============================================
Django 2.0 release notes - UNDER DEVELOPMENT
============================================

Welcome to Django 2.0!

These release notes cover the :ref:`new features <whats-new-2.0>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-2.0>` you'll
want to be aware of when upgrading from Django 1.11 or earlier. We've
:ref:`dropped some features<removed-features-2.0>` that have reached the end of
their deprecation cycle, and we've :ref:`begun the deprecation process for some
features <deprecated-features-2.0>`.

See the :doc:`/howto/upgrade-version` guide if you're updating an existing
project.

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

Django 2.0 supports Python 3.5+. Since Django 1.11, support for Python 2.7 and
3.4 is removed. We **highly recommend** and only officially support the latest
release of each series.

Third-party library support for older version of Django
=======================================================

Following the release of Django 2.0, we suggest that third-party app authors
drop support for all versions of Django prior to 1.11. At that time, you should
be able run your package's tests using ``python -Wd`` so that deprecation
warnings do appear. After making the deprecation warning fixes, your app should
be compatible with Django 2.0.

.. _whats-new-2.0:

What's new in Django 2.0
========================

Minor features
--------------

:mod:`django.contrib.admin`
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.admindocs`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.auth`
~~~~~~~~~~~~~~~~~~~~~~~~~~

* The default iteration count for the PBKDF2 password hasher is increased from
  36,000 to 100,000.

:mod:`django.contrib.contenttypes`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.gis`
~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.messages`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.postgres`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* The new ``distinct`` argument for
  :class:`~django.contrib.postgres.aggregates.ArrayAgg` determines if
  concatenated values will be distinct.

:mod:`django.contrib.redirects`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.sessions`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.sitemaps`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.sites`
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.staticfiles`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

:mod:`django.contrib.syndication`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* ...

Cache
~~~~~

* ...

CSRF
~~~~

* ...

Database backends
~~~~~~~~~~~~~~~~~

* ...

Email
~~~~~

* ...

File Storage
~~~~~~~~~~~~

* ...

File Uploads
~~~~~~~~~~~~

* ...

Forms
~~~~~

* The new ``date_attrs`` and ``time_attrs`` arguments for
  :class:`~django.forms.SplitDateTimeWidget` and
  :class:`~django.forms.SplitHiddenDateTimeWidget` allow specifying different
  HTML attributes for the ``DateInput`` and ``TimeInput`` (or hidden)
  subwidgets.

Generic Views
~~~~~~~~~~~~~

* ...

Internationalization
~~~~~~~~~~~~~~~~~~~~

* ...

Management Commands
~~~~~~~~~~~~~~~~~~~

* ...

Migrations
~~~~~~~~~~

* ...

Models
~~~~~~

* ...

Requests and Responses
~~~~~~~~~~~~~~~~~~~~~~

* The :djadmin:`runserver` Web server supports HTTP 1.1.

Serialization
~~~~~~~~~~~~~

* ...

Signals
~~~~~~~

* ...

Templates
~~~~~~~~~

* ...

Tests
~~~~~

* Added threading support to :class:`~django.test.LiveServerTestCase`.

URLs
~~~~

* ...

Validators
~~~~~~~~~~

* ...

.. _backwards-incompatible-2.0:

Backwards incompatible changes in 2.0
=====================================

Removed support for bytestrings in some places
----------------------------------------------

To support native Python 2 strings, older Django versions had to accept both
bytestrings and unicode strings. Now that Python 2 support is dropped,
bytestrings should only be encountered around input/output boundaries (handling
of binary fields or HTTP streams, for example). You might have to update your
code to limit bytestring usage to a minimum, as Django no longer accepts
bytestrings in certain code paths.

Database backend API
--------------------

* The ``DatabaseOperations.datetime_cast_date_sql()``,
  ``datetime_cast_time_sql()``, ``datetime_trunc_sql()``, and
  ``datetime_extract_sql()`` methods now return only the SQL to perform the
  operation instead of SQL and a list of parameters.

Dropped support for Oracle 11.2
-------------------------------

The end of upstream support for Oracle 11.2 is Dec. 2020. Django 1.11 will be
supported until April 2020 which almost reaches this date. Django 2.0
officially supports Oracle 12.1+.

Default MySQL isolation level is read committed
-----------------------------------------------

MySQL's default isolation level, repeatable read, may cause data loss in
typical Django usage. To prevent that and for consistency with other databases,
the default isolation level is now read committed. You can use the
:setting:`DATABASES` setting to :ref:`use a different isolation level
<mysql-isolation-level>`, if needed.

:attr:`AbstractUser.last_name <django.contrib.auth.models.User.last_name>` ``max_length`` increased to 150
----------------------------------------------------------------------------------------------------------

A migration for :attr:`django.contrib.auth.models.User.last_name` is included.
If you have a custom user model inheriting from ``AbstractUser``, you'll need
to generate and apply a database migration for your user model.

If you want to preserve the 30 character limit for last names, use a custom
form::

    from django.contrib.auth.forms import UserChangeForm

    class MyUserChangeForm(UserChangeForm):
        last_name = forms.CharField(max_length=30, required=False)

If you wish to keep this restriction in the admin when editing users, set
``UserAdmin.form`` to use this form::

    from django.contrib.auth.admin import UserAdmin
    from django.contrib.auth.models import User

    class MyUserAdmin(UserAdmin):
        form = MyUserChangeForm

    admin.site.unregister(User)
    admin.site.register(User, MyUserAdmin)

Miscellaneous
-------------

* The ``SessionAuthenticationMiddleware`` class is removed. It provided no
  functionality since session authentication is unconditionally enabled in
  Django 1.10.

* The default HTTP error handlers (``handler404``, etc.) are now callables
  instead of dotted Python path strings. Django favors callable references
  since they provide better performance and debugging experience.

.. _deprecated-features-2.0:

Features deprecated in 2.0
==========================

Miscellaneous
-------------

* The ``django.db.backends.postgresql_psycopg2`` module is deprecated in favor
  of ``django.db.backends.postgresql``. It's been an alias since Django 1.9.
  This only affects code that imports from the module directly. The
  ``DATABASES`` setting can still use
  ``'django.db.backends.postgresql_psycopg2'``, though you can simplify that by
  using the ``'django.db.backends.postgresql'`` name added in Django 1.9.

* ``django.shortcuts.render_to_response()`` is deprecated in favor of
  :func:`django.shortcuts.render`. ``render()`` takes the same arguments
  except that is also requires a ``request``.

* The ``DEFAULT_CONTENT_TYPE`` setting is deprecated. It doesn't interact well
  well with third-party apps and is obsolete since HTML5 has mostly superseded
  XHTML.

.. _removed-features-2.0:

Features removed in 2.0
=======================

These features have reached the end of their deprecation cycle and are removed
in Django 2.0. See :ref:`deprecated-features-1.9` and
:ref:`deprecated-features-1.10` for details, including how to remove usage of
these features.

* The ``weak`` argument to ``django.dispatch.signals.Signal.disconnect()`` is
  removed.

* ``django.db.backends.base.BaseDatabaseOperations.check_aggregate_support()``
  is removed.

* The ``django.forms.extras`` package is removed.

* The ``assignment_tag`` helper is removed.

* The ``host`` argument to ``SimpleTestCase.assertsRedirects()`` is removed.
  The compatibility layer which allows absolute URLs to be considered equal to
  relative ones when the path is identical is also removed.

* ``Field.rel`` and ``Field.remote_field.to`` are removed.

* The ``on_delete`` argument for ``ForeignKey`` and ``OneToOneField`` are now
  required.

* ``django.db.models.fields.add_lazy_relation()`` is removed.

* When time zone support is enabled, database backends that don't support time
  zones no longer convert aware datetimes to naive values in UTC anymore when
  such values are passed as parameters to SQL queries executed outside of the
  ORM, e.g. with ``cursor.execute()``.

* ``django.contrib.auth.tests.utils.skipIfCustomUser()`` is removed.

* The ``GeoManager`` and ``GeoQuerySet`` classes are removed.

* The ``django.contrib.gis.geoip`` module is removed.

* The ``supports_recursion`` check for template loaders is removed from:

  * ``django.template.engine.Engine.find_template()``
  * ``django.template.loader_tags.ExtendsNode.find_template()``
  * ``django.template.loaders.base.Loader.supports_recursion()``
  * ``django.template.loaders.cached.Loader.supports_recursion()``

* The ``load_template`` and ``load_template_sources`` template loader methods
  are removed.

* The ``template_dirs`` argument for template loaders is removed:

  * ``django.template.loaders.base.Loader.get_template()``
  * ``django.template.loaders.cached.Loader.cache_key()``
  * ``django.template.loaders.cached.Loader.get_template()``
  * ``django.template.loaders.cached.Loader.get_template_sources()``
  * ``django.template.loaders.filesystem.Loader.get_template_sources()``

* ``django.template.loaders.base.Loader.__call__()`` is removed.

* Support for custom error views that don't accept an ``exception`` parameter
  is removed.

* The ``mime_type`` attribute of ``django.utils.feedgenerator.Atom1Feed`` and
  ``django.utils.feedgenerator.RssFeed`` is removed.

* The ``app_name`` argument to ``include()`` is removed.

* Support for passing a 3-tuple (including ``admin.site.urls``) as the first
  argument to ``include()`` is removed.

* Support for setting a URL instance namespace without an application namespace
  is removed.

* ``Field._get_val_from_obj()`` is removed.

* ``django.template.loaders.eggs.Loader`` is removed.

* The ``current_app`` parameter to the ``contrib.auth`` function-based views is
  removed.

* The ``callable_obj`` keyword argument to
  ``SimpleTestCase.assertRaisesMessage()`` is removed.

* Support for the ``allow_tags`` attribute on ``ModelAdmin`` methods is
  removed.

* The ``enclosure`` keyword argument to ``SyndicationFeed.add_item()`` is
  removed.

* The ``django.template.loader.LoaderOrigin`` and
  ``django.template.base.StringOrigin`` aliases for
  ``django.template.base.Origin`` are removed.

* The ``makemigrations --exit`` option is removed.

* Support for direct assignment to a reverse foreign key or many-to-many
  relation is removed.

* The ``get_srid()`` and ``set_srid()`` methods of
  ``django.contrib.gis.geos.GEOSGeometry`` are removed.

* The ``get_x()``, ``set_x()``, ``get_y()``, ``set_y()``, ``get_z()``, and
  ``set_z()`` methods of ``django.contrib.gis.geos.Point`` are removed.

* The ``get_coords()`` and ``set_coords()`` methods of
  ``django.contrib.gis.geos.Point`` are removed.

* The ``cascaded_union`` property of ``django.contrib.gis.geos.MultiPolygon``
  is removed.

* ``django.utils.functional.allow_lazy()`` is removed.

* The ``shell --plain`` option is removed.

* The ``django.core.urlresolvers`` module is removed.

* ``CommaSeparatedIntegerField`` is removed, except for support in historical
  migrations.

* The template ``Context.has_key()`` method is removed.

* Support for the ``django.core.files.storage.Storage.accessed_time()``,
  ``created_time()``, and ``modified_time()`` methods is removed.

* Support for query lookups using the model name when
  ``Meta.default_related_name`` is set is removed.

* The MySQL ``__search`` lookup is removed.

* The shim for supporting custom related manager classes without a
  ``_apply_rel_filters()`` method is removed.

* Using ``User.is_authenticated()`` and ``User.is_anonymous()`` as methods
  rather than properties is no longer supported.

* The  ``Model._meta.virtual_fields`` attribute is removed.

* The keyword arguments ``virtual_only`` in ``Field.contribute_to_class()`` and
  ``virtual`` in ``Model._meta.add_field()`` are removed.

* The ``javascript_catalog()`` and ``json_catalog()`` views are removed.

* ``django.contrib.gis.utils.precision_wkt()`` is removed.

* In multi-table inheritance, implicit promotion of a ``OneToOneField`` to a
  ``parent_link`` is removed.

* Support for ``Widget._format_value()`` is removed.

* ``FileField`` methods ``get_directory_name()`` and ``get_filename()`` are
  removed.

* The ``mark_for_escaping()`` function and the classes it uses: ``EscapeData``,
  ``EscapeBytes``, ``EscapeText``, ``EscapeString``, and ``EscapeUnicode`` are
  removed.

* The ``escape`` filter now uses ``django.utils.html.conditional_escape()``.

* ``Manager.use_for_related_fields`` is removed.

* Model ``Manager`` inheritance follows MRO inheritance rules. The requirement
  to use ``Meta.manager_inheritance_from_future`` to opt-in to the behavior is
  removed.

* Support for old-style middleware using ``settings.MIDDLEWARE_CLASSES`` is
  removed.
