============================================ Django 3.1 release notes - UNDER DEVELOPMENT ============================================ *Expected August 2020* Welcome to Django 3.1! These release notes cover the :ref:`new features `, as well as some :ref:`backwards incompatible changes ` you'll want to be aware of when upgrading from Django 3.0 or earlier. We've :ref:`dropped some features` that have reached the end of their deprecation cycle, and we've :ref:`begun the deprecation process for some features `. See the :doc:`/howto/upgrade-version` guide if you're updating an existing project. Python compatibility ==================== Django 3.1 supports Python 3.6, 3.7, and 3.8. We **highly recommend** and only officially support the latest release of each series. .. _whats-new-3.1: What's new in Django 3.1 ======================== Asynchronous views and middleware support ----------------------------------------- Django now supports a fully asynchronous request path, including: * :ref:`Asynchronous views ` * :ref:`Asynchronous middleware ` * :ref:`Asynchronous tests and test client ` To get started with async views, you need to declare a view using ``async def``:: async def my_view(request): await asyncio.sleep(0.5) return HttpResponse('Hello, async world!') All asynchronous features are supported whether you are running under WSGI or ASGI mode. However, there will be performance penalties using async code in WSGI mode. You can read more about the specifics in :doc:`/topics/async` documentation. You are free to mix async and sync views, middleware, and tests as much as you want. Django will ensure that you always end up with the right execution context. We expect most projects will keep the majority of their views synchronous, and only have a select few running in async mode - but it is entirely your choice. Django's ORM, cache layer, and other pieces of code that do long-running network calls do not yet support async access. We expect to add support for them in upcoming releases. Async views are ideal, however, if you are doing a lot of API or HTTP calls inside your view, you can now natively do all those HTTP calls in parallel to considerably speed up your view's execution. Asynchronous support should be entirely backwards-compatible and we have tried to ensure that it has no speed regressions for your existing, synchronous code. It should have no noticeable effect on any existing Django projects. Minor features -------------- :mod:`django.contrib.admin` ~~~~~~~~~~~~~~~~~~~~~~~~~~~ * The new ``django.contrib.admin.EmptyFieldListFilter`` for :attr:`.ModelAdmin.list_filter` allows filtering on empty values (empty strings and nulls) in the admin changelist view. * Filters in the right sidebar of the admin changelist view now contains a link to clear all filters. :mod:`django.contrib.admindocs` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * ... :mod:`django.contrib.auth` ~~~~~~~~~~~~~~~~~~~~~~~~~~ * The default iteration count for the PBKDF2 password hasher is increased from 180,000 to 216,000. * Added the :setting:`PASSWORD_RESET_TIMEOUT` setting to define the minimum number of seconds a password reset link is valid for. This is encouraged instead of deprecated ``PASSWORD_RESET_TIMEOUT_DAYS``, which will be removed in Django 4.0. * The password reset mechanism now uses the SHA-256 hashing algorithm. Support for tokens that use the old hashing algorithm remains until Django 4.0. :mod:`django.contrib.contenttypes` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * The new :option:`remove_stale_contenttypes --include-stale-apps` option allows removing stale content types from previously installed apps that have been removed from :setting:`INSTALLED_APPS`. :mod:`django.contrib.gis` ~~~~~~~~~~~~~~~~~~~~~~~~~ * :lookup:`relate` lookup is now supported on MariaDB. * Added the :attr:`.LinearRing.is_counterclockwise` property. * :class:`~django.contrib.gis.db.models.functions.AsGeoJSON` is now supported on Oracle. * Added the :class:`~django.contrib.gis.db.models.functions.AsWKB` and :class:`~django.contrib.gis.db.models.functions.AsWKT` functions. * Added support for PostGIS 3. :mod:`django.contrib.humanize` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * :tfilter:`intword` template filter now supports negative integers. :mod:`django.contrib.messages` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * ... :mod:`django.contrib.postgres` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * The new :class:`~django.contrib.postgres.indexes.BloomIndex` class allows creating ``bloom`` indexes in the database. The new :class:`~django.contrib.postgres.operations.BloomExtension` migration operation installs the ``bloom`` extension to add support for this index. * :meth:`~django.db.models.Model.get_FOO_display` now supports :class:`~django.contrib.postgres.fields.ArrayField` and :class:`~django.contrib.postgres.fields.RangeField`. * The new :lookup:`rangefield.lower_inc`, :lookup:`rangefield.lower_inf`, :lookup:`rangefield.upper_inc`, and :lookup:`rangefield.upper_inf` allows querying :class:`~django.contrib.postgres.fields.RangeField` by a bound type. * :lookup:`rangefield.contained_by` now supports :class:`~django.db.models.SmallAutoField`, :class:`~django.db.models.AutoField`, :class:`~django.db.models.BigAutoField`, :class:`~django.db.models.SmallIntegerField`, and :class:`~django.db.models.DecimalField`. * :class:`~django.contrib.postgres.search.SearchQuery` now supports ``'websearch'`` search type on PostgreSQL 11+. * :class:`SearchQuery.value ` now supports query expressions. * The new :class:`~django.contrib.postgres.search.SearchHeadline` class allows highlighting search results. * :lookup:`search` lookup now supports query expressions. * The new ``cover_density`` parameter of :class:`~django.contrib.postgres.search.SearchRank` allows ranking by cover density. * The new ``normalization`` parameter of :class:`~django.contrib.postgres.search.SearchRank` allows rank normalization. :mod:`django.contrib.redirects` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * ... :mod:`django.contrib.sessions` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * The :setting:`SESSION_COOKIE_SAMESITE` setting now allows ``'None'`` (string) value to explicitly state that the cookie is sent with all same-site and cross-site requests. :mod:`django.contrib.sitemaps` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * ... :mod:`django.contrib.sites` ~~~~~~~~~~~~~~~~~~~~~~~~~~~ * ... :mod:`django.contrib.staticfiles` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * The :setting:`STATICFILES_DIRS` setting now supports :class:`pathlib.Path`. :mod:`django.contrib.syndication` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * ... Cache ~~~~~ * The :func:`~django.views.decorators.cache.cache_control` decorator and :func:`~django.utils.cache.patch_cache_control` method now support multiple field names in the ``no-cache`` directive for the ``Cache-Control`` header, according to :rfc:`7234#section-5.2.2.2`. * :meth:`~django.core.caches.cache.delete` now returns ``True`` if the key was successfully deleted, ``False`` otherwise. CSRF ~~~~ * The :setting:`CSRF_COOKIE_SAMESITE` setting now allows ``'None'`` (string) value to explicitly state that the cookie is sent with all same-site and cross-site requests. Email ~~~~~ * The :setting:`EMAIL_FILE_PATH` setting, used by the :ref:`file email backend `, now supports :class:`pathlib.Path`. Error Reporting ~~~~~~~~~~~~~~~ * :class:`django.views.debug.SafeExceptionReporterFilter` now filters sensitive values from ``request.META`` in exception reports. * The new :attr:`.SafeExceptionReporterFilter.cleansed_substitute` and :attr:`.SafeExceptionReporterFilter.hidden_settings` attributes allow customization of sensitive settings and ``request.META`` filtering in exception reports. * The technical 404 debug view now respects :setting:`DEFAULT_EXCEPTION_REPORTER_FILTER` when applying settings filtering. * The new :setting:`DEFAULT_EXCEPTION_REPORTER` allows providing a :class:`django.views.debug.ExceptionReporter` subclass to customize exception report generation. See :ref:`custom-error-reports` for details. File Storage ~~~~~~~~~~~~ * ``FileSystemStorage.save()`` method now supports :class:`pathlib.Path`. * :class:`~django.db.models.FileField` and :class:`~django.db.models.ImageField` now accept a callable for ``storage``. This allows you to modify the used storage at runtime, selecting different storages for different environments, for example. File Uploads ~~~~~~~~~~~~ * ... Forms ~~~~~ * :class:`~django.forms.ModelChoiceIterator`, used by :class:`~django.forms.ModelChoiceField` and :class:`~django.forms.ModelMultipleChoiceField`, now uses :class:`~django.forms.ModelChoiceIteratorValue` that can be used by widgets to access model instances. See :ref:`iterating-relationship-choices` for details. * :class:`django.forms.DateTimeField` now accepts dates in a subset of ISO 8601 datetime formats, including optional timezone (e.g. ``2019-10-10T06:47``, ``2019-10-10T06:47:23+04:00``, or ``2019-10-10T06:47:23Z``). Additionally, it now uses ``DATE_INPUT_FORMATS`` in addition to ``DATETIME_INPUT_FORMATS`` when converting a field input to a ``datetime`` value. * :attr:`.MultiWidget.widgets` now accepts a dictionary which allows customizing subwidget ``name`` attributes. * The new :attr:`.BoundField.widget_type` property can be used to dynamically adjust form rendering based upon the widget type. Generic Views ~~~~~~~~~~~~~ * ... Internationalization ~~~~~~~~~~~~~~~~~~~~ * The :setting:`LANGUAGE_COOKIE_SAMESITE` setting now allows ``'None'`` (string) value to explicitly state that the cookie is sent with all same-site and cross-site requests. * Added support and translations for the Algerian Arabic language. Logging ~~~~~~~ * ... Management Commands ~~~~~~~~~~~~~~~~~~~ * The new :option:`check --database` option allows specifying database aliases for running the ``database`` system checks. Previously these checks were enabled for all configured :setting:`DATABASES` by passing the ``database`` tag to the command. * The new :option:`migrate --check` option makes the command exit with a non-zero status when unapplied migrations are detected. * The new ``returncode`` argument for :attr:`~django.core.management.CommandError` allows customizing the exit status for management commands. * The new :option:`dbshell -- ARGUMENTS ` option allows passing extra arguments to the command-line client for the database. Migrations ~~~~~~~~~~ * Migrations are now loaded also from directories without ``__init__.py`` files. Models ~~~~~~ * The new :class:`~django.db.models.functions.ExtractIsoWeekDay` function extracts ISO-8601 week days from :class:`~django.db.models.DateField` and :class:`~django.db.models.DateTimeField`, and the new :lookup:`iso_week_day` lookup allows querying by an ISO-8601 day of week. * :meth:`.QuerySet.explain` now supports: * ``TREE`` format on MySQL 8.0.16+, * ``analyze`` option on MySQL 8.0.18+ and MariaDB. * Added :class:`~django.db.models.PositiveBigIntegerField` which acts much like a :class:`~django.db.models.PositiveIntegerField` except that it only allows values under a certain (database-dependent) limit. Values from ``0`` to ``9223372036854775807`` are safe in all databases supported by Django. * The new :class:`~django.db.models.RESTRICT` option for :attr:`~django.db.models.ForeignKey.on_delete` argument of ``ForeignKey`` and ``OneToOneField`` emulates the behavior of the SQL constraint ``ON DELETE RESTRICT``. * :attr:`.CheckConstraint.check` now supports boolean expressions. * The :meth:`.RelatedManager.add`, :meth:`~.RelatedManager.create`, and :meth:`~.RelatedManager.set` methods now accept callables as values in the ``through_defaults`` argument. * The new ``is_dst`` parameter of the :meth:`.QuerySet.datetimes` determines the treatment of nonexistent and ambiguous datetimes. * The new :class:`~django.db.models.F` expression ``bitxor()`` method allows :ref:`bitwise XOR operation `. * :meth:`.QuerySet.bulk_create` now sets the primary key on objects when using MariaDB 10.5+. * The ``DatabaseOperations.sql_flush()`` method now generates more efficient SQL on MySQL by using ``DELETE`` instead of ``TRUNCATE`` statements for tables which don't require resetting sequences. * SQLite functions are now marked as :py:meth:`deterministic ` on Python 3.8+. This allows using them in check constraints and partial indexes. Pagination ~~~~~~~~~~ * :class:`~django.core.paginator.Paginator` can now be iterated over to yield its pages. Requests and Responses ~~~~~~~~~~~~~~~~~~~~~~ * If :setting:`ALLOWED_HOSTS` is empty and ``DEBUG=True``, subdomains of localhost are now allowed in the ``Host`` header, e.g. ``static.localhost``. * :meth:`.HttpResponse.set_cookie` and :meth:`.HttpResponse.set_signed_cookie` now allow using ``samesite='None'`` (string) to explicitly state that the cookie is sent with all same-site and cross-site requests. * The new :meth:`.HttpRequest.accepts` method returns whether the request accepts the given MIME type according to the ``Accept`` HTTP header. .. _whats-new-security-3.1: Security ~~~~~~~~ * The :setting:`SECURE_REFERRER_POLICY` setting now defaults to ``'same-origin'``. With this configured, :class:`~django.middleware.security.SecurityMiddleware` sets the :ref:`referrer-policy` header to ``same-origin`` on all responses that do not already have it. This prevents the ``Referer`` header being sent to other origins. If you need the previous behavior, explicitly set :setting:`SECURE_REFERRER_POLICY` to ``None``. * The default :class:`django.core.signing.Signer` algorithm is changed to the SHA-256. Support for signatures made with the old SHA-1 algorithm remains until Django 4.0. Also, the new ``algorithm`` parameter of the :class:`~django.core.signing.Signer` allows customizing the hashing algorithm. Serialization ~~~~~~~~~~~~~ * ... Signals ~~~~~~~ * ... Templates ~~~~~~~~~ * The renamed :ttag:`translate` and :ttag:`blocktranslate` template tags are introduced for internationalization in template code. The older :ttag:`trans` and :ttag:`blocktrans` template tags aliases continue to work, and will be retained for the foreseeable future. * The :ttag:`include` template tag now accepts iterables of template names. Tests ~~~~~ * :class:`~django.test.SimpleTestCase` now implements the ``debug()`` method to allow running a test without collecting the result and catching exceptions. This can be used to support running tests under a debugger. * The new :setting:`MIGRATE ` test database setting allows disabling of migrations during a test database creation. * Django test runner now supports a :option:`test --buffer` option to discard output for passing tests. * :class:`~django.test.runner.DiscoverRunner` now skips running the system checks on databases not :ref:`referenced by tests`. * :class:`~django.test.TransactionTestCase` teardown is now faster on MySQL due to :djadmin:`flush` command improvements. As a side effect the latter doesn't automatically reset sequences on teardown anymore. Enable :attr:`.TransactionTestCase.reset_sequences` if your tests require this feature. URLs ~~~~ * :ref:`Path converters ` can now raise ``ValueError`` in ``to_url()`` to indicate no match when reversing URLs. Utilities ~~~~~~~~~ * :func:`~django.utils.encoding.filepath_to_uri` now supports :class:`pathlib.Path`. * :func:`~django.utils.dateparse.parse_duration` now supports comma separators for decimal fractions in the ISO 8601 format. * :func:`~django.utils.dateparse.parse_datetime`, :func:`~django.utils.dateparse.parse_duration`, and :func:`~django.utils.dateparse.parse_time` now support comma separators for milliseconds. Validators ~~~~~~~~~~ * ... Miscellaneous ~~~~~~~~~~~~~ * The SQLite backend now supports :class:`pathlib.Path` for the ``NAME`` setting. * The ``settings.py`` generated by the :djadmin:`startproject` command now uses :class:`pathlib.Path` instead of :mod:`os.path` for building filesystem paths. * The :setting:`TIME_ZONE ` setting is now allowed on databases that support time zones. .. _backwards-incompatible-3.1: Backwards incompatible changes in 3.1 ===================================== Database backend API -------------------- This section describes changes that may be needed in third-party database backends. * ``DatabaseOperations.fetch_returned_insert_columns()`` now requires an additional ``returning_params`` argument. * ``connection.timezone`` property is now ``'UTC'`` by default, or the :setting:`TIME_ZONE ` when :setting:`USE_TZ` is ``True`` on databases that support time zones. Previously, it was ``None`` on databases that support time zones. * ``connection._nodb_connection`` property is changed to the ``connection._nodb_cursor()`` method and now returns a context manager that yields a cursor and automatically closes the cursor and connection upon exiting the ``with`` statement. * ``DatabaseClient.runshell()`` now requires an additional ``parameters`` argument as a list of extra arguments to pass on to the command-line client. Dropped support for MariaDB 10.1 -------------------------------- Upstream support for MariaDB 10.1 ends in October 2020. Django 3.1 supports MariaDB 10.2 and higher. ``contrib.admin`` browser support --------------------------------- The admin no longer supports the legacy Internet Explorer browser. See :ref:`the admin FAQ ` for details on supported browsers. :attr:`AbstractUser.first_name ` ``max_length`` increased to 150 ------------------------------------------------------------------------------------------------------------ A migration for :attr:`django.contrib.auth.models.User.first_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 first names, use a custom form:: from django import forms from django.contrib.auth.forms import UserChangeForm class MyUserChangeForm(UserChangeForm): first_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 cache keys used by :ttag:`cache` and generated by :func:`~django.core.cache.utils.make_template_fragment_key` are different from the keys generated by older versions of Django. After upgrading to Django 3.1, the first request to any previously cached template fragment will be a cache miss. * The logic behind the decision to return a redirection fallback or a 204 HTTP response from the :func:`~django.views.i18n.set_language` view is now based on the ``Accept`` HTTP header instead of the ``X-Requested-With`` HTTP header presence. * The compatibility imports of ``django.core.exceptions.EmptyResultSet`` in ``django.db.models.query``, ``django.db.models.sql``, and ``django.db.models.sql.datastructures`` are removed. * The compatibility import of ``django.core.exceptions.FieldDoesNotExist`` in ``django.db.models.fields`` is removed. * The compatibility imports of ``django.forms.utils.pretty_name()`` and ``django.forms.boundfield.BoundField`` in ``django.forms.forms`` are removed. * The compatibility imports of ``Context``, ``ContextPopException``, and ``RequestContext`` in ``django.template.base`` are removed. * The compatibility import of ``django.contrib.admin.helpers.ACTION_CHECKBOX_NAME`` in ``django.contrib.admin`` is removed. * The :setting:`STATIC_URL` and :setting:`MEDIA_URL` settings set to relative paths are now prefixed by the server-provided value of ``SCRIPT_NAME`` (or ``/`` if not set). This change should not affect settings set to valid URLs or absolute paths. * :class:`~django.middleware.http.ConditionalGetMiddleware` no longer adds the ``ETag`` header to responses with an empty :attr:`~django.http.HttpResponse.content`. * ``django.utils.decorators.classproperty()`` decorator is made public and moved to :class:`django.utils.functional.classproperty()`. * :tfilter:`floatformat` template filter now outputs (positive) ``0`` for negative numbers which round to zero. * :attr:`Meta.ordering ` and :attr:`Meta.unique_together ` options on models in ``django.contrib`` modules that were formerly tuples are now lists. * The admin calendar widget now handles two-digit years according to the Open Group Specification, i.e. values between 69 and 99 are mapped to the previous century, and values between 0 and 68 are mapped to the current century. * Date-only formats are removed from the default list for :setting:`DATETIME_INPUT_FORMATS`. * The :class:`~django.forms.FileInput` widget no longer renders with the ``required`` HTML attribute when initial data exists. * The undocumented ``django.views.debug.ExceptionReporterFilter`` class is removed. As per the :ref:`custom-error-reports` documentation, classes to be used with :setting:`DEFAULT_EXCEPTION_REPORTER_FILTER` needs to inherit from :class:`django.views.debug.SafeExceptionReporterFilter`. * The cache timeout set by :func:`~django.views.decorators.cache.cache_page` decorator now takes precedence over the ``max-age`` directive from the ``Cache-Control`` header. * Providing a non-local remote field in the :attr:`.ForeignKey.to_field` argument now raises :class:`~django.core.exceptions.FieldError`. * :setting:`SECURE_REFERRER_POLICY` now defaults to ``'same-origin'``. See the *What's New* :ref:`Security section ` above for more details. * :djadmin:`check` management command now runs the ``database`` system checks only for database aliases specified using :option:`check --database` option. * :djadmin:`migrate` management command now runs the ``database`` system checks only for a database to migrate. * The admin CSS classes ``row1`` and ``row2`` are removed in favor of ``:nth-child(odd)`` and ``:nth-child(even)`` pseudo-classes. * The :func:`~django.contrib.auth.hashers.make_password` now requires its argument to be a string or bytes. Other types should be explicitly cast to one of these. * The undocumented ``version`` parameter to the :class:`~django.contrib.gis.db.models.functions.AsKML` function is removed. .. _deprecated-features-3.1: Features deprecated in 3.1 ========================== Miscellaneous ------------- * ``PASSWORD_RESET_TIMEOUT_DAYS`` setting is deprecated in favor of :setting:`PASSWORD_RESET_TIMEOUT`. * The undocumented usage of the :lookup:`isnull` lookup with non-boolean values as the right-hand side is deprecated, use ``True`` or ``False`` instead. * The barely documented ``django.db.models.query_utils.InvalidQuery`` exception class is deprecated in favor of :class:`~django.core.exceptions.FieldDoesNotExist` and :class:`~django.core.exceptions.FieldError`. * The ``django-admin.py`` entry point is deprecated in favor of ``django-admin``. * The ``HttpRequest.is_ajax()`` method is deprecated as it relied on a jQuery-specific way of signifying AJAX calls, while current usage tends to use the JavaScript `Fetch API `_. Depending on your use case, you can either write your own AJAX detection method, or use the new :meth:`.HttpRequest.accepts` method if your code depends on the client ``Accept`` HTTP header. If you are writing your own AJAX detection method, ``request.is_ajax()`` can be reproduced exactly as ``request.headers.get('x-requested-with') == 'XMLHttpRequest'``. * Passing ``None`` as the first argument to ``django.utils.deprecation.MiddlewareMixin.__init__()`` is deprecated. * The encoding format of cookies values used by :class:`~django.contrib.messages.storage.cookie.CookieStorage` is different from the format generated by older versions of Django. Support for the old format remains until Django 4.0. * The encoding format of sessions is different from the format generated by older versions of Django. Support for the old format remains until Django 4.0. * The purely documentational ``providing_args`` argument for :class:`~django.dispatch.Signal` is deprecated. If you rely on this argument as documentation, you can move the text to a code comment or docstring. * Calling ``django.utils.crypto.get_random_string()`` without a ``length`` argument is deprecated. * The ``list`` message for :class:`~django.forms.ModelMultipleChoiceField` is deprecated in favor of ``invalid_list``. * The passing of URL kwargs directly to the context by :class:`~django.views.generic.base.TemplateView` is deprecated. Reference them in the template with ``view.kwargs`` instead. * Passing raw column aliases to :meth:`.QuerySet.order_by` is deprecated. The same result can be achieved by passing aliases in a :class:`~django.db.models.expressions.RawSQL` instead beforehand. .. _removed-features-3.1: Features removed in 3.1 ======================= These features have reached the end of their deprecation cycle and are removed in Django 3.1. See :ref:`deprecated-features-2.2` for details on these changes, including how to remove usage of these features. * ``django.utils.timezone.FixedOffset`` is removed. * ``django.core.paginator.QuerySetPaginator`` is removed. * A model's ``Meta.ordering`` doesn't affect ``GROUP BY`` queries. * ``django.contrib.postgres.fields.FloatRangeField`` and ``django.contrib.postgres.forms.FloatRangeField`` are removed. * The ``FILE_CHARSET`` setting is removed. * ``django.contrib.staticfiles.storage.CachedStaticFilesStorage`` is removed. * The ``RemoteUserBackend.configure_user()`` method requires ``request`` as the first positional argument. * Support for ``SimpleTestCase.allow_database_queries`` and ``TransactionTestCase.multi_db`` is removed.