Django urlresolvers: Need more than 2 values to unpack - django

Question

I'm trying to upgrade from Django 1.3 to Django 1.4. I'm stuck with this error:
Python Version: 2.7.3
Django Version: 1.4.10
Exception Type: ValueError
Exception Value: need more than 2 values to unpack
The line that triggers that error is (In template /var/www/proj/src_1.4/templates/fragments/header.html, error at line 20):
<a id="login" href="{% url login %}" rel="nofollow">{% trans "Login" %}</a>
It works fine in Django 1.3.
I've tried the following:
python manage.py shell
>> from django.conf.urls import *
>> from django.core.urlresolvers import reverse
>> reverse('login')
Then this error appears:
ValueError Traceback (most recent call last)
/var/www/proj/env_1.4/local/lib/python2.7/site-packages/django/core/management/commands/shell.pyc in <module>()
----> 1 reverse('login')
/var/www/proj/env_1.4/local/lib/python2.7/site-packages/django/core/urlresolvers.pyc in reverse(viewname, urlconf, args, kwargs, prefix, current_app)
474 resolver = get_ns_resolver(ns_pattern, resolver)
475
--> 476 return iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs))
477
478 reverse_lazy = lazy(reverse, str)
/var/www/proj/env_1.4/local/lib/python2.7/site-packages/django/core/urlresolvers.pyc in _reverse_with_prefix(self, lookup_view, _prefix, *args, **kwargs)
363 possibilities = self.reverse_dict.getlist(lookup_view)
364 prefix_norm, prefix_args = normalize(_prefix)[0]
--> 365 for possibility, pattern, defaults in possibilities:
366 for result, params in possibility:
367 if args:
ValueError: need more than 2 values to unpack
If I look at the info showed by Django when I try to load my project, "Local vars" shows that info:
self <RegexURLResolver urls (None:None) ^/>
args ()
_prefix u'/'
possibilities [([(u'accounts/login/', [])], 'accounts/login/$')]
lookup_view u'login'
prefix_norm u'/'
prefix_args []
kwargs {}
Code in proj/urls.py
from django.conf.urls import *
urlpatterns += patterns('',
url(r'^', include('home.urls')),
url(r'^admin/', include(admin.site.urls)),
url(r'^accounts', include('accounts.urls')),
Code in apps/accounts/urls.py
from django.conf.urls import patterns, url
urlpatterns = patterns('',
url(r'^/register$',
'accounts.views.register',
name='register'),
url(r'^/login/$',
'django.contrib.auth.views.login',
{'template_name': 'accounts/login.html', 'authentication_form': AuthenticationForm},
name='login'),
I'll appreciate any help about that. Thanks.
Finally I found the error. It was an old app used for internationalization of URLs (i18nurls). Django 1.3 uses an external app, in Django > 1.4 internationalization was included in the core (Django: Internationalization: in URL patterns).
Thanks.

Answer 1

Not sure if this will fix your errors, but try to do the following:
In your main url.py replace
url(r'^accounts', include('accounts.urls')),
with
url(r'^accounts/', include('accounts.urls')), ### add the slash /
It is better to include the slash / in the outer urlpatterns rather then in the inner one.
Then, in the urls.py inside accounts replace
url(r'^/register$',...
url(r'^/login/$',....
with
url(r'^register/$',... ### delete dhe leading slashed, because you added it in `accounts/`
url(r'^login/$',.... ### finish both regex with the slash
Another suggestion would be to add a namespace:
url(r'^accounts/', include('accounts.urls', namespace='accounts')),
Now refer inside to your template with "{% url 'accounts:login' %}"
In this way you will know better which url comes from which app. Check if these tips fixed your bug and if no, let me know

Answer 2

If this is your full urls.py code
from django.conf.urls import patterns, url
urlpatterns = patterns('',
url(r'^/register$',
'accounts.views.register',
name='register'),
url(r'^/login/$',
'django.contrib.auth.views.login',
{'template_name': 'accounts/login.html', 'authentication_form': AuthenticationForm},
name='login'),
check you have not added the closing bracket )
from django.conf.urls import patterns, url
urlpatterns = patterns('',
url(r'^/register$',
'accounts.views.register',
name='register'),
url(r'^/login/$',
'django.contrib.auth.views.login',
{'template_name': 'accounts/login.html', 'authentication_form': AuthenticationForm},
name='login'),
)