[1.5.x] Fixed #19779 -- Checked contrib.sites presence in RedirectFallbackMiddleware

Thanks Aymeric Augustin for the report and directions for the patch.
Backport of 2ed90eac from master.

2 files changed, 6 insertions, 4 deletions

diff --git a/docs/ref/contrib/redirects.txt b/docs/ref/contrib/redirects.txt
index e34ba405f4..0c0cb2a3c2 100644
--- a/docs/ref/contrib/redirects.txt
+++ b/docs/ref/contrib/redirects.txt
@@ -13,11 +13,12 @@ Installation
 
 To install the redirects app, follow these steps:
 
-1. Add ``'django.contrib.redirects'`` to your :setting:`INSTALLED_APPS`
-   setting.
-2. Add ``'django.contrib.redirects.middleware.RedirectFallbackMiddleware'``
+1. Ensure that the ``django.contrib.sites`` framework
+   :ref:`is installed <enabling-the-sites-framework>`.
+2. Add ``'django.contrib.redirects'`` to your :setting:`INSTALLED_APPS` setting.
+3. Add ``'django.contrib.redirects.middleware.RedirectFallbackMiddleware'``
    to your :setting:`MIDDLEWARE_CLASSES` setting.
-3. Run the command :djadmin:`manage.py syncdb <syncdb>`.
+4. Run the command :djadmin:`manage.py syncdb <syncdb>`.
 
 How it works
 ============
diff --git a/docs/ref/contrib/sites.txt b/docs/ref/contrib/sites.txt
index 7e5448b3d3..c9ee4d04fe 100644
--- a/docs/ref/contrib/sites.txt
+++ b/docs/ref/contrib/sites.txt
@@ -246,6 +246,7 @@ To do this, you can use the sites framework. A simple example::
     >>> 'http://%s%s' % (Site.objects.get_current().domain, obj.get_absolute_url())
     'http://example.com/mymodel/objects/3/'
 
+.. _enabling-the-sites-framework:
 
 Default site and ``syncdb``
 ===========================