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  1. ============================================
  2. Django 3.1 release notes - UNDER DEVELOPMENT
  3. ============================================
  4. *Expected August 2020*
  5. Welcome to Django 3.1!
  6. These release notes cover the :ref:`new features <whats-new-3.1>`, as well as
  7. some :ref:`backwards incompatible changes <backwards-incompatible-3.1>` you'll
  8. want to be aware of when upgrading from Django 3.0 or earlier. We've
  9. :ref:`dropped some features<removed-features-3.1>` that have reached the end of
  10. their deprecation cycle, and we've :ref:`begun the deprecation process for
  11. some features <deprecated-features-3.1>`.
  12. See the :doc:`/howto/upgrade-version` guide if you're updating an existing
  13. project.
  14. Python compatibility
  15. ====================
  16. Django 3.1 supports Python 3.6, 3.7, and 3.8. We **highly recommend** and only
  17. officially support the latest release of each series.
  18. .. _whats-new-3.1:
  19. What's new in Django 3.1
  20. ========================
  21. Asynchronous views and middleware support
  22. -----------------------------------------
  23. Django now supports a fully asynchronous request path, including:
  24. * :ref:`Asynchronous views <async-views>`
  25. * :ref:`Asynchronous middleware <async-middleware>`
  26. * :ref:`Asynchronous tests and test client <async-tests>`
  27. To get started with async views, you need to declare a view using
  28. ``async def``::
  29. async def my_view(request):
  30. await asyncio.sleep(0.5)
  31. return HttpResponse('Hello, async world!')
  32. All asynchronous features are supported whether you are running under WSGI or
  33. ASGI mode. However, there will be performance penalties using async code in
  34. WSGI mode. You can read more about the specifics in :doc:`/topics/async`
  35. documentation.
  36. You are free to mix async and sync views, middleware, and tests as much as you
  37. want. Django will ensure that you always end up with the right execution
  38. context. We expect most projects will keep the majority of their views
  39. synchronous, and only have a select few running in async mode - but it is
  40. entirely your choice.
  41. Django's ORM, cache layer, and other pieces of code that do long-running
  42. network calls do not yet support async access. We expect to add support for
  43. them in upcoming releases. Async views are ideal, however, if you are doing a
  44. lot of API or HTTP calls inside your view, you can now natively do all those
  45. HTTP calls in parallel to considerably speed up your view's execution.
  46. Asynchronous support should be entirely backwards-compatible and we have tried
  47. to ensure that it has no speed regressions for your existing, synchronous code.
  48. It should have no noticeable effect on any existing Django projects.
  49. Minor features
  50. --------------
  51. :mod:`django.contrib.admin`
  52. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  53. * The new ``django.contrib.admin.EmptyFieldListFilter`` for
  54. :attr:`.ModelAdmin.list_filter` allows filtering on empty values (empty
  55. strings and nulls) in the admin changelist view.
  56. * Filters in the right sidebar of the admin changelist view now contains a link
  57. to clear all filters.
  58. :mod:`django.contrib.admindocs`
  59. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  60. * ...
  61. :mod:`django.contrib.auth`
  62. ~~~~~~~~~~~~~~~~~~~~~~~~~~
  63. * The default iteration count for the PBKDF2 password hasher is increased from
  64. 180,000 to 216,000.
  65. * Added the :setting:`PASSWORD_RESET_TIMEOUT` setting to define the minimum
  66. number of seconds a password reset link is valid for. This is encouraged
  67. instead of deprecated ``PASSWORD_RESET_TIMEOUT_DAYS``, which will be removed
  68. in Django 4.0.
  69. * The password reset mechanism now uses the SHA-256 hashing algorithm. Support
  70. for tokens that use the old hashing algorithm remains until Django 4.0.
  71. :mod:`django.contrib.contenttypes`
  72. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  73. * The new :option:`remove_stale_contenttypes --include-stale-apps` option
  74. allows removing stale content types from previously installed apps that have
  75. been removed from :setting:`INSTALLED_APPS`.
  76. :mod:`django.contrib.gis`
  77. ~~~~~~~~~~~~~~~~~~~~~~~~~
  78. * :lookup:`relate` lookup is now supported on MariaDB.
  79. * Added the :attr:`.LinearRing.is_counterclockwise` property.
  80. * :class:`~django.contrib.gis.db.models.functions.AsGeoJSON` is now supported
  81. on Oracle.
  82. * Added the :class:`~django.contrib.gis.db.models.functions.AsWKB` and
  83. :class:`~django.contrib.gis.db.models.functions.AsWKT` functions.
  84. * Added support for PostGIS 3.
  85. :mod:`django.contrib.humanize`
  86. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  87. * :tfilter:`intword` template filter now supports negative integers.
  88. :mod:`django.contrib.messages`
  89. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  90. * ...
  91. :mod:`django.contrib.postgres`
  92. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  93. * The new :class:`~django.contrib.postgres.indexes.BloomIndex` class allows
  94. creating ``bloom`` indexes in the database. The new
  95. :class:`~django.contrib.postgres.operations.BloomExtension` migration
  96. operation installs the ``bloom`` extension to add support for this index.
  97. * :meth:`~django.db.models.Model.get_FOO_display` now supports
  98. :class:`~django.contrib.postgres.fields.ArrayField` and
  99. :class:`~django.contrib.postgres.fields.RangeField`.
  100. * The new :lookup:`rangefield.lower_inc`, :lookup:`rangefield.lower_inf`,
  101. :lookup:`rangefield.upper_inc`, and :lookup:`rangefield.upper_inf` allows
  102. querying :class:`~django.contrib.postgres.fields.RangeField` by a bound type.
  103. * :lookup:`rangefield.contained_by` now supports
  104. :class:`~django.db.models.SmallAutoField`,
  105. :class:`~django.db.models.AutoField`,
  106. :class:`~django.db.models.BigAutoField`,
  107. :class:`~django.db.models.SmallIntegerField`, and
  108. :class:`~django.db.models.DecimalField`.
  109. * :class:`~django.contrib.postgres.search.SearchQuery` now supports
  110. ``'websearch'`` search type on PostgreSQL 11+.
  111. * :class:`SearchQuery.value <django.contrib.postgres.search.SearchQuery>` now
  112. supports query expressions.
  113. * The new :class:`~django.contrib.postgres.search.SearchHeadline` class allows
  114. highlighting search results.
  115. * :lookup:`search` lookup now supports query expressions.
  116. * The new ``cover_density`` parameter of
  117. :class:`~django.contrib.postgres.search.SearchRank` allows ranking by cover
  118. density.
  119. * The new ``normalization`` parameter of
  120. :class:`~django.contrib.postgres.search.SearchRank` allows rank
  121. normalization.
  122. :mod:`django.contrib.redirects`
  123. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  124. * ...
  125. :mod:`django.contrib.sessions`
  126. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  127. * The :setting:`SESSION_COOKIE_SAMESITE` setting now allows ``'None'`` (string)
  128. value to explicitly state that the cookie is sent with all same-site and
  129. cross-site requests.
  130. :mod:`django.contrib.sitemaps`
  131. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  132. * ...
  133. :mod:`django.contrib.sites`
  134. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  135. * ...
  136. :mod:`django.contrib.staticfiles`
  137. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  138. * The :setting:`STATICFILES_DIRS` setting now supports :class:`pathlib.Path`.
  139. :mod:`django.contrib.syndication`
  140. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  141. * ...
  142. Cache
  143. ~~~~~
  144. * The :func:`~django.views.decorators.cache.cache_control` decorator and
  145. :func:`~django.utils.cache.patch_cache_control` method now support multiple
  146. field names in the ``no-cache`` directive for the ``Cache-Control`` header,
  147. according to :rfc:`7234#section-5.2.2.2`.
  148. * :meth:`~django.core.caches.cache.delete` now returns ``True`` if the key was
  149. successfully deleted, ``False`` otherwise.
  150. CSRF
  151. ~~~~
  152. * The :setting:`CSRF_COOKIE_SAMESITE` setting now allows ``'None'`` (string)
  153. value to explicitly state that the cookie is sent with all same-site and
  154. cross-site requests.
  155. Email
  156. ~~~~~
  157. * The :setting:`EMAIL_FILE_PATH` setting, used by the :ref:`file email backend
  158. <topic-email-file-backend>`, now supports :class:`pathlib.Path`.
  159. Error Reporting
  160. ~~~~~~~~~~~~~~~
  161. * :class:`django.views.debug.SafeExceptionReporterFilter` now filters sensitive
  162. values from ``request.META`` in exception reports.
  163. * The new :attr:`.SafeExceptionReporterFilter.cleansed_substitute` and
  164. :attr:`.SafeExceptionReporterFilter.hidden_settings` attributes allow
  165. customization of sensitive settings and ``request.META`` filtering in
  166. exception reports.
  167. * The technical 404 debug view now respects
  168. :setting:`DEFAULT_EXCEPTION_REPORTER_FILTER` when applying settings
  169. filtering.
  170. * The new :setting:`DEFAULT_EXCEPTION_REPORTER` allows providing a
  171. :class:`django.views.debug.ExceptionReporter` subclass to customize exception
  172. report generation. See :ref:`custom-error-reports` for details.
  173. File Storage
  174. ~~~~~~~~~~~~
  175. * ``FileSystemStorage.save()`` method now supports :class:`pathlib.Path`.
  176. * :class:`~django.db.models.FileField` and
  177. :class:`~django.db.models.ImageField` now accept a callable for ``storage``.
  178. This allows you to modify the used storage at runtime, selecting different
  179. storages for different environments, for example.
  180. File Uploads
  181. ~~~~~~~~~~~~
  182. * ...
  183. Forms
  184. ~~~~~
  185. * :class:`~django.forms.ModelChoiceIterator`, used by
  186. :class:`~django.forms.ModelChoiceField` and
  187. :class:`~django.forms.ModelMultipleChoiceField`, now uses
  188. :class:`~django.forms.ModelChoiceIteratorValue` that can be used by widgets
  189. to access model instances. See :ref:`iterating-relationship-choices` for
  190. details.
  191. * :class:`django.forms.DateTimeField` now accepts dates in a subset of ISO 8601
  192. datetime formats, including optional timezone (e.g. ``2019-10-10T06:47``,
  193. ``2019-10-10T06:47:23+04:00``, or ``2019-10-10T06:47:23Z``). Additionally, it
  194. now uses ``DATE_INPUT_FORMATS`` in addition to ``DATETIME_INPUT_FORMATS``
  195. when converting a field input to a ``datetime`` value.
  196. * :attr:`.MultiWidget.widgets` now accepts a dictionary which allows
  197. customizing subwidget ``name`` attributes.
  198. * The new :attr:`.BoundField.widget_type` property can be used to dynamically
  199. adjust form rendering based upon the widget type.
  200. Generic Views
  201. ~~~~~~~~~~~~~
  202. * ...
  203. Internationalization
  204. ~~~~~~~~~~~~~~~~~~~~
  205. * The :setting:`LANGUAGE_COOKIE_SAMESITE` setting now allows ``'None'``
  206. (string) value to explicitly state that the cookie is sent with all same-site
  207. and cross-site requests.
  208. * Added support and translations for the Algerian Arabic language.
  209. Logging
  210. ~~~~~~~
  211. * ...
  212. Management Commands
  213. ~~~~~~~~~~~~~~~~~~~
  214. * The new :option:`check --database` option allows specifying database aliases
  215. for running the ``database`` system checks. Previously these checks were
  216. enabled for all configured :setting:`DATABASES` by passing the ``database``
  217. tag to the command.
  218. * The new :option:`migrate --check` option makes the command exit with a
  219. non-zero status when unapplied migrations are detected.
  220. Migrations
  221. ~~~~~~~~~~
  222. * Migrations are now loaded also from directories without ``__init__.py``
  223. files.
  224. Models
  225. ~~~~~~
  226. * The new :class:`~django.db.models.functions.ExtractIsoWeekDay` function
  227. extracts ISO-8601 week days from :class:`~django.db.models.DateField` and
  228. :class:`~django.db.models.DateTimeField`, and the new :lookup:`iso_week_day`
  229. lookup allows querying by an ISO-8601 day of week.
  230. * :meth:`.QuerySet.explain` now supports:
  231. * ``TREE`` format on MySQL 8.0.16+,
  232. * ``analyze`` option on MySQL 8.0.18+ and MariaDB.
  233. * Added :class:`~django.db.models.PositiveBigIntegerField` which acts much like
  234. a :class:`~django.db.models.PositiveIntegerField` except that it only allows
  235. values under a certain (database-dependent) limit. Values from ``0`` to
  236. ``9223372036854775807`` are safe in all databases supported by Django.
  237. * The new :class:`~django.db.models.RESTRICT` option for
  238. :attr:`~django.db.models.ForeignKey.on_delete` argument of ``ForeignKey`` and
  239. ``OneToOneField`` emulates the behavior of the SQL constraint ``ON DELETE
  240. RESTRICT``.
  241. * :attr:`.CheckConstraint.check` now supports boolean expressions.
  242. * The :meth:`.RelatedManager.add`, :meth:`~.RelatedManager.create`, and
  243. :meth:`~.RelatedManager.set` methods now accept callables as values in the
  244. ``through_defaults`` argument.
  245. * The new ``is_dst`` parameter of the :meth:`.QuerySet.datetimes` determines
  246. the treatment of nonexistent and ambiguous datetimes.
  247. * The new :class:`~django.db.models.F` expression ``bitxor()`` method allows
  248. :ref:`bitwise XOR operation <using-f-expressions-in-filters>`.
  249. * :meth:`.QuerySet.bulk_create` now sets the primary key on objects when using
  250. MariaDB 10.5+.
  251. * The ``DatabaseOperations.sql_flush()`` method now generates more efficient
  252. SQL on MySQL by using ``DELETE`` instead of ``TRUNCATE`` statements for
  253. tables which don't require resetting sequences.
  254. * SQLite functions are now marked as :py:meth:`deterministic
  255. <sqlite3.Connection.create_function>` on Python 3.8+. This allows using them
  256. in check constraints and partial indexes.
  257. Pagination
  258. ~~~~~~~~~~
  259. * :class:`~django.core.paginator.Paginator` can now be iterated over to yield
  260. its pages.
  261. Requests and Responses
  262. ~~~~~~~~~~~~~~~~~~~~~~
  263. * If :setting:`ALLOWED_HOSTS` is empty and ``DEBUG=True``, subdomains of
  264. localhost are now allowed in the ``Host`` header, e.g. ``static.localhost``.
  265. * :meth:`.HttpResponse.set_cookie` and :meth:`.HttpResponse.set_signed_cookie`
  266. now allow using ``samesite='None'`` (string) to explicitly state that the
  267. cookie is sent with all same-site and cross-site requests.
  268. * The new :meth:`.HttpRequest.accepts` method returns whether the request
  269. accepts the given MIME type according to the ``Accept`` HTTP header.
  270. .. _whats-new-security-3.1:
  271. Security
  272. ~~~~~~~~
  273. * The :setting:`SECURE_REFERRER_POLICY` setting now defaults to
  274. ``'same-origin'``. With this configured,
  275. :class:`~django.middleware.security.SecurityMiddleware` sets the
  276. :ref:`referrer-policy` header to ``same-origin`` on all responses that do not
  277. already have it. This prevents the ``Referer`` header being sent to other
  278. origins. If you need the previous behavior, explicitly set
  279. :setting:`SECURE_REFERRER_POLICY` to ``None``.
  280. Serialization
  281. ~~~~~~~~~~~~~
  282. * ...
  283. Signals
  284. ~~~~~~~
  285. * ...
  286. Templates
  287. ~~~~~~~~~
  288. * The renamed :ttag:`translate` and :ttag:`blocktranslate` template tags are
  289. introduced for internationalization in template code. The older :ttag:`trans`
  290. and :ttag:`blocktrans` template tags aliases continue to work, and will be
  291. retained for the foreseeable future.
  292. * The :ttag:`include` template tag now accepts iterables of template names.
  293. Tests
  294. ~~~~~
  295. * :class:`~django.test.SimpleTestCase` now implements the ``debug()`` method to
  296. allow running a test without collecting the result and catching exceptions.
  297. This can be used to support running tests under a debugger.
  298. * The new :setting:`MIGRATE <TEST_MIGRATE>` test database setting allows
  299. disabling of migrations during a test database creation.
  300. * Django test runner now supports a :option:`test --buffer` option to discard
  301. output for passing tests.
  302. * :class:`~django.test.runner.DiscoverRunner` now skips running the system
  303. checks on databases not :ref:`referenced by tests<testing-multi-db>`.
  304. * :class:`~django.test.TransactionTestCase` teardown is now faster on MySQL
  305. due to :djadmin:`flush` command improvements. As a side effect the latter
  306. doesn't automatically reset sequences on teardown anymore. Enable
  307. :attr:`.TransactionTestCase.reset_sequences` if your tests require this
  308. feature.
  309. URLs
  310. ~~~~
  311. * :ref:`Path converters <registering-custom-path-converters>` can now raise
  312. ``ValueError`` in ``to_url()`` to indicate no match when reversing URLs.
  313. Utilities
  314. ~~~~~~~~~
  315. * :func:`~django.utils.encoding.filepath_to_uri` now supports
  316. :class:`pathlib.Path`.
  317. * :func:`~django.utils.dateparse.parse_duration` now supports comma separators
  318. for decimal fractions in the ISO 8601 format.
  319. * :func:`~django.utils.dateparse.parse_datetime`,
  320. :func:`~django.utils.dateparse.parse_duration`, and
  321. :func:`~django.utils.dateparse.parse_time` now support comma separators for
  322. milliseconds.
  323. Validators
  324. ~~~~~~~~~~
  325. * ...
  326. Miscellaneous
  327. ~~~~~~~~~~~~~
  328. * The SQLite backend now supports :class:`pathlib.Path` for the ``NAME``
  329. setting.
  330. * The ``settings.py`` generated by the :djadmin:`startproject` command now uses
  331. :class:`pathlib.Path` instead of :mod:`os.path` for building filesystem
  332. paths.
  333. * The :setting:`TIME_ZONE <DATABASE-TIME_ZONE>` setting is now allowed on
  334. databases that support time zones.
  335. .. _backwards-incompatible-3.1:
  336. Backwards incompatible changes in 3.1
  337. =====================================
  338. Database backend API
  339. --------------------
  340. This section describes changes that may be needed in third-party database
  341. backends.
  342. * ``DatabaseOperations.fetch_returned_insert_columns()`` now requires an
  343. additional ``returning_params`` argument.
  344. * ``connection.timezone`` property is now ``'UTC'`` by default, or the
  345. :setting:`TIME_ZONE <DATABASE-TIME_ZONE>` when :setting:`USE_TZ` is ``True``
  346. on databases that support time zones. Previously, it was ``None`` on
  347. databases that support time zones.
  348. * ``connection._nodb_connection`` property is changed to the
  349. ``connection._nodb_cursor()`` method and now returns a context manager that
  350. yields a cursor and automatically closes the cursor and connection upon
  351. exiting the ``with`` statement.
  352. Dropped support for MariaDB 10.1
  353. --------------------------------
  354. Upstream support for MariaDB 10.1 ends in October 2020. Django 3.1 supports
  355. MariaDB 10.2 and higher.
  356. ``contrib.admin`` browser support
  357. ---------------------------------
  358. The admin no longer supports the legacy Internet Explorer browser. See
  359. :ref:`the admin FAQ <admin-browser-support>` for details on supported browsers.
  360. :attr:`AbstractUser.first_name <django.contrib.auth.models.User.first_name>` ``max_length`` increased to 150
  361. ------------------------------------------------------------------------------------------------------------
  362. A migration for :attr:`django.contrib.auth.models.User.first_name` is included.
  363. If you have a custom user model inheriting from ``AbstractUser``, you'll need
  364. to generate and apply a database migration for your user model.
  365. If you want to preserve the 30 character limit for first names, use a custom
  366. form::
  367. from django import forms
  368. from django.contrib.auth.forms import UserChangeForm
  369. class MyUserChangeForm(UserChangeForm):
  370. first_name = forms.CharField(max_length=30, required=False)
  371. If you wish to keep this restriction in the admin when editing users, set
  372. ``UserAdmin.form`` to use this form::
  373. from django.contrib.auth.admin import UserAdmin
  374. from django.contrib.auth.models import User
  375. class MyUserAdmin(UserAdmin):
  376. form = MyUserChangeForm
  377. admin.site.unregister(User)
  378. admin.site.register(User, MyUserAdmin)
  379. Miscellaneous
  380. -------------
  381. * The cache keys used by :ttag:`cache` and generated by
  382. :func:`~django.core.cache.utils.make_template_fragment_key` are different
  383. from the keys generated by older versions of Django. After upgrading to
  384. Django 3.1, the first request to any previously cached template fragment will
  385. be a cache miss.
  386. * The logic behind the decision to return a redirection fallback or a 204 HTTP
  387. response from the :func:`~django.views.i18n.set_language` view is now based
  388. on the ``Accept`` HTTP header instead of the ``X-Requested-With`` HTTP header
  389. presence.
  390. * The compatibility imports of ``django.core.exceptions.EmptyResultSet`` in
  391. ``django.db.models.query``, ``django.db.models.sql``, and
  392. ``django.db.models.sql.datastructures`` are removed.
  393. * The compatibility import of ``django.core.exceptions.FieldDoesNotExist`` in
  394. ``django.db.models.fields`` is removed.
  395. * The compatibility imports of ``django.forms.utils.pretty_name()`` and
  396. ``django.forms.boundfield.BoundField`` in ``django.forms.forms`` are removed.
  397. * The compatibility imports of ``Context``, ``ContextPopException``, and
  398. ``RequestContext`` in ``django.template.base`` are removed.
  399. * The compatibility import of
  400. ``django.contrib.admin.helpers.ACTION_CHECKBOX_NAME`` in
  401. ``django.contrib.admin`` is removed.
  402. * The :setting:`STATIC_URL` and :setting:`MEDIA_URL` settings set to relative
  403. paths are now prefixed by the server-provided value of ``SCRIPT_NAME`` (or
  404. ``/`` if not set). This change should not affect settings set to valid URLs
  405. or absolute paths.
  406. * :class:`~django.middleware.http.ConditionalGetMiddleware` no longer adds the
  407. ``ETag`` header to responses with an empty
  408. :attr:`~django.http.HttpResponse.content`.
  409. * ``django.utils.decorators.classproperty()`` decorator is made public and
  410. moved to :class:`django.utils.functional.classproperty()`.
  411. * :tfilter:`floatformat` template filter now outputs (positive) ``0`` for
  412. negative numbers which round to zero.
  413. * :attr:`Meta.ordering <django.db.models.Options.ordering>` and
  414. :attr:`Meta.unique_together <django.db.models.Options.unique_together>`
  415. options on models in ``django.contrib`` modules that were formerly tuples are
  416. now lists.
  417. * The admin calendar widget now handles two-digit years according to the Open
  418. Group Specification, i.e. values between 69 and 99 are mapped to the previous
  419. century, and values between 0 and 68 are mapped to the current century.
  420. * Date-only formats are removed from the default list for
  421. :setting:`DATETIME_INPUT_FORMATS`.
  422. * The :class:`~django.forms.FileInput` widget no longer renders with the
  423. ``required`` HTML attribute when initial data exists.
  424. * The undocumented ``django.views.debug.ExceptionReporterFilter`` class is
  425. removed. As per the :ref:`custom-error-reports` documentation, classes to be
  426. used with :setting:`DEFAULT_EXCEPTION_REPORTER_FILTER` needs to inherit from
  427. :class:`django.views.debug.SafeExceptionReporterFilter`.
  428. * The cache timeout set by :func:`~django.views.decorators.cache.cache_page`
  429. decorator now takes precedence over the ``max-age`` directive from the
  430. ``Cache-Control`` header.
  431. * Providing a non-local remote field in the :attr:`.ForeignKey.to_field`
  432. argument now raises :class:`~django.core.exceptions.FieldError`.
  433. * :setting:`SECURE_REFERRER_POLICY` now defaults to ``'same-origin'``. See the
  434. *What's New* :ref:`Security section <whats-new-security-3.1>` above for more
  435. details.
  436. * :djadmin:`check` management command now runs the ``database`` system checks
  437. only for database aliases specified using :option:`check --database` option.
  438. * :djadmin:`migrate` management command now runs the ``database`` system checks
  439. only for a database to migrate.
  440. * The admin CSS classes ``row1`` and ``row2`` are removed in favor of
  441. ``:nth-child(odd)`` and ``:nth-child(even)`` pseudo-classes.
  442. * The :func:`~django.contrib.auth.hashers.make_password` now requires its
  443. argument to be a string or bytes. Other types should be explicitly cast to
  444. one of these.
  445. * The undocumented ``version`` parameter to the
  446. :class:`~django.contrib.gis.db.models.functions.AsKML` function is removed.
  447. .. _deprecated-features-3.1:
  448. Features deprecated in 3.1
  449. ==========================
  450. Miscellaneous
  451. -------------
  452. * ``PASSWORD_RESET_TIMEOUT_DAYS`` setting is deprecated in favor of
  453. :setting:`PASSWORD_RESET_TIMEOUT`.
  454. * The undocumented usage of the :lookup:`isnull` lookup with non-boolean values
  455. as the right-hand side is deprecated, use ``True`` or ``False`` instead.
  456. * The barely documented ``django.db.models.query_utils.InvalidQuery`` exception
  457. class is deprecated in favor of
  458. :class:`~django.core.exceptions.FieldDoesNotExist` and
  459. :class:`~django.core.exceptions.FieldError`.
  460. * The ``django-admin.py`` entry point is deprecated in favor of
  461. ``django-admin``.
  462. * The ``HttpRequest.is_ajax()`` method is deprecated as it relied on a
  463. jQuery-specific way of signifying AJAX calls, while current usage tends to
  464. use the JavaScript `Fetch API
  465. <https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API>`_. Depending on
  466. your use case, you can either write your own AJAX detection method, or use
  467. the new :meth:`.HttpRequest.accepts` method if your code depends on the
  468. client ``Accept`` HTTP header.
  469. If you are writing your own AJAX detection method, ``request.is_ajax()`` can
  470. be reproduced exactly as
  471. ``request.headers.get('x-requested-with') == 'XMLHttpRequest'``.
  472. * Passing ``None`` as the first argument to
  473. ``django.utils.deprecation.MiddlewareMixin.__init__()`` is deprecated.
  474. * The encoding format of cookies values used by
  475. :class:`~django.contrib.messages.storage.cookie.CookieStorage` is different
  476. from the format generated by older versions of Django. Support for the old
  477. format remains until Django 4.0.
  478. * The encoding format of sessions is different from the format generated by
  479. older versions of Django. Support for the old format remains until Django
  480. 4.0.
  481. * The purely documentational ``providing_args`` argument for
  482. :class:`~django.dispatch.Signal` is deprecated. If you rely on this
  483. argument as documentation, you can move the text to a code comment or
  484. docstring.
  485. * Calling ``django.utils.crypto.get_random_string()`` without a ``length``
  486. argument is deprecated.
  487. * The ``list`` message for :class:`~django.forms.ModelMultipleChoiceField` is
  488. deprecated in favor of ``invalid_list``.
  489. * The passing of URL kwargs directly to the context by
  490. :class:`~django.views.generic.base.TemplateView` is deprecated. Reference
  491. them in the template with ``view.kwargs`` instead.
  492. * Passing raw column aliases to :meth:`.QuerySet.order_by` is deprecated. The
  493. same result can be achieved by passing aliases in a
  494. :class:`~django.db.models.expressions.RawSQL` instead beforehand.
  495. .. _removed-features-3.1:
  496. Features removed in 3.1
  497. =======================
  498. These features have reached the end of their deprecation cycle and are removed
  499. in Django 3.1.
  500. See :ref:`deprecated-features-2.2` for details on these changes, including how
  501. to remove usage of these features.
  502. * ``django.utils.timezone.FixedOffset`` is removed.
  503. * ``django.core.paginator.QuerySetPaginator`` is removed.
  504. * A model's ``Meta.ordering`` doesn't affect ``GROUP BY`` queries.
  505. * ``django.contrib.postgres.fields.FloatRangeField`` and
  506. ``django.contrib.postgres.forms.FloatRangeField`` are removed.
  507. * The ``FILE_CHARSET`` setting is removed.
  508. * ``django.contrib.staticfiles.storage.CachedStaticFilesStorage`` is removed.
  509. * The ``RemoteUserBackend.configure_user()`` method requires ``request`` as the
  510. first positional argument.
  511. * Support for ``SimpleTestCase.allow_database_queries`` and
  512. ``TransactionTestCase.multi_db`` is removed.