Viewing github.com/django/django-stable-4.1.x/docs/releases/2.0.txt

```
========================
```
```
Django 2.0 release notes
```
```
========================
```
```
*December 2, 2017*
```
```
Welcome to Django 2.0!
```

These release notes cover the :ref:`new features <whats-new-2.0>`, as well as

some :ref:`backwards incompatible changes <backwards-incompatible-2.0>` you'll

want to be aware of when upgrading from Django 1.11 or earlier. We've

:ref:`dropped some features<removed-features-2.0>` that have reached the end of

their deprecation cycle, and we've :ref:`begun the deprecation process for some

```
features <deprecated-features-2.0>`.
```

This release starts Django's use of a :ref:`loose form of semantic versioning

<internal-release-cadence>`, but there aren't any major backwards incompatible

changes that might be expected of a 2.0 release. Upgrading should be a similar

amount of effort as past feature releases.

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

```
project.
```
```
Python compatibility
```
```
====================
```

Django 2.0 supports Python 3.4, 3.5, 3.6, and 3.7. We **highly recommend** and

only officially support the latest release of each series.

The Django 1.11.x series is the last to support Python 2.7.

Django 2.0 will be the last release series to support Python 3.4. If you plan

a deployment of Python 3.4 beyond the end-of-life for Django 2.0 (April 2019),

stick with Django 1.11 LTS (supported until April 2020) instead. Note, however,

that the end-of-life for Python 3.4 is March 2019.

Third-party library support for older version of Django

=======================================================

Following the release of Django 2.0, we suggest that third-party app authors

drop support for all versions of Django prior to 1.11. At that time, you should

be able to run your package's tests using ``python -Wd`` so that deprecation

warnings do appear. After making the deprecation warning fixes, your app should

```
be compatible with Django 2.0.
```
```
.. _whats-new-2.0:
```
```
What's new in Django 2.0
```
```
========================
```
```
Simplified URL routing syntax
```
```
-----------------------------
```

The new :func:`django.urls.path()` function allows a simpler, more readable URL

routing syntax. For example, this example from previous Django releases::

    url(r'^articles/(?P<year>[0-9]{4})/$', views.year_archive),

```
could be written as::
```

    path('articles/<int:year>/', views.year_archive),

The new syntax supports type coercion of URL parameters. In the example, the

view will receive the ``year`` keyword argument as an integer rather than as

a string. Also, the URLs that will match are slightly less constrained in the

rewritten example. For example, the year 10000 will now match since the year

integers aren't constrained to be exactly four digits long as they are in the

```
regular expression.
```

The ``django.conf.urls.url()`` function from previous versions is now available

as :func:`django.urls.re_path`. The old location remains for backwards

compatibility, without an imminent deprecation. The old

``django.conf.urls.include()`` function is now importable from ``django.urls``

so you can use ``from django.urls import include, path, re_path`` in your

```
URLconfs.
```

The :doc:`/topics/http/urls` document is rewritten to feature the new syntax

```
and provide more details.
```
```
Mobile-friendly ``contrib.admin``
```
```
---------------------------------
```

The admin is now responsive and supports all major mobile devices. Older

browsers may experience varying levels of graceful degradation.

```
Window expressions
```
```
------------------
```

The new :class:`~django.db.models.expressions.Window` expression allows

adding an ``OVER`` clause to querysets. You can use :ref:`window functions

<window-functions>` and :ref:`aggregate functions <aggregation-functions>` in

```
the expression.
```
```
Minor features
```
```
--------------
```
```
:mod:`django.contrib.admin`
```
```
~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

* The new :attr:`.ModelAdmin.autocomplete_fields` attribute and

  :meth:`.ModelAdmin.get_autocomplete_fields` method allow using a

  `Select2 <https://select2.org/>`_ search widget for ``ForeignKey`` and

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

* The default iteration count for the PBKDF2 password hasher is increased from

```
  36,000 to 100,000.
```
```
:mod:`django.contrib.gis`
```
```
~~~~~~~~~~~~~~~~~~~~~~~~~
```
```
* Added MySQL support for the
```

  :class:`~django.contrib.gis.db.models.functions.AsGeoJSON` function,

  :class:`~django.contrib.gis.db.models.functions.GeoHash` function,

  :class:`~django.contrib.gis.db.models.functions.IsValid` function,

  :lookup:`isvalid` lookup, and :ref:`distance lookups <distance-lookups>`.

* Added the :class:`~django.contrib.gis.db.models.functions.Azimuth` and

  :class:`~django.contrib.gis.db.models.functions.LineLocatePoint` functions,

```
  supported on PostGIS and SpatiaLite.
```

* Any :class:`~django.contrib.gis.geos.GEOSGeometry` imported from GeoJSON now

```
  has its SRID set.
```

* Added the :attr:`.OSMWidget.default_zoom` attribute to customize the map's

```
  default zoom level.
```

* Made metadata readable and editable on rasters through the

  :attr:`~django.contrib.gis.gdal.GDALRaster.metadata`,

  :attr:`~django.contrib.gis.gdal.GDALRaster.info`, and

  :attr:`~django.contrib.gis.gdal.GDALBand.metadata` attributes.

* Allowed passing driver-specific creation options to

  :class:`~django.contrib.gis.gdal.GDALRaster` objects using ``papsz_options``.

* Allowed creating :class:`~django.contrib.gis.gdal.GDALRaster` objects in

  GDAL's internal virtual filesystem. Rasters can now be :ref:`created from and

  converted to binary data <gdal-raster-vsimem>` in-memory.

* The new :meth:`GDALBand.color_interp()

  <django.contrib.gis.gdal.GDALBand.color_interp>` method returns the color

```
  interpretation for the band.
```
```
:mod:`django.contrib.postgres`
```
```
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
```
* The new ``distinct`` argument for
```

  :class:`~django.contrib.postgres.aggregates.ArrayAgg` determines if

  concatenated values will be distinct.

* The new :class:`~django.contrib.postgres.functions.RandomUUID` database

  function returns a version 4 UUID. It requires use of PostgreSQL's

  ``pgcrypto`` extension which can be activated using the new

  :class:`~django.contrib.postgres.operations.CryptoExtension` migration

```
  operation.
```

* :class:`django.contrib.postgres.indexes.GinIndex` now supports the

  ``fastupdate`` and ``gin_pending_list_limit`` parameters.

* The new :class:`~django.contrib.postgres.indexes.GistIndex` class allows

  creating ``GiST`` indexes in the database. The new

  :class:`~django.contrib.postgres.operations.BtreeGistExtension` migration

  operation installs the ``btree_gist`` extension to add support for operator

```
  classes that aren't built-in.
```

* :djadmin:`inspectdb` can now introspect ``JSONField`` and various

  ``RangeField``\s (``django.contrib.postgres`` must be in ``INSTALLED_APPS``).

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

* Added the ``protocol`` keyword argument to the

  :class:`~django.contrib.sitemaps.GenericSitemap` constructor.

```
Cache
```
```
~~~~~
```

* ``cache.set_many()`` now returns a list of keys that failed to be inserted.

  For the built-in backends, failed inserts can only happen on memcached.

```
File Storage
```
```
~~~~~~~~~~~~
```

* :meth:`File.open() <django.core.files.File.open>` can be used as a context

  manager, e.g. ``with file.open() as f:``.

```
Forms
```
```
~~~~~
```

* The new ``date_attrs`` and ``time_attrs`` arguments for

  :class:`~django.forms.SplitDateTimeWidget` and

  :class:`~django.forms.SplitHiddenDateTimeWidget` allow specifying different

  HTML attributes for the ``DateInput`` and ``TimeInput`` (or hidden)

```
  subwidgets.
```

* The new :meth:`Form.errors.get_json_data()

  <django.forms.Form.errors.get_json_data>` method returns form errors as

  a dictionary suitable for including in a JSON response.

```
Generic Views
```
```
~~~~~~~~~~~~~
```

* The new :attr:`.ContextMixin.extra_context` attribute allows adding context

```
  in ``View.as_view()``.
```
```
Management Commands
```
```
~~~~~~~~~~~~~~~~~~~
```

* :djadmin:`inspectdb` now translates MySQL's unsigned integer columns to

  ``PositiveIntegerField`` or ``PositiveSmallIntegerField``.

* The new :option:`makemessages --add-location` option controls the comment

```
  format in ``.po`` files.
```

* :djadmin:`loaddata` can now :ref:`read from stdin <loading-fixtures-stdin>`.

* The new :option:`diffsettings --output` option allows formatting the output

```
  in a unified diff format.
```

* On Oracle, :djadmin:`inspectdb` can now introspect ``AutoField`` if the

  column is created as an identity column.

* On MySQL, :djadmin:`dbshell` now supports client-side TLS certificates.

```
Migrations
```
```
~~~~~~~~~~
```

* The new :option:`squashmigrations --squashed-name` option allows naming the

```
  squashed migration.
```
```
Models
```
```
~~~~~~
```

* The new :class:`~django.db.models.functions.StrIndex` database function

  finds the starting index of a string inside another string.

* On Oracle, ``AutoField`` and ``BigAutoField`` are now created as `identity

  columns <https://docs.oracle.com/en/database/oracle/oracle-database/21/drdaa/

  intro-to-tools-and-products-supporting-migraiton.html#GUID-14E4817B-F3BC-4D99

```
  -B471-A0ACDC303CC9>`__.
```

* The new ``chunk_size`` parameter of :meth:`.QuerySet.iterator` controls the

  number of rows fetched by the Python database client when streaming results

  from the database. For databases that don't support server-side cursors, it

  controls the number of results Django fetches from the database adapter.

* :meth:`.QuerySet.earliest`, :meth:`.QuerySet.latest`, and

  :attr:`Meta.get_latest_by <django.db.models.Options.get_latest_by>` now

```
  allow ordering by several fields.
```

* Added the :class:`~django.db.models.functions.ExtractQuarter` function to

  extract the quarter from :class:`~django.db.models.DateField` and

  :class:`~django.db.models.DateTimeField`, and exposed it through the

```
  :lookup:`quarter` lookup.
```

* Added the :class:`~django.db.models.functions.TruncQuarter` function to

  truncate :class:`~django.db.models.DateField` and

  :class:`~django.db.models.DateTimeField` to the first day of a quarter.

* Added the :attr:`~django.db.models.Index.db_tablespace` parameter to

```
  class-based indexes.
```

* If the database supports a native duration field (Oracle and PostgreSQL),

  :class:`~django.db.models.functions.Extract` now works with

  :class:`~django.db.models.DurationField`.

* Added the ``of`` argument to :meth:`.QuerySet.select_for_update()`, supported

  on PostgreSQL and Oracle, to lock only rows from specific tables rather than

  all selected tables. It may be helpful particularly when

  :meth:`~.QuerySet.select_for_update()` is used in conjunction with

```
  :meth:`~.QuerySet.select_related()`.
```

* The new ``field_name`` parameter of :meth:`.QuerySet.in_bulk` allows fetching

  results based on any unique model field.

* :meth:`.CursorWrapper.callproc()` now takes an optional dictionary of keyword

  parameters, if the backend supports this feature. Of Django's built-in

```
  backends, only Oracle supports it.
```

* The new :meth:`connection.execute_wrapper()

  <django.db.backends.base.DatabaseWrapper.execute_wrapper>` method allows

  :doc:`installing wrappers around execution of database queries

```
  </topics/db/instrumentation>`.
```

* The new ``filter`` argument for built-in aggregates allows :ref:`adding

  different conditionals <conditional-aggregation>` to multiple aggregations

```
  over the same fields or relations.
```

* Added support for expressions in :attr:`Meta.ordering

  <django.db.models.Options.ordering>`.

* The new ``named`` parameter of :meth:`.QuerySet.values_list` allows fetching

```
  results as named tuples.
```

* The new :class:`.FilteredRelation` class allows adding an ``ON`` clause to

```
  querysets.
```
```
Pagination
```
```
~~~~~~~~~~
```

* Added :meth:`Paginator.get_page() <django.core.paginator.Paginator.get_page>`

  to provide the documented pattern of handling invalid page numbers.

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

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

```
Templates
```
```
~~~~~~~~~
```

* To increase the usefulness of :meth:`.Engine.get_default` in third-party

  apps, it now returns the first engine if multiple ``DjangoTemplates`` engines

  are configured in ``TEMPLATES`` rather than raising ``ImproperlyConfigured``.

* Custom template tags may now accept keyword-only arguments.

```
Tests
```
```
~~~~~
```

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

* Added settings that allow customizing the test tablespace parameters for

  Oracle: :setting:`DATAFILE_SIZE`, :setting:`DATAFILE_TMP_SIZE`,

  :setting:`DATAFILE_EXTSIZE`, and :setting:`DATAFILE_TMP_EXTSIZE`.

```
Validators
```
```
~~~~~~~~~~
```

* The new :class:`.ProhibitNullCharactersValidator` disallows the null

  character in the input of the :class:`~django.forms.CharField` form field

  and its subclasses. Null character input was observed from vulnerability

  scanning tools. Most databases silently discard null characters, but

  psycopg2 2.7+ raises an exception when trying to save a null character to

```
  a char/text field with PostgreSQL.
```
```
.. _backwards-incompatible-2.0:
```
```
Backwards incompatible changes in 2.0
```
```
=====================================
```

Removed support for bytestrings in some places

----------------------------------------------

To support native Python 2 strings, older Django versions had to accept both

bytestrings and Unicode strings. Now that Python 2 support is dropped,

bytestrings should only be encountered around input/output boundaries (handling

of binary fields or HTTP streams, for example). You might have to update your

code to limit bytestring usage to a minimum, as Django no longer accepts

bytestrings in certain code paths. Python's :option:`-b` option may help detect

```
that mistake in your code.
```

For example, ``reverse()`` now uses ``str()`` instead of ``force_text()`` to

coerce the ``args`` and ``kwargs`` it receives, prior to their placement in

the URL. For bytestrings, this creates a string with an undesired ``b`` prefix

as well as additional quotes (``str(b'foo')`` is ``"b'foo'"``). To adapt, call

``decode()`` on the bytestring before passing it to ``reverse()``.

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

This section describes changes that may be needed in third-party database

```
backends.
```

* The ``DatabaseOperations.datetime_cast_date_sql()``,

  ``datetime_cast_time_sql()``, ``datetime_trunc_sql()``,

  ``datetime_extract_sql()``, and ``date_interval_sql()`` methods now return

  only the SQL to perform the operation instead of SQL and a list of

```
  parameters.
```

* Third-party database backends should add a ``DatabaseWrapper.display_name``

  attribute with the name of the database that your backend works with. Django

  may use it in various messages, such as in system checks.

* The first argument of ``SchemaEditor._alter_column_type_sql()`` is now

```
  ``model`` rather than ``table``.
```

* The first argument of ``SchemaEditor._create_index_name()`` is now

  ``table_name`` rather than ``model``.

* To enable ``FOR UPDATE OF`` support, set

  ``DatabaseFeatures.has_select_for_update_of = True``. If the database

  requires that the arguments to ``OF`` be columns rather than tables, set

  ``DatabaseFeatures.select_for_update_of_column = True``.

* To enable support for :class:`~django.db.models.expressions.Window`

  expressions, set ``DatabaseFeatures.supports_over_clause`` to ``True``. You

  may need to customize the ``DatabaseOperations.window_start_rows_start_end()``

  and/or ``window_start_range_start_end()`` methods.

* Third-party database backends should add a

  ``DatabaseOperations.cast_char_field_without_max_length`` attribute with the

  database data type that will be used in the

  :class:`~django.db.models.functions.Cast` function for a ``CharField`` if the

  ``max_length`` argument isn't provided.

* The first argument of ``DatabaseCreation._clone_test_db()`` and

  ``get_test_db_clone_settings()`` is now ``suffix`` rather

  than ``number`` (in case you want to rename the signatures in your backend

  for consistency). ``django.test`` also now passes those values as strings

```
  rather than as integers.
```

* Third-party database backends should add a

  ``DatabaseIntrospection.get_sequences()`` method based on the stub in

```
  ``BaseDatabaseIntrospection``.
```
```
Dropped support for Oracle 11.2
```
```
-------------------------------
```

The end of upstream support for Oracle 11.2 is Dec. 2020. Django 1.11 will be

supported until April 2020 which almost reaches this date. Django 2.0

```
officially supports Oracle 12.1+.
```

Default MySQL isolation level is read committed

-----------------------------------------------

MySQL's default isolation level, repeatable read, may cause data loss in

typical Django usage. To prevent that and for consistency with other databases,

the default isolation level is now read committed. You can use the

:setting:`DATABASES` setting to :ref:`use a different isolation level

```
<mysql-isolation-level>`, if needed.
```

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

----------------------------------------------------------------------------------------------------------

A migration for :attr:`django.contrib.auth.models.User.last_name` is included.

If you have a custom user model inheriting from ``AbstractUser``, you'll need

to generate and apply a database migration for your user model.

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

```
form::
```

    from django.contrib.auth.forms import UserChangeForm

    class MyUserChangeForm(UserChangeForm):

        last_name = forms.CharField(max_length=30, required=False)

If you wish to keep this restriction in the admin when editing users, set

```
``UserAdmin.form`` to use this form::
```

    from django.contrib.auth.admin import UserAdmin

    from django.contrib.auth.models import User

```
    class MyUserAdmin(UserAdmin):
```
```
        form = MyUserChangeForm
```
```
    admin.site.unregister(User)
```

    admin.site.register(User, MyUserAdmin)

``QuerySet.reverse()`` and ``last()`` are prohibited after slicing

------------------------------------------------------------------

Calling ``QuerySet.reverse()`` or ``last()`` on a sliced queryset leads to

unexpected results due to the slice being applied after reordering. This is

```
now prohibited, e.g.::
```

    >>> Model.objects.all()[:2].reverse()

```
    Traceback (most recent call last):
```
```
    ...
```

    TypeError: Cannot reverse a query once a slice has been taken.

Form fields no longer accept optional arguments as positional arguments

-----------------------------------------------------------------------

To help prevent runtime errors due to incorrect ordering of form field

arguments, optional arguments of built-in form fields are no longer accepted

```
as positional arguments. For example::
```
```
    forms.IntegerField(25, 10)
```

raises an exception and should be replaced with::

    forms.IntegerField(max_value=25, min_value=10)

``call_command()`` validates the options it receives

----------------------------------------------------

``call_command()`` now validates that the argument parser of the command being

called defines all of the options passed to ``call_command()``.

For custom management commands that use options not created using

``parser.add_argument()``, add a ``stealth_options`` attribute on the command::

```
    class MyCommand(BaseCommand):
```

        stealth_options = ('option_name', ...)

Indexes no longer accept positional arguments

---------------------------------------------

```
For example::
```

    models.Index(['headline', '-pub_date'], 'index_name')

raises an exception and should be replaced with::

    models.Index(fields=['headline', '-pub_date'], name='index_name')

Foreign key constraints are now enabled on SQLite

-------------------------------------------------

This will appear as a backwards-incompatible change (``IntegrityError:

FOREIGN KEY constraint failed``) if attempting to save an existing model

instance that's violating a foreign key constraint.

Foreign keys are now created with ``DEFERRABLE INITIALLY DEFERRED`` instead of

``DEFERRABLE IMMEDIATE``. Thus, tables may need to be rebuilt to recreate

foreign keys with the new definition, particularly if you're using a pattern

```
like this::
```
```
    from django.db import transaction
```
```
    with transaction.atomic():
```

        Book.objects.create(author_id=1)

```
        Author.objects.create(id=1)
```

If you don't recreate the foreign key as ``DEFERRED``, the first ``create()``

would fail now that foreign key constraints are enforced.

Backup your database first! After upgrading to Django 2.0, you can then

rebuild tables using a script similar to this::

```
    from django.apps import apps
```
```
    from django.db import connection
```
```
    for app in apps.get_app_configs():
```

        for model in app.get_models(include_auto_created=True):

            if model._meta.managed and not (model._meta.proxy or model._meta.swapped):

                for base in model.__bases__:

                    if hasattr(base, '_meta'):

                        base._meta.local_many_to_many = []

                model._meta.local_many_to_many = []

                with connection.schema_editor() as editor:

                    editor._remake_table(model)

This script hasn't received extensive testing and needs adaption for various

cases such as multiple databases. Feel free to contribute improvements.

In addition, because of a table alteration limitation of SQLite, it's prohibited

to perform :class:`~django.db.migrations.operations.RenameModel` and

:class:`~django.db.migrations.operations.RenameField` operations on models or

fields referenced by other models in a transaction. In order to allow migrations

containing these operations to be applied, you must set the

``Migration.atomic`` attribute to ``False``.

```
Miscellaneous
```
```
-------------
```

* The ``SessionAuthenticationMiddleware`` class is removed. It provided no

  functionality since session authentication is unconditionally enabled in

```
  Django 1.10.
```

* The default HTTP error handlers (``handler404``, etc.) are now callables

  instead of dotted Python path strings. Django favors callable references

  since they provide better performance and debugging experience.

* :class:`~django.views.generic.base.RedirectView` no longer silences

  ``NoReverseMatch`` if the ``pattern_name`` doesn't exist.

* When ``USE_L10N`` is off, :class:`~django.forms.FloatField` and

  :class:`~django.forms.DecimalField` now respect :setting:`DECIMAL_SEPARATOR`

  and :setting:`THOUSAND_SEPARATOR` during validation. For example, with the

```
  settings::
```
```
     USE_L10N = False
```
```
     USE_THOUSAND_SEPARATOR = True
```
```
     DECIMAL_SEPARATOR = ','
```
```
     THOUSAND_SEPARATOR = '.'
```

  an input of ``"1.345"`` is now converted to ``1345`` instead of ``1.345``.

* Subclasses of :class:`~django.contrib.auth.models.AbstractBaseUser` are no

  longer required to implement ``get_short_name()`` and ``get_full_name()``.

  (The base implementations that raise ``NotImplementedError`` are removed.)

  ``django.contrib.admin`` uses these methods if implemented but doesn't

  require them. Third-party apps that use these methods may want to adopt a

```
  similar approach.
```

* The ``FIRST_DAY_OF_WEEK`` and ``NUMBER_GROUPING`` format settings are now

  kept as integers in JavaScript and JSON i18n view outputs.

* :meth:`~django.test.TransactionTestCase.assertNumQueries` now ignores

  connection configuration queries. Previously, if a test opened a new database

  connection, those queries could be included as part of the

```
  ``assertNumQueries()`` count.
```

* The default size of the Oracle test tablespace is increased from 20M to 50M

  and the default autoextend size is increased from 10M to 25M.

* To improve performance when streaming large result sets from the database,

  :meth:`.QuerySet.iterator` now fetches 2000 rows at a time instead of 100.

  The old behavior can be restored using the ``chunk_size`` parameter. For

```
  example::
```

      Book.objects.iterator(chunk_size=100)

* Providing unknown package names in the ``packages`` argument of the

  :class:`~django.views.i18n.JavaScriptCatalog` view now raises ``ValueError``

```
  instead of passing silently.
```

* A model instance's primary key now appears in the default ``Model.__str__()``

  method, e.g. ``Question object (1)``.

* ``makemigrations`` now detects changes to the model field ``limit_choices_to``

  option. Add this to your existing migrations or accept an auto-generated

```
  migration for fields that use it.
```

* Performing queries that require :ref:`automatic spatial transformations

  <automatic-spatial-transformations>` now raises ``NotImplementedError``

  on MySQL instead of silently using non-transformed geometries.

* ``django.core.exceptions.DjangoRuntimeWarning`` is removed. It was only used

  in the cache backend as an intermediate class in ``CacheKeyWarning``'s

```
  inheritance of ``RuntimeWarning``.
```

* Renamed ``BaseExpression._output_field`` to ``output_field``. You may need

```
  to update custom expressions.
```

* In older versions, forms and formsets combine their ``Media`` with widget

  ``Media`` by concatenating the two. The combining now tries to :ref:`preserve

  the relative order of elements in each list <form-media-asset-order>`.

  ``MediaOrderConflictWarning`` is issued if the order can't be preserved.

* ``django.contrib.gis.gdal.OGRException`` is removed. It's been an alias for

```
  ``GDALException`` since Django 1.8.
```
```
* Support for GEOS 3.3.x is dropped.
```

* The way data is selected for ``GeometryField`` is changed to improve

  performance, and in raw SQL queries, those fields must now be wrapped in

  ``connection.ops.select``. See the :ref:`Raw queries note<gis-raw-sql>` in

```
  the GIS tutorial for an example.
```
```
.. _deprecated-features-2.0:
```
```
Features deprecated in 2.0
```
```
==========================
```

``context`` argument of ``Field.from_db_value()`` and ``Expression.convert_value()``

------------------------------------------------------------------------------------

The ``context`` argument of ``Field.from_db_value()`` and

``Expression.convert_value()`` is unused as it's always an empty dictionary.

```
The signature of both methods is now::
```

    (self, value, expression, connection)

```
instead of::
```

    (self, value, expression, connection, context)

Support for the old signature in custom fields and expressions remains until

```
Django 3.0.
```
```
Miscellaneous
```
```
-------------
```

* The ``django.db.backends.postgresql_psycopg2`` module is deprecated in favor

  of ``django.db.backends.postgresql``. It's been an alias since Django 1.9.

  This only affects code that imports from the module directly. The

```
  ``DATABASES`` setting can still use
```

  ``'django.db.backends.postgresql_psycopg2'``, though you can simplify that by

  using the ``'django.db.backends.postgresql'`` name added in Django 1.9.

* ``django.shortcuts.render_to_response()`` is deprecated in favor of

  :func:`django.shortcuts.render`. ``render()`` takes the same arguments

  except that it also requires a ``request``.

* The ``DEFAULT_CONTENT_TYPE`` setting is deprecated. It doesn't interact well

  with third-party apps and is obsolete since HTML5 has mostly superseded

```
  XHTML.
```

* ``HttpRequest.xreadlines()`` is deprecated in favor of iterating over the

```
  request.
```

* The ``field_name`` keyword argument to :meth:`.QuerySet.earliest` and

  :meth:`.QuerySet.latest` is deprecated in favor of passing the field

  names as arguments. Write ``.earliest('pub_date')`` instead of

  ``.earliest(field_name='pub_date')``.

```
.. _removed-features-2.0:
```
```
Features removed in 2.0
```
```
=======================
```

These features have reached the end of their deprecation cycle and are removed

```
in Django 2.0.
```

See :ref:`deprecated-features-1.9` for details on these changes, including how

```
to remove usage of these features.
```

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

```
  removed.
```

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

```
  is removed.
```

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

* The ``assignment_tag`` helper is removed.

* The ``host`` argument to ``SimpleTestCase.assertsRedirects()`` is removed.

  The compatibility layer which allows absolute URLs to be considered equal to

  relative ones when the path is identical is also removed.

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

* The ``on_delete`` argument for ``ForeignKey`` and ``OneToOneField`` is now

  required in models and migrations. Consider squashing migrations so that you

```
  have fewer of them to update.
```

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

* When time zone support is enabled, database backends that don't support time

  zones no longer convert aware datetimes to naive values in UTC anymore when

  such values are passed as parameters to SQL queries executed outside of the

```
  ORM, e.g. with ``cursor.execute()``.
```

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

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

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

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

  * ``django.template.engine.Engine.find_template()``

  * ``django.template.loader_tags.ExtendsNode.find_template()``

  * ``django.template.loaders.base.Loader.supports_recursion()``

  * ``django.template.loaders.cached.Loader.supports_recursion()``

* The ``load_template`` and ``load_template_sources`` template loader methods

```
  are removed.
```

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

  * ``django.template.loaders.base.Loader.get_template()``

  * ``django.template.loaders.cached.Loader.cache_key()``

  * ``django.template.loaders.cached.Loader.get_template()``

  * ``django.template.loaders.cached.Loader.get_template_sources()``

  * ``django.template.loaders.filesystem.Loader.get_template_sources()``

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

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

```
  is removed.
```

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

  ``django.utils.feedgenerator.RssFeed`` is removed.

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

* Support for passing a 3-tuple (including ``admin.site.urls``) as the first

  argument to ``include()`` is removed.

* Support for setting a URL instance namespace without an application namespace

```
  is removed.
```

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

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

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

```
  removed.
```

* The ``callable_obj`` keyword argument to

  ``SimpleTestCase.assertRaisesMessage()`` is removed.

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

```
  removed.
```

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

```
  removed.
```

* The ``django.template.loader.LoaderOrigin`` and

  ``django.template.base.StringOrigin`` aliases for

  ``django.template.base.Origin`` are removed.

See :ref:`deprecated-features-1.10` for details on these changes.

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

* Support for direct assignment to a reverse foreign key or many-to-many

```
  relation is removed.
```

* The ``get_srid()`` and ``set_srid()`` methods of

  ``django.contrib.gis.geos.GEOSGeometry`` are removed.

* The ``get_x()``, ``set_x()``, ``get_y()``, ``set_y()``, ``get_z()``, and

  ``set_z()`` methods of ``django.contrib.gis.geos.Point`` are removed.

* The ``get_coords()`` and ``set_coords()`` methods of

  ``django.contrib.gis.geos.Point`` are removed.

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

```
  is removed.
```

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

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

* The ``django.core.urlresolvers`` module is removed in favor of its new

```
  location, ``django.urls``.
```

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

```
  migrations.
```

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

* Support for the ``django.core.files.storage.Storage.accessed_time()``,

  ``created_time()``, and ``modified_time()`` methods is removed.

* Support for query lookups using the model name when

  ``Meta.default_related_name`` is set is removed.

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

* The shim for supporting custom related manager classes without a

  ``_apply_rel_filters()`` method is removed.

* Using ``User.is_authenticated()`` and ``User.is_anonymous()`` as methods

  rather than properties is no longer supported.

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

* The keyword arguments ``virtual_only`` in ``Field.contribute_to_class()`` and

  ``virtual`` in ``Model._meta.add_field()`` are removed.

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

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

* In multi-table inheritance, implicit promotion of a ``OneToOneField`` to a

```
  ``parent_link`` is removed.
```

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

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

```
  removed.
```

* The ``mark_for_escaping()`` function and the classes it uses: ``EscapeData``,

  ``EscapeBytes``, ``EscapeText``, ``EscapeString``, and ``EscapeUnicode`` are

```
  removed.
```

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

* ``Manager.use_for_related_fields`` is removed.

* Model ``Manager`` inheritance follows MRO inheritance rules. The requirement

  to use ``Meta.manager_inheritance_from_future`` to opt-in to the behavior is

```
  removed.
```

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

```
  removed.
```