Fixed #14200 -- Added a fallback if HttpRequest.urlconf is None.

Made BaseHandler fall back to settings.ROOT_URLCONF if
HttpRequest.urlconf is set to None, rather than raising
ImproperlyConfigured.

3 files changed, 15 insertions, 3 deletions

diff --git a/docs/ref/request-response.txt b/docs/ref/request-response.txt
index eba47005a8..6656de5321 100644
--- a/docs/ref/request-response.txt
+++ b/docs/ref/request-response.txt
@@ -184,6 +184,14 @@ All attributes should be considered read-only, unless stated otherwise below.
     URLconf for the current request, overriding the :setting:`ROOT_URLCONF`
     setting. See :ref:`how-django-processes-a-request` for details.
 
+    ``urlconf`` can be set to ``None`` to revert any changes made by previous
+    middleware and return to using the :setting:`ROOT_URLCONF`.
+
+    .. versionchanged:: 1.9
+
+        Setting ``urlconf=None`` raised
+        :exc:`~django.core.exceptions.ImproperlyConfigured` in older versions.
+
 .. attribute:: HttpRequest.resolver_match
 
     An instance of :class:`~django.core.urlresolvers.ResolverMatch` representing
diff --git a/docs/releases/1.9.txt b/docs/releases/1.9.txt
index a8c0b960c7..02dba8d2df 100644
--- a/docs/releases/1.9.txt
+++ b/docs/releases/1.9.txt
@@ -435,6 +435,10 @@ Requests and Responses
   :class:`~django.template.response.TemplateResponse`, commonly used with
   class-based views.
 
+* Request middleware can now set :attr:`HttpRequest.urlconf
+  <django.http.HttpRequest.urlconf>` to ``None`` to revert any changes made
+  by previous middleware and return to using the :setting:`ROOT_URLCONF`.
+
 Tests
 ^^^^^
 
diff --git a/docs/topics/http/urls.txt b/docs/topics/http/urls.txt
index aec8b74c3d..79b06dae15 100644
--- a/docs/topics/http/urls.txt
+++ b/docs/topics/http/urls.txt
@@ -40,9 +40,9 @@ algorithm the system follows to determine which Python code to execute:
 
 1. Django determines the root URLconf module to use. Ordinarily,
    this is the value of the :setting:`ROOT_URLCONF` setting, but if the incoming
-   ``HttpRequest`` object has an attribute called ``urlconf`` (set by
-   middleware :ref:`request processing <request-middleware>`), its value
-   will be used in place of the :setting:`ROOT_URLCONF` setting.
+   ``HttpRequest`` object has a :attr:`~django.http.HttpRequest.urlconf`
+   attribute (set by middleware :ref:`request processing <request-middleware>`),
+   its value will be used in place of the :setting:`ROOT_URLCONF` setting.
 
 2. Django loads that Python module and looks for the variable
    ``urlpatterns``. This should be a Python list of :func:`django.conf.urls.url`