Django Tutorial 04 NoReverseMatch at /polls/1/ - u'polls' is not a registered namespace

Question

I'm trying to do the django tutorial. I am on Tutorial 04. I got the following:

• Django 1.5.1 (64-bit)
• Python 2.7 (64-bit)

On the page detail, it says:

NoReverseMatch at /polls/1/

It says: u'polls' is not a registered namespace.

polls/views.py

from django.http import HttpResponse, Http404, HttpResponseRedirect
from django.shortcuts import render, get_object_or_404
from django.template import Context, loader
from django.core.urlresolvers import reverse
from polls.models import Poll


def index(request):
    latest_poll_list = Poll.objects.order_by('-pub_date')[:5]
    template = loader.get_template('polls/index.html')
    context = Context({
        'latest_poll_list': latest_poll_list,
    })
    return HttpResponse(template.render(context))


def detail(request, poll_id):
    try: 
      poll = Poll.objects.get(pk=poll_id)
    except Poll.DoesNotExist:
      raise Http404
    #return HttpResponseRedirect(reverse('poll_results', kwargs={'object_id': p.id}))      
    return render(request,'polls/detail.html',{'poll':poll})
'''
    poll = get_object_or_404(Poll, pk=poll_id)
    return render(request, 'polls/detail.html', {'poll': poll})
'''

def results(request, poll_id):
    poll = get_object_or_404(Poll, pk=poll_id)
    return render(request, 'polls/results', {'poll': poll})


def vote(request, poll_id):
    p = get_object_or_404(Poll, pk=poll_id)
    try:
        selected_choice = p.choice_set.get(pk=request.POST['choice'])
    except (KeyError, Choice.DoesNotExist):
        # Redisplay the poll voting form.
        return render(request, 'polls/detail.html', {
            'poll': p,
            'error_message': "You didn't select a choice.",
        })
    else:
        selected_choice.votes += 1
        selected_choice.save()
        # Always return an HttpResponseRedirect after successfully dealing
        # with POST data. This prevents data from being posted twice if a
        # user hits the Back button.
        return HttpResponseRedirect(reverse('polls:results', args=(p.id,)))

polls/urls.py :

from django.conf.urls import patterns, url
from django.views.generic import DetailView, ListView
from polls.models import Poll

urlpatterns = patterns('',
    url(r'^$',
        ListView.as_view(
            queryset=Poll.objects.order_by('-pub_date')[:5],
            context_object_name='latest_poll_list',
            template_name='polls/index.html'),
        name='index'),
    url(r'^(?P<pk>\d+)/$',
        DetailView.as_view(
            model=Poll,
            template_name='polls/detail.html'),
        name='detail'),
    url(r'^(?P<pk>\d+)/results/$',
        DetailView.as_view(
            model=Poll,
            template_name='polls/results.html'),
        name='results'),
    url(r'^(?P<poll_id>\d+)/vote/$', 'polls.views.vote', name='vote'),
)

polls/templates/polls/detail.html

{% load url from future %}
<h1>{{ poll.question }}</h1>

{% if error_message %}<p><strong>{{ error_message }}</strong></p>{% endif %}

<form action="{% url 'polls:detail' poll.id %}" method="post"> <!-- -->
    {% csrf_token %}
{% for choice in poll.choice_set.all %}
    <input type="radio" name="choice" id="choice{{ forloop.counter }}" value="{{ choice.id }}" />
    <label for="choice{{ forloop.counter }}">{{ choice.choice_text }}</label><br />
{% endfor %}
<input type="submit" value="Vote" />
</form>

Answer 1

Never mind. I just missed one step. I just changed the line from:

url(r'^polls/', include('polls.urls')),

To:

url(r'^polls/', include('polls.urls', namespace="polls")),

On site/urls.py, it now says:

urlpatterns = patterns('',
    # Examples:
    # url(r'^$', 'hello.views.home', name='home'),
    # url(r'^hello/', include('hello.foo.urls')),

    # Uncomment the admin/doc line below to enable admin documentation:
    # url(r'^admin/doc/', include('django.contrib.admindocs.urls')),

    # Uncomment the next line to enable the admin:
    url(r'^polls/', include('polls.urls', namespace="polls")),
    url(r'^admin/', include(admin.site.urls)),
)

And now it works.