Fixed #27515 -- Made AuthenticationForm's username field use the max_length from the model field.

Thanks Ramin Farajpour Cami for the report.

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/auth_tests/test_forms.py b/tests/auth_tests/test_forms.py
index f7d0e71ea9..f15aef37e3 100644
--- a/tests/auth_tests/test_forms.py
+++ b/tests/auth_tests/test_forms.py
@@ -377,6 +377,19 @@ class AuthenticationFormTest(TestDataMixin, TestCase):
         self.assertTrue(form.is_valid())
         self.assertEqual(form.non_field_errors(), [])
 
+    @override_settings(AUTH_USER_MODEL='auth_tests.CustomEmailField')
+    def test_username_field_max_length_matches_user_model(self):
+        self.assertEqual(CustomEmailField._meta.get_field('username').max_length, 255)
+        data = {
+            'username': 'u' * 255,
+            'password': 'pwd',
+            'email': 'test@example.com',
+        }
+        CustomEmailField.objects.create_user(**data)
+        form = AuthenticationForm(None, data)
+        self.assertEqual(form.fields['username'].max_length, 255)
+        self.assertEqual(form.errors, {})
+
     @override_settings(AUTH_USER_MODEL='auth_tests.IntegerUsernameUser')
     def test_username_field_max_length_defaults_to_254(self):
         self.assertIsNone(IntegerUsernameUser._meta.get_field('username').max_length)