Fixed #21755 -- Added ForeignKey support to REQUIRED_FIELDS.

This allows specifying ForeignKeys in REQUIRED_FIELDS when using a
custom User model.

Thanks cjerdonek and bmispelon for suggestion and timgraham for review.

6 files changed, 101 insertions, 9 deletions

diff --git a/django/contrib/auth/management/commands/createsuperuser.py b/django/contrib/auth/management/commands/createsuperuser.py
index 5b660031ba..de0b46770a 100644
--- a/django/contrib/auth/management/commands/createsuperuser.py
+++ b/django/contrib/auth/management/commands/createsuperuser.py
@@ -115,7 +115,7 @@ class Command(BaseCommand):
                     field = self.UserModel._meta.get_field(field_name)
                     user_data[field_name] = options.get(field_name)
                     while user_data[field_name] is None:
-                        raw_value = input(force_str('%s: ' % capfirst(field.verbose_name)))
+                        raw_value = input(force_str('%s%s: ' % (capfirst(field.verbose_name), ' (%s.%s)' % (field.rel.to._meta.object_name, field.rel.field_name) if field.rel else '')))
                         try:
                             user_data[field_name] = field.clean(raw_value, None)
                         except exceptions.ValidationError as e:
diff --git a/django/contrib/auth/tests/custom_user.py b/django/contrib/auth/tests/custom_user.py
index 394baa3204..cfa998ad2f 100644
--- a/django/contrib/auth/tests/custom_user.py
+++ b/django/contrib/auth/tests/custom_user.py
@@ -38,6 +38,18 @@ class CustomUserManager(BaseUserManager):
         return u
 
 
+class CustomUserWithFKManager(BaseUserManager):
+    def create_superuser(self, username, email, group, password):
+        user = self.model(username=username, email_id=email, group_id=group)
+        user.set_password(password)
+        user.save(using=self._db)
+        return user
+
+
+class Email(models.Model):
+    email = models.EmailField(verbose_name='email address', max_length=255, unique=True)
+
+
 class CustomUser(AbstractBaseUser):
     email = models.EmailField(verbose_name='email address', max_length=255, unique=True)
     is_active = models.BooleanField(default=True)
@@ -83,6 +95,20 @@ class CustomUser(AbstractBaseUser):
         return self.is_admin
 
 
+class CustomUserWithFK(AbstractBaseUser):
+    username = models.CharField(max_length=30, unique=True)
+    email = models.ForeignKey(Email, to_field='email')
+    group = models.ForeignKey(Group)
+
+    custom_objects = CustomUserWithFKManager()
+
+    USERNAME_FIELD = 'username'
+    REQUIRED_FIELDS = ['email', 'group']
+
+    class Meta:
+        app_label = 'auth'
+
+
 # At this point, temporarily remove the groups and user_permissions M2M
 # fields from the AbstractUser class, so they don't clash with the related_name
 # that sets.
diff --git a/django/contrib/auth/tests/test_management.py b/django/contrib/auth/tests/test_management.py
index fc016135b2..e774d3a071 100644
--- a/django/contrib/auth/tests/test_management.py
+++ b/django/contrib/auth/tests/test_management.py
@@ -9,8 +9,8 @@ from django.contrib.auth import models, management
 from django.contrib.auth.checks import check_user_model
 from django.contrib.auth.management import create_permissions
 from django.contrib.auth.management.commands import changepassword, createsuperuser
-from django.contrib.auth.models import User
-from django.contrib.auth.tests.custom_user import CustomUser
+from django.contrib.auth.models import User, Group
+from django.contrib.auth.tests.custom_user import CustomUser, CustomUserWithFK, Email
 from django.contrib.auth.tests.utils import skipIfCustomUser
 from django.contrib.contenttypes.models import ContentType
 from django.core import checks
@@ -349,6 +349,62 @@ class CreatesuperuserManagementCommandTestCase(TestCase):
         )
         self.assertIs(command.stdin, sys.stdin)
 
+    @override_settings(AUTH_USER_MODEL='auth.CustomUserWithFK')
+    def test_required_field_with_fk(self):
+        new_io = six.StringIO()
+        group = Group.objects.create(name='mygroup')
+        email = Email.objects.create(email='mymail@gmail.com')
+        call_command(
+            'createsuperuser',
+            interactive=False,
+            username='user',
+            email='mymail@gmail.com',
+            group=group.pk,
+            stdout=new_io,
+            skip_checks=True,
+        )
+        command_output = new_io.getvalue().strip()
+        self.assertEqual(command_output, 'Superuser created successfully.')
+        u = CustomUserWithFK._default_manager.get(email=email)
+        self.assertEqual(u.username, "user")
+        self.assertEqual(u.group, group)
+
+        non_existent_email = 'mymail2@gmail.com'
+        with self.assertRaisesMessage(CommandError,
+                'email instance with email %r does not exist.' % non_existent_email):
+            call_command(
+                'createsuperuser',
+                interactive=False,
+                username='user',
+                email=non_existent_email,
+                stdout=new_io,
+                skip_checks=True,
+            )
+
+    @override_settings(AUTH_USER_MODEL='auth.CustomUserWithFK')
+    def test_required_fields_with_fk_interactive(self):
+        new_io = six.StringIO()
+        group = Group.objects.create(name='mygroup')
+        email = Email.objects.create(email='mymail@gmail.com')
+
+        @mock_inputs({'password': "nopasswd", 'username': "user", 'email': "mymail@gmail.com", 'group': group.pk})
+        def test(self):
+            call_command(
+                'createsuperuser',
+                interactive=True,
+                stdout=new_io,
+                stdin=MockTTY(),
+                skip_checks=True,
+            )
+
+            command_output = new_io.getvalue().strip()
+            self.assertEqual(command_output, 'Superuser created successfully.')
+            u = CustomUserWithFK._default_manager.get(email=email)
+            self.assertEqual(u.username, 'user')
+            self.assertEqual(u.group, group)
+
+        test(self)
+
 
 class CustomUserModelValidationTestCase(TestCase):
     @override_settings(AUTH_USER_MODEL='auth.CustomUserNonListRequiredFields')
diff --git a/django/db/utils.py b/django/db/utils.py
index 4fb75e3150..f1f43ee5ed 100644
--- a/django/db/utils.py
+++ b/django/db/utils.py
@@ -286,10 +286,10 @@ class ConnectionRouter(object):
                     chosen_db = method(model, **hints)
                     if chosen_db:
                         return chosen_db
-            try:
-                return hints['instance']._state.db or DEFAULT_DB_ALIAS
-            except KeyError:
-                return DEFAULT_DB_ALIAS
+            instance = hints.get('instance')
+            if instance is not None and instance._state.db:
+                return instance._state.db
+            return DEFAULT_DB_ALIAS
         return _route_db
 
     db_for_read = _router_func('db_for_read')
diff --git a/docs/releases/1.8.txt b/docs/releases/1.8.txt
index 3e2790c602..70858869c9 100644
--- a/docs/releases/1.8.txt
+++ b/docs/releases/1.8.txt
@@ -49,6 +49,8 @@ Minor features
 * The ``max_length`` of :attr:`Permission.name
   <django.contrib.auth.models.Permission.name>` has been increased from 50 to
   255 characters. Please run the database migration.
+* :attr:`~django.contrib.auth.models.CustomUser.REQUIRED_FIELDS` now supports
+  :class:`~django.db.models.ForeignKey`\s.
 
 :mod:`django.contrib.formtools`
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/docs/topics/auth/customizing.txt b/docs/topics/auth/customizing.txt
index a70753132c..0b0582775a 100644
--- a/docs/topics/auth/customizing.txt
+++ b/docs/topics/auth/customizing.txt
@@ -515,8 +515,7 @@ password resets. You must then provide some key implementation details:
         will be prompted to supply a value for each of these fields. It must
         include any field for which :attr:`~django.db.models.Field.blank` is
         ``False`` or undefined and may include additional fields you want
-        prompted for when a user is created interactively. However, it will not
-        work for :class:`~django.db.models.ForeignKey` fields.
+        prompted for when a user is created interactively.
         ``REQUIRED_FIELDS`` has no effect in other parts of Django, like
         creating a user in the admin.
 
@@ -536,6 +535,15 @@ password resets. You must then provide some key implementation details:
             ``User`` model, but should *not* contain the ``USERNAME_FIELD`` or
             ``password`` as these fields will always be prompted for.
 
+        .. versionadded:: 1.8
+
+        :attr:`REQUIRED_FIELDS` now supports
+        :class:`~django.db.models.ForeignKey`\s. Since there is no way to pass
+        model instances during the :djadmin:`createsuperuser` prompt, expect the
+        user to enter the value of :attr:`~django.db.models.ForeignKey.to_field`
+        value (the :attr:`~django.db.models.Field.primary_key` by default) of an
+        existing instance.
+
     .. attribute:: is_active
 
         A boolean attribute that indicates whether the user is considered