Fixed #17733 -- Discouraged setting TIME_ZONE to None when USE_TZ is True.…

Fixed #17733 -- Discouraged setting TIME_ZONE to None when USE_TZ is True. Thanks berdario for the report.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@17809 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/conf/project_template/project_name/settings.py

@@ -23,10 +23,7 @@ DATABASES = {
 # Local time zone for this installation. Choices can be found here:
 # http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
 # although not all choices may be available on all operating systems.
-# On Unix systems, a value of None will cause Django to use the same
-# timezone as the operating system.
-# If running in a Windows environment this must be set to the same as your
-# system time zone.
+# In a Windows environment this must be set to your system time zone.
 TIME_ZONE = 'America/Chicago'
 
 # Language code for this installation. All choices can be found here:

docs/ref/settings.txt

@@ -2131,8 +2131,10 @@ environment variable under the following conditions:
   :ref:`manually configuring settings
   <settings-without-django-settings-module>`, or
 
-* If you specify ``TIME_ZONE = None``. This will cause Django to fall
-  back to using the system time zone.
+* If you specify ``TIME_ZONE = None``. This will cause Django to fall back to
+  using the system timezone. However, this is discouraged when :setting:`USE_TZ
+  = True <USE_TZ>`, because it makes conversions between local time and UTC
+  less reliable.
 
 If Django doesn't set the ``TZ`` environment variable, it's up to you
 to ensure your processes are running in the correct environment.