From 283526a5a6854d1ba43f2b277d43cdd2b7f19c54 Mon Sep 17 00:00:00 2001
From: Jannis Leidel <jannis@leidel.info>
Date: Mon, 15 Aug 2011 09:01:12 +0000
Subject: [PATCH] Fixed #15206 -- Added select_related call to the permissions
 field of the GroupAdmin to lower the number of queries. Thanks, Chris Adams.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16620 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/contrib/auth/admin.py               |  9 +++++
 tests/regressiontests/admin_views/tests.py | 40 +++++++++++++++++++++-
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/django/contrib/auth/admin.py b/django/contrib/auth/admin.py
index 5a8bdc2246..24d45e33bc 100644
--- a/django/contrib/auth/admin.py
+++ b/django/contrib/auth/admin.py
@@ -21,6 +21,15 @@ class GroupAdmin(admin.ModelAdmin):
     ordering = ('name',)
     filter_horizontal = ('permissions',)
 
+    def formfield_for_manytomany(self, db_field, request=None, **kwargs):
+        if db_field.name == 'permissions':
+            qs = kwargs.get('queryset', db_field.rel.to.objects)
+            # Avoid a major performance hit resolving permission names which
+            # triggers a content_type load:
+            kwargs['queryset'] = qs.select_related('content_type')
+        return super(GroupAdmin, self).formfield_for_manytomany(db_field, request=request, **kwargs)
+
+
 class UserAdmin(admin.ModelAdmin):
     add_form_template = 'admin/auth/user/add_form.html'
     change_user_password_template = None
diff --git a/tests/regressiontests/admin_views/tests.py b/tests/regressiontests/admin_views/tests.py
index 8daa4662a9..0d1628c366 100644
--- a/tests/regressiontests/admin_views/tests.py
+++ b/tests/regressiontests/admin_views/tests.py
@@ -12,7 +12,7 @@ from django.core.files import temp as tempfile
 from django.core.urlresolvers import reverse
 # Register auth models with the admin.
 from django.contrib.auth import REDIRECT_FIELD_NAME, admin
-from django.contrib.auth.models import User, Permission, UNUSABLE_PASSWORD
+from django.contrib.auth.models import Group, User, Permission, UNUSABLE_PASSWORD
 from django.contrib.contenttypes.models import ContentType
 from django.contrib.admin.models import LogEntry, DELETION
 from django.contrib.admin.sites import LOGIN_FORM_KEY
@@ -2911,6 +2911,44 @@ class UserAdminTest(TestCase):
         self.assertEqual(User.objects.count(), user_count + 1)
         self.assertNotEqual(new_user.password, UNUSABLE_PASSWORD)
 
+    def test_user_permission_performance(self):
+        u = User.objects.all()[0]
+
+        with self.assertNumQueries(7):
+            response = self.client.get('/test_admin/admin/auth/user/%s/' % u.pk)
+            self.assertEqual(response.status_code, 200)
+
+
+class GroupAdminTest(TestCase):
+    """
+    Tests group CRUD functionality.
+    """
+    fixtures = ['admin-views-users.xml']
+
+    def setUp(self):
+        self.client.login(username='super', password='secret')
+
+    def tearDown(self):
+        self.client.logout()
+
+    def test_save_button(self):
+        group_count = Group.objects.count()
+        response = self.client.post('/test_admin/admin/auth/group/add/', {
+            'name': 'newgroup',
+        })
+
+        new_group = Group.objects.order_by('-id')[0]
+        self.assertRedirects(response, '/test_admin/admin/auth/group/')
+        self.assertEqual(Group.objects.count(), group_count + 1)
+
+    def test_group_permission_performance(self):
+        g = Group.objects.create(name="test_group")
+
+        with self.assertNumQueries(6):  # instead of 259!
+            response = self.client.get('/test_admin/admin/auth/group/%s/' % g.pk)
+            self.assertEqual(response.status_code, 200)
+
+
 try:
     import docutils
 except ImportError: