django/docs/releases/1.3.txt

========================
Django 1.3 release notes
========================

*March 23, 2011*

Welcome to Django 1.3!

Nearly a year in the making, Django 1.3 includes quite a few `new
features`_ and plenty of bug fixes and improvements to existing
features. These release notes cover the new features in 1.3, as well
as some `backwards-incompatible changes`_ you'll want to be aware of
when upgrading from Django 1.2 or older versions.

Overview
========

Django 1.3's focus has mostly been on resolving smaller, long-standing
feature requests, but that hasn't prevented a few fairly significant
new features from landing, including:

* A framework for writing `class-based views`_.

* Built-in support for `using Python's logging facilities`_.

* Contrib support for `easy handling of static files`_.

* Django's testing framework now supports (and ships with a copy of)
  `the unittest2 library`_.

There's plenty more, of course; see the coverage of `new features`_
below for a full rundown and details.

Wherever possible, of course, new features are introduced in a
backwards-compatible manner per :doc:`our API stability policy
</misc/api-stability>` policy. As a result of this policy, Django 1.3
`begins the deprecation process for some features`_.

Some changes, unfortunately, are genuinely backwards-incompatible; in
most cases these are due to security issues or bugs which simply
couldn't be fixed any other way. Django 1.3 includes a few of these,
and descriptions of them -- along with the (minor) modifications
you'll need to make to handle them -- are documented in the list of
`backwards-incompatible changes`_ below.

.. _new features: `What's new in Django 1.3`_
.. _backwards-incompatible changes: backwards-incompatible-changes-1.3_
.. _using Python's logging facilities: `Logging`_
.. _easy handling of static files: `Extended static files handling`_
.. _the unittest2 library: `unittest2 support`_
.. _begins the deprecation process for some features: `deprecated-features-1.3`_

Python compatibility
====================

The release of Django 1.2 was notable for having the first shift in
Django's Python compatibility policy; prior to Django 1.2, Django
supported any 2.x version of Python from 2.3 up. As of Django 1.2, the
minimum requirement was raised to Python 2.4.

Django 1.3 continues to support Python 2.4, but will be the final
Django release series to do so; beginning with Django 1.4, the minimum
supported Python version will be 2.5. A document outlining our full
timeline for deprecating Python 2.x and moving to Python 3.x will be
published shortly after the release of Django 1.3.

What's new in Django 1.3
========================

Class-based views
~~~~~~~~~~~~~~~~~

Django 1.3 adds a framework that allows you to use a class as a view.
This means you can compose a view out of a collection of methods that
can be subclassed and overridden to provide common views of data without
having to write too much code.

Analogs of all the old function-based generic views have been
provided, along with a completely generic view base class that can be
used as the basis for reusable applications that can be easily
extended.

See :doc:`the documentation on class-based generic views</topics/class-based-views>`
for more details. There is also a document to help you :doc:`convert
your function-based generic views to class-based
views</topics/generic-views-migration>`.

Logging
~~~~~~~

Django 1.3 adds framework-level support for Python's ``logging``
module.  This means you can now easily configure and control logging
as part of your Django project. A number of logging handlers and
logging calls have been added to Django's own code as well -- most
notably, the error emails sent on a HTTP 500 server error are now
handled as a logging activity. See :doc:`the documentation on Django's
logging interface </topics/logging>` for more details.

Extended static files handling
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Django 1.3 ships with a new contrib app --
``django.contrib.staticfiles`` -- to help developers handle the static
media files (images, CSS, Javascript, etc.) that are needed to render
a complete web page.

In previous versions of Django, it was common to place static assets
in :setting:`MEDIA_ROOT` along with user-uploaded files, and serve
them both at :setting:`MEDIA_URL`. Part of the purpose of introducing
the ``staticfiles`` app is to make it easier to keep static files
separate from user-uploaded files. Static assets should now go in
``static/`` subdirectories of your apps or in other static assets
directories listed in :setting:`STATICFILES_DIRS`, and will be served
at :setting:`STATIC_URL`.

See the :doc:`reference documentation of the app </ref/contrib/staticfiles>`
for more details or learn how to :doc:`manage static files
</howto/static-files>`.

unittest2 support
~~~~~~~~~~~~~~~~~

Python 2.7 introduced some major changes to the ``unittest`` library,
adding some extremely useful features. To ensure that every Django
project can benefit from these new features, Django ships with a copy
of unittest2_, a copy of the Python 2.7 unittest library, backported
for Python 2.4 compatibility.

To access this library, Django provides the ``django.utils.unittest``
module alias. If you are using Python 2.7, or you have installed
``unittest2`` locally, Django will map the alias to the installed
version of the unittest library. Otherwise, Django will use its own
bundled version of unittest2.

To take advantage of this alias, simply use::

    from django.utils import unittest

wherever you would have historically used::

    import unittest

If you want to continue to use the base unittest library, you can --
you just won't get any of the nice new unittest2 features.

.. _unittest2: http://pypi.python.org/pypi/unittest2

Transaction context managers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Users of Python 2.5 and above may now use :ref:`transaction management functions
<transaction-management-functions>` as `context managers`_. For example::

    with transaction.autocommit():
        # ...

.. _context managers: http://docs.python.org/glossary.html#term-context-manager

For more information, see :ref:`transaction-management-functions`.

Configurable delete-cascade
~~~~~~~~~~~~~~~~~~~~~~~~~~~

:class:`~django.db.models.ForeignKey` and
:class:`~django.db.models.OneToOneField` now accept an
:attr:`~django.db.models.ForeignKey.on_delete` argument to customize behavior
when the referenced object is deleted. Previously, deletes were always
cascaded; available alternatives now include set null, set default, set to any
value, protect, or do nothing.

For more information, see the :attr:`~django.db.models.ForeignKey.on_delete`
documentation.

Contextual markers and comments for translatable strings
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For translation strings with ambiguous meaning, you can now
use the ``pgettext`` function to specify the context of the string.

And if you just want to add some information for translators, you
can also add special translator comments in the source.

For more information, see :ref:`contextual-markers` and
:ref:`translator-comments`.

Improvements to built-in template tags
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A number of improvements have been made to Django's built-in template tags:

    * The :ttag:`include` tag now accepts a ``with`` option, allowing
      you to specify context variables to the included template

    * The :ttag:`include` tag now accepts an ``only`` option, allowing
      you to exclude the current context from the included context

    * The :ttag:`with` tag now allows you to define multiple context
      variables in a single :ttag:`with` block.

    * The :ttag:`load` tag now accepts a ``from`` argument, allowing
      you to load a single tag or filter from a library.

TemplateResponse
~~~~~~~~~~~~~~~~

It can sometimes be beneficial to allow decorators or middleware to
modify a response *after* it has been constructed by the view. For
example, you may want to change the template that is used, or put
additional data into the context.

However, you can't (easily) modify the content of a basic
:class:`~django.http.HttpResponse` after it has been constructed. To
overcome this limitation, Django 1.3 adds a new
:class:`~django.template.response.TemplateResponse` class. Unlike basic
:class:`~django.http.HttpResponse` objects,
:class:`~django.template.response.TemplateResponse` objects retain the details
of the template and context that was provided by the view to compute
the response. The final output of the response is not computed until
it is needed, later in the response process.

For more details, see the :doc:`documentation </ref/template-response>`
on the :class:`~django.template.response.TemplateResponse` class.

Caching changes
~~~~~~~~~~~~~~~

Django 1.3 sees the introduction of several improvements to the
Django's caching infrastructure.

Firstly, Django now supports multiple named caches. In the same way
that Django 1.2 introduced support for multiple database connections,
Django 1.3 allows you to use the new :setting:`CACHES` setting to
define multiple named cache connections.

Secondly, :ref:`versioning <cache_versioning>`, :ref:`site-wide
prefixing <cache_key_prefixing>` and :ref:`transformation
<cache_key_transformation>` have been added to the cache API.

Thirdly, :ref:`cache key creation <using-vary-headers>` has been
updated to take the request query string into account on ``GET``
requests.

Finally, support for pylibmc_ has been added to the memcached cache
backend.

For more details, see the :doc:`documentation on
caching in Django</topics/cache>`.

.. _pylibmc: http://sendapatch.se/projects/pylibmc/

Permissions for inactive users
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you provide a custom auth backend with ``supports_inactive_user``
set to ``True``, an inactive ``User`` instance will check the backend
for permissions.  This is useful for further centralizing the
permission handling. See the :doc:`authentication docs </topics/auth>`
for more details.

GeoDjango
~~~~~~~~~

The GeoDjango test suite is now included when
:ref:`running the Django test suite <running-unit-tests>` with ``runtests.py``
when using :ref:`spatial database backends <spatial-backends>`.

``MEDIA_URL`` and ``STATIC_URL`` must end in a slash
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Previously, the :setting:`MEDIA_URL` setting only required a trailing slash if
it contained a suffix beyond the domain name.

A trailing slash is now *required* for :setting:`MEDIA_URL` and the new
:setting:`STATIC_URL` setting as long as it is not blank. This ensures there is
a consistent way to combine paths in templates.

Project settings which provide either of both settings without a trailing
slash will now raise a ``PendingDeprecationWarning``.

In Django 1.4 this same condition will raise ``DeprecationWarning``,
and in Django 1.5 will raise an ``ImproperlyConfigured`` exception.

Everything else
~~~~~~~~~~~~~~~

Django :doc:`1.1 <1.1>` and :doc:`1.2 <1.2>` added
lots of big ticket items to Django, like multiple-database support,
model validation, and a session-based messages framework. However,
this focus on big features came at the cost of lots of smaller
features.

To compensate for this, the focus of the Django 1.3 development
process has been on adding lots of smaller, long standing feature
requests. These include:

* Improved tools for accessing and manipulating the current
  :class:`~django.contrib.sites.models.Site` object in
  :doc:`the sites framework </ref/contrib/sites>`.

* A :class:`~django.test.client.RequestFactory` for mocking requests
  in tests.

* A new test assertion --
  :meth:`~django.test.TestCase.assertNumQueries` -- making it
  easier to test the database activity associated with a view.

* Support for lookups spanning relations in admin's
  :attr:`~django.contrib.admin.ModelAdmin.list_filter`.

* Support for HTTPOnly_ cookies.

* :meth:`~django.core.mail.mail_admins()` and
  :meth:`~django.core.mail.mail_managers()` now support easily attaching
  HTML content to messages.

* :class:`~django.core.mail.EmailMessage` now supports CC's.

* Error emails now include more of the detail and formatting of the
  debug server error page.

* :meth:`~django.template.Library.simple_tag` now accepts a
  ``takes_context`` argument, making it easier to write simple
  template tags that require access to template context.

* A new :meth:`~django.shortcuts.render()` shortcut -- an alternative
  to :meth:`~django.shortcuts.render_to_response()` providing a
  :class:`~django.template.RequestContext` by default.

* Support for combining :ref:`F() expressions <query-expressions>`
  with timedelta values when retrieving or updating database values.

.. _HTTPOnly: http://www.owasp.org/index.php/HTTPOnly

.. _backwards-incompatible-changes-1.3:

Backwards-incompatible changes in 1.3
=====================================

CSRF validation now applies to AJAX requests
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Prior to Django 1.2.5, Django's CSRF-prevention system exempted AJAX
requests from CSRF verification; due to `security issues`_ reported to
us, however, *all* requests are now subjected to CSRF
verification. Consult :doc:`the Django CSRF documentation
</ref/contrib/csrf>` for details on how to handle CSRF verification in
AJAX requests.

.. _security issues: http://www.djangoproject.com/weblog/2011/feb/08/security/

Restricted filters in admin interface
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Prior to Django 1.2.5, the Django administrative interface allowed
filtering on any model field or relation -- not just those specified
in ``list_filter`` -- via query string manipulation. Due to security
issues reported to us, however, query string lookup arguments in the
admin must be for fields or relations specified in ``list_filter`` or
``date_hierarchy``.

Deleting a model doesn't delete associated files
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In earlier Django versions, when a model instance containing a
:class:`~django.db.models.FileField` was deleted,
:class:`~django.db.models.FileField` took it upon itself to also delete the
file from the backend storage. This opened the door to several data-loss
scenarios, including rolled-back transactions and fields on different models
referencing the same file. In Django 1.3, when a model is deleted the
:class:`~django.db.models.FileField`'s
:func:`~django.db.models.FileField.delete` method won't be called.  If you
need cleanup of orphaned files, you'll need to handle it yourself (for
instance, with a custom management command that can be run manually or
scheduled to run periodically via e.g. cron).

PasswordInput default rendering behavior
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The :class:`~django.forms.PasswordInput` form widget, intended for use
with form fields which represent passwords, accepts a boolean keyword
argument ``render_value`` indicating whether to send its data back to
the browser when displaying a submitted form with errors. Prior to
Django 1.3, this argument defaulted to ``True``, meaning that the
submitted password would be sent back to the browser as part of the
form. Developers who wished to add a bit of additional security by
excluding that value from the redisplayed form could instantiate a
:class:`~django.forms.PasswordInput` passing ``render_value=False`` .

Due to the sensitive nature of passwords, however, Django 1.3 takes
this step automatically; the default value of ``render_value`` is now
``False``, and developers who want the password value returned to the
browser on a submission with errors (the previous behavior) must now
explicitly indicate this. For example::

    class LoginForm(forms.Form):
        username = forms.CharField(max_length=100)
        password = forms.CharField(widget=forms.PasswordInput(render_value=True))

Clearable default widget for FileField
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Django 1.3 now includes a :class:`~django.forms.ClearableFileInput` form widget
in addition to :class:`~django.forms.FileInput`. ``ClearableFileInput`` renders
with a checkbox to clear the field's value (if the field has a value and is not
required); ``FileInput`` provided no means for clearing an existing file from
a ``FileField``.

``ClearableFileInput`` is now the default widget for a ``FileField``, so
existing forms including ``FileField`` without assigning a custom widget will
need to account for the possible extra checkbox in the rendered form output.

To return to the previous rendering (without the ability to clear the
``FileField``), use the ``FileInput`` widget in place of
``ClearableFileInput``. For instance, in a ``ModelForm`` for a hypothetical
``Document`` model with a ``FileField`` named ``document``::

    from django import forms
    from myapp.models import Document

    class DocumentForm(forms.ModelForm):
        class Meta:
            model = Document
            widgets = {'document': forms.FileInput}

New index on database session table
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Prior to Django 1.3, the database table used by the database backend
for the :doc:`sessions </topics/http/sessions>` app had no index on
the ``expire_date`` column. As a result, date-based queries on the
session table -- such as the query that is needed to purge old
sessions -- would be very slow if there were lots of sessions.

If you have an existing project that is using the database session
backend, you don't have to do anything to accommodate this change.
However, you may get a significant performance boost if you manually
add the new index to the session table. The SQL that will add the
index can be found by running the :djadmin:`sqlindexes` admin
command::

    python manage.py sqlindexes sessions

No more naughty words
~~~~~~~~~~~~~~~~~~~~~

Django has historically provided (and enforced) a list of profanities.
The :doc:`comments app </ref/contrib/comments/index>` has enforced this
list of profanities, preventing people from submitting comments that
contained one of those profanities.

Unfortunately, the technique used to implement this profanities list
was woefully naive, and prone to the `Scunthorpe problem`_. Improving
the built-in filter to fix this problem would require significant
effort, and since natural language processing isn't the normal domain
of a web framework, we have "fixed" the problem by making the list of
prohibited words an empty list.

If you want to restore the old behavior, simply put a
:setting:`PROFANITIES_LIST` setting in your settings file that includes the
words that you want to prohibit (see the `commit that implemented this
change`_ if you want to see the list of words that was historically
prohibited). However, if avoiding profanities is important to you, you
would be well advised to seek out a better, less naive approach to the
problem.

.. _Scunthorpe problem: http://en.wikipedia.org/wiki/Scunthorpe_problem
.. _commit that implemented this change: http://code.djangoproject.com/changeset/13996

Localflavor changes
~~~~~~~~~~~~~~~~~~~

Django 1.3 introduces the following backwards-incompatible changes to
local flavors:

* Canada (ca) -- The province "Newfoundland and Labrador" has had its
  province code updated to "NL", rather than the older "NF". In
  addition, the Yukon Territory has had its province code corrected to
  "YT", instead of "YK".

* Indonesia (id) -- The province "Nanggroe Aceh Darussalam (NAD)" has
  been removed from the province list in favor of the new official
  designation "Aceh (ACE)".

* United States of America (us) -- The list of "states" used by
  ``USStateField`` has expanded to include Armed Forces postal
  codes. This is backwards-incompatible if you were relying on
  ``USStateField`` not including them.

FormSet updates
~~~~~~~~~~~~~~~

In Django 1.3 ``FormSet`` creation behavior is modified slightly. Historically
the class didn't make a distinction between not being passed data and being
passed empty dictionary. This was inconsistent with behavior in other parts of
the framework. Starting with 1.3 if you pass in empty dictionary the
``FormSet`` will raise a ``ValidationError``.

For example with a ``FormSet``::

    >>> class ArticleForm(Form):
    ...     title = CharField()
    ...     pub_date = DateField()
    >>> ArticleFormSet = formset_factory(ArticleForm)

the following code will raise a ``ValidationError``::

    >>> ArticleFormSet({})
    Traceback (most recent call last):
    ...
    ValidationError: [u'ManagementForm data is missing or has been tampered with']

if you need to instantiate an empty ``FormSet``, don't pass in the data or use
``None``::

    >>> formset = ArticleFormSet()
    >>> formset = ArticleFormSet(data=None)

Callables in templates
~~~~~~~~~~~~~~~~~~~~~~

Previously, a callable in a template would only be called automatically as part
of the variable resolution process if it was retrieved via attribute
lookup. This was an inconsistency that could result in confusing and unhelpful
behavior::

    >>> Template("{{ user.get_full_name }}").render(Context({'user': user}))
    u'Joe Bloggs'
    >>> Template("{{ full_name }}").render(Context({'full_name': user.get_full_name}))
    u'&lt;bound method User.get_full_name of &lt;...

This has been resolved in Django 1.3 - the result in both cases will be ``u'Joe
Bloggs'``. Although the previous behavior was not useful for a template language
designed for web designers, and was never deliberately supported, it is possible
that some templates may be broken by this change.

Use of custom SQL to load initial data in tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Django provides a custom SQL hooks as a way to inject hand-crafted SQL
into the database synchronization process. One of the possible uses
for this custom SQL is to insert data into your database. If your
custom SQL contains ``INSERT`` statements, those insertions will be
performed every time your database is synchronized. This includes the
synchronization of any test databases that are created when you run a
test suite.

However, in the process of testing the Django 1.3, it was discovered
that this feature has never completely worked as advertised. When
using database backends that don't support transactions, or when using
a TransactionTestCase, data that has been inserted using custom SQL
will not be visible during the testing process.

Unfortunately, there was no way to rectify this problem without
introducing a backwards incompatibility. Rather than leave
SQL-inserted initial data in an uncertain state, Django now enforces
the policy that data inserted by custom SQL will *not* be visible
during testing.

This change only affects the testing process. You can still use custom
SQL to load data into your production database as part of the syncdb
process. If you require data to exist during test conditions, you
should either insert it using :ref:`test fixtures
<topics-testing-fixtures>`, or using the ``setUp()`` method of your
test case.

Changed priority of translation loading
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Work has been done to simplify, rationalize and properly document the algorithm
used by Django at runtime to build translations from the different translations
found on disk, namely:

For translatable literals found in Python code and templates (``'django'``
gettext domain):

 * Priorities of translations included with applications listed in the
   :setting:`INSTALLED_APPS` setting were changed. To provide a behavior
   consistent with other parts of Django that also use such setting (templates,
   etc.) now, when building the translation that will be made available, the
   apps listed first have higher precedence than the ones listed later.

 * Now it is possible to override the translations shipped with applications by
   using the :setting:`LOCALE_PATHS` setting whose translations have now higher
   precedence than the translations of ``INSTALLED_APPS`` applications.
   The relative priority among the values listed in this setting has also been
   modified so the paths listed first have higher precedence than the
   ones listed later.

 * The ``locale`` subdirectory of the directory containing the settings, that
   usually coincides with and is know as the *project directory* is being
   deprecated in this release as a source of translations. (the precedence of
   these translations is intermediate between applications and ``LOCALE_PATHS``
   translations). See the `corresponding deprecated features section`_
   of this document.

For translatable literals found in Javascript code (``'djangojs'`` gettext
domain):

 * Similarly to the ``'django'`` domain translations: Overriding of
   translations shipped with applications by using the :setting:`LOCALE_PATHS`
   setting is now possible for this domain too. These translations have higher
   precedence than the translations of Python packages passed to the
   :ref:`javascript_catalog view <javascript_catalog-view>`.  Paths listed first
   have higher precedence than the ones listed later.

 * Translations under the ``locale`` subdirectory of the *project directory*
   have never been taken in account for JavaScript translations and remain in
   the same situation considering the deprecation of such location.

.. _corresponding deprecated features section: loading_of_project_level_translations_

Transaction management
~~~~~~~~~~~~~~~~~~~~~~

When using managed transactions -- that is, anything but the default
autocommit mode -- it is important when a transaction is marked as
"dirty". Dirty transactions are committed by the
:func:`~django.db.transaction.commit_on_success` decorator or the
:class:`~django.middleware.transaction.TransactionMiddleware`, and
:func:`~django.db.transaction.commit_manually` forces them to be
closed explicitly; clean transactions "get a pass", which means they
are usually rolled back at the end of a request when the connection is
closed.

Until Django 1.3, transactions were only marked dirty when Django was
aware of a modifying operation performed in them; that is, either some
model was saved, some bulk update or delete was performed, or the user
explicitly called ``transaction.set_dirty()``. In Django 1.3, a
transaction is marked dirty when *any* database operation is
performed.

As a result of this change, you no longer need to set a transaction
dirty explicitly when you execute raw SQL or use a data-modifying
``SELECT``. However, you *do* need to explicitly close any read-only
transactions that are being managed using
:func:`~django.db.transaction.commit_manually`. For example::

      @transaction.commit_manually
      def my_view(request, name):
          obj = get_object_or_404(MyObject, name__iexact=name)
          return render_to_response('template', {'object':obj})

Prior to Django 1.3, this would work without error. However, under
Django 1.3, this will raise a
:class:`~django.db.transaction.TransactionManagementError` because
the read operation that retrieves the ``MyObject`` instance leaves the
transaction in a dirty state.

No password reset for inactive users
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Prior to Django 1.3, inactive users were able to request a password reset email
and reset their password. In Django 1.3 inactive users will receive the same
message as a nonexistent account.

.. _deprecated-features-1.3:

Features deprecated in 1.3
==========================

Django 1.3 deprecates some features from earlier releases.
These features are still supported, but will be gradually phased out
over the next few release cycles.

Code taking advantage of any of the features below will raise a
``PendingDeprecationWarning`` in Django 1.3. This warning will be
silent by default, but may be turned on using Python's `warnings
module`_, or by running Python with a ``-Wd`` or `-Wall` flag.

.. _warnings module: http://docs.python.org/library/warnings.html

In Django 1.4, these warnings will become a ``DeprecationWarning``,
which is *not* silent. In Django 1.5 support for these features will
be removed entirely.

.. seealso::

    For more details, see the documentation :doc:`Django's release process
    </internals/release-process>` and our :doc:`deprecation timeline
    </internals/deprecation>`.

``mod_python`` support
~~~~~~~~~~~~~~~~~~~~~~

The ``mod_python`` library has not had a release since 2007 or a commit since
2008. The Apache Foundation board voted to remove ``mod_python`` from the set
of active projects in its version control repositories, and its lead developer
has shifted all of his efforts toward the lighter, slimmer, more stable, and
more flexible ``mod_wsgi`` backend.

If you are currently using the ``mod_python`` request handler, you
should redeploy your Django projects using another request handler.
:doc:`mod_wsgi </howto/deployment/modwsgi>` is the request handler
recommended by the Django project, but :doc:`FastCGI
</howto/deployment/fastcgi>` is also supported. Support for
``mod_python`` deployment will be removed in Django 1.5.

Function-based generic views
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

As a result of the introduction of class-based generic views, the
function-based generic views provided by Django have been deprecated.
The following modules and the views they contain have been deprecated:

* :mod:`django.views.generic.create_update`

* :mod:`django.views.generic.date_based`

* :mod:`django.views.generic.list_detail`

* :mod:`django.views.generic.simple`

Test client response ``template`` attribute
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Django's :ref:`test client <test-client>` returns
:class:`~django.test.client.Response` objects annotated with extra testing
information. In Django versions prior to 1.3, this included a
:attr:`~django.test.client.Response.template` attribute containing information
about templates rendered in generating the response: either None, a single
:class:`~django.template.Template` object, or a list of
:class:`~django.template.Template` objects. This inconsistency in return values
(sometimes a list, sometimes not) made the attribute difficult to work with.

In Django 1.3 the :attr:`~django.test.client.Response.template` attribute is
deprecated in favor of a new :attr:`~django.test.client.Response.templates`
attribute, which is always a list, even if it has only a single element or no
elements.

``DjangoTestRunner``
~~~~~~~~~~~~~~~~~~~~

As a result of the introduction of support for unittest2, the features
of :class:`django.test.simple.DjangoTestRunner` (including fail-fast
and Ctrl-C test termination) have been made redundant. In view of this
redundancy, :class:`~django.test.simple.DjangoTestRunner` has been
turned into an empty placeholder class, and will be removed entirely
in Django 1.5.

Changes to :ttag:`url` and :ttag:`ssi`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Most template tags will allow you to pass in either constants or
variables as arguments -- for example::

    {% extends "base.html" %}

allows you to specify a base template as a constant, but if you have a
context variable ``templ`` that contains the value ``base.html``::

    {% extends templ %}

is also legal.

However, due to an accident of history, the :ttag:`url` and
:ttag:`ssi` are different. These tags use the second, quoteless
syntax, but interpret the argument as a constant. This means it isn't
possible to use a context variable as the target of a :ttag:`url` and
:ttag:`ssi` tag.

Django 1.3 marks the start of the process to correct this historical
accident. Django 1.3 adds a new template library -- ``future`` -- that
provides alternate implementations of the :ttag:`url` and :ttag:`ssi`
template tags. This ``future`` library implement behavior that makes
the handling of the first argument consistent with the handling of all
other variables. So, an existing template that contains::

    {% url sample %}

should be replaced with::

    {% load url from future %}
    {% url 'sample' %}

The tags implementing the old behavior have been deprecated, and in
Django 1.5, the old behavior will be replaced with the new behavior.
To ensure compatibility with future versions of Django, existing
templates should be modified to use the new ``future`` libraries and
syntax.

Changes to the login methods of the admin
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In previous version the admin app defined login methods in multiple locations
and ignored the almost identical implementation in the already used auth app.
A side effect of this duplication was the missing adoption of the changes made
in r12634_ to support a broader set of characters for usernames.

This release refactors the admin's login mechanism to use a subclass of the
:class:`~django.contrib.auth.forms.AuthenticationForm` instead of a manual
form validation. The previously undocumented method
``'django.contrib.admin.sites.AdminSite.display_login_form'`` has been removed
in favor of a new :attr:`~django.contrib.admin.AdminSite.login_form`
attribute.

.. _r12634: http://code.djangoproject.com/changeset/12634

``reset`` and ``sqlreset`` management commands
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Those commands have been deprecated. The ``flush`` and ``sqlflush`` commands
can be used to delete everything. You can also use ALTER TABLE or DROP TABLE
statements manually.


GeoDjango
~~~~~~~~~

* The function-based :setting:`TEST_RUNNER` previously used to execute
  the GeoDjango test suite,
  :func:`django.contrib.gis.tests.run_gis_tests`, was deprecated for
  the class-based runner,
  :class:`django.contrib.gis.tests.GeoDjangoTestSuiteRunner`.

* Previously, calling
  :meth:`~django.contrib.gis.geos.GEOSGeometry.transform` would
  silently do nothing when GDAL wasn't available.  Now, a
  :class:`~django.contrib.gis.geos.GEOSException` is properly raised
  to indicate possible faulty application code.  A warning is now
  raised if :meth:`~django.contrib.gis.geos.GEOSGeometry.transform` is
  called when the SRID of the geometry is less than 0 or ``None``.

``CZBirthNumberField.clean``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Previously this field's ``clean()`` method accepted a second, gender, argument
which allowed stronger validation checks to be made, however since this
argument could never actually be passed from the Django form machinery it is
now pending deprecation.

``CompatCookie``
~~~~~~~~~~~~~~~~

Previously, ``django.http`` exposed an undocumented ``CompatCookie`` class,
which was a bug-fix wrapper around the standard library ``SimpleCookie``. As the
fixes are moving upstream, this is now deprecated - you should use ``from
django.http import SimpleCookie`` instead.

.. _loading_of_project_level_translations:

Loading of *project-level* translations
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This release of Django starts the deprecation process for inclusion of
translations located under the so-called *project path* in the translation
building process performed at runtime. The :setting:`LOCALE_PATHS` setting can
be used for the same task by adding the filesystem path to a ``locale``
directory containing project-level translations to the value of that setting.

Rationale for this decision:

* The *project path* has always been a loosely defined concept
  (actually, the directory used for locating project-level
  translations is the directory containing the settings module) and
  there has been a shift in other parts of the framework to stop using
  it as a reference for location of assets at runtime.

* Detection of the ``locale`` subdirectory tends to fail when the
  deployment scenario is more complex than the basic one. e.g. it
  fails when the settings module is a directory (ticket #10765).

* There are potential strange development- and deployment-time
  problems like the fact that the ``project_dir/locale/`` subdir can
  generate spurious error messages when the project directory is added
  to the Python path (``manage.py runserver`` does this) and then it
  clashes with the equally named standard library module, this is a
  typical warning message::

     /usr/lib/python2.6/gettext.py:49: ImportWarning: Not importing directory '/path/to/project/locale': missing __init__.py.
     import locale, copy, os, re, struct, sys

* This location wasn't included in the translation building process
  for JavaScript literals. This deprecation removes such
  inconsistency.

``PermWrapper`` moved to ``django.contrib.auth.context_processors``
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In Django 1.2, we began the process of changing the location of the
``auth`` context processor from ``django.core.context_processors`` to
``django.contrib.auth.context_processors``. However, the
``PermWrapper`` support class was mistakenly omitted from that
migration. In Django 1.3, the ``PermWrapper`` class has also been
moved to ``django.contrib.auth.context_processors``, along with the
``PermLookupDict`` support class. The new classes are functionally
identical to their old versions; only the module location has changed.

Removal of ``XMLField``
~~~~~~~~~~~~~~~~~~~~~~~

When Django was first released, Django included an
:class:`~django.db.models.XMLField` that performed automatic XML validation
for any field input. However, this validation function hasn't been
performed since the introduction of ``newforms``, prior to the 1.0 release.
As a result, ``XMLField`` as currently implemented is functionally
indistinguishable from a simple :class:`~django.db.models.TextField`.

For this reason, Django 1.3 has fast-tracked the deprecation of
``XMLField`` -- instead of a two-release deprecation, ``XMLField``
will be removed entirely in Django 1.4.

It's easy to update your code to accommodate this change -- just
replace all uses of ``XMLField`` with ``TextField``, and remove the
``schema_path`` keyword argument (if it is specified).