Fixed #16288 -- Enabled django.request exception logger regardless of DEBUG setting.

Thanks Matt Bennett for report and draft patch; Vinay Sajip and Russell Keith-Magee for review.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16444 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/internals/deprecation.txt

@@ -210,6 +210,11 @@ their deprecation, as per the :ref:`Django deprecation policy
         * Legacy ways of calling
           :func:`~django.views.decorators.cache.cache_page` will be removed.
 
+        * The backward-compatibility shim to automatically add a debug-false
+          filter to the ``'mail_admins'`` logging handler will be removed. The
+          :setting:`LOGGING` setting should include this filter explicitly if
+          it is desired.
+
     * 2.0
         * ``django.views.defaults.shortcut()``. This function has been moved
           to ``django.contrib.contenttypes.views.shortcut()`` as part of the

docs/releases/1.4.txt

@@ -387,3 +387,44 @@ releases 8.0 and 8.1 was near (November 2010.)
 
 Django 1.4 takes that policy further and sets 8.2 as the minimum PostgreSQL
 version it officially supports.
+
+Request exceptions are now always logged
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When :doc:`logging support </topics/logging/>` was added to Django in 1.3, the
+admin error email support was moved into the
+:class:`django.utils.log.AdminEmailHandler`, attached to the
+``'django.request'`` logger. In order to maintain the established behavior of
+error emails, the ``'django.request'`` logger was called only when
+:setting:`DEBUG` was `False`.
+
+To increase the flexibility of request-error logging, the ``'django.request'``
+logger is now called regardless of the value of :setting:`DEBUG`, and the
+default settings file for new projects now includes a separate filter attached
+to :class:`django.utils.log.AdminEmailHandler` to prevent admin error emails in
+`DEBUG` mode::
+
+   'filters': {
+        'require_debug_false': {
+            '()': 'django.utils.log.CallbackFilter',
+            'callback': lambda r: not DEBUG
+        }
+    },
+    'handlers': {
+        'mail_admins': {
+            'level': 'ERROR',
+            'filters': ['require_debug_false'],
+            'class': 'django.utils.log.AdminEmailHandler'
+        }
+    },
+
+If your project was created prior to this change, your :setting:`LOGGING`
+setting will not include this new filter. In order to maintain
+backwards-compatibility, Django will detect that your ``'mail_admins'`` handler
+configuration includes no ``'filters'`` section, and will automatically add
+this filter for you and issue a pending-deprecation warning. This will become a
+deprecation warning in Django 1.5, and in Django 1.6 the
+backwards-compatibility shim will be removed entirely.
+
+The existence of any ``'filters'`` key under the ``'mail_admins'`` handler will
+disable this backward-compatibility shim and deprecation warning.

docs/topics/logging.txt

@@ -501,3 +501,37 @@ Python logging module.
     :ref:`Filtering error reports<filtering-error-reports>`.
 
 .. _django-sentry: http://pypi.python.org/pypi/django-sentry
+
+
+Filters
+-------
+
+Django provides one log filter in addition to those provided by the
+Python logging module.
+
+.. class:: CallbackFilter(callback)
+
+   .. versionadded:: 1.4
+
+   This filter accepts a callback function (which should accept a single
+   argument, the record to be logged), and calls it for each record that passes
+   through the filter. Handling of that record will not proceed if the callback
+   returns False.
+
+   This filter is used as follows in the default :setting:`LOGGING`
+   configuration to ensure that the :class:`AdminEmailHandler` only sends error
+   emails to admins when :setting:`DEBUG` is `False`::
+
+       'filters': {
+            'require_debug_false': {
+                '()': 'django.utils.log.CallbackFilter',
+                'callback': lambda r: not DEBUG
+            }
+        },
+        'handlers': {
+            'mail_admins': {
+                'level': 'ERROR',
+                'filters': ['require_debug_false'],
+                'class': 'django.utils.log.AdminEmailHandler'
+            }
+        },