django/docs/releases/3.0.txt

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============================================
Django 3.0 release notes - UNDER DEVELOPMENT
============================================
*Expected December 2019*
Welcome to Django 3.0!
These release notes cover the :ref:`new features <whats-new-3.0>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-3.0>` you'll
want to be aware of when upgrading from Django 2.2 or earlier. We've
:ref:`dropped some features<removed-features-3.0>` that have reached the end of
their deprecation cycle, and we've :ref:`begun the deprecation process for
some features <deprecated-features-3.0>`.
See the :doc:`/howto/upgrade-version` guide if you're updating an existing
project.
Python compatibility
====================
Django 3.0 supports Python 3.6, 3.7, and 3.8. We **highly recommend** and only
officially support the latest release of each series.
The Django 2.2.x series is the last to support Python 3.5.
Third-party library support for older version of Django
=======================================================
Following the release of Django 3.0, we suggest that third-party app authors
drop support for all versions of Django prior to 2.2. At that time, you should
be able to run your package's tests using ``python -Wd`` so that deprecation
warnings appear. After making the deprecation warning fixes, your app should be
compatible with Django 3.0.
.. _whats-new-3.0:
What's new in Django 3.0
========================
Minor features
--------------
:mod:`django.contrib.admin`
~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Added support for the ``admin_order_field`` attribute on properties in
:attr:`.ModelAdmin.list_display`.
* The new :meth:`ModelAdmin.get_inlines()
<django.contrib.admin.ModelAdmin.get_inlines>` method allows specifying the
inlines based on the request or model instance.
:mod:`django.contrib.admindocs`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.auth`
~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.contenttypes`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.gis`
~~~~~~~~~~~~~~~~~~~~~~~~~
* Allowed MySQL spatial lookup functions to operate on real geometries.
Previous support was limited to bounding boxes.
* Added the :class:`~django.contrib.gis.db.models.functions.GeometryDistance`
function, supported on PostGIS.
* Added support for the ``furlong`` unit in
:class:`~django.contrib.gis.measure.Distance`.
:mod:`django.contrib.messages`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.postgres`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.redirects`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.sessions`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* The new
:meth:`~django.contrib.sessions.backends.base.SessionBase.get_session_cookie_age()`
methods allows dynamically specifying the session cookie age.
:mod:`django.contrib.sitemaps`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.sites`
~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.staticfiles`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* ...
:mod:`django.contrib.syndication`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Added the ``language`` class attribute to the
:class:`django.contrib.syndication.views.Feed` to customize a feed language.
The default value is :func:`~django.utils.translation.get_language()` instead
of :setting:`LANGUAGE_CODE`.
Cache
~~~~~
* ...
CSRF
~~~~
* ...
Email
~~~~~
* ...
File Storage
~~~~~~~~~~~~
* ...
File Uploads
~~~~~~~~~~~~
* ...
Forms
~~~~~
* Formsets may control the widget used when ordering forms via
:attr:`~django.forms.formsets.BaseFormSet.can_order` by setting the
:attr:`~django.forms.formsets.BaseFormSet.ordering_widget` attribute or
overriding :attr:`~django.forms.formsets.BaseFormSet.get_ordering_widget()`.
Generic Views
~~~~~~~~~~~~~
* ...
Internationalization
~~~~~~~~~~~~~~~~~~~~
* Added the :setting:`LANGUAGE_COOKIE_HTTPONLY`,
:setting:`LANGUAGE_COOKIE_SAMESITE`, and :setting:`LANGUAGE_COOKIE_SECURE`
settings to set the ``HttpOnly``, ``SameSite``, and ``Secure`` flags on
language cookies. The default values of these settings preserve the previous
behavior.
Management Commands
~~~~~~~~~~~~~~~~~~~
* The new :option:`compilemessages --ignore` option allows ignoring specific
directories when searching for ``.po`` files to compile.
* :option:`showmigrations --list` now shows the applied datetimes when
``--verbosity`` is 2 and above.
* On PostgreSQL, :djadmin:`dbshell` now supports client-side TLS certificates.
* :djadmin:`inspectdb` now introspects :class:`~django.db.models.OneToOneField`
when a foreign key has a unique or primary key constraint.
* The new :option:`--skip-checks` option skips running system checks prior to
running the command.
Migrations
~~~~~~~~~~
* ...
Models
~~~~~~
* Added hash database functions :class:`~django.db.models.functions.MD5`,
:class:`~django.db.models.functions.SHA1`,
:class:`~django.db.models.functions.SHA224`,
:class:`~django.db.models.functions.SHA256`,
:class:`~django.db.models.functions.SHA384`, and
:class:`~django.db.models.functions.SHA512`.
* Added the :class:`~django.db.models.functions.Sign` database function.
* The new ``is_dst`` parameter of the
:class:`~django.db.models.functions.Trunc` database functions determines the
treatment of nonexistent and ambiguous datetimes.
* ``connection.queries`` now shows ``COPY … TO`` statements on PostgreSQL.
* :class:`~django.db.models.FilePathField` now accepts a callable ``path``.
Requests and Responses
~~~~~~~~~~~~~~~~~~~~~~
* Allowed :class:`~django.http.HttpResponse` to be initialized with
:class:`memoryview` content.
* For use in, for example, Django templates, :attr:`.HttpRequest.headers` now
allows look ups using underscores (e.g. ``user_agent``) in place of hyphens.
Serialization
~~~~~~~~~~~~~
* ...
Signals
~~~~~~~
* ...
Templates
~~~~~~~~~
* ...
Tests
~~~~~
* The new test :class:`~django.test.Client` argument
``raise_request_exception`` allows controlling whether or not exceptions
raised during the request should also be raised in the test. The value
defaults to ``True`` for backwards compatibility. If it is ``False`` and an
exception occurs, the test client will return a 500 response with the
attribute :attr:`~django.test.Response.exc_info`, a tuple providing
information of the exception that occurred.
* Tests and test cases to run can be selected by test name pattern using the
new :option:`test -k` option.
* HTML comparison, as used by
:meth:`~django.test.SimpleTestCase.assertHTMLEqual`, now treats text, character
references, and entity references that refer to the same character as
equivalent.
* Django test runner now supports headless mode for selenium tests on supported
browsers. Add the ``--headless`` option to enable this mode.
URLs
~~~~
* ...
Validators
~~~~~~~~~~
* ...
.. _backwards-incompatible-3.0:
Backwards incompatible changes in 3.0
=====================================
Database backend API
--------------------
This section describes changes that may be needed in third-party database
backends.
* The second argument of ``DatabaseIntrospection.get_geometry_type()`` is now
the row description instead of the column name.
* ``DatabaseIntrospection.get_field_type()`` may no longer return tuples.
* If the database can create foreign keys in the same SQL statement that adds a
field, add ``SchemaEditor.sql_create_column_inline_fk`` with the appropriate
SQL; otherwise, set ``DatabaseFeatures.can_create_inline_fk = False``.
* ``DatabaseFeatures.can_return_id_from_insert`` and
``can_return_ids_from_bulk_insert`` are renamed to
``can_return_columns_from_insert`` and ``can_return_rows_from_bulk_insert``.
:mod:`django.contrib.gis`
-------------------------
* Support for PostGIS 2.1 is removed.
* Support for SpatiaLite 4.1 and 4.2 is removed.
* Support for GDAL 1.11 and GEOS 3.4 is removed.
Dropped support for PostgreSQL 9.4
----------------------------------
Upstream support for PostgreSQL 9.4 ends in December 2019. Django 3.0 supports
PostgreSQL 9.5 and higher.
Dropped support for Oracle 12.1
-------------------------------
Upstream support for Oracle 12.1 ends in July 2021. Django 2.2 will be
supported until April 2022. Django 3.0 officially supports Oracle 12.2 and 18c.
Removed private Python 2 compatibility APIs
-------------------------------------------
While Python 2 support was removed in Django 2.0, some private APIs weren't
removed from Django so that third party apps could continue using them until
the Python 2 end-of-life.
Since we expect apps to drop Python 2 compatibility when adding support for
Django 3.0, we're removing these APIs at this time.
* ``django.test.utils.str_prefix()`` - Strings don't have 'u' prefixes in
Python 3.
* ``django.test.utils.patch_logger()`` - Use
:meth:`unittest.TestCase.assertLogs` instead.
* ``django.utils.lru_cache.lru_cache()`` - Alias of
:func:`functools.lru_cache`.
* ``django.utils.decorators.available_attrs()`` - This function returns
``functools.WRAPPER_ASSIGNMENTS``.
* ``django.utils.decorators.ContextDecorator`` - Alias of
:class:`contextlib.ContextDecorator`.
* ``django.utils._os.abspathu()`` - Alias of :func:`os.path.abspath`.
* ``django.utils._os.upath()`` and ``npath()`` - These functions do nothing on
Python 3.
* ``django.utils.six`` - Remove usage of this vendored library or switch to
`six <https://pypi.org/project/six/>`_.
* ``django.utils.encoding.python_2_unicode_compatible()`` - Alias of
``six.python_2_unicode_compatible()``.
* ``django.utils.functional.curry()`` - Use :func:`functools.partial` or
:class:`functools.partialmethod`. See :commit:`5b1c389603a353625ae1603`.
* ``django.utils.safestring.SafeBytes`` - Unused since Django 2.0.
New default value for the ``FILE_UPLOAD_PERMISSIONS`` setting
-------------------------------------------------------------
In older versions, the :setting:`FILE_UPLOAD_PERMISSIONS` setting defaults to
``None``. With the default :setting:`FILE_UPLOAD_HANDLERS`, this results in
uploaded files having different permissions depending on their size and which
upload handler is used.
``FILE_UPLOAD_PERMISSION`` now defaults to ``0o644`` to avoid this
inconsistency.
Miscellaneous
-------------
* ``ContentType.__str__()`` now includes the model's ``app_label`` to
disambiguate model's with the same name in different apps.
* Because accessing the language in the session rather than in the cookie is
deprecated, ``LocaleMiddleware`` no longer looks for the user's language in
the session and :func:`django.contrib.auth.logout` no longer preserves the
session's language after logout.
* :func:`django.utils.html.escape` now uses :func:`html.escape` to escape HTML.
This converts ``'`` to ``&#x27;`` instead of the previous equivalent decimal
code ``&#39;``.
* The ``django-admin test -k`` option now works as the :option:`unittest
-k<unittest.-k>` option rather than as a shortcut for ``--keepdb``.
* Support for ``pywatchman`` < 1.2.0 is removed.
* HTML rendered by :class:`~django.forms.SelectDateWidget` for required fields
now have the ``placeholder`` attribute, which mainly may require some
adjustments in tests that compare HTML.
.. _deprecated-features-3.0:
Features deprecated in 3.0
==========================
``django.utils.encoding.force_text()`` and ``smart_text()``
-----------------------------------------------------------
The ``smart_text()`` and ``force_text()`` aliases (since Django 2.0) of
``smart_str()`` and ``force_str()`` are deprecated. Ignore this deprecation if
your code supports Python 2 as the behavior of ``smart_str()`` and
``force_str()`` is different there.
Miscellaneous
-------------
* ``django.utils.http.urlquote()``, ``urlquote_plus()``, ``urlunquote()``, and
``urlunquote_plus()`` are deprecated in favor of the functions that they're
aliases for: :func:`urllib.parse.quote`, :func:`~urllib.parse.quote_plus`,
:func:`~urllib.parse.unquote`, and :func:`~urllib.parse.unquote_plus`.
* ``django.utils.translation.ugettext()``, ``ugettext_lazy()``,
``ugettext_noop()``, ``ungettext()``, and ``ungettext_lazy()`` are deprecated
in favor of the functions that they're aliases for:
:func:`django.utils.translation.gettext`,
:func:`~django.utils.translation.gettext_lazy`,
:func:`~django.utils.translation.gettext_noop`,
:func:`~django.utils.translation.ngettext`, and
:func:`~django.utils.translation.ngettext_lazy`.
* To limit creation of sessions and hence favor some caching strategies,
:func:`django.views.i18n.set_language` will stop setting the user's language
in the session in Django 4.0. Since Django 2.1, the language is always stored
in the :setting:`LANGUAGE_COOKIE_NAME` cookie.
* ``alias=None`` is added to the signature of
:meth:`.Expression.get_group_by_cols`.
* ``django.utils.text.unescape_entities()`` is deprecated in favor of
:func:`html.unescape`. Note that unlike ``unescape_entities()``,
``html.unescape()`` evaluates lazy strings immediately.
.. _removed-features-3.0:
Features removed in 3.0
=======================
These features have reached the end of their deprecation cycle and are removed
in Django 3.0.
See :ref:`deprecated-features-2.0` for details on these changes, including how
to remove usage of these features.
* The ``django.db.backends.postgresql_psycopg2`` module is removed.
* ``django.shortcuts.render_to_response()`` is removed.
* The ``DEFAULT_CONTENT_TYPE`` setting is removed.
* ``HttpRequest.xreadlines()`` is removed.
* Support for the ``context`` argument of ``Field.from_db_value()`` and
``Expression.convert_value()`` is removed.
* The ``field_name`` keyword argument of ``QuerySet.earliest()`` and
``latest()`` is removed.
See :ref:`deprecated-features-2.1` for details on these changes, including how
to remove usage of these features.
* The ``ForceRHR`` GIS function is removed.
* ``django.utils.http.cookie_date()`` is removed.
* The ``staticfiles`` and ``admin_static`` template tag libraries are removed.
* ``django.contrib.staticfiles.templatetags.staticfiles.static()`` is removed.