Pin django to latest version 3.0

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This PR pins django to the latest release 3.0.

Changelog

3.0

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

*December 2, 2019*

Welcome to Django 3.0!

These release notes cover the :ref:`new features <whats-new-3.0>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-3.0>` you'll
want to be aware of when upgrading from Django 2.2 or earlier. We've
:ref:`dropped some features<removed-features-3.0>` that have reached the end of
their deprecation cycle, and we've :ref:`begun the deprecation process for
some features <deprecated-features-3.0>`.

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

Python compatibility
====================

Django 3.0 supports Python 3.6, 3.7, and 3.8. We **highly recommend** and only
officially support the latest release of each series.

The Django 2.2.x series is the last to support Python 3.5.

Third-party library support for older version of Django
=======================================================

Following the release of Django 3.0, we suggest that third-party app authors
drop support for all versions of Django prior to 2.2. At that time, you should
be able to run your package's tests using ``python -Wd`` so that deprecation
warnings appear. After making the deprecation warning fixes, your app should be
compatible with Django 3.0.

.. _whats-new-3.0:

What's new in Django 3.0
========================

MariaDB support
---------------

Django now officially supports `MariaDB <https://mariadb.org/>`_ 10.1 and
higher. See :ref:`MariaDB notes <mariadb-notes>` for more details.

ASGI support
------------

Django 3.0 begins our journey to making Django fully async-capable by providing
support for running as an `ASGI <https://asgi.readthedocs.io/>`_ application.

This is in addition to our existing WSGI support. Django intends to support
both for the foreseeable future. Async features will only be available to
applications that run under ASGI, however.

There is no need to switch your applications over unless you want to start
experimenting with asynchronous code, but we have
:doc:`documentation on deploying with ASGI </howto/deployment/asgi/index>` if
you want to learn more.

Note that as a side-effect of this change, Django is now aware of asynchronous
event loops and will block you calling code marked as "async unsafe" - such as
ORM operations - from an asynchronous context. If you were using Django from
async code before, this may trigger if you were doing it incorrectly. If you
see a ``SynchronousOnlyOperation`` error, then closely examine your code and
move any database operations to be in a synchronous child thread.

Exclusion constraints on PostgreSQL
-----------------------------------

The new :class:`~django.contrib.postgres.constraints.ExclusionConstraint` class
enable adding exclusion constraints on PostgreSQL. Constraints are added to
models using the
:attr:`Meta.constraints <django.db.models.Options.constraints>` option.

Filter expressions
------------------

Expressions that output :class:`~django.db.models.BooleanField` may now be
used directly in ``QuerySet`` filters, without having to first annotate and
then filter against the annotation.

Enumerations for model field choices
------------------------------------

Custom enumeration types ``TextChoices``, ``IntegerChoices``, and ``Choices``
are now available as a way to define :attr:`.Field.choices`. ``TextChoices``
and ``IntegerChoices`` types are provided for text and integer fields. The
``Choices`` class allows defining a compatible enumeration for other concrete
data types. These custom enumeration types support human-readable labels that
can be translated and accessed via a property on the enumeration or its
members. See :ref:`Enumeration types <field-choices-enum-types>` for more
details and examples.

Minor features
--------------

:mod:`django.contrib.admin`
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* Added support for the ``admin_order_field`` attribute on properties in
:attr:`.ModelAdmin.list_display`.

* The new :meth:`ModelAdmin.get_inlines()
<django.contrib.admin.ModelAdmin.get_inlines>` method allows specifying the
inlines based on the request or model instance.

* Select2 library is upgraded from version 4.0.3 to 4.0.7.

* jQuery is upgraded from version 3.3.1 to 3.4.1.

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

* The new ``reset_url_token`` attribute in
:class:`~django.contrib.auth.views.PasswordResetConfirmView` allows
specifying a token parameter displayed as a component of password reset
URLs.

* Added :class:`~django.contrib.auth.backends.BaseBackend` class to ease
customization of authentication backends.

* Added :meth:`~django.contrib.auth.models.User.get_user_permissions()` method
to mirror the existing
:meth:`~django.contrib.auth.models.User.get_group_permissions()` method.

* Added HTML ``autocomplete`` attribute to widgets of username, email, and
password fields in :mod:`django.contrib.auth.forms` for better interaction
with browser password managers.

* :djadmin:`createsuperuser` now falls back to environment variables for
password and required fields, when a corresponding command line argument
isn't provided in non-interactive mode.

* :attr:`~django.contrib.auth.models.CustomUser.REQUIRED_FIELDS` now supports
:class:`~django.db.models.ManyToManyField`\s.

* The new :meth:`.UserManager.with_perm` method returns users that have the
specified permission.

* The default iteration count for the PBKDF2 password hasher is increased from
150,000 to 180,000.

:mod:`django.contrib.gis`
~~~~~~~~~~~~~~~~~~~~~~~~~

* Allowed MySQL spatial lookup functions to operate on real geometries.
Previous support was limited to bounding boxes.

* Added the :class:`~django.contrib.gis.db.models.functions.GeometryDistance`
function, supported on PostGIS.

* Added support for the ``furlong`` unit in
:class:`~django.contrib.gis.measure.Distance`.

* The :setting:`GEOIP_PATH` setting now supports :class:`pathlib.Path`.

* The :class:`~django.contrib.gis.geoip2.GeoIP2` class now accepts
:class:`pathlib.Path` ``path``.

:mod:`django.contrib.postgres`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* The new :class:`~django.contrib.postgres.fields.RangeOperators` helps to
avoid typos in SQL operators that can be used together with
:class:`~django.contrib.postgres.fields.RangeField`.

* The new :class:`~django.contrib.postgres.fields.RangeBoundary` expression
represents the range boundaries.

* The new :class:`~django.contrib.postgres.operations.AddIndexConcurrently`
and :class:`~django.contrib.postgres.operations.RemoveIndexConcurrently`
classes allow creating and dropping indexes ``CONCURRENTLY`` on PostgreSQL.

:mod:`django.contrib.sessions`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* The new
:meth:`~django.contrib.sessions.backends.base.SessionBase.get_session_cookie_age()`
method allows dynamically specifying the session cookie age.

:mod:`django.contrib.syndication`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* Added the ``language`` class attribute to the
:class:`django.contrib.syndication.views.Feed` to customize a feed language.
The default value is :func:`~django.utils.translation.get_language()` instead
of :setting:`LANGUAGE_CODE`.

Cache
~~~~~

* :func:`~django.utils.cache.add_never_cache_headers` and
:func:`~django.views.decorators.cache.never_cache` now add the ``private``
directive to ``Cache-Control`` headers.

File Storage
~~~~~~~~~~~~

* The new :meth:`.Storage.get_alternative_name` method allows customizing the
algorithm for generating filenames if a file with the uploaded name already
exists.

Forms
~~~~~

* Formsets may control the widget used when ordering forms via
:attr:`~django.forms.formsets.BaseFormSet.can_order` by setting the
:attr:`~django.forms.formsets.BaseFormSet.ordering_widget` attribute or
overriding :attr:`~django.forms.formsets.BaseFormSet.get_ordering_widget()`.

Internationalization
~~~~~~~~~~~~~~~~~~~~

* Added the :setting:`LANGUAGE_COOKIE_HTTPONLY`,
:setting:`LANGUAGE_COOKIE_SAMESITE`, and :setting:`LANGUAGE_COOKIE_SECURE`
settings to set the ``HttpOnly``, ``SameSite``, and ``Secure`` flags on
language cookies. The default values of these settings preserve the previous
behavior.

* Added support and translations for the Uzbek language.

Logging
~~~~~~~

* The new ``reporter_class`` parameter of
:class:`~django.utils.log.AdminEmailHandler` allows providing an
``django.views.debug.ExceptionReporter`` subclass to customize the traceback
text sent to site :setting:`ADMINS` when :setting:`DEBUG` is ``False``.

Management Commands
~~~~~~~~~~~~~~~~~~~

* The new :option:`compilemessages --ignore` option allows ignoring specific
directories when searching for ``.po`` files to compile.

* :option:`showmigrations --list` now shows the applied datetimes when
``--verbosity`` is 2 and above.

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

* :djadmin:`inspectdb` now introspects :class:`~django.db.models.OneToOneField`
when a foreign key has a unique or primary key constraint.

* The new :option:`--skip-checks` option skips running system checks prior to
running the command.

* The :option:`startapp --template` and :option:`startproject --template`
options now support templates stored in XZ archives (``.tar.xz``, ``.txz``)
and LZMA archives (``.tar.lzma``, ``.tlz``).

Models
~~~~~~

* Added hash database functions :class:`~django.db.models.functions.MD5`,
:class:`~django.db.models.functions.SHA1`,
:class:`~django.db.models.functions.SHA224`,
:class:`~django.db.models.functions.SHA256`,
:class:`~django.db.models.functions.SHA384`, and
:class:`~django.db.models.functions.SHA512`.

* Added the :class:`~django.db.models.functions.Sign` database function.

* The new ``is_dst``  parameter of the
:class:`~django.db.models.functions.Trunc` database functions determines the
treatment of nonexistent and ambiguous datetimes.

* ``connection.queries`` now shows ``COPY … TO`` statements on PostgreSQL.

* :class:`~django.db.models.FilePathField` now accepts a callable for ``path``.

* Allowed symmetrical intermediate table for self-referential
:class:`~django.db.models.ManyToManyField`.

* The ``name`` attributes of :class:`~django.db.models.CheckConstraint`,
:class:`~django.db.models.UniqueConstraint`, and
:class:`~django.db.models.Index` now support app label and class
interpolation using the ``'%(app_label)s'`` and ``'%(class)s'`` placeholders.

* The new :attr:`.Field.descriptor_class` attribute allows model fields to
customize the get and set behavior by overriding their
:py:ref:`descriptors <descriptors>`.

* :class:`~django.db.models.Avg` and :class:`~django.db.models.Sum` now support
the ``distinct`` argument.

* Added :class:`~django.db.models.SmallAutoField` which acts much like an
:class:`~django.db.models.AutoField` except that it only allows values under
a certain (database-dependent) limit. Values from ``1`` to ``32767`` are safe
in all databases supported by Django.

* :class:`~django.db.models.AutoField`,
:class:`~django.db.models.BigAutoField`, and
:class:`~django.db.models.SmallAutoField` now inherit from
``IntegerField``, ``BigIntegerField`` and ``SmallIntegerField`` respectively.
System checks and validators are now also properly inherited.

* :attr:`.FileField.upload_to` now supports :class:`pathlib.Path`.

* :class:`~django.db.models.CheckConstraint` is now supported on MySQL 8.0.16+.

* The new ``allows_group_by_selected_pks_on_model()`` method of
``django.db.backends.base.BaseDatabaseFeatures`` allows optimization of
``GROUP BY`` clauses to require only the selected models' primary keys. By
default, it's supported only for managed models on PostgreSQL.

To enable the ``GROUP BY`` primary key-only optimization for unmanaged
models, you have to subclass the PostgreSQL database engine, overriding the
features class ``allows_group_by_selected_pks_on_model()`` method as you
require. See :ref:`Subclassing the built-in database backends
<subclassing-database-backends>` for an example.

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

* Allowed :class:`~django.http.HttpResponse` to be initialized with
:class:`memoryview` content.

* For use in, for example, Django templates, :attr:`.HttpRequest.headers` now
allows look ups using underscores (e.g. ``user_agent``) in place of hyphens.

.. _whats-new-security-3.0:

Security
~~~~~~~~

* :setting:`X_FRAME_OPTIONS` now defaults to ``'DENY'``. In older versions, the
:setting:`X_FRAME_OPTIONS` setting defaults to ``'SAMEORIGIN'``. If your site
uses frames of itself, you will need to explicitly set ``X_FRAME_ORIGINS =
'SAMEORIGIN'`` for them to continue working.

* :setting:`SECURE_CONTENT_TYPE_NOSNIFF` setting now defaults to ``True``. With
the enabled :setting:`SECURE_CONTENT_TYPE_NOSNIFF`, the
:class:`~django.middleware.security.SecurityMiddleware` sets the
:ref:`x-content-type-options` header on all responses that do not already
have it.

* :class:`~django.middleware.security.SecurityMiddleware` can now send the
:ref:`Referrer-Policy <referrer-policy>` header.

Tests
~~~~~

* The new test :class:`~django.test.Client` argument
``raise_request_exception`` allows controlling whether or not exceptions
raised during the request should also be raised in the test. The value
defaults to ``True`` for backwards compatibility. If it is ``False`` and an
exception occurs, the test client will return a 500 response with the
attribute :attr:`~django.test.Response.exc_info`, a tuple providing
information of the exception that occurred.

* Tests and test cases to run can be selected by test name pattern using the
new :option:`test -k` option.

* HTML comparison, as used by
:meth:`~django.test.SimpleTestCase.assertHTMLEqual`, now treats text, character
references, and entity references that refer to the same character as
equivalent.

* Django test runner now supports headless mode for selenium tests on supported
browsers. Add the ``--headless`` option to enable this mode.

* Django test runner now supports ``--start-at`` and ``--start-after`` options
to run tests starting from a specific top-level module.

* Django test runner now supports a ``--pdb`` option to spawn a debugger at
each error or failure.

.. _backwards-incompatible-3.0:

Backwards incompatible changes in 3.0
=====================================

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

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

* The second argument of ``DatabaseIntrospection.get_geometry_type()`` is now
the row description instead of the column name.

* ``DatabaseIntrospection.get_field_type()`` may no longer return tuples.

* If the database can create foreign keys in the same SQL statement that adds a
field, add ``SchemaEditor.sql_create_column_inline_fk`` with the appropriate
SQL; otherwise, set ``DatabaseFeatures.can_create_inline_fk = False``.

* ``DatabaseFeatures.can_return_id_from_insert`` and
``can_return_ids_from_bulk_insert`` are renamed to
``can_return_columns_from_insert`` and ``can_return_rows_from_bulk_insert``.

* Database functions now handle :class:`datetime.timezone` formats when created
using :class:`datetime.timedelta` instances (e.g.
``timezone(timedelta(hours=5))``, which would output ``'UTC+05:00'``).
Third-party backends should handle this format when preparing
:class:`~django.db.models.DateTimeField` in ``datetime_cast_date_sql()``,
``datetime_extract_sql()``, etc.

* Entries for ``AutoField``, ``BigAutoField``, and ``SmallAutoField`` are added
to  ``DatabaseOperations.integer_field_ranges`` to support the integer range
validators on these field types. Third-party backends may need to customize
the default entries.

* ``DatabaseOperations.fetch_returned_insert_id()`` is replaced by
``fetch_returned_insert_columns()`` which returns a list of values returned
by the ``INSERT … RETURNING`` statement, instead of a single value.

* ``DatabaseOperations.return_insert_id()`` is replaced by
``return_insert_columns()`` that accepts a ``fields``
argument, which is an iterable of fields to be returned after insert. Usually
this is only the auto-generated primary key.

:mod:`django.contrib.admin`
---------------------------

* Admin's model history change messages now prefers more readable field labels
instead of field names.

:mod:`django.contrib.gis`
-------------------------

* Support for PostGIS 2.1 is removed.

* Support for SpatiaLite 4.1 and 4.2 is removed.

* Support for GDAL 1.11 and GEOS 3.4 is removed.

Dropped support for PostgreSQL 9.4
----------------------------------

Upstream support for PostgreSQL 9.4 ends in December 2019. Django 3.0 supports
PostgreSQL 9.5 and higher.

Dropped support for Oracle 12.1
-------------------------------

Upstream support for Oracle 12.1 ends in July 2021. Django 2.2 will be
supported until April 2022. Django 3.0 officially supports Oracle 12.2 and 18c.

Removed private Python 2 compatibility APIs
-------------------------------------------

While Python 2 support was removed in Django 2.0, some private APIs weren't
removed from Django so that third party apps could continue using them until
the Python 2 end-of-life.

Since we expect apps to drop Python 2 compatibility when adding support for
Django 3.0, we're removing these APIs at this time.

* ``django.test.utils.str_prefix()`` - Strings don't have 'u' prefixes in
Python 3.

* ``django.test.utils.patch_logger()`` - Use
:meth:`unittest.TestCase.assertLogs` instead.

* ``django.utils.lru_cache.lru_cache()`` - Alias of
:func:`functools.lru_cache`.

* ``django.utils.decorators.available_attrs()`` - This function returns
``functools.WRAPPER_ASSIGNMENTS``.

* ``django.utils.decorators.ContextDecorator`` - Alias of
:class:`contextlib.ContextDecorator`.

* ``django.utils._os.abspathu()`` - Alias of :func:`os.path.abspath`.

* ``django.utils._os.upath()`` and ``npath()`` - These functions do nothing on
Python 3.

* ``django.utils.six`` - Remove usage of this vendored library or switch to
`six <https://pypi.org/project/six/>`_.

* ``django.utils.encoding.python_2_unicode_compatible()`` - Alias of
``six.python_2_unicode_compatible()``.

* ``django.utils.functional.curry()`` - Use :func:`functools.partial` or
:class:`functools.partialmethod`. See :commit:`5b1c389603a353625ae1603`.

* ``django.utils.safestring.SafeBytes`` - Unused since Django 2.0.

New default value for the ``FILE_UPLOAD_PERMISSIONS`` setting
-------------------------------------------------------------

In older versions, the :setting:`FILE_UPLOAD_PERMISSIONS` setting defaults to
``None``. With the default :setting:`FILE_UPLOAD_HANDLERS`, this results in
uploaded files having different permissions depending on their size and which
upload handler is used.

``FILE_UPLOAD_PERMISSION`` now defaults to ``0o644`` to avoid this
inconsistency.

New default values for security settings
----------------------------------------

To make Django projects more secure by default, some security settings now have
more secure default values:

* :setting:`X_FRAME_OPTIONS` now defaults to ``'DENY'``.

* :setting:`SECURE_CONTENT_TYPE_NOSNIFF` now defaults to ``True``.

See the *What's New* :ref:`Security section <whats-new-security-3.0>` above for
more details on these changes.

Miscellaneous
-------------

* ``ContentType.__str__()`` now includes the model's ``app_label`` to
disambiguate model's with the same name in different apps.

* Because accessing the language in the session rather than in the cookie is
deprecated, ``LocaleMiddleware`` no longer looks for the user's language in
the session and :func:`django.contrib.auth.logout` no longer preserves the
session's language after logout.

* :func:`django.utils.html.escape` now uses :func:`html.escape` to escape HTML.
This converts ``'`` to ``&x27;`` instead of the previous equivalent decimal
code ``&39;``.

* The ``django-admin test -k`` option now works as the :option:`unittest
-k<unittest.-k>` option rather than as a shortcut for ``--keepdb``.

* Support for ``pywatchman`` < 1.2.0 is removed.

* :func:`~django.utils.http.urlencode` now encodes iterable values as they are
when ``doseq=False``, rather than iterating them, bringing it into line with
the standard library :func:`urllib.parse.urlencode` function.

* ``intword`` template filter now translates ``1.0`` as a singular phrase and
all other numeric values as plural. This may be incorrect for some languages.

* Assigning a value to a model's :class:`~django.db.models.ForeignKey` or
:class:`~django.db.models.OneToOneField` ``'_id'`` attribute now unsets the
corresponding field. Accessing the field afterwards will result in a query.

* :func:`~django.utils.cache.patch_vary_headers` now handles an asterisk
``'*'`` according to :rfc:`7231section-7.1.4`, i.e. if a list of header
field names contains an asterisk, then the ``Vary`` header will consist of a
single asterisk ``'*'``.

* On MySQL 8.0.16+, ``PositiveIntegerField`` and ``PositiveSmallIntegerField``
now include a check constraint to prevent negative values in the database.

* ``alias=None`` is added to the signature of
:meth:`.Expression.get_group_by_cols`.

* Support for ``sqlparse`` < 0.2.2 is removed.

.. _deprecated-features-3.0:

Features deprecated in 3.0
==========================

``django.utils.encoding.force_text()`` and ``smart_text()``
-----------------------------------------------------------

The ``smart_text()`` and ``force_text()`` aliases (since Django 2.0) of
``smart_str()`` and ``force_str()`` are deprecated. Ignore this deprecation if
your code supports Python 2 as the behavior of ``smart_str()`` and
``force_str()`` is different there.

Miscellaneous
-------------

* ``django.utils.http.urlquote()``, ``urlquote_plus()``, ``urlunquote()``, and
``urlunquote_plus()`` are deprecated in favor of the functions that they're
aliases for: :func:`urllib.parse.quote`, :func:`~urllib.parse.quote_plus`,
:func:`~urllib.parse.unquote`, and :func:`~urllib.parse.unquote_plus`.

* ``django.utils.translation.ugettext()``, ``ugettext_lazy()``,
``ugettext_noop()``, ``ungettext()``, and ``ungettext_lazy()`` are deprecated
in favor of the functions that they're aliases for:
:func:`django.utils.translation.gettext`,
:func:`~django.utils.translation.gettext_lazy`,
:func:`~django.utils.translation.gettext_noop`,
:func:`~django.utils.translation.ngettext`, and
:func:`~django.utils.translation.ngettext_lazy`.

* To limit creation of sessions and hence favor some caching strategies,
:func:`django.views.i18n.set_language` will stop setting the user's language
in the session in Django 4.0. Since Django 2.1, the language is always stored
in the :setting:`LANGUAGE_COOKIE_NAME` cookie.

* ``django.utils.text.unescape_entities()`` is deprecated in favor of
:func:`html.unescape`. Note that unlike ``unescape_entities()``,
``html.unescape()`` evaluates lazy strings immediately.

* To avoid possible confusion as to effective scope, the private internal
utility ``is_safe_url()`` is renamed to
``url_has_allowed_host_and_scheme()``. That a URL has an allowed host and
scheme doesn't in general imply that it's "safe". It may still be quoted
incorrectly, for example. Ensure to also use
:func:`~django.utils.encoding.iri_to_uri` on the path component of untrusted
URLs.

.. _removed-features-3.0:

Features removed in 3.0
=======================

These features have reached the end of their deprecation cycle and are removed
in Django 3.0.

See :ref:`deprecated-features-2.0` for details on these changes, including how
to remove usage of these features.

* The ``django.db.backends.postgresql_psycopg2`` module is removed.

* ``django.shortcuts.render_to_response()`` is removed.

* The ``DEFAULT_CONTENT_TYPE`` setting is removed.

* ``HttpRequest.xreadlines()`` is removed.

* Support for the ``context`` argument of ``Field.from_db_value()`` and
``Expression.convert_value()`` is removed.

* The ``field_name`` keyword argument of ``QuerySet.earliest()`` and
``latest()`` is removed.

See :ref:`deprecated-features-2.1` for details on these changes, including how
to remove usage of these features.

* The ``ForceRHR`` GIS function is removed.

* ``django.utils.http.cookie_date()`` is removed.

* The ``staticfiles`` and ``admin_static`` template tag libraries are removed.

* ``django.contrib.staticfiles.templatetags.staticfiles.static()`` is removed.


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

2.2.8

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

*December 2, 2019*

Django 2.2.8 fixes a security issue, several bugs in 2.2.7, and adds
compatibility with Python 3.8.

CVE-2019-19118: Privilege escalation in the Django admin.
=========================================================

Since Django 2.1, a Django model admin displaying a parent model with related
model inlines, where the user has view-only permissions to a parent model but
edit permissions to the inline model, would display a read-only view of the
parent model but editable forms for the inline.

Submitting these forms would not allow direct edits to the parent model, but
would trigger the parent model's ``save()`` method, and cause pre and post-save
signal handlers to be invoked. This is a privilege escalation as a user who
lacks permission to edit a model should not be able to trigger its save-related
signals.

To resolve this issue, the permission handling code of the Django admin
interface has been changed. Now, if a user has only the "view" permission for a
parent model, the entire displayed form will not be editable, even if the user
has permission to edit models included in inlines.

This is a backwards-incompatible change, and the Django security team is aware
that some users of Django were depending on the ability to allow editing of
inlines in the admin form of an otherwise view-only parent model.

Given the complexity of the Django admin, and in-particular the permissions
related checks, it is the view of the Django security team that this change was
necessary: that it is not currently feasible to maintain the existing behavior
whilst escaping the potential privilege escalation in a way that would avoid a
recurrence of similar issues in the future, and that would be compatible with
Django's *safe by default* philosophy.

For the time being, developers whose applications are affected by this change
should replace the use of inlines in read-only parents with custom forms and
views that explicitly implement the desired functionality. In the longer term,
adding a documented, supported, and properly-tested mechanism for
partially-editable multi-model forms to the admin interface may occur in Django
itself.

Bugfixes
========

* Fixed a data loss possibility in the admin changelist view when a custom
:ref:`formset's prefix <formset-prefix>` contains regular expression special
characters, e.g. `'$'` (:ticket:`31031`).

* Fixed a regression in Django 2.2.1 that caused a crash when migrating
permissions for proxy models with a multiple database setup if the
``default`` entry was empty (:ticket:`31021`).

* Fixed a data loss possibility in the
:meth:`~django.db.models.query.QuerySet.select_for_update()`. When using
``'self'`` in the ``of`` argument with :ref:`multi-table inheritance
<multi-table-inheritance>`, a parent model was locked instead of the
queryset's model (:ticket:`30953`).


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

2.2.7

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

*November 4, 2019*

Django 2.2.7 fixes several bugs in 2.2.6.

Bugfixes
========

* Fixed a crash when using a ``contains``, ``contained_by``, ``has_key``,
``has_keys``, or ``has_any_keys`` lookup on
:class:`~django.contrib.postgres.fields.JSONField`, if the right or left hand
side of an expression is a key transform (:ticket:`30826`).

* Prevented :option:`migrate --plan` from showing that ``RunPython`` operations
are irreversible when ``reverse_code`` callables don't have docstrings or
when showing a forward migration plan (:ticket:`30870`).

* Fixed migrations crash on PostgreSQL when adding an
:class:`~django.db.models.Index` with fields ordering and
:attr:`~.Index.opclasses` (:ticket:`30903`).

* Restored the ability to override
:meth:`~django.db.models.Model.get_FOO_display` (:ticket:`30931`).


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

2.2.6

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

*October 1, 2019*

Django 2.2.6 fixes several bugs in 2.2.5.

Bugfixes
========

* Fixed migrations crash on SQLite when altering a model containing partial
indexes (:ticket:`30754`).

* Fixed a regression in Django 2.2.4 that caused a crash when filtering with a
``Subquery()`` annotation of a queryset containing
:class:`~django.contrib.postgres.fields.JSONField` or
:class:`~django.contrib.postgres.fields.HStoreField` (:ticket:`30769`).


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

2.2.5

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

*September 2, 2019*

Django 2.2.5 fixes several bugs in 2.2.4.

Bugfixes
========

* Relaxed the system check added in Django 2.2 for models to reallow use of the
same ``db_table`` by multiple models when database routers are installed
(:ticket:`30673`).

* Fixed crash of ``KeyTransform()`` for
:class:`~django.contrib.postgres.fields.JSONField` and
:class:`~django.contrib.postgres.fields.HStoreField` when using on
expressions with params (:ticket:`30672`).

* Fixed a regression in Django 2.2 where
:attr:`ModelAdmin.list_filter <django.contrib.admin.ModelAdmin.list_filter>`
choices to foreign objects don't respect a model's ``Meta.ordering``
(:ticket:`30449`).


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

2.2.4

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

*August 1, 2019*

Django 2.2.4 fixes security issues and several bugs in 2.2.3.

CVE-2019-14232: Denial-of-service possibility in ``django.utils.text.Truncator``
================================================================================

If ``django.utils.text.Truncator``'s ``chars()`` and ``words()`` methods
were passed the ``html=True`` argument, they were extremely slow to evaluate
certain inputs due to a catastrophic backtracking vulnerability in a regular
expression. The ``chars()`` and ``words()`` methods are used to implement the
:tfilter:`truncatechars_html` and :tfilter:`truncatewords_html` template
filters, which were thus vulnerable.

The regular expressions used by ``Truncator`` have been simplified in order to
avoid potential backtracking issues. As a consequence, trailing punctuation may
now at times be included in the truncated output.

CVE-2019-14233: Denial-of-service possibility in ``strip_tags()``
=================================================================

Due to the behavior of the underlying ``HTMLParser``,
:func:`django.utils.html.strip_tags` would be extremely slow to evaluate
certain inputs containing large sequences of nested incomplete HTML entities.
The ``strip_tags()`` method is used to implement the corresponding
:tfilter:`striptags` template filter, which was thus also vulnerable.

``strip_tags()`` now avoids recursive calls to ``HTMLParser`` when progress
removing tags, but necessarily incomplete HTML entities, stops being made.

Remember that absolutely NO guarantee is provided about the results of
``strip_tags()`` being HTML safe. So NEVER mark safe the result of a
``strip_tags()`` call without escaping it first, for example with
:func:`django.utils.html.escape`.

CVE-2019-14234: SQL injection possibility in key and index lookups for ``JSONField``/``HStoreField``
====================================================================================================

:lookup:`Key and index lookups <jsonfield.key>` for
:class:`~django.contrib.postgres.fields.JSONField` and :lookup:`key lookups
<hstorefield.key>` for :class:`~django.contrib.postgres.fields.HStoreField`
were subject to SQL injection, using a suitably crafted dictionary, with
dictionary expansion, as the ``**kwargs`` passed to ``QuerySet.filter()``.

CVE-2019-14235: Potential memory exhaustion in ``django.utils.encoding.uri_to_iri()``
=====================================================================================

If passed certain inputs, :func:`django.utils.encoding.uri_to_iri` could lead
to significant memory usage due to excessive recursion when re-percent-encoding
invalid UTF-8 octet sequences.

``uri_to_iri()`` now avoids recursion when re-percent-encoding invalid UTF-8
octet sequences.

Bugfixes
========

* Fixed a regression in Django 2.2 when ordering a ``QuerySet.union()``,
``intersection()``, or ``difference()`` by a field type present more than
once results in the wrong ordering being used (:ticket:`30628`).

* Fixed a migration crash on PostgreSQL when adding a check constraint
with a ``contains`` lookup on
:class:`~django.contrib.postgres.fields.DateRangeField` or
:class:`~django.contrib.postgres.fields.DateTimeRangeField`, if the right
hand side of an expression is the same type (:ticket:`30621`).

* Fixed a regression in Django 2.2 where auto-reloader crashes if a file path
contains nulls characters (``'\x00'``) (:ticket:`30506`).

* Fixed a regression in Django 2.2 where auto-reloader crashes if a translation
directory cannot be resolved (:ticket:`30647`).


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

2.2.3

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

*July 1, 2019*

Django 2.2.3 fixes a security issue and several bugs in 2.2.2. Also, the latest
string translations from Transifex are incorporated.

CVE-2019-12781: Incorrect HTTP detection with reverse-proxy connecting via HTTPS
--------------------------------------------------------------------------------

When deployed behind a reverse-proxy connecting to Django via HTTPS,
:attr:`django.http.HttpRequest.scheme` would incorrectly detect client
requests made via HTTP as using HTTPS. This entails incorrect results for
:meth:`~django.http.HttpRequest.is_secure`, and
:meth:`~django.http.HttpRequest.build_absolute_uri`, and that HTTP
requests would not be redirected to HTTPS in accordance with
:setting:`SECURE_SSL_REDIRECT`.

``HttpRequest.scheme`` now respects :setting:`SECURE_PROXY_SSL_HEADER`, if it is
configured, and the appropriate header is set on the request, for both HTTP and
HTTPS requests.

If you deploy Django behind a reverse-proxy that forwards HTTP requests, and
that connects to Django via HTTPS, be sure to verify that your application
correctly handles code paths relying on ``scheme``, ``is_secure()``,
``build_absolute_uri()``, and ``SECURE_SSL_REDIRECT``.

Bugfixes
========

* Fixed a regression in Django 2.2 where :class:`~django.db.models.Avg`,
:class:`~django.db.models.StdDev`, and :class:`~django.db.models.Variance`
crash with ``filter`` argument (:ticket:`30542`).

* Fixed a regression in Django 2.2.2 where auto-reloader crashes with
``AttributeError``, e.g. when using ``ipdb`` (:ticket:`30588`).


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

2.2.2

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

*June 3, 2019*

Django 2.2.2 fixes security issues and several bugs in 2.2.1.

CVE-2019-12308: AdminURLFieldWidget XSS
---------------------------------------

The clickable "Current URL" link generated by ``AdminURLFieldWidget`` displayed
the provided value without validating it as a safe URL. Thus, an unvalidated
value stored in the database, or a value provided as a URL query parameter
payload, could result in an clickable JavaScript link.

``AdminURLFieldWidget`` now validates the provided value using
:class:`~django.core.validators.URLValidator` before displaying the clickable
link. You may customize the validator by passing a ``validator_class`` kwarg to
``AdminURLFieldWidget.__init__()``, e.g. when using
:attr:`~django.contrib.admin.ModelAdmin.formfield_overrides`.

Patched bundled jQuery for CVE-2019-11358: Prototype pollution
--------------------------------------------------------------

jQuery before 3.4.0, mishandles ``jQuery.extend(true, {}, ...)`` because of
``Object.prototype`` pollution. If an unsanitized source object contained an
enumerable ``__proto__`` property, it could extend the native
``Object.prototype``.

The bundled version of jQuery used by the Django admin has been patched to
allow for the ``select2`` library's use of ``jQuery.extend()``.

Bugfixes
========

* Fixed a regression in Django 2.2 that stopped Show/Hide toggles working on
dynamically added admin inlines (:ticket:`30459`).

* Fixed a regression in Django 2.2 where deprecation message crashes if
``Meta.ordering`` contains an expression (:ticket:`30463`).

* Fixed a regression in Django 2.2.1 where
:class:`~django.contrib.postgres.search.SearchVector` generates SQL with a
redundant ``Coalesce`` call (:ticket:`30488`).

* Fixed a regression in Django 2.2 where auto-reloader doesn't detect changes
in ``manage.py`` file when using ``StatReloader`` (:ticket:`30479`).

* Fixed crash of :class:`~django.contrib.postgres.aggregates.ArrayAgg` and
:class:`~django.contrib.postgres.aggregates.StringAgg` with ``ordering``
argument when used in a ``Subquery`` (:ticket:`30315`).

* Fixed a regression in Django 2.2 that caused a crash of auto-reloader when
an exception with custom signature is raised (:ticket:`30516`).

* Fixed a regression in Django 2.2.1 where auto-reloader unnecessarily reloads
translation files multiple times when using ``StatReloader``
(:ticket:`30523`).


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

2.2.1

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

*May 1, 2019*

Django 2.2.1 fixes several bugs in 2.2.

Bugfixes
========

* Fixed a regression in Django 2.1 that caused the incorrect quoting of
database user password when using :djadmin:`dbshell` on Oracle
(:ticket:`30307`).

* Added compatibility for ``psycopg2`` 2.8 (:ticket:`30331`).

* Fixed a regression in Django 2.2 that caused a crash when loading the
template for the technical 500 debug page (:ticket:`30324`).

* Fixed crash of ``ordering`` argument in
:class:`~django.contrib.postgres.aggregates.ArrayAgg` and
:class:`~django.contrib.postgres.aggregates.StringAgg` when it contains an
expression with params (:ticket:`30332`).

* Fixed a regression in Django 2.2 that caused a single instance fast-delete
to not set the primary key to ``None`` (:ticket:`30330`).

* Prevented :djadmin:`makemigrations` from generating infinite migrations for
check constraints and partial indexes when ``condition`` contains
a :class:`~python:range` object (:ticket:`30350`).

* Reverted an optimization in Django 2.2 (:ticket:`29725`) that caused the
inconsistent behavior of ``count()`` and ``exists()`` on a reverse
many-to-many relationship with a custom manager (:ticket:`30325`).

* Fixed a regression in Django 2.2 where
:class:`~django.core.paginator.Paginator` crashes if ``object_list`` is
a queryset ordered or aggregated over a nested ``JSONField`` key transform
(:ticket:`30335`).

* Fixed a regression in Django 2.2 where ``IntegerField`` validation of
database limits crashes if ``limit_value`` attribute in a custom validator is
callable (:ticket:`30328`).

* Fixed a regression in Django 2.2 where
:class:`~django.contrib.postgres.search.SearchVector` generates SQL that is
not indexable (:ticket:`30385`).

* Fixed a regression in Django 2.2 that caused an exception to be raised when
a custom error handler could not be imported (:ticket:`30318`).

* Relaxed the system check added in Django 2.2 for the admin app's dependencies
to reallow use of
:class:`~django.contrib.sessions.middleware.SessionMiddleware` subclasses,
rather than requiring :mod:`django.contrib.sessions` to be in
:setting:`INSTALLED_APPS` (:ticket:`30312`).

* Increased the default timeout when using ``Watchman`` to 5 seconds to prevent
falling back to ``StatReloader`` on larger projects and made it customizable
via the ``DJANGO_WATCHMAN_TIMEOUT`` environment variable (:ticket:`30361`).

* Fixed a regression in Django 2.2 that caused a crash when migrating
permissions for proxy models if the target permissions already existed. For
example, when a permission had been created manually or a model had been
migrated from concrete to proxy (:ticket:`30351`).

* Fixed a regression in Django 2.2 that caused a crash of :djadmin:`runserver`
when URLConf modules raised exceptions (:ticket:`30323`).

* Fixed a regression in Django 2.2 where changes were not reliably detected by
auto-reloader when using ``StatReloader`` (:ticket:`30323`).

* Fixed a migration crash on Oracle and PostgreSQL when adding a check
constraint with a ``contains``, ``startswith``, or ``endswith`` lookup (or
their case-insensitive variant) (:ticket:`30408`).

* Fixed a migration crash on Oracle and SQLite when adding a check constraint
with ``condition`` contains ``|`` (``OR``) operator (:ticket:`30412`).


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

2.2

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

*April 1, 2019*

Welcome to Django 2.2!

These release notes cover the :ref:`new features <whats-new-2.2>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-2.2>` you'll
want to be aware of when upgrading from Django 2.1 or earlier. We've
:ref:`begun the deprecation process for some features
<deprecated-features-2.2>`.

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

Django 2.2 is designated as a :term:`long-term support release`. It will
receive security updates for at least three years after its release. Support
for the previous LTS, Django 1.11, will end in April 2020.

Python compatibility
====================

Django 2.2 supports Python 3.5, 3.6, 3.7, and 3.8 (as of 2.2.8). We
**highly recommend** and only officially support the latest release of each
series.

.. _whats-new-2.2:

What's new in Django 2.2
========================

Constraints
-----------

The new :class:`~django.db.models.CheckConstraint` and
:class:`~django.db.models.UniqueConstraint` classes enable adding custom
database constraints. Constraints are added to models using the
:attr:`Meta.constraints <django.db.models.Options.constraints>` option.

Minor features
--------------

:mod:`django.contrib.admin`
~~~~~~~~~~~~~~~~~~~~~~~~~~~

* Added a CSS class to the column headers of
:class:`~django.contrib.admin.TabularInline`.

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

* The ``HttpRequest`` is now passed as the first positional argument to
:meth:`.RemoteUserBackend.configure_user`, if it accepts it.

:mod:`django.contrib.gis`
~~~~~~~~~~~~~~~~~~~~~~~~~

* Added Oracle support for the
:class:`~django.contrib.gis.db.models.functions.Envelope` function.

* Added SpatiaLite support for the :lookup:`coveredby` and :lookup:`covers`
lookups.

:mod:`django.contrib.postgres`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* The new ``ordering`` argument for
:class:`~django.contrib.postgres.aggregates.ArrayAgg` and
:class:`~django.contrib.postgres.aggregates.StringAgg` determines the
ordering of the aggregated elements.

* The new :class:`~django.contrib.postgres.indexes.BTreeIndex`,
:class:`~django.contrib.postgres.indexes.HashIndex` and
:class:`~django.contrib.postgres.indexes.SpGistIndex` classes allow
creating ``B-Tree``, ``hash``, and ``SP-GiST`` indexes in the database.

* :class:`~django.contrib.postgres.indexes.BrinIndex` now has the
``autosummarize`` parameter.

* The new ``search_type`` parameter of
:class:`~django.contrib.postgres.search.SearchQuery` allows searching for
a phrase or raw expression.

:mod:`django.contrib.staticfiles`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* Added path matching to the :option:`collectstatic --ignore` option so that
patterns like ``/vendor/*.js`` can be used.

Database backends
~~~~~~~~~~~~~~~~~

* Added result streaming for :meth:`.QuerySet.iterator` on SQLite.

Generic Views
~~~~~~~~~~~~~

* The new :meth:`View.setup <django.views.generic.base.View.setup>` hook
initializes view attributes before calling
:meth:`~django.views.generic.base.View.dispatch`. It allows mixins to setup
instance attributes for reuse in child classes.

Internationalization
~~~~~~~~~~~~~~~~~~~~

* Added support and translations for the Armenian language.

Management Commands
~~~~~~~~~~~~~~~~~~~

* The new :option:`--force-color` option forces colorization of the command
output.

* :djadmin:`inspectdb` now creates models for foreign tables on PostgreSQL.

* :option:`inspectdb --include-views` now creates models for materialized views
on Oracle and PostgreSQL.

* The new :option:`inspectdb --include-partitions` option allows creating
models for partition tables on PostgreSQL. In older versions, models are
created child tables instead the parent.

* :djadmin:`inspectdb` now introspects :class:`~django.db.models.DurationField`
for Oracle and PostgreSQL, and :class:`~django.db.models.AutoField` for
SQLite.

* On Oracle, :djadmin:`dbshell` is wrapped with ``rlwrap``, if available.
``rlwrap`` provides a command history and editing of keyboard input.

* The new :option:`makemigrations --no-header` option avoids writing header
comments in generated migration file(s). This option is also available for
:djadmin:`squashmigrations`.

* :djadmin:`runserver` can now use `Watchman
<https://facebook.github.io/watchman/>`_ to improve the performance of
watching a large number of files for changes.

Migrations
~~~~~~~~~~

* The new :option:`migrate --plan` option prints the list of migration
operations that will be performed.

* ``NoneType`` can now be serialized in migrations.

* You can now :ref:`register custom serializers <custom-migration-serializers>`
for migrations.

Models
~~~~~~

* Added support for PostgreSQL operator classes (:attr:`.Index.opclasses`).

* Added support for partial indexes (:attr:`.Index.condition`).

* Added the :class:`~django.db.models.functions.NullIf` and
:class:`~django.db.models.functions.Reverse` database functions, as well as
many :ref:`math database functions <math-functions>`.

* Setting the new ``ignore_conflicts`` parameter of
:meth:`.QuerySet.bulk_create` to ``True`` tells the database to ignore
failure to insert rows that fail uniqueness constraints or other checks.

* The new :class:`~django.db.models.functions.ExtractIsoYear` function extracts
ISO-8601 week-numbering years from :class:`~django.db.models.DateField` and
:class:`~django.db.models.DateTimeField`, and the new :lookup:`iso_year`
lookup allows querying by an ISO-8601 week-numbering year.

* The new :meth:`.QuerySet.bulk_update` method allows efficiently updating
specific fields on multiple model instances.

* Django no longer always starts a transaction when a single query is being
performed, such as ``Model.save()``, ``QuerySet.update()``, and
``Model.delete()``. This improves the performance of autocommit by reducing
the number of database round trips.

* Added SQLite support for the :class:`~django.db.models.StdDev` and
:class:`~django.db.models.Variance` functions.

* The handling of ``DISTINCT`` aggregation is added to the
:class:`~django.db.models.Aggregate` class. Adding :attr:`allow_distinct =
True <django.db.models.Aggregate.allow_distinct>` as a class attribute on
``Aggregate`` subclasses allows a ``distinct`` keyword argument to be
specified on initialization to ensure that the aggregate function is only
called for each distinct value of ``expressions``.

* The :meth:`.RelatedManager.add`, :meth:`~.RelatedManager.create`,
:meth:`~.RelatedManager.remove`,  :meth:`~.RelatedManager.set`,
``get_or_create()``, and ``update_or_create()`` methods are now allowed on
many-to-many relationships with intermediate models. The new
``through_defaults`` argument is used to specify values for new intermediate
model instance(s).

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

* Added :attr:`.HttpRequest.headers` to allow simple access to a request's
headers.

Serialization
~~~~~~~~~~~~~

* You can now deserialize data using natural keys containing :ref:`forward
references <natural-keys-and-forward-references>` by passing
``handle_forward_references=True`` to ``serializers.deserialize()``.
Additionally, :djadmin:`loaddata` handles forward references automatically.

Tests
~~~~~

* The new :meth:`.SimpleTestCase.assertURLEqual` assertion checks for a given
URL, ignoring the ordering of the query string.
:meth:`~.SimpleTestCase.assertRedirects` uses the new assertion.

* The test :class:`~.django.test.Client` now supports automatic JSON
serialization of list and tuple ``data`` when
``content_type='application/json'``.

* The new :setting:`ORACLE_MANAGED_FILES <TEST_ORACLE_MANAGED_FILES>` test
database setting allows using Oracle Managed Files (OMF) tablespaces.

* Deferrable database constraints are now checked at the end of each
:class:`~django.test.TestCase` test on SQLite 3.20+, just like on other
backends that support deferrable constraints. These checks aren't implemented
for older versions of SQLite because they would require expensive table
introspection there.

* :class:`~django.test.runner.DiscoverRunner` now skips the setup of databases
not :ref:`referenced by tests<testing-multi-db>`.

URLs
~~~~

* The new :attr:`.ResolverMatch.route` attribute stores the route of the
matching URL pattern.

Validators
~~~~~~~~~~

* :class:`.MaxValueValidator`, :class:`.MinValueValidator`,
:class:`.MinLengthValidator`, and :class:`.MaxLengthValidator` now accept
a callable ``limit_value``.

.. _backwards-incompatible-2.2:

Backwards incompatible changes in 2.2
=====================================

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

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

* Third-party database backends must implement support for table check
constraints or set ``DatabaseFeatures.supports_table_check_constraints`` to
``False``.

* Third party database backends must implement support for ignoring
constraints or uniqueness errors while inserting or set
``DatabaseFeatures.supports_ignore_conflicts`` to ``False``.

* Third party database backends must implement introspection for
``DurationField`` or set ``DatabaseFeatures.can_introspect_duration_field``
to ``False``.

* ``DatabaseFeatures.uses_savepoints`` now defaults to ``True``.

* Third party database backends must implement support for partial indexes or
set ``DatabaseFeatures.supports_partial_indexes`` to ``False``.

* ``DatabaseIntrospection.table_name_converter()`` and
``column_name_converter()`` are removed. Third party database backends may
need to instead implement ``DatabaseIntrospection.identifier_converter()``.
In that case, the constraint names that
``DatabaseIntrospection.get_constraints()`` returns must be normalized by
``identifier_converter()``.

* SQL generation for indexes is moved from :class:`~django.db.models.Index` to
``SchemaEditor`` and these ``SchemaEditor`` methods are added:

* ``_create_primary_key_sql()`` and ``_delete_primary_key_sql()``
* ``_delete_index_sql()`` (to pair with ``_create_index_sql()``)
* ``_delete_unique_sql`` (to pair with ``_create_unique_sql()``)
* ``_delete_fk_sql()`` (to pair with ``_create_fk_sql()``)
* ``_create_check_sql()`` and ``_delete_check_sql()``

* The third argument of ``DatabaseWrapper.__init__()``,
``allow_thread_sharing``, is removed.

Admin actions are no longer collected from base ``ModelAdmin`` classes
----------------------------------------------------------------------

For example, in older versions of Django::

 from django.contrib import admin

 class BaseAdmin(admin.ModelAdmin):
     actions = ['a']

 class SubAdmin(BaseAdmin):
     actions = ['b']

``SubAdmin`` would have actions ``'a'`` and ``'b'``.

Now ``actions`` follows standard Python inheritance. To get the same result as
before::

 class SubAdmin(BaseAdmin):
     actions = BaseAdmin.actions + ['b']

:mod:`django.contrib.gis`
-------------------------

* Support for GDAL 1.9 and 1.10 is dropped.

``TransactionTestCase`` serialized data loading
-----------------------------------------------

Initial data migrations are now loaded in
:class:`~django.test.TransactionTestCase` at the end of the test, after the
database flush. In older versions, this data was loaded at the beginning of the
test, but this prevents the :option:`test --keepdb` option from working
properly (the database was empty at the end of the whole test suite). This
change shouldn't have an impact on your tests unless you've customized
:class:`~django.test.TransactionTestCase`'s internals.

``sqlparse`` is required dependency
-----------------------------------

To simplify a few parts of Django's database handling, `sqlparse
<https://pypi.org/project/sqlparse/>`_ is now a required dependency. It's
automatically installed along with Django.

``cached_property`` aliases
---------------------------

In usage like::

 from django.utils.functional import cached_property

 class A:

     cached_property
     def base(self):
         return ...

     alias = base

``alias`` is not cached. Where the problem can be detected (Python 3.6 and
later), such usage now raises ``TypeError: Cannot assign the same
cached_property to two different names ('base' and 'alias').``

Use this instead::

 import operator

 class A:

     ...

     alias = property(operator.attrgetter('base'))

Permissions for proxy models
----------------------------

:ref:`Permissions for proxy models <proxy-models-permissions-topic>` are now
created using the content type of the proxy model rather than the content type
of the concrete model. A migration will update existing permissions when you
run :djadmin:`migrate`.

In the admin, the change is transparent for proxy models having the same
``app_label`` as their concrete model. However, in older versions, users with
permissions for a proxy model with a *different* ``app_label`` than its
concrete model couldn't access the model in the admin. That's now fixed, but
you might want to audit the permissions assignments for such proxy models
(``[add|view|change|delete]_myproxy``) prior to upgrading to ensure the new
access is appropriate.

Finally, proxy model permission strings must be updated to use their own
``app_label``. For example, for ``app.MyProxyModel`` inheriting from
``other_app.ConcreteModel``, update
``user.has_perm('other_app.add_myproxymodel')`` to
``user.has_perm('app.add_myproxymodel')``.

Merging of form ``Media`` assets
--------------------------------

Form ``Media`` assets are now merged using a topological sort algorithm, as the
old pairwise merging algorithm is insufficient for some cases. CSS and
JavaScript files which don't include their dependencies may now be sorted
incorrectly (where the old algorithm produced results correctly by
coincidence).

Audit all ``Media`` classes for any missing dependencies. For example,
widgets depending on ``django.jQuery`` must specify
``js=['admin/js/jquery.init.js', ...]`` when :ref:`declaring form media assets
<assets-as-a-static-definition>`.

Miscellaneous
-------------

* To improve readability, the ``UUIDField`` form field now displays values with
dashes, e.g. ``550e8400-e29b-41d4-a716-446655440000`` instead of
``550e8400e29b41d4a716446655440000``.

* On SQLite, ``PositiveIntegerField`` and ``PositiveSmallIntegerField`` now
include a check constraint to prevent negative values in the database. If you
have existing invalid data and run a migration that recreates a table, you'll
see ``CHECK constraint failed``.

* For consistency with WSGI servers, the test client now sets the
``Content-Length`` header to a string rather than an integer.

* The return value of :func:`django.utils.text.slugify` is no longer marked as
HTML safe.

* The default truncation character used by the :tfilter:`urlizetrunc`,
:tfilter:`truncatechars`, :tfilter:`truncatechars_html`,
:tfilter:`truncatewords`, and :tfilter:`truncatewords_html` template filters
is now the real ellipsis character (``…``) instead of 3 dots. You may have to
adapt some test output comparisons.

* Support for bytestring paths in the template filesystem loader is removed.

* :func:`django.utils.http.urlsafe_base64_encode` now returns a string instead
of a bytestring, and :func:`django.utils.http.urlsafe_base64_decode` may no
longer be passed a bytestring.

* Support for ``cx_Oracle`` < 6.0 is removed.

* The minimum supported version of ``mysqlclient`` is increased from 1.3.7 to
1.3.13.

* The minimum supported version of SQLite is increased from 3.7.15 to 3.8.3.

* In an attempt to provide more semantic query data, ``NullBooleanSelect`` now
renders ``<option>`` values of ``unknown``, ``true``, and ``false`` instead
of ``1``, ``2``, and ``3``. For backwards compatibility, the old values are
still accepted as data.

* :attr:`Group.name <django.contrib.auth.models.Group.name>` ``max_length``
is increased from 80 to 150 characters.

* Tests that violate deferrable database constraints now error when run on
SQLite 3.20+, just like on other backends that support such constraints.

* To catch usage mistakes, the test :class:`~django.test.Client` and
:func:`django.utils.http.urlencode` now raise ``TypeError`` if ``None`` is
passed as a value to encode because ``None`` can't be encoded in GET and POST
data. Either pass an empty string or omit the value.

* The :djadmin:`ping_google` management command now defaults to ``https``
instead of ``http`` for the sitemap's URL. If your site uses http, use the
new :option:`ping_google --sitemap-uses-http` option. If you use the
:func:`~django.contrib.sitemaps.ping_google` function, set the new
``sitemap_uses_https`` argument to ``False``.

* :djadmin:`runserver` no longer supports `pyinotify` (replaced by Watchman).

* The :class:`~django.db.models.Avg`, :class:`~django.db.models.StdDev`, and
:class:`~django.db.models.Variance` aggregate functions now return a
``Decimal`` instead of a ``float`` when the input is ``Decimal``.

* Tests will fail on SQLite if apps without migrations have relations to apps
with migrations. This has been a documented restriction since migrations were
added in Django 1.7, but it fails more reliably now. You'll see tests failing
with errors like ``no such table: <app_label>_<model>``. This was observed
with several third-party apps that had models in tests without migrations.
You must add migrations for such models.

* Providing an integer in the ``key`` argument of the :meth:`.cache.delete` or
:meth:`.cache.get` now raises :exc:`ValueError`.

.. _deprecated-features-2.2:

Features deprecated in 2.2
==========================

Model ``Meta.ordering`` will no longer affect ``GROUP BY`` queries
------------------------------------------------------------------

A model's ``Meta.ordering`` affecting ``GROUP BY`` queries (such as
``.annotate().values()``) is a common source of confusion. Such queries now
issue a deprecation warning with the advice to add an ``order_by()`` to retain
the current query. ``Meta.ordering`` will be ignored in such queries starting
in Django 3.1.

Miscellaneous
-------------

* ``django.utils.timezone.FixedOffset`` is deprecated in favor of
:class:`datetime.timezone`.

* The undocumented ``QuerySetPaginator`` alias of
``django.core.paginator.Paginator`` is deprecated.

* The ``FloatRangeField`` model and form fields in ``django.contrib.postgres``
are deprecated in favor of a new name, ``DecimalRangeField``, to match the
underlying ``numrange`` data type used in the database.

* The ``FILE_CHARSET`` setting is deprecated. Starting with Django 3.1, files
read from disk must be UTF-8 encoded.

* ``django.contrib.staticfiles.storage.CachedStaticFilesStorage`` is
deprecated due to the intractable problems that it has. Use
:class:`.ManifestStaticFilesStorage` or a third-party cloud storage instead.

* :meth:`.RemoteUserBackend.configure_user` is now passed ``request`` as the
first positional argument, if it accepts it. Support for overrides that don't
accept it will be removed in Django 3.1.

* The ``SimpleTestCase.allow_database_queries``,
``TransactionTestCase.multi_db``, and ``TestCase.multi_db``
attributes are deprecated in favor of :attr:`.SimpleTestCase.databases`,
:attr:`.TransactionTestCase.databases`, and :attr:`.TestCase.databases`.
These new attributes allow databases dependencies to be declared in order to
prevent unexpected queries against non-default databases to leak state
between tests. The previous behavior of ``allow_database_queries=True`` and
``multi_db=True`` can be achieved by setting ``databases='__all__'``.


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

2.1.15

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

*December 2, 2019*

Django 2.1.15 fixes a security issue and a data loss bug in 2.1.14.

CVE-2019-19118: Privilege escalation in the Django admin.
=========================================================

Since Django 2.1, a Django model admin displaying a parent model with related
model inlines, where the user has view-only permissions to a parent model but
edit permissions to the inline model, would display a read-only view of the
parent model but editable forms for the inline.

Submitting these forms would not allow direct edits to the parent model, but
would trigger the parent model's ``save()`` method, and cause pre and post-save
signal handlers to be invoked. This is a privilege escalation as a user who
lacks permission to edit a model should not be able to trigger its save-related
signals.

To resolve this issue, the permission handling code of the Django admin
interface has been changed. Now, if a user has only the "view" permission for a
parent model, the entire displayed form will not be editable, even if the user
has permission to edit models included in inlines.

This is a backwards-incompatible change, and the Django security team is aware
that some users of Django were depending on the ability to allow editing of
inlines in the admin form of an otherwise view-only parent model.

Given the complexity of the Django admin, and in-particular the permissions
related checks, it is the view of the Django security team that this change was
necessary: that it is not currently feasible to maintain the existing behavior
whilst escaping the potential privilege escalation in a way that would avoid a
recurrence of similar issues in the future, and that would be compatible with
Django's *safe by default* philosophy.

For the time being, developers whose applications are affected by this change
should replace the use of inlines in read-only parents with custom forms and
views that explicitly implement the desired functionality. In the longer term,
adding a documented, supported, and properly-tested mechanism for
partially-editable multi-model forms to the admin interface may occur in Django
itself.

Bugfixes
========

* Fixed a data loss possibility in the
:meth:`~django.db.models.query.QuerySet.select_for_update()`. When using
``'self'`` in the ``of`` argument with :ref:`multi-table inheritance
<multi-table-inheritance>`, a parent model was locked instead of the
queryset's model (:ticket:`30953`).


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

2.1.14

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

*November 4, 2019*

Django 2.1.14 fixes a regression in 2.1.13.

Bugfixes
========

* Fixed a crash when using a ``contains``, ``contained_by``, ``has_key``,
``has_keys``, or ``has_any_keys`` lookup on
:class:`~django.contrib.postgres.fields.JSONField`, if the right or left hand
side of an expression is a key transform (:ticket:`30826`).


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

2.1.13

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

*October 1, 2019*

Django 2.1.13 fixes a regression in 2.1.11.

Bugfixes
========

* Fixed a crash when filtering with a ``Subquery()`` annotation of a queryset
containing :class:`~django.contrib.postgres.fields.JSONField` or
:class:`~django.contrib.postgres.fields.HStoreField` (:ticket:`30769`).


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

2.1.12

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

*September 2, 2019*

Django 2.1.12 fixes a regression in 2.1.11.

Bugfixes
========

* Fixed crash of ``KeyTransform()`` for
:class:`~django.co

[coveralls]

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[peterfarrell]

OBE