Fixed #20249 - Removed a "feature" in the tutorial that doesn't actually work.

Thanks bmispelon for the report and draft patch.

docs/intro/tutorial04.txt

@@ -185,7 +185,7 @@ conversion. We will:
 
 2. Delete some of the old, unneeded views.
 
-3. Fix up URL handling for the new views.
+3. Introduce new views based on Django's generic views.
 
 Read on for details.
 
@@ -205,32 +205,51 @@ Amend URLconf
 First, open the ``polls/urls.py`` URLconf and change it like so::
 
     from django.conf.urls import patterns, url
-    from django.views.generic import DetailView, ListView
-    from polls.models import Poll
+
+    from polls import views
 
     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'),
+        url(r'^$', views.IndexView.as_view(), name='index'),
+        url(r'^(?P<pk>\d+)/$', views.DetailView.as_view(), name='detail'),
+        url(r'^(?P<pk>\d+)/results/$', views.ResultsView.as_view(), name='results'),
+        url(r'^(?P<poll_id>\d+)/vote/$', views.vote, name='vote'),
     )
 
 Amend views
 -----------
 
+Next, we're going to remove our old ``index``, ``detail``, and ``results``
+views and use Django's generic views instead. To do so, open the
+``polls/views.py`` file and change it like so::
+
+    from django.shortcuts import get_object_or_404, render
+    from django.http import HttpResponseRedirect
+    from django.core.urlresolvers import reverse
+    from django.views import generic
+
+    from polls.models import Choice, Poll
+
+    class IndexView(generic.ListView):
+        template_name = 'polls/index.html'
+        context_object_name = 'latest_poll_list'
+
+        def get_queryset(self):
+            """Return the last five published polls."""
+            return Poll.objects.order_by('-pub_date')[:5]
+
+
+    class DetailView(generic.DetailView):
+        model = Poll
+        template_name = 'polls/detail.html'
+
+
+    class ResultsView(generic.DetailView):
+        model = Poll
+        template_name = 'polls/results.html'
+
+    def vote(request, poll_id):
+        ....
+
 We're using two generic views here:
 :class:`~django.views.generic.list.ListView` and
 :class:`~django.views.generic.detail.DetailView`. Respectively, those
@@ -238,7 +257,7 @@ two views abstract the concepts of "display a list of objects" and
 "display a detail page for a particular type of object."
 
 * Each generic view needs to know what model it will be acting
-  upon. This is provided using the ``model`` parameter.
+  upon. This is provided using the ``model`` attribute.
 
 * The :class:`~django.views.generic.detail.DetailView` generic view
   expects the primary key value captured from the URL to be called
@@ -248,7 +267,7 @@ two views abstract the concepts of "display a list of objects" and
 By default, the :class:`~django.views.generic.detail.DetailView` generic
 view uses a template called ``<app name>/<model name>_detail.html``.
 In our case, it'll use the template ``"polls/poll_detail.html"``. The
-``template_name`` argument is used to tell Django to use a specific
+``template_name`` attribute is used to tell Django to use a specific
 template name instead of the autogenerated default template name. We
 also specify the ``template_name`` for the ``results`` list view --
 this ensures that the results view and the detail view have a
@@ -268,16 +287,11 @@ automatically -- since we're using a Django model (``Poll``), Django
 is able to determine an appropriate name for the context variable.
 However, for ListView, the automatically generated context variable is
 ``poll_list``. To override this we provide the ``context_object_name``
-option, specifying that we want to use ``latest_poll_list`` instead.
+attribute, specifying that we want to use ``latest_poll_list`` instead.
 As an alternative approach, you could change your templates to match
 the new default context variables -- but it's a lot easier to just
 tell Django to use the variable you want.
 
-You can now delete the ``index()``, ``detail()`` and ``results()`` views from
-``polls/views.py``. We don't need them anymore -- they have been replaced by
-generic views. You can also delete the import for ``HttpResponse``, which is no
-longer required.
-
 Run the server, and use your new polling app based on generic views.
 
 For full details on generic views, see the :doc:`generic views documentation

docs/intro/tutorial05.txt

@@ -378,45 +378,40 @@ Improving our view
 The list of polls shows polls that aren't published yet (i.e. those that have a
 ``pub_date`` in the future). Let's fix that.
 
-In :doc:`Tutorial 4 </intro/tutorial04>` we deleted the view functions from
-``views.py`` in favor of a :class:`~django.views.generic.list.ListView` in
-``urls.py``::
+In :doc:`Tutorial 4 </intro/tutorial04>` we introduced a class-based view,
+based on :class:`~django.views.generic.list.ListView`::
 
-    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'),
+    class IndexView(generic.ListView):
+        template_name = 'polls/index.html'
+        context_object_name = 'latest_poll_list'
+
+        def get_queryset(self):
+            """Return the last five published polls."""
+            return Poll.objects.order_by('-pub_date')[:5]
 
 ``response.context_data['latest_poll_list']`` extracts the data this view
 places into the context.
 
-We need to amend the line that gives us the ``queryset``::
-
-    queryset=Poll.objects.order_by('-pub_date')[:5],
-
-Let's change the queryset so that it also checks the date by comparing it with
-``timezone.now()``. First we need to add an import::
+We need to amend the ``get_queryset`` method and change it so that it also
+checks the date by comparing it with ``timezone.now()``. First we need to add
+an import::
 
     from django.utils import timezone
 
-and then we must amend the existing ``url`` function to::
+and then we must amend the ``get_queryset`` method like so::
 
-    url(r'^$',
-        ListView.as_view(
-            queryset=Poll.objects.filter(pub_date__lte=timezone.now) \
-                .order_by('-pub_date')[:5],
-            context_object_name='latest_poll_list',
-            template_name='polls/index.html'),
-        name='index'),
+    def get_queryset(self):
+        """
+        Return the last five published polls (not including those set to be
+        published in the future).
+        """
+        return Poll.objects.filter(
+            pub_date__lte=timezone.now()
+        ).order_by('-pub_date')[:5]
 
-``Poll.objects.filter(pub_date__lte=timezone.now)`` returns a queryset
+``Poll.objects.filter(pub_date__lte=timezone.now())`` returns a queryset
 containing Polls whose ``pub_date`` is less than or equal to - that is, earlier
-than or equal to - ``timezone.now``. Notice that we use a callable queryset
-argument, ``timezone.now``, which will be evaluated at request time. If we had
-included the parentheses, ``timezone.now()`` would be evaluated just once when
-the web server is started.
+than or equal to - ``timezone.now``.
 
 Testing our new view
 --------------------
@@ -527,20 +522,18 @@ Testing the ``DetailView``
 
 What we have works well; however, even though future polls don't appear in the
 *index*, users can still reach them if they know or guess the right URL. So we
-need similar constraints in the ``DetailViews``, by adding::
-
-    queryset=Poll.objects.filter(pub_date__lte=timezone.now)
+need to add a similar  constraint to ``DetailView``::
 
-to them - for example::
 
-    url(r'^(?P<pk>\d+)/$',
-        DetailView.as_view(
-            queryset=Poll.objects.filter(pub_date__lte=timezone.now),
-            model=Poll,
-            template_name='polls/detail.html'),
-        name='detail'),
+    class DetailView(generic.DetailView):
+        ...
+        def get_queryset(self):
+            """
+            Excludes any polls that aren't published yet.
+            """
+            return Poll.objects.filter(pub_date__lte=timezone.now())
 
-and of course, we will add some tests, to check that a ``Poll`` whose
+And of course, we will add some tests, to check that a ``Poll`` whose
 ``pub_date`` is in the past can be displayed, and that one with a ``pub_date``
 in the future is not::
 
@@ -566,9 +559,9 @@ in the future is not::
 Ideas for more tests
 --------------------
 
-We ought to add similar ``queryset`` arguments to the other ``DetailView``
-URLs, and create a new test class for each view. They'll be very similar to
-what we have just created; in fact there will be a lot of repetition.
+We ought to add a similar ``get_queryset`` method to ``ResultsView`` and
+create a new test class for that view. It'll be very similar to what we have
+just created; in fact there will be a lot of repetition.
 
 We could also improve our application in other ways, adding tests along the
 way. For example, it's silly that ``Polls`` can be published on the site that