From b88f98738fbbdf119f4ff001e4eccf72a77d9518 Mon Sep 17 00:00:00 2001
From: Yan Mitrofanov <mmxlviii@mail.ru>
Date: Thu, 13 Aug 2020 13:27:00 +0300
Subject: [PATCH] Fixed #31878 -- Made createsuperuser respect --database
 option in default usernames.

---
 django/contrib/auth/management/__init__.py    |  9 +++--
 .../management/commands/createsuperuser.py    |  2 +-
 tests/auth_tests/test_management.py           | 40 +++++++++++++++++++
 3 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/django/contrib/auth/management/__init__.py b/django/contrib/auth/management/__init__.py
index deda238c78d..1170cb0b20a 100644
--- a/django/contrib/auth/management/__init__.py
+++ b/django/contrib/auth/management/__init__.py
@@ -101,14 +101,15 @@ def get_system_username():
     return result
 
 
-def get_default_username(check_db=True):
+def get_default_username(check_db=True, database=DEFAULT_DB_ALIAS):
     """
     Try to determine the current system user's username to use as a default.
 
     :param check_db: If ``True``, requires that the username does not match an
         existing ``auth.User`` (otherwise returns an empty string).
+    :param database: The database where the unique check will be performed.
     :returns: The username, or an empty string if no username can be
-        determined.
+        determined or the suggested username is already taken.
     """
     # This file is used in apps.py, it should not trigger models import.
     from django.contrib.auth import models as auth_app
@@ -137,7 +138,9 @@ def get_default_username(check_db=True):
     # Don't return the default username if it is already taken.
     if check_db and default_username:
         try:
-            auth_app.User._default_manager.get(username=default_username)
+            auth_app.User._default_manager.db_manager(database).get(
+                username=default_username,
+            )
         except auth_app.User.DoesNotExist:
             pass
         else:
diff --git a/django/contrib/auth/management/commands/createsuperuser.py b/django/contrib/auth/management/commands/createsuperuser.py
index 3b76477f018..3eb8abff066 100644
--- a/django/contrib/auth/management/commands/createsuperuser.py
+++ b/django/contrib/auth/management/commands/createsuperuser.py
@@ -97,7 +97,7 @@ class Command(BaseCommand):
                 fake_user_data = {}
                 if hasattr(self.stdin, 'isatty') and not self.stdin.isatty():
                     raise NotRunningInTTYException
-                default_username = get_default_username()
+                default_username = get_default_username(database=database)
                 if username:
                     error_msg = self._validate_username(username, verbose_field_name, database)
                     if error_msg:
diff --git a/tests/auth_tests/test_management.py b/tests/auth_tests/test_management.py
index 6a8e623129d..517c0697da8 100644
--- a/tests/auth_tests/test_management.py
+++ b/tests/auth_tests/test_management.py
@@ -102,6 +102,7 @@ class MockInputTests(TestCase):
 
 
 class GetDefaultUsernameTestCase(TestCase):
+    databases = {'default', 'other'}
 
     def setUp(self):
         self.old_get_system_username = management.get_system_username
@@ -128,6 +129,15 @@ class GetDefaultUsernameTestCase(TestCase):
         management.get_system_username = lambda: 'J\xfalia'
         self.assertEqual(management.get_default_username(), 'julia')
 
+    def test_with_database(self):
+        User.objects.create(username='joe')
+        management.get_system_username = lambda: 'joe'
+        self.assertEqual(management.get_default_username(), '')
+        self.assertEqual(management.get_default_username(database='other'), 'joe')
+
+        User.objects.using('other').create(username='joe')
+        self.assertEqual(management.get_default_username(database='other'), '')
+
 
 @override_settings(AUTH_PASSWORD_VALIDATORS=[
     {'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator'},
@@ -1047,6 +1057,36 @@ class MultiDBCreatesuperuserTestCase(TestCase):
         user = User.objects.using('other').get(username='joe')
         self.assertEqual(user.email, 'joe@somewhere.org')
 
+    def test_createsuperuser_command_suggested_username_with_database_option(self):
+        default_username = get_default_username(database='other')
+        qs = User.objects.using('other')
+
+        @mock_inputs({'password': 'nopasswd', 'username': '', 'email': ''})
+        def test_other_create_with_suggested_username(self):
+            call_command(
+                'createsuperuser',
+                interactive=True,
+                stdin=MockTTY(),
+                verbosity=0,
+                database='other',
+            )
+            self.assertIs(qs.filter(username=default_username).exists(), True)
+
+        test_other_create_with_suggested_username(self)
+
+        @mock_inputs({'password': 'nopasswd', 'Username: ': 'other', 'email': ''})
+        def test_other_no_suggestion(self):
+            call_command(
+                'createsuperuser',
+                interactive=True,
+                stdin=MockTTY(),
+                verbosity=0,
+                database='other',
+            )
+            self.assertIs(qs.filter(username='other').exists(), True)
+
+        test_other_no_suggestion(self)
+
 
 class CreatePermissionsTests(TestCase):