Fixed #24097 -- Prevented AttributeError in redirect_to_login

Thanks Peter Schmidt for the report and the initial patch.
Thanks to ​Oktay Sancak for writing the original failing test and
Alvin Savoy for supporting contributing back to the community.

1 files changed, 7 insertions, 0 deletions

diff --git a/django/shortcuts.py b/django/shortcuts.py
index b43c23a891..3bb2412526 100644
--- a/django/shortcuts.py
+++ b/django/shortcuts.py
@@ -18,6 +18,8 @@ from django.db.models.query import QuerySet
 from django.core import urlresolvers
 from django.utils import six
 from django.utils.deprecation import RemovedInDjango20Warning
+from django.utils.encoding import force_text
+from django.utils.functional import Promise
 
 
 def render_to_response(template_name, context=None,
@@ -182,6 +184,11 @@ def resolve_url(to, *args, **kwargs):
     if hasattr(to, 'get_absolute_url'):
         return to.get_absolute_url()
 
+    if isinstance(to, Promise):
+        # Expand the lazy instance, as it can cause issues when it is passed
+        # further to some Python functions like urlparse.
+        to = force_text(to)
+
     if isinstance(to, six.string_types):
         # Handle relative URLs
         if any(to.startswith(path) for path in ('./', '../')):