Fixed #26823 -- Prevented update_last_login signal receiver from crashing if User model doesn't have last_login field.

tests/auth_tests/test_signals.py

@@ -1,8 +1,12 @@
+from django.apps import apps
 from django.contrib.auth import authenticate, signals
 from django.contrib.auth.models import User
+from django.core.exceptions import FieldDoesNotExist
 from django.test import TestCase, override_settings
 from django.test.client import RequestFactory
 
+from .models import MinimalUser
+
 
 @override_settings(ROOT_URLCONF='auth_tests.urls')
 class SignalTestCase(TestCase):
@@ -82,3 +86,23 @@ class SignalTestCase(TestCase):
     def test_failed_login_without_request(self):
         authenticate(username='testclient', password='bad')
         self.assertIsNone(self.login_failed[0]['request'])
+
+    def test_login_with_custom_user_without_last_login_field(self):
+        """
+        The user_logged_in signal is only registered if the user model has a
+        last_login field.
+        """
+        last_login_receivers = signals.user_logged_in.receivers
+        try:
+            signals.user_logged_in.receivers = []
+            with self.assertRaises(FieldDoesNotExist):
+                MinimalUser._meta.get_field('last_login')
+            with self.settings(AUTH_USER_MODEL='auth_tests.MinimalUser'):
+                apps.get_app_config('auth').ready()
+            self.assertEqual(signals.user_logged_in.receivers, [])
+
+            with self.settings(AUTH_USER_MODEL='auth.User'):
+                apps.get_app_config('auth').ready()
+            self.assertEqual(len(signals.user_logged_in.receivers), 1)
+        finally:
+            signals.user_logged_in.receivers = last_login_receivers