[1.10.x] Fixed #27018 -- Fixed admindocs crash with a view in a class.

Generated correct admindocs URLs on Python 3. URLs generate 404s on
Python 2, as in older versions of Django.

Backport of bc1e2d8e8edde6cc7d2657c68242a13ee65a15b8 from master

7 files changed, 91 insertions, 5 deletions

diff --git a/AUTHORS b/AUTHORS
index 3acb9b89a5..7c1ed70c44 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -289,6 +289,7 @@ answer newbie questions, and generally made Django that much better:
     hambaloney
     Hannes Struß <x@hannesstruss.de>
     Hawkeye
+    Helen Sherwood-Taylor <helen@rrdlabs.co.uk>
     Henrique Romano <onaiort@gmail.com>
     hipertracker@gmail.com
     Hiroki Kiyohara <hirokiky@gmail.com>
diff --git a/django/contrib/admindocs/views.py b/django/contrib/admindocs/views.py
index fb1afc296a..c221789e82 100644
--- a/django/contrib/admindocs/views.py
+++ b/django/contrib/admindocs/views.py
@@ -13,6 +13,7 @@ from django.db import models
 from django.http import Http404
 from django.template.engine import Engine
 from django.urls import get_mod_func, get_resolver, get_urlconf, reverse
+from django.utils import six
 from django.utils.decorators import method_decorator
 from django.utils.inspect import (
     func_accepts_kwargs, func_accepts_var_args, func_has_no_args,
@@ -126,13 +127,23 @@ class TemplateFilterIndexView(BaseAdminDocsView):
 class ViewIndexView(BaseAdminDocsView):
     template_name = 'admin_doc/view_index.html'
 
+    @staticmethod
+    def _get_full_name(func):
+        mod_name = func.__module__
+        if six.PY3:
+            return '%s.%s' % (mod_name, func.__qualname__)
+        else:
+            # PY2 does not support __qualname__
+            func_name = getattr(func, '__name__', func.__class__.__name__)
+            return '%s.%s' % (mod_name, func_name)
+
     def get_context_data(self, **kwargs):
         views = []
         urlconf = import_module(settings.ROOT_URLCONF)
         view_functions = extract_views_from_urlpatterns(urlconf.urlpatterns)
         for (func, regex, namespace, name) in view_functions:
             views.append({
-                'full_name': '%s.%s' % (func.__module__, getattr(func, '__name__', func.__class__.__name__)),
+                'full_name': self._get_full_name(func),
                 'url': simplify_regex(regex),
                 'url_name': ':'.join((namespace or []) + (name and [name] or [])),
                 'namespace': ':'.join((namespace or [])),
@@ -145,13 +156,34 @@ class ViewIndexView(BaseAdminDocsView):
 class ViewDetailView(BaseAdminDocsView):
     template_name = 'admin_doc/view_detail.html'
 
-    def get_context_data(self, **kwargs):
-        view = self.kwargs['view']
+    @staticmethod
+    def _get_view_func(view):
         urlconf = get_urlconf()
         if get_resolver(urlconf)._is_callback(view):
             mod, func = get_mod_func(view)
-            view_func = getattr(import_module(mod), func)
-        else:
+            try:
+                # Separate the module and function, e.g.
+                # 'mymodule.views.myview' -> 'mymodule.views', 'myview').
+                return getattr(import_module(mod), func)
+            except ImportError:
+                # Import may fail because view contains a class name, e.g.
+                # 'mymodule.views.ViewContainer.my_view', so mod takes the form
+                # 'mymodule.views.ViewContainer'. Parse it again to separate
+                # the module and class.
+                mod, klass = get_mod_func(mod)
+                return getattr(getattr(import_module(mod), klass), func)
+            except AttributeError:
+                # PY2 generates incorrect paths for views that are methods,
+                # e.g. 'mymodule.views.ViewContainer.my_view' will be
+                # listed as 'mymodule.views.my_view' because the class name
+                # can't be detected. This causes an AttributeError when
+                # trying to resolve the view.
+                return None
+
+    def get_context_data(self, **kwargs):
+        view = self.kwargs['view']
+        view_func = self._get_view_func(view)
+        if view_func is None:
             raise Http404
         title, body, metadata = utils.parse_docstring(view_func.__doc__)
         if title:
diff --git a/django/urls/resolvers.py b/django/urls/resolvers.py
index 6af847caa0..cec960dc1b 100644
--- a/django/urls/resolvers.py
+++ b/django/urls/resolvers.py
@@ -143,7 +143,10 @@ class RegexURLPattern(LocaleRegexProvider):
             callback = callback.func
         if not hasattr(callback, '__name__'):
             return callback.__module__ + "." + callback.__class__.__name__
+        elif six.PY3:
+            return callback.__module__ + "." + callback.__qualname__
         else:
+            # PY2 does not support __qualname__
             return callback.__module__ + "." + callback.__name__
 
 
diff --git a/docs/releases/1.10.1.txt b/docs/releases/1.10.1.txt
index 0094f8137e..e8dc05c7eb 100644
--- a/docs/releases/1.10.1.txt
+++ b/docs/releases/1.10.1.txt
@@ -58,3 +58,6 @@ Bugfixes
 * Fixed ``makemigrations`` crash if a database is read-only (:ticket:`27054`).
 
 * Removed duplicated managers in ``Model._meta.managers`` (:ticket:`27073`).
+
+* Fixed ``contrib.admindocs`` crash when a view is in a class, such as some of
+  the admin views (:ticket:`27018`).
diff --git a/tests/admin_docs/tests.py b/tests/admin_docs/tests.py
index e3091738a8..26e9c04d29 100644
--- a/tests/admin_docs/tests.py
+++ b/tests/admin_docs/tests.py
@@ -9,6 +9,7 @@ from django.contrib.sites.models import Site
 from django.test import TestCase, modify_settings, override_settings
 from django.test.utils import captured_stderr
 from django.urls import reverse
+from django.utils import six
 
 from .models import Company, Person
 
@@ -82,6 +83,18 @@ class AdminDocViewTests(TestDataMixin, AdminDocsTestCase):
         self.assertContains(response, 'Views by namespace test')
         self.assertContains(response, 'Name: <code>test:func</code>.')
 
+    @unittest.skipIf(six.PY2, "Python 2 doesn't support __qualname__.")
+    def test_view_index_with_method(self):
+        """
+        Views that are methods are listed correctly.
+        """
+        response = self.client.get(reverse('django-admindocs-views-index'))
+        self.assertContains(
+            response,
+            '<h3><a href="/admindocs/views/django.contrib.admin.sites.AdminSite.index/">/admin/</a></h3>',
+            html=True
+        )
+
     def test_view_detail(self):
         url = reverse('django-admindocs-views-detail', args=['django.contrib.admindocs.views.BaseAdminDocsView'])
         response = self.client.get(url)
@@ -103,6 +116,14 @@ class AdminDocViewTests(TestDataMixin, AdminDocsTestCase):
         self.assertEqual(response.status_code, 404)
         self.assertNotIn("urlpatterns_reverse.nonimported_module", sys.modules)
 
+    def test_view_detail_as_method(self):
+        """
+        Views that are methods can be displayed.
+        """
+        url = reverse('django-admindocs-views-detail', args=['django.contrib.admin.sites.AdminSite.index'])
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 200 if six.PY3 else 404)
+
     def test_model_index(self):
         response = self.client.get(reverse('django-admindocs-models-index'))
         self.assertContains(
diff --git a/tests/urlpatterns_reverse/method_view_urls.py b/tests/urlpatterns_reverse/method_view_urls.py
new file mode 100644
index 0000000000..d2f24ecffa
--- /dev/null
+++ b/tests/urlpatterns_reverse/method_view_urls.py
@@ -0,0 +1,18 @@
+from django.conf.urls import url
+
+
+class ViewContainer(object):
+    def method_view(self, request):
+        pass
+
+    @classmethod
+    def classmethod_view(cls, request):
+        pass
+
+view_container = ViewContainer()
+
+
+urlpatterns = [
+    url(r'^$', view_container.method_view, name='instance-method-url'),
+    url(r'^$', ViewContainer.classmethod_view, name='instance-method-url'),
+]
diff --git a/tests/urlpatterns_reverse/tests.py b/tests/urlpatterns_reverse/tests.py
index 67a4370e78..522899e886 100644
--- a/tests/urlpatterns_reverse/tests.py
+++ b/tests/urlpatterns_reverse/tests.py
@@ -6,6 +6,7 @@ from __future__ import unicode_literals
 
 import sys
 import threading
+import unittest
 
 from admin_scripts.tests import AdminScriptTestCase
 
@@ -430,6 +431,13 @@ class ResolverTests(SimpleTestCase):
         self.assertTrue(resolver._is_callback('urlpatterns_reverse.nested_urls.View3'))
         self.assertFalse(resolver._is_callback('urlpatterns_reverse.nested_urls.blub'))
 
+    @unittest.skipIf(six.PY2, "Python 2 doesn't support __qualname__.")
+    def test_view_detail_as_method(self):
+        # Views which have a class name as part of their path.
+        resolver = get_resolver('urlpatterns_reverse.method_view_urls')
+        self.assertTrue(resolver._is_callback('urlpatterns_reverse.method_view_urls.ViewContainer.method_view'))
+        self.assertTrue(resolver._is_callback('urlpatterns_reverse.method_view_urls.ViewContainer.classmethod_view'))
+
     def test_populate_concurrency(self):
         """
         RegexURLResolver._populate() can be called concurrently, but not more