[1.2.X] Fixed #13190 -- Improved error handling for the case where no authentication backends are defined. Thanks to Joel3000 for the report, and Łukasz Rekucki for the final patch.

Backport of r14793 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14799 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/contrib/auth/__init__.py

@@ -39,6 +39,8 @@ def get_backends():
     backends = []
     for backend_path in settings.AUTHENTICATION_BACKENDS:
         backends.append(load_backend(backend_path))
+    if not backends:
+        raise ImproperlyConfigured('No authentication backends have been defined. Does AUTHENTICATION_BACKENDS contain anything?')
     return backends
 
 def authenticate(**credentials):

django/contrib/auth/tests/__init__.py

@@ -1,4 +1,4 @@
-from django.contrib.auth.tests.auth_backends import BackendTest, RowlevelBackendTest, AnonymousUserBackendTest, NoAnonymousUserBackendTest
+from django.contrib.auth.tests.auth_backends import BackendTest, RowlevelBackendTest, AnonymousUserBackendTest, NoAnonymousUserBackendTest, NoBackendsTest
 from django.contrib.auth.tests.basic import BasicTestCase
 from django.contrib.auth.tests.decorators import LoginRequiredTestCase
 from django.contrib.auth.tests.forms import UserCreationFormTest, AuthenticationFormTest, SetPasswordFormTest, PasswordChangeFormTest, UserChangeFormTest, PasswordResetFormTest

django/contrib/auth/tests/auth_backends.py

@@ -1,6 +1,7 @@
 from django.conf import settings
 from django.contrib.auth.models import User, Group, Permission, AnonymousUser
 from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import ImproperlyConfigured
 from django.test import TestCase
 
 
@@ -245,3 +246,18 @@ class NoAnonymousUserBackendTest(TestCase):
 
     def test_get_all_permissions(self):
         self.assertEqual(self.user1.get_all_permissions(TestObj()), set())
+
+class NoBackendsTest(TestCase):
+    """
+    Tests that an appropriate error is raised if no auth backends are provided.
+    """
+    def setUp(self):
+        self.old_AUTHENTICATION_BACKENDS = settings.AUTHENTICATION_BACKENDS
+        settings.AUTHENTICATION_BACKENDS = []
+        self.user = User.objects.create_user('test', 'test@example.com', 'test')
+
+    def tearDown(self):
+        settings.AUTHENTICATION_BACKENDS = self.old_AUTHENTICATION_BACKENDS
+
+    def test_raises_exception(self):
+        self.assertRaises(ImproperlyConfigured, self.user.has_perm, ('perm', TestObj(),))