2.0.txt 29 KB

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  1. ============================================
  2. Django 2.0 release notes - UNDER DEVELOPMENT
  3. ============================================
  4. Welcome to Django 2.0!
  5. These release notes cover the :ref:`new features <whats-new-2.0>`, as well as
  6. some :ref:`backwards incompatible changes <backwards-incompatible-2.0>` you'll
  7. want to be aware of when upgrading from Django 1.11 or earlier. We've
  8. :ref:`dropped some features<removed-features-2.0>` that have reached the end of
  9. their deprecation cycle, and we've :ref:`begun the deprecation process for some
  10. features <deprecated-features-2.0>`.
  11. This release starts Django's use of a :ref:`loose form of semantic versioning
  12. <internal-release-cadence>`, however, there aren't any major backwards
  13. incompatible changes that might be expected of a 2.0 release. Upgrading should
  14. be a similar amount of effort as past feature releases.
  15. See the :doc:`/howto/upgrade-version` guide if you're updating an existing
  16. project.
  17. Python compatibility
  18. ====================
  19. Django 2.0 supports Python 3.4, 3.5, and 3.6. We **highly recommend** and only
  20. officially support the latest release of each series.
  21. The Django 1.11.x series is the last to support Python 2.7.
  22. Django 2.0 will be the last release series to support Python 3.4. If you plan
  23. a deployment of Python 3.4 beyond the end-of-life for Django 2.0 (April 2019),
  24. stick with Django 1.11 LTS (supported until April 2020) instead. Note, however,
  25. that the end-of-life for Python 3.4 is March 2019.
  26. Third-party library support for older version of Django
  27. =======================================================
  28. Following the release of Django 2.0, we suggest that third-party app authors
  29. drop support for all versions of Django prior to 1.11. At that time, you should
  30. be able to run your package's tests using ``python -Wd`` so that deprecation
  31. warnings do appear. After making the deprecation warning fixes, your app should
  32. be compatible with Django 2.0.
  33. .. _whats-new-2.0:
  34. What's new in Django 2.0
  35. ========================
  36. Minor features
  37. --------------
  38. :mod:`django.contrib.admin`
  39. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  40. * ...
  41. :mod:`django.contrib.admindocs`
  42. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  43. * ...
  44. :mod:`django.contrib.auth`
  45. ~~~~~~~~~~~~~~~~~~~~~~~~~~
  46. * The default iteration count for the PBKDF2 password hasher is increased from
  47. 36,000 to 100,000.
  48. :mod:`django.contrib.contenttypes`
  49. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  50. * ...
  51. :mod:`django.contrib.gis`
  52. ~~~~~~~~~~~~~~~~~~~~~~~~~
  53. * Added MySQL support for the
  54. :class:`~django.contrib.gis.db.models.functions.AsGeoJSON` function,
  55. :class:`~django.contrib.gis.db.models.functions.GeoHash` function,
  56. :class:`~django.contrib.gis.db.models.functions.IsValid` function,
  57. :lookup:`isvalid` lookup, and :ref:`distance lookups <distance-lookups>`.
  58. * Added the :class:`~django.contrib.gis.db.models.functions.Azimuth` and
  59. :class:`~django.contrib.gis.db.models.functions.LineLocatePoint` functions,
  60. supported on PostGIS and SpatiaLite.
  61. * Any :class:`~django.contrib.gis.geos.GEOSGeometry` imported from GeoJSON now
  62. has its SRID set.
  63. * Added the :attr:`.OSMWidget.default_zoom` attribute to customize the map's
  64. default zoom level.
  65. * Made metadata readable and editable on rasters through the
  66. :attr:`~django.contrib.gis.gdal.GDALRaster.metadata`,
  67. :attr:`~django.contrib.gis.gdal.GDALRaster.info`, and
  68. :attr:`~django.contrib.gis.gdal.GDALBand.metadata` attributes.
  69. * Allowed passing driver-specific creation options to
  70. :class:`~django.contrib.gis.gdal.GDALRaster` objects using ``papsz_options``.
  71. * Allowed creating :class:`~django.contrib.gis.gdal.GDALRaster` objects in
  72. GDAL's internal virtual filesystem. Rasters can now be :ref:`created from and
  73. converted to binary data <gdal-raster-vsimem>` in-memory.
  74. :mod:`django.contrib.messages`
  75. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  76. * ...
  77. :mod:`django.contrib.postgres`
  78. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  79. * The new ``distinct`` argument for
  80. :class:`~django.contrib.postgres.aggregates.ArrayAgg` determines if
  81. concatenated values will be distinct.
  82. * The new :class:`~django.contrib.postgres.functions.RandomUUID` database
  83. function returns a version 4 UUID. It requires use of PostgreSQL's
  84. ``pgcrypto`` extension which can be activated using the new
  85. :class:`~django.contrib.postgres.operations.CryptoExtension` migration
  86. operation.
  87. * :class:`django.contrib.postgres.indexes.GinIndex` now supports the
  88. ``fastupdate`` and ``gin_pending_list_limit`` parameters.
  89. * The new :class:`~django.contrib.postgres.indexes.GistIndex` class allows
  90. creating ``GiST`` indexes in the database. The new
  91. :class:`~django.contrib.postgres.operations.BtreeGistExtension` migration
  92. operation installs the ``btree_gist`` extension to add support for operator
  93. classes that aren't built-in.
  94. * :djadmin:`inspectdb` can now introspect ``JSONField`` and various
  95. ``RangeField``\s (``django.contrib.postgres`` must be in ``INSTALLED_APPS``).
  96. :mod:`django.contrib.redirects`
  97. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  98. * ...
  99. :mod:`django.contrib.sessions`
  100. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  101. * ...
  102. :mod:`django.contrib.sitemaps`
  103. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  104. * Added the ``protocol`` keyword argument to the
  105. :class:`~django.contrib.sitemaps.GenericSitemap` constructor.
  106. :mod:`django.contrib.sites`
  107. ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  108. * ...
  109. :mod:`django.contrib.staticfiles`
  110. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  111. * ...
  112. :mod:`django.contrib.syndication`
  113. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  114. * ...
  115. Cache
  116. ~~~~~
  117. * On memcached, ``cache.set_many()`` returns a list of keys that failed to be
  118. inserted.
  119. CSRF
  120. ~~~~
  121. * ...
  122. Database backends
  123. ~~~~~~~~~~~~~~~~~
  124. * ...
  125. Email
  126. ~~~~~
  127. * ...
  128. File Storage
  129. ~~~~~~~~~~~~
  130. * :meth:`File.open() <django.core.files.File.open>` can be used as a context
  131. manager, e.g. ``with file.open() as f:``.
  132. File Uploads
  133. ~~~~~~~~~~~~
  134. * ...
  135. Forms
  136. ~~~~~
  137. * The new ``date_attrs`` and ``time_attrs`` arguments for
  138. :class:`~django.forms.SplitDateTimeWidget` and
  139. :class:`~django.forms.SplitHiddenDateTimeWidget` allow specifying different
  140. HTML attributes for the ``DateInput`` and ``TimeInput`` (or hidden)
  141. subwidgets.
  142. * The new :meth:`Form.errors.get_json_data()
  143. <django.forms.Form.errors.get_json_data>` method returns form errors as
  144. a dictionary suitable for including in a JSON response.
  145. Generic Views
  146. ~~~~~~~~~~~~~
  147. * The new :attr:`.ContextMixin.extra_context` attribute allows adding context
  148. in ``View.as_view()``.
  149. Internationalization
  150. ~~~~~~~~~~~~~~~~~~~~
  151. * ...
  152. Management Commands
  153. ~~~~~~~~~~~~~~~~~~~
  154. * :djadmin:`inspectdb` now translates MySQL's unsigned integer columns to
  155. ``PositiveIntegerField`` or ``PositiveSmallIntegerField``.
  156. * The new :option:`makemessages --add-location` option controls the comment
  157. format in PO files.
  158. * :djadmin:`loaddata` can now :ref:`read from stdin <loading-fixtures-stdin>`.
  159. * The new :option:`diffsettings --output` option allows formatting the output
  160. in a unified diff format.
  161. * On Oracle, :djadmin:`inspectdb` can now introspect ``AutoField`` if the
  162. column is created as an identity column.
  163. * On MySQL, :djadmin:`dbshell` now supports client-side TLS certificates.
  164. Migrations
  165. ~~~~~~~~~~
  166. * The new :option:`squashmigrations --squashed-name` option allows naming
  167. the squashed migration.
  168. Models
  169. ~~~~~~
  170. * The new :class:`~django.db.models.functions.StrIndex` database function
  171. finds the starting index of a string inside another string.
  172. * On Oracle, ``AutoField`` and ``BigAutoField`` are now created as `identity
  173. columns`_.
  174. .. _`identity columns`: https://docs.oracle.com/database/121/DRDAA/migr_tools_feat.htm#DRDAA109
  175. * The new ``chunk_size`` parameter of :meth:`.QuerySet.iterator` controls the
  176. number of rows fetched by the Python database client when streaming results
  177. from the database. For databases that don't support server-side cursors, it
  178. controls the number of results Django fetches from the database adapter.
  179. * :meth:`.QuerySet.earliest`, :meth:`.QuerySet.latest`, and
  180. :attr:`Meta.get_latest_by <django.db.models.Options.get_latest_by>` now
  181. allow ordering by several fields.
  182. * Added the :class:`~django.db.models.functions.datetime.ExtractQuarter`
  183. function to extract the quarter from :class:`~django.db.models.DateField` and
  184. :class:`~django.db.models.DateTimeField`, and exposed it through the
  185. :lookup:`quarter` lookup.
  186. * Added the :class:`~django.db.models.functions.datetime.TruncQuarter`
  187. function to truncate :class:`~django.db.models.DateField` and
  188. :class:`~django.db.models.DateTimeField` to the first day of a quarter.
  189. * Added the :attr:`~django.db.models.Index.db_tablespace` parameter to
  190. class-based indexes.
  191. * If the database supports a native duration field (Oracle and PostgreSQL),
  192. :class:`~django.db.models.functions.datetime.Extract` now works with
  193. :class:`~django.db.models.DurationField`.
  194. * Added the ``of`` argument to :meth:`.QuerySet.select_for_update()`, supported
  195. on PostgreSQL and Oracle, to lock only rows from specific tables rather than
  196. all selected tables. It may be helpful particularly when
  197. :meth:`~.QuerySet.select_for_update()` is used in conjunction with
  198. :meth:`~.QuerySet.select_related()`.
  199. * The new ``field_name`` parameter of :meth:`.QuerySet.in_bulk` allows fetching
  200. results based on any unique model field.
  201. * :meth:`.CursorWrapper.callproc()` now takes an optional dictionary of keyword
  202. parameters, if the backend supports this feature. Of Django's built-in
  203. backends, only Oracle supports it.
  204. * The new ``filter`` argument for built-in aggregates allows :ref:`adding
  205. different conditionals <conditional-aggregation>` to multiple aggregations
  206. over the same fields or relations.
  207. * Added support for expressions in :attr:`Meta.ordering
  208. <django.db.models.Options.ordering>`.
  209. * The new ``named`` parameter of :meth:`.QuerySet.values_list` allows fetching
  210. results as named tuples.
  211. Pagination
  212. ~~~~~~~~~~
  213. * Added :meth:`Paginator.get_page() <django.core.paginator.Paginator.get_page>`
  214. to provide the documented pattern of handling invalid page numbers.
  215. Requests and Responses
  216. ~~~~~~~~~~~~~~~~~~~~~~
  217. * The :djadmin:`runserver` Web server supports HTTP 1.1.
  218. Serialization
  219. ~~~~~~~~~~~~~
  220. * ...
  221. Signals
  222. ~~~~~~~
  223. * ...
  224. Templates
  225. ~~~~~~~~~
  226. * To increase the usefulness of :meth:`.Engine.get_default` in third-party
  227. apps, it now returns the first engine if multiple ``DjangoTemplates`` engines
  228. are configured in ``TEMPLATES`` rather than raising ``ImproperlyConfigured``.
  229. * Custom template tags may now accept keyword-only arguments.
  230. Tests
  231. ~~~~~
  232. * Added threading support to :class:`~django.test.LiveServerTestCase`.
  233. * Added settings that allow customizing the test tablespace parameters for
  234. Oracle: :setting:`DATAFILE_SIZE`, :setting:`DATAFILE_TMP_SIZE`,
  235. :setting:`DATAFILE_EXTSIZE`, and :setting:`DATAFILE_TMP_EXTSIZE`.
  236. URLs
  237. ~~~~
  238. * ...
  239. Validators
  240. ~~~~~~~~~~
  241. * The new :class:`.ProhibitNullCharactersValidator` disallows the null
  242. character in the input of the :class:`~django.forms.CharField` form field
  243. and its subclasses. Null character input was observed from vulnerability
  244. scanning tools. Most databases silently discard null characters, but
  245. psycopg2 2.7+ raises an exception when trying to save a null character to
  246. a char/text field with PostgreSQL.
  247. .. _backwards-incompatible-2.0:
  248. Backwards incompatible changes in 2.0
  249. =====================================
  250. Removed support for bytestrings in some places
  251. ----------------------------------------------
  252. To support native Python 2 strings, older Django versions had to accept both
  253. bytestrings and unicode strings. Now that Python 2 support is dropped,
  254. bytestrings should only be encountered around input/output boundaries (handling
  255. of binary fields or HTTP streams, for example). You might have to update your
  256. code to limit bytestring usage to a minimum, as Django no longer accepts
  257. bytestrings in certain code paths.
  258. Database backend API
  259. --------------------
  260. This section describes changes that may be needed in third-party database
  261. backends.
  262. * The ``DatabaseOperations.datetime_cast_date_sql()``,
  263. ``datetime_cast_time_sql()``, ``datetime_trunc_sql()``,
  264. ``datetime_extract_sql()``, and ``date_interval_sql()`` methods now return
  265. only the SQL to perform the operation instead of SQL and a list of
  266. parameters.
  267. * Third-party database backends should add a ``DatabaseWrapper.display_name``
  268. attribute with the name of the database that your backend works with. Django
  269. may use it in various messages, such as in system checks.
  270. * The first argument of ``SchemaEditor._alter_column_type_sql()`` is now
  271. ``model`` rather than ``table``.
  272. * The first argument of ``SchemaEditor._create_index_name()`` is now
  273. ``table_name`` rather than ``model``.
  274. * To enable ``FOR UPDATE OF`` support, set
  275. ``DatabaseFeatures.has_select_for_update_of = True``. If the database
  276. requires that the arguments to ``OF`` be columns rather than tables, set
  277. ``DatabaseFeatures.select_for_update_of_column = True``.
  278. * Third-party database backends should add a
  279. ``DatabaseOperations.cast_char_field_without_max_length`` attribute with the
  280. database data type that will be used in the
  281. :class:`~django.db.models.functions.Cast` function for a ``CharField`` if the
  282. ``max_length`` argument isn't provided.
  283. Dropped support for Oracle 11.2
  284. -------------------------------
  285. The end of upstream support for Oracle 11.2 is Dec. 2020. Django 1.11 will be
  286. supported until April 2020 which almost reaches this date. Django 2.0
  287. officially supports Oracle 12.1+.
  288. Default MySQL isolation level is read committed
  289. -----------------------------------------------
  290. MySQL's default isolation level, repeatable read, may cause data loss in
  291. typical Django usage. To prevent that and for consistency with other databases,
  292. the default isolation level is now read committed. You can use the
  293. :setting:`DATABASES` setting to :ref:`use a different isolation level
  294. <mysql-isolation-level>`, if needed.
  295. :attr:`AbstractUser.last_name <django.contrib.auth.models.User.last_name>` ``max_length`` increased to 150
  296. ----------------------------------------------------------------------------------------------------------
  297. A migration for :attr:`django.contrib.auth.models.User.last_name` is included.
  298. If you have a custom user model inheriting from ``AbstractUser``, you'll need
  299. to generate and apply a database migration for your user model.
  300. If you want to preserve the 30 character limit for last names, use a custom
  301. form::
  302. from django.contrib.auth.forms import UserChangeForm
  303. class MyUserChangeForm(UserChangeForm):
  304. last_name = forms.CharField(max_length=30, required=False)
  305. If you wish to keep this restriction in the admin when editing users, set
  306. ``UserAdmin.form`` to use this form::
  307. from django.contrib.auth.admin import UserAdmin
  308. from django.contrib.auth.models import User
  309. class MyUserAdmin(UserAdmin):
  310. form = MyUserChangeForm
  311. admin.site.unregister(User)
  312. admin.site.register(User, MyUserAdmin)
  313. ``QuerySet.reverse()`` and ``last()`` are prohibited after slicing
  314. ------------------------------------------------------------------
  315. Calling ``QuerySet.reverse()`` or ``last()`` on a sliced queryset leads to
  316. unexpected results due to the slice being applied after reordering. This is
  317. now prohibited, e.g.::
  318. >>> Model.objects.all()[:2].reverse()
  319. Traceback (most recent call last):
  320. ...
  321. TypeError: Cannot reverse a query once a slice has been taken.
  322. Form fields no longer accept optional arguments as positional arguments
  323. -----------------------------------------------------------------------
  324. To help prevent runtime errors due to incorrect ordering of form field
  325. arguments, optional arguments of built-in form fields are no longer accepted
  326. as positional arguments. For example::
  327. forms.IntegerField(25, 10)
  328. raises an exception and should be replaced with::
  329. forms.IntegerField(max_value=25, min_value=10)
  330. ``call_command()`` validates the options it receives
  331. ----------------------------------------------------
  332. ``call_command()`` now validates that the argument parser of the command being
  333. called defines all of the options passed to ``call_command()``.
  334. For custom management commands that use options not created using
  335. ``parser.add_argument()``, add a ``stealth_options`` attribute on the command::
  336. class MyCommand(BaseCommand):
  337. stealth_options = ('option_name', ...)
  338. Indexes no longer accept positional arguments
  339. ---------------------------------------------
  340. For example::
  341. models.Index(['headline', '-pub_date'], 'index_name')
  342. raises an exception and should be replaced with::
  343. models.Index(fields=['headline', '-pub_date'], name='index_name')
  344. Foreign key constraints are now enabled on SQLite
  345. -------------------------------------------------
  346. This will appear as a backwards-incompatible change (``IntegrityError:
  347. FOREIGN KEY constraint failed``) if attempting to save an existing model
  348. instance that's violating a foreign key constraint.
  349. Foreign keys are now created with ``DEFERRABLE INITIALLY DEFERRED`` instead of
  350. ``DEFERRABLE IMMEDIATE``. Thus, tables may need to be rebuilt to recreate
  351. foreign keys with the new definition, particularly if you're using a pattern
  352. like this::
  353. from django.db import transaction
  354. with transaction.atomic():
  355. Book.objects.create(author_id=1)
  356. Author.objects.create(id=1)
  357. If you don't recreate the foreign key as ``DEFERRED``, the first ``create()``
  358. would fail now that foreign key constraints are enforced.
  359. Backup your database first! After upgrading to Django 2.0, you can then
  360. rebuild tables using a script similar to this::
  361. from django.apps import apps
  362. from django.db import connection
  363. for app in apps.get_app_configs():
  364. for model in app.get_models(include_auto_created=True):
  365. if model._meta.managed and not (model._meta.proxy or model._meta.swapped):
  366. for base in model.__bases__:
  367. if hasattr(base, '_meta'):
  368. base._meta.local_many_to_many = []
  369. model._meta.local_many_to_many = []
  370. with connection.schema_editor() as editor:
  371. editor._remake_table(model)
  372. This script hasn't received extensive testing and needs adaption for various
  373. cases such as multiple databases. Feel free to contribute improvements.
  374. Miscellaneous
  375. -------------
  376. * The ``SessionAuthenticationMiddleware`` class is removed. It provided no
  377. functionality since session authentication is unconditionally enabled in
  378. Django 1.10.
  379. * The default HTTP error handlers (``handler404``, etc.) are now callables
  380. instead of dotted Python path strings. Django favors callable references
  381. since they provide better performance and debugging experience.
  382. * :class:`~django.views.generic.base.RedirectView` no longer silences
  383. ``NoReverseMatch`` if the ``pattern_name`` doesn't exist.
  384. * When :setting:`USE_L10N` is off, :class:`~django.forms.FloatField` and
  385. :class:`~django.forms.DecimalField` now respect :setting:`DECIMAL_SEPARATOR`
  386. and :setting:`THOUSAND_SEPARATOR` during validation. For example, with the
  387. settings::
  388. USE_L10N = False
  389. USE_THOUSAND_SEPARATOR = True
  390. DECIMAL_SEPARATOR = ','
  391. THOUSAND_SEPARATOR = '.'
  392. an input of ``"1.345"`` is now converted to ``1345`` instead of ``1.345``.
  393. * Subclasses of :class:`~django.contrib.auth.models.AbstractBaseUser` are no
  394. longer required to implement ``get_short_name()`` and ``get_full_name()``.
  395. (The base implementations that raise ``NotImplementedError`` are removed.)
  396. ``django.contrib.admin`` uses these methods if implemented but doesn't
  397. require them. Third-party apps that use these methods may want to adopt a
  398. similar approach.
  399. * The ``FIRST_DAY_OF_WEEK`` and ``NUMBER_GROUPING`` format settings are now
  400. kept as integers in JavaScript and JSON i18n view outputs.
  401. * :meth:`~django.test.TransactionTestCase.assertNumQueries` now ignores
  402. connection configuration queries. Previously, if a test opened a new database
  403. connection, those queries could be included as part of the
  404. ``assertNumQueries()`` count.
  405. * The ``PASSWORD_RESET_TIMEOUT_DAYS`` setting is more properly respected in
  406. ``contrib.auth`` password reset. Previously, resets were allowed for one day
  407. longer than expected. For example, with the default of
  408. ``PASSWORD_RESET_TIMEOUT_DAYS = 3``, password reset tokens are now valid for
  409. 72 hours rather than 96 hours.
  410. * The default size of the Oracle test tablespace is increased from 20M to 50M
  411. and the default autoextend size is increased from 10M to 25M.
  412. * To improve performance when streaming large result sets from the database,
  413. :meth:`.QuerySet.iterator` now fetches 2000 rows at a time instead of 100.
  414. The old behavior can be restored using the ``chunk_size`` parameter. For
  415. example::
  416. Book.objects.iterator(chunk_size=100)
  417. * Providing unknown package names in the ``packages`` argument of the
  418. :class:`~django.views.i18n.JavaScriptCatalog` view now raises ``ValueError``
  419. instead of passing silently.
  420. * A model instance's primary key now appears in the default ``Model.__str__()``
  421. method, e.g. ``Question object (1)``.
  422. * ``makemigrations`` now detects changes to the model field ``limit_choices_to``
  423. option. Add this to your existing migrations or accept an auto-generated
  424. migration for fields that use it.
  425. * Performing queries that require :ref:`automatic spatial transformations
  426. <automatic-spatial-transformations>` now raises ``NotImplementedError``
  427. on MySQL instead of silently using non-transformed geometries.
  428. * ``django.core.exceptions.DjangoRuntimeWarning`` is removed. It was only used
  429. in the cache backend as an intermediate class in ``CacheKeyWarning``'s
  430. inheritance of ``RuntimeWarning``.
  431. * Renamed ``BaseExpression._output_field`` to ``output_field``. You may need
  432. to update custom expressions.
  433. * In older versions, forms and formsets combine their ``Media`` with widget
  434. ``Media`` by concatenating the two. The combining now tries to :ref:`preserve
  435. the relative order of elements in each list <form-media-asset-order>`.
  436. ``MediaOrderConflictWarning`` is issued if the order can't be preserved.
  437. * ``django.contrib.gis.gdal.OGRException`` is removed. It's been an alias for
  438. ``GDALException`` since Django 1.8.
  439. .. _deprecated-features-2.0:
  440. Features deprecated in 2.0
  441. ==========================
  442. ``context`` argument of ``Field.from_db_value()`` and ``Expression.convert_value()``
  443. ------------------------------------------------------------------------------------
  444. The ``context`` argument of ``Field.from_db_value()`` and
  445. ``Expression.convert_value()`` is unused as it's always an empty dictionary.
  446. The signature of both methods is now::
  447. (self, value, expression, connection)
  448. instead of::
  449. (self, value, expression, connection, context)
  450. Support for the old signature in custom fields and expressions remains until
  451. Django 3.0.
  452. Miscellaneous
  453. -------------
  454. * The ``django.db.backends.postgresql_psycopg2`` module is deprecated in favor
  455. of ``django.db.backends.postgresql``. It's been an alias since Django 1.9.
  456. This only affects code that imports from the module directly. The
  457. ``DATABASES`` setting can still use
  458. ``'django.db.backends.postgresql_psycopg2'``, though you can simplify that by
  459. using the ``'django.db.backends.postgresql'`` name added in Django 1.9.
  460. * ``django.shortcuts.render_to_response()`` is deprecated in favor of
  461. :func:`django.shortcuts.render`. ``render()`` takes the same arguments
  462. except that is also requires a ``request``.
  463. * The ``DEFAULT_CONTENT_TYPE`` setting is deprecated. It doesn't interact well
  464. well with third-party apps and is obsolete since HTML5 has mostly superseded
  465. XHTML.
  466. * ``HttpRequest.xreadlines()`` is deprecated in favor of iterating over the
  467. request.
  468. * The ``field_name`` keyword argument to :meth:`.QuerySet.earliest` and
  469. :meth:`.QuerySet.latest` is deprecated in favor of passing the field
  470. names as arguments. Write ``.earliest('pub_date')`` instead of
  471. ``.earliest(field_name='pub_date')``.
  472. .. _removed-features-2.0:
  473. Features removed in 2.0
  474. =======================
  475. These features have reached the end of their deprecation cycle and are removed
  476. in Django 2.0. See :ref:`deprecated-features-1.9` and
  477. :ref:`deprecated-features-1.10` for details, including how to remove usage of
  478. these features.
  479. * The ``weak`` argument to ``django.dispatch.signals.Signal.disconnect()`` is
  480. removed.
  481. * ``django.db.backends.base.BaseDatabaseOperations.check_aggregate_support()``
  482. is removed.
  483. * The ``django.forms.extras`` package is removed.
  484. * The ``assignment_tag`` helper is removed.
  485. * The ``host`` argument to ``SimpleTestCase.assertsRedirects()`` is removed.
  486. The compatibility layer which allows absolute URLs to be considered equal to
  487. relative ones when the path is identical is also removed.
  488. * ``Field.rel`` and ``Field.remote_field.to`` are removed.
  489. * The ``on_delete`` argument for ``ForeignKey`` and ``OneToOneField`` are now
  490. required.
  491. * ``django.db.models.fields.add_lazy_relation()`` is removed.
  492. * When time zone support is enabled, database backends that don't support time
  493. zones no longer convert aware datetimes to naive values in UTC anymore when
  494. such values are passed as parameters to SQL queries executed outside of the
  495. ORM, e.g. with ``cursor.execute()``.
  496. * ``django.contrib.auth.tests.utils.skipIfCustomUser()`` is removed.
  497. * The ``GeoManager`` and ``GeoQuerySet`` classes are removed.
  498. * The ``django.contrib.gis.geoip`` module is removed.
  499. * The ``supports_recursion`` check for template loaders is removed from:
  500. * ``django.template.engine.Engine.find_template()``
  501. * ``django.template.loader_tags.ExtendsNode.find_template()``
  502. * ``django.template.loaders.base.Loader.supports_recursion()``
  503. * ``django.template.loaders.cached.Loader.supports_recursion()``
  504. * The ``load_template`` and ``load_template_sources`` template loader methods
  505. are removed.
  506. * The ``template_dirs`` argument for template loaders is removed:
  507. * ``django.template.loaders.base.Loader.get_template()``
  508. * ``django.template.loaders.cached.Loader.cache_key()``
  509. * ``django.template.loaders.cached.Loader.get_template()``
  510. * ``django.template.loaders.cached.Loader.get_template_sources()``
  511. * ``django.template.loaders.filesystem.Loader.get_template_sources()``
  512. * ``django.template.loaders.base.Loader.__call__()`` is removed.
  513. * Support for custom error views that don't accept an ``exception`` parameter
  514. is removed.
  515. * The ``mime_type`` attribute of ``django.utils.feedgenerator.Atom1Feed`` and
  516. ``django.utils.feedgenerator.RssFeed`` is removed.
  517. * The ``app_name`` argument to ``include()`` is removed.
  518. * Support for passing a 3-tuple (including ``admin.site.urls``) as the first
  519. argument to ``include()`` is removed.
  520. * Support for setting a URL instance namespace without an application namespace
  521. is removed.
  522. * ``Field._get_val_from_obj()`` is removed.
  523. * ``django.template.loaders.eggs.Loader`` is removed.
  524. * The ``current_app`` parameter to the ``contrib.auth`` function-based views is
  525. removed.
  526. * The ``callable_obj`` keyword argument to
  527. ``SimpleTestCase.assertRaisesMessage()`` is removed.
  528. * Support for the ``allow_tags`` attribute on ``ModelAdmin`` methods is
  529. removed.
  530. * The ``enclosure`` keyword argument to ``SyndicationFeed.add_item()`` is
  531. removed.
  532. * The ``django.template.loader.LoaderOrigin`` and
  533. ``django.template.base.StringOrigin`` aliases for
  534. ``django.template.base.Origin`` are removed.
  535. * The ``makemigrations --exit`` option is removed.
  536. * Support for direct assignment to a reverse foreign key or many-to-many
  537. relation is removed.
  538. * The ``get_srid()`` and ``set_srid()`` methods of
  539. ``django.contrib.gis.geos.GEOSGeometry`` are removed.
  540. * The ``get_x()``, ``set_x()``, ``get_y()``, ``set_y()``, ``get_z()``, and
  541. ``set_z()`` methods of ``django.contrib.gis.geos.Point`` are removed.
  542. * The ``get_coords()`` and ``set_coords()`` methods of
  543. ``django.contrib.gis.geos.Point`` are removed.
  544. * The ``cascaded_union`` property of ``django.contrib.gis.geos.MultiPolygon``
  545. is removed.
  546. * ``django.utils.functional.allow_lazy()`` is removed.
  547. * The ``shell --plain`` option is removed.
  548. * The ``django.core.urlresolvers`` module is removed.
  549. * ``CommaSeparatedIntegerField`` is removed, except for support in historical
  550. migrations.
  551. * The template ``Context.has_key()`` method is removed.
  552. * Support for the ``django.core.files.storage.Storage.accessed_time()``,
  553. ``created_time()``, and ``modified_time()`` methods is removed.
  554. * Support for query lookups using the model name when
  555. ``Meta.default_related_name`` is set is removed.
  556. * The MySQL ``__search`` lookup is removed.
  557. * The shim for supporting custom related manager classes without a
  558. ``_apply_rel_filters()`` method is removed.
  559. * Using ``User.is_authenticated()`` and ``User.is_anonymous()`` as methods
  560. rather than properties is no longer supported.
  561. * The ``Model._meta.virtual_fields`` attribute is removed.
  562. * The keyword arguments ``virtual_only`` in ``Field.contribute_to_class()`` and
  563. ``virtual`` in ``Model._meta.add_field()`` are removed.
  564. * The ``javascript_catalog()`` and ``json_catalog()`` views are removed.
  565. * ``django.contrib.gis.utils.precision_wkt()`` is removed.
  566. * In multi-table inheritance, implicit promotion of a ``OneToOneField`` to a
  567. ``parent_link`` is removed.
  568. * Support for ``Widget._format_value()`` is removed.
  569. * ``FileField`` methods ``get_directory_name()`` and ``get_filename()`` are
  570. removed.
  571. * The ``mark_for_escaping()`` function and the classes it uses: ``EscapeData``,
  572. ``EscapeBytes``, ``EscapeText``, ``EscapeString``, and ``EscapeUnicode`` are
  573. removed.
  574. * The ``escape`` filter now uses ``django.utils.html.conditional_escape()``.
  575. * ``Manager.use_for_related_fields`` is removed.
  576. * Model ``Manager`` inheritance follows MRO inheritance rules. The requirement
  577. to use ``Meta.manager_inheritance_from_future`` to opt-in to the behavior is
  578. removed.
  579. * Support for old-style middleware using ``settings.MIDDLEWARE_CLASSES`` is
  580. removed.