[1.9.x] Fixed #25457 -- Improved formatting of password validation errors in…

[1.9.x] Fixed #25457 -- Improved formatting of password validation errors in management command output.

Backport of 7372cdeb from master

django/contrib/auth/management/commands/changepassword.py

@@ -60,7 +60,7 @@ class Command(BaseCommand):
             try:
                 validate_password(p2, u)
             except ValidationError as err:
-                self.stdout.write(', '.join(err.messages))
+                self.stderr.write('\n'.join(err.messages))
                 count += 1
             else:
                 password_validated = True

django/contrib/auth/management/commands/createsuperuser.py

@@ -153,7 +153,7 @@ class Command(BaseCommand):
                     try:
                         validate_password(password2, self.UserModel(**fake_user_data))
                     except exceptions.ValidationError as err:
-                        self.stderr.write(', '.join(err.messages))
+                        self.stderr.write('\n'.join(err.messages))
                         password = None
 
             except KeyboardInterrupt:

tests/auth_tests/test_management.py

@@ -160,7 +160,7 @@ class ChangepasswordManagementCommandTestCase(TestCase):
         abort_msg = "Aborting password change for user 'joe' after 3 attempts"
         with self.assertRaisesMessage(CommandError, abort_msg):
             command.execute(username="joe", stdout=self.stdout, stderr=self.stderr)
-        self.assertIn('This password is entirely numeric.', self.stdout.getvalue())
+        self.assertIn('This password is entirely numeric.', self.stderr.getvalue())
 
     def test_that_changepassword_command_works_with_nonascii_output(self):
         """