.inspectors.FieldInspector` that removes the ``t
    This means that you should generally avoid view or method-specific ``FieldInspector``\ s if you are dealing with
    references (a.k.a named models), because you can never know which view will be the first to generate the schema
    for a given serializer.
+
+   **IMPORTANT:** nested fields on ``ModelSerializer``\ s that are generated from model ``ForeignKeys`` will always be
+   output by value. If you want the by-reference behaviour you have to explictly set the serializer class of nested
+   fields instead of letting ``ModelSerializer`` generate one automatically; for example:
+
+   .. code-block:: python
+
+      class OneSerializer(serializers.ModelSerializer):
+         class Meta:
+            model = SomeModel
+            fields = ('id',)
+
+
+      class AnotherSerializer(serializers.ModelSerializer):
+         chilf = OneSerializer()
+
+         class Meta:
+            model = SomeParentModel
+            fields = ('id', 'child')
+
+   Another caveat that stems from this is that any serializer named "``NestedSerializer``" will be forced inline
+   unless it has a ``ref_name`` set explicitly.

src/drf_yasg/inspectors/base.py

@@ -234,7 +234,8 @@ def SwaggerType(existing_object=None, **instance_kwargs):
                     if default is not None:
                         instance_kwargs['default'] = default
 
-            instance_kwargs.setdefault('title', title)
+            if instance_kwargs.get('type', None) != openapi.TYPE_ARRAY:
+                instance_kwargs.setdefault('title', title)
             instance_kwargs.setdefault('description', description)
             instance_kwargs.update(kwargs)
 

src/drf_yasg/inspectors/field.py

@@ -1,3 +1,4 @@
+import logging
 import operator
 from collections import OrderedDict
 from decimal import Decimal
@@ -12,6 +13,8 @@
 from ..utils import decimal_as_float, filter_none
 from .base import FieldInspector, NotHandled, SerializerInspector
 
+logger = logging.getLogger(__name__)
+
 
 class InlineSerializerInspector(SerializerInspector):
     """Provides serializer conversions using :meth:`.FieldInspector.field_to_swagger_object`."""
@@ -54,10 +57,14 @@ def field_to_swagger_object(self, field, swagger_object_type, use_references, **
 
             serializer = field
             serializer_meta = getattr(serializer, 'Meta', None)
+            serializer_name = type(serializer).__name__
             if hasattr(serializer_meta, 'ref_name'):
                 ref_name = serializer_meta.ref_name
+            elif serializer_name == 'NestedSerializer' and isinstance(serializer, serializers.ModelSerializer):
+                logger.debug("Forcing inline output for ModelSerializer named 'NestedSerializer': " + str(serializer))
+                ref_name = None
             else:
-                ref_name = type(serializer).__name__
+                ref_name = serializer_name
                 if ref_name.endswith('Serializer'):
                     ref_name = ref_name[:-len('Serializer')]
 
@@ -77,11 +84,17 @@ def make_schema_definition():
                     if child.required:
                         required.append(property_name)
 
-                return SwaggerType(
+                result = SwaggerType(
                     type=openapi.TYPE_OBJECT,
                     properties=properties,
                     required=required or None,
                 )
+                if not ref_name:
+                    # on an inline model, the title is derived from the field name
+                    # but is visually displayed like the model named, which is confusing
+                    # it is better to just remove title from inline models
+                    del result.title
+                return result
 
             if not ref_name or not use_references:
                 return make_schema_definition()

testproj/testproj/settings/base.py

@@ -26,6 +26,7 @@
     'snippets',
     'users',
     'articles',
+    'todo',
 ]
 
 MIDDLEWARE = [

testproj/testproj/urls.py

@@ -62,5 +62,6 @@ def root_redirect(request):
     url(r'^snippets/', include('snippets.urls')),
     url(r'^articles/', include('articles.urls')),
     url(r'^users/', include('users.urls')),
+    url(r'^todo/', include('todo.urls')),
     url(r'^plain/', plain_view),
 ]

testproj/todo/migrations/0001_initial.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11 on 2018-02-21 23:26
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='Todo',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=50)),
+            ],
+        ),
+        migrations.CreateModel(
+            name='TodoAnother',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=50)),
+                ('todo', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='todo.Todo')),
+            ],
+        ),
+        migrations.CreateModel(
+            name='TodoYetAnother',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('title', models.CharField(max_length=50)),
+                ('todo', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='todo.TodoAnother')),
+            ],
+        ),
+    ]

testproj/todo/models.py

@@ -0,0 +1,15 @@
+from django.db import models
+
+
+class Todo(models.Model):
+    title = models.CharField(max_length=50)
+
+
+class TodoAnother(models.Model):
+    todo = models.ForeignKey(Todo, on_delete=models.CASCADE)
+    title = models.CharField(max_length=50)
+
+
+class TodoYetAnother(models.Model):
+    todo = models.ForeignKey(TodoAnother, on_delete=models.CASCADE)
+    title = models.CharField(max_length=50)

testproj/todo/serializer.py

@@ -0,0 +1,24 @@
+from rest_framework import serializers
+
+from .models import Todo, TodoAnother, TodoYetAnother
+
+
+class TodoSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = Todo
+        fields = ('title',)
+
+
+class TodoAnotherSerializer(serializers.ModelSerializer):
+    todo = TodoSerializer()
+
+    class Meta:
+        model = TodoAnother
+        fields = ('title', 'todo')
+
+
+class TodoYetAnotherSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = TodoYetAnother
+        fields = ('title', 'todo')
+        depth = 2

testproj/todo/urls.py

@@ -0,0 +1,10 @@
+from rest_framework import routers
+
+from todo import views
+
+router = routers.DefaultRouter()
+router.register(r'', views.TodoViewSet)
+router.register(r'another', views.TodoAnotherViewSet)
+router.register(r'yetanother', views.TodoYetAnotherViewSet)
+
+urlpatterns = router.urls

testproj/todo/views.py

@@ -0,0 +1,19 @@
+from rest_framework import viewsets
+
+from .models import Todo, TodoAnother, TodoYetAnother
+from .serializer import TodoAnotherSerializer, TodoSerializer, TodoYetAnotherSerializer
+
+
+class TodoViewSet(viewsets.ReadOnlyModelViewSet):
+    queryset = Todo.objects.all()
+    serializer_class = TodoSerializer
+
+
+class TodoAnotherViewSet(viewsets.ReadOnlyModelViewSet):
+    queryset = TodoAnother.objects.all()
+    serializer_class = TodoAnotherSerializer
+
+
+class TodoYetAnotherViewSet(viewsets.ReadOnlyModelViewSet):
+    queryset = TodoYetAnother.objects.all()
+    serializer_class = TodoYetAnotherSerializer