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1.8.txt
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========================
Django 1.8 release notes
========================
*April 1, 2015*
Welcome to Django 1.8!
These release notes cover the :ref:`new features <whats-new-1.8>`, as well as
some :ref:`backwards incompatible changes <backwards-incompatible-1.8>` you'll
want to be aware of when upgrading from Django 1.7 or older versions. We've
also :ref:`begun the deprecation process for some features
<deprecated-features-1.8>`, and some features have reached the end of their
deprecation process and :ref:`have been removed <removed-features-1.8>`.
See the :doc:`/howto/upgrade-version` guide if you're updating an existing
project.
Django 1.8 has been designated as Django's second :term:`long-term support
release <Long-term support release>`. It will receive security updates for at
least three years after its release. Support for the previous LTS, Django 1.4,
will end 6 months from the release date of Django 1.8.
Python compatibility
====================
Django 1.8 requires Python 2.7, 3.2, 3.3, 3.4, or 3.5. We **highly recommend**
and only officially support the latest release of each series.
Django 1.8 is the first release to support Python 3.5.
Due to the end of upstream support for Python 3.2 in February 2016, we won't
test Django 1.8.x on Python 3.2 after the end of 2016.
.. _whats-new-1.8:
What's new in Django 1.8
========================
``Model._meta`` API
-------------------
Django now has a formalized API for :doc:`Model._meta </ref/models/meta>`,
providing an officially supported way to :ref:`retrieve fields
<model-meta-field-api>` and filter fields based on their :ref:`attributes
<model-field-attributes>`.
The ``Model._meta`` object has been part of Django since the days of pre-0.96
"Magic Removal" -- it just wasn't an official, stable API. In recognition of
this, we've endeavored to maintain backwards-compatibility with the old
API endpoint where possible. However, API endpoints that aren't part of the
new official API have been deprecated and will eventually be removed.
Multiple template engines
-------------------------
Django 1.8 defines a stable API for integrating template backends. It includes
built-in support for the Django template language and for
:class:`~django.template.backends.jinja2.Jinja2`. It supports rendering
templates with multiple engines within the same project. Learn more about the
new features in the :doc:`topic guide </topics/templates>` and check the
upgrade instructions in older versions of the documentation.
Security enhancements
---------------------
Several features of the django-secure_ third-party library have been
integrated into Django. :class:`django.middleware.security.SecurityMiddleware`
provides several security enhancements to the request/response cycle. The new
:option:`check --deploy` option allows you to check your production settings
file for ways to increase the security of your site.
.. _django-secure: https://pypi.org/project/django-secure/
New PostgreSQL specific functionality
-------------------------------------
Django now has a module with extensions for PostgreSQL specific features, such
as :class:`~django.contrib.postgres.fields.ArrayField`,
:class:`~django.contrib.postgres.fields.HStoreField`, :ref:`range-fields`, and
:lookup:`unaccent` lookup. A full breakdown of the features is available
:doc:`in the documentation </ref/contrib/postgres/index>`.
New data types
--------------
* Django now has a :class:`~django.db.models.UUIDField` for storing
universally unique identifiers. It is stored as the native ``uuid`` data type
on PostgreSQL and as a fixed length character field on other backends. There
is a corresponding :class:`form field <django.forms.UUIDField>`.
* Django now has a :class:`~django.db.models.DurationField` for storing periods
of time - modeled in Python by :class:`~python:datetime.timedelta`. It is
stored in the native ``interval`` data type on PostgreSQL, as a ``INTERVAL
DAY(9) TO SECOND(6)`` on Oracle, and as a ``bigint`` of microseconds on other
backends. Date and time related arithmetic has also been improved on all
backends. There is a corresponding :class:`form field
<django.forms.DurationField>`.
Query Expressions, Conditional Expressions, and Database Functions
------------------------------------------------------------------
:doc:`Query Expressions </ref/models/expressions>` allow you to create,
customize, and compose complex SQL expressions. This has enabled annotate
to accept expressions other than aggregates. Aggregates are now able to
reference multiple fields, as well as perform arithmetic, similar to ``F()``
objects. :meth:`~django.db.models.query.QuerySet.order_by` has also gained the
ability to accept expressions.
:doc:`Conditional Expressions </ref/models/conditional-expressions>` allow
you to use :keyword:`if` ... :keyword:`elif` ... :keyword:`else` logic within
queries.
A collection of :doc:`database functions </ref/models/database-functions>` is
also included with functionality such as
:class:`~django.db.models.functions.Coalesce`,
:class:`~django.db.models.functions.Concat`, and
:class:`~django.db.models.functions.Substr`.
``TestCase`` data setup
-----------------------
:class:`~django.test.TestCase` has been refactored to allow for data
initialization at the class level using transactions and savepoints. Database
backends which do not support transactions, like MySQL with the MyISAM storage
engine, will still be able to run these tests but won't benefit from the
improvements. Tests are now run within two nested
:func:`~django.db.transaction.atomic()` blocks: one for the whole class and one
for each test.
* The class method
:meth:`TestCase.setUpTestData() <django.test.TestCase.setUpTestData>` adds
the ability to setup test data at the class level. Using this technique can
speed up the tests as compared to using ``setUp()``.
* Fixture loading within ``TestCase`` is now performed once for the whole
``TestCase``.
Minor features
--------------
:mod:`django.contrib.admin`
~~~~~~~~~~~~~~~~~~~~~~~~~~~
* :class:`~django.contrib.admin.ModelAdmin` now has a
:meth:`~django.contrib.admin.ModelAdmin.has_module_permission`
method to allow limiting access to the module on the admin index page.
* :class:`~django.contrib.admin.InlineModelAdmin` now has an attribute
:attr:`~django.contrib.admin.InlineModelAdmin.show_change_link` that
supports showing a link to an inline object's change form.
* Use the new ``django.contrib.admin.RelatedOnlyFieldListFilter`` in
:attr:`ModelAdmin.list_filter <django.contrib.admin.ModelAdmin.list_filter>`
to limit the ``list_filter`` choices to foreign objects which are attached to
those from the ``ModelAdmin``.
* The :meth:`ModelAdmin.delete_view()
<django.contrib.admin.ModelAdmin.delete_view>` displays a summary of objects
to be deleted on the deletion confirmation page.
* The jQuery library embedded in the admin has been upgraded to version 1.11.2.
* You can now specify :attr:`AdminSite.site_url
<django.contrib.admin.AdminSite.site_url>` in order to display a link to the
front-end site.
* You can now specify :attr:`ModelAdmin.show_full_result_count
<django.contrib.admin.ModelAdmin.show_full_result_count>` to control whether
or not the full count of objects should be displayed on a filtered admin page.
* The ``AdminSite.password_change()`` method now has an ``extra_context``
parameter.
* You can now control who may login to the admin site by overriding only
:meth:`AdminSite.has_permission()
<django.contrib.admin.AdminSite.has_permission>` and
:attr:`AdminSite.login_form <django.contrib.admin.AdminSite.login_form>`.
The ``base.html`` template has a new block ``usertools`` which contains the
user-specific header. A new context variable ``has_permission``, which gets
its value from :meth:`~django.contrib.admin.AdminSite.has_permission`,
indicates whether the user may access the site.
* Foreign key dropdowns now have buttons for changing or deleting related
objects using a popup.
:mod:`django.contrib.admindocs`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* reStructuredText is now parsed in model docstrings.
:mod:`django.contrib.auth`
~~~~~~~~~~~~~~~~~~~~~~~~~~
* Authorization backends can now raise
:class:`~django.core.exceptions.PermissionDenied` in
:meth:`~django.contrib.auth.models.User.has_perm`
and :meth:`~django.contrib.auth.models.User.has_module_perms`
to short-circuit permission checking.
* :class:`~django.contrib.auth.forms.PasswordResetForm` now
has a method :meth:`~django.contrib.auth.forms.PasswordResetForm.send_mail`
that can be overridden to customize the mail to be sent.
* The ``max_length`` of :attr:`Permission.name
<django.contrib.auth.models.Permission.name>` has been increased from 50 to
255 characters. Please run the database migration.
* :attr:`~django.contrib.auth.models.CustomUser.USERNAME_FIELD` and
:attr:`~django.contrib.auth.models.CustomUser.REQUIRED_FIELDS` now supports
:class:`~django.db.models.ForeignKey`\s.
* The default iteration count for the PBKDF2 password hasher has been
increased by 33%. This backwards compatible change will not affect users who
have subclassed ``django.contrib.auth.hashers.PBKDF2PasswordHasher`` to
change the default value.
:mod:`django.contrib.gis`
~~~~~~~~~~~~~~~~~~~~~~~~~
* A new :doc:`GeoJSON serializer </ref/contrib/gis/serializers>` is now
available.
* It is now allowed to include a subquery as a geographic lookup argument, for
example ``City.objects.filter(point__within=Country.objects.filter(continent='Africa').values('mpoly'))``.
* The SpatiaLite backend now supports ``Collect`` and ``Extent`` aggregates
when the database version is 3.0 or later.
* The PostGIS 2 ``CREATE EXTENSION postgis`` and the SpatiaLite
``SELECT InitSpatialMetaData`` initialization commands are now automatically
run by :djadmin:`migrate`.
* The GDAL interface now supports retrieving properties of
:ref:`raster (image) data file <raster-data-source-objects>`.
* Compatibility shims for ``SpatialRefSys`` and ``GeometryColumns`` changed in
Django 1.2 have been removed.
* All GDAL-related exceptions are now raised with ``GDALException``. The former
``OGRException`` has been kept for backwards compatibility but should not be
used any longer.
:mod:`django.contrib.sessions`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Session cookie is now deleted after
:meth:`~django.contrib.sessions.backends.base.SessionBase.flush()` is called.
:mod:`django.contrib.sitemaps`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* The new :attr:`Sitemap.i18n <django.contrib.sitemaps.Sitemap.i18n>` attribute
allows you to generate a sitemap based on the :setting:`LANGUAGES` setting.
:mod:`django.contrib.sites`
~~~~~~~~~~~~~~~~~~~~~~~~~~~
* :func:`~django.contrib.sites.shortcuts.get_current_site` will now lookup
the current site based on :meth:`request.get_host()
<django.http.HttpRequest.get_host>` if the :setting:`SITE_ID` setting is not
defined.
* The default :class:`~django.contrib.sites.models.Site` created when running
``migrate`` now respects the :setting:`SITE_ID` setting (instead of always
using ``pk=1``).
Cache
~~~~~
* The ``incr()`` method of the
``django.core.cache.backends.locmem.LocMemCache`` backend is now thread-safe.
Cryptography
~~~~~~~~~~~~
* The ``max_age`` parameter of the
:meth:`django.core.signing.TimestampSigner.unsign` method now also accepts a
:py:class:`datetime.timedelta` object.
Database backends
~~~~~~~~~~~~~~~~~
* The MySQL backend no longer strips microseconds from ``datetime`` values as
MySQL 5.6.4 and up supports fractional seconds depending on the declaration
of the datetime field (when ``DATETIME`` includes fractional precision greater
than 0). New datetime database columns created with Django 1.8 and MySQL 5.6.4
and up will support microseconds. See the :ref:`MySQL database notes
<mysql-fractional-seconds>` for more details.
* The MySQL backend no longer creates explicit indexes for foreign keys when
using the InnoDB storage engine, as MySQL already creates them automatically.
* The Oracle backend no longer defines the ``connection_persists_old_columns``
feature as ``True``. Instead, Oracle will now include a cache busting clause
when getting the description of a table.
Email
~~~~~
* :ref:`Email backends <topic-email-backends>` now support the context manager
protocol for opening and closing connections.
* The SMTP email backend now supports ``keyfile`` and ``certfile``
authentication with the :setting:`EMAIL_SSL_CERTFILE` and
:setting:`EMAIL_SSL_KEYFILE` settings.
* The SMTP :class:`~django.core.mail.backends.smtp.EmailBackend` now supports
setting the ``timeout`` parameter with the :setting:`EMAIL_TIMEOUT` setting.
* :class:`~django.core.mail.EmailMessage` and ``EmailMultiAlternatives`` now
support the ``reply_to`` parameter.
File Storage
~~~~~~~~~~~~
* :meth:`Storage.get_available_name()
<django.core.files.storage.Storage.get_available_name>` and
:meth:`Storage.save() <django.core.files.storage.Storage.save>`
now take a ``max_length`` argument to implement storage-level maximum
filename length constraints. Filenames exceeding this argument will get
truncated. This prevents a database error when appending a unique suffix to a
long filename that already exists on the storage. See the :ref:`deprecation
note <storage-max-length-update>` about adding this argument to your custom
storage classes.
Forms
~~~~~
* Form widgets now render attributes with a value of ``True`` or ``False``
as HTML5 boolean attributes.
* The new :meth:`~django.forms.Form.has_error()` method allows checking
if a specific error has happened.
* If :attr:`~django.forms.Form.required_css_class` is defined on a form, then
the ``<label>`` tags for required fields will have this class present in its
attributes.
* The rendering of non-field errors in unordered lists (``<ul>``) now includes
``nonfield`` in its list of classes to distinguish them from field-specific
errors.
* :class:`~django.forms.Field` now accepts a
:attr:`~django.forms.Field.label_suffix` argument, which will override the
form's :attr:`~django.forms.Form.label_suffix`. This enables customizing the
suffix on a per-field basis — previously it wasn't possible to override
a form's :attr:`~django.forms.Form.label_suffix` while using shortcuts such
as ``{{ form.as_p }}`` in templates.
* :class:`~django.forms.SelectDateWidget` now accepts an
:attr:`~django.forms.SelectDateWidget.empty_label` argument, which will
override the top list choice label when :class:`~django.forms.DateField`
is not required.
* After an :class:`~django.forms.ImageField` has been cleaned and validated, the
``UploadedFile`` object will have an additional ``image`` attribute containing
the Pillow ``Image`` instance used to check if the file was a valid image. It
will also update ``UploadedFile.content_type`` with the image's content type
as determined by Pillow.
* You can now pass a callable that returns an iterable of choices when
instantiating a :class:`~django.forms.ChoiceField`.
Generic Views
~~~~~~~~~~~~~
* Generic views that use :class:`~django.views.generic.list.MultipleObjectMixin`
may now specify the ordering applied to the
:attr:`~django.views.generic.list.MultipleObjectMixin.queryset` by setting
:attr:`~django.views.generic.list.MultipleObjectMixin.ordering` or overriding
:meth:`~django.views.generic.list.MultipleObjectMixin.get_ordering()`.
* The new :attr:`SingleObjectMixin.query_pk_and_slug
<django.views.generic.detail.SingleObjectMixin.query_pk_and_slug>`
attribute allows changing the behavior of
:meth:`~django.views.generic.detail.SingleObjectMixin.get_object()`
so that it'll perform its lookup using both the primary key and the slug.
* The :meth:`~django.views.generic.edit.FormMixin.get_form()` method doesn't
require a ``form_class`` to be provided anymore. If not provided ``form_class``
defaults to :meth:`~django.views.generic.edit.FormMixin.get_form_class()`.
* Placeholders in :attr:`ModelFormMixin.success_url
<django.views.generic.edit.ModelFormMixin.success_url>` now support the Python
:py:meth:`str.format()` syntax. The legacy ``%(<foo>)s`` syntax is still
supported but will be removed in Django 1.10.
Internationalization
~~~~~~~~~~~~~~~~~~~~
* :setting:`FORMAT_MODULE_PATH` can now be a list of strings representing
module paths. This allows importing several format modules from different
reusable apps. It also allows overriding those custom formats in your main
Django project.
Logging
~~~~~~~
* The :class:`django.utils.log.AdminEmailHandler` class now has a
:meth:`~django.utils.log.AdminEmailHandler.send_mail` method to make it more
subclass friendly.
Management Commands
~~~~~~~~~~~~~~~~~~~
* Database connections are now always closed after a management command called
from the command line has finished doing its job.
* Commands from alternate package formats like eggs are now also discovered.
* The new :option:`dumpdata --output` option allows specifying a file to which
the serialized data is written.
* The new :option:`makemessages --exclude` and :option:`compilemessages
--exclude` options allow excluding specific locales from processing.
* :djadmin:`compilemessages` now has a ``--use-fuzzy`` or ``-f`` option which
includes fuzzy translations into compiled files.
* The :option:`loaddata --ignorenonexistent` option now ignores data for models
that no longer exist.
* :djadmin:`runserver` now uses daemon threads for faster reloading.
* :djadmin:`inspectdb` now outputs ``Meta.unique_together``. It is also able to
introspect :class:`~django.db.models.AutoField` for MySQL and PostgreSQL
databases.
* When calling management commands with options using
:func:`~django.core.management.call_command`, the option name can match the
command line option name (without the initial dashes) or the final option
destination variable name, but in either case, the resulting option received
by the command is now always the ``dest`` name specified in the command
option definition (as long as the command uses the :mod:`argparse` module).
* The :djadmin:`dbshell` command now supports MySQL's optional SSL certificate
authority setting (``--ssl-ca``).
* The new :option:`makemigrations --name` allows giving the migration(s) a
custom name instead of a generated one.
* The :djadmin:`loaddata` command now prevents repeated fixture loading. If
:setting:`FIXTURE_DIRS` contains duplicates or a default fixture directory
path (``app_name/fixtures``), an exception is raised.
* The new ``makemigrations --exit`` option allows exiting with an error
code if no migrations are created.
* The new :djadmin:`showmigrations` command allows listing all migrations and
their dependencies in a project.
Middleware
~~~~~~~~~~
* The :attr:`CommonMiddleware.response_redirect_class
<django.middleware.common.CommonMiddleware.response_redirect_class>`
attribute allows you to customize the redirects issued by the middleware.
* A debug message will be logged to the ``django.request`` logger when a
middleware raises a :exc:`~django.core.exceptions.MiddlewareNotUsed` exception
in :setting:`DEBUG` mode.
Migrations
~~~~~~~~~~
* The :class:`~django.db.migrations.operations.RunSQL` operation can now handle
parameters passed to the SQL statements.
* It is now possible to have migrations (most probably :ref:`data migrations
<data-migrations>`) for applications without models.
* Migrations can now :ref:`serialize model managers
<using-managers-in-migrations>` as part of the model state.
* A :ref:`generic mechanism to handle the deprecation of model fields
<migrations-removing-model-fields>` was added.
* The :meth:`RunPython.noop() <django.db.migrations.operations.RunPython.noop>`
and :attr:`RunSQL.noop <django.db.migrations.operations.RunSQL.noop>` class
method/attribute were added to ease in making ``RunPython`` and ``RunSQL``
operations reversible.
* The migration operations :class:`~django.db.migrations.operations.RunPython`
and :class:`~django.db.migrations.operations.RunSQL` now call the
:meth:`allow_migrate` method of database routers. The router can use the
newly introduced ``app_label`` and ``hints`` arguments to make a routing
decision. To take advantage of this feature you need to update the router to
the new ``allow_migrate`` signature, see the :ref:`deprecation section
<deprecated-signature-of-allow-migrate>` for more details.
Models
~~~~~~
* Django now logs at most 9000 queries in ``connections.queries``, in order
to prevent excessive memory usage in long-running processes in debug mode.
* There is now a model ``Meta`` option to define a
:attr:`default related name <django.db.models.Options.default_related_name>`
for all relational fields of a model.
* Pickling models and querysets across different versions of Django isn't
officially supported (it may work, but there's no guarantee). An extra
variable that specifies the current Django version is now added to the
pickled state of models and querysets, and Django raises a ``RuntimeWarning``
when these objects are unpickled in a different version than the one in
which they were pickled.
* Added :meth:`Model.from_db() <django.db.models.Model.from_db()>` which
Django uses whenever objects are loaded using the ORM. The method allows
customizing model loading behavior.
* ``extra(select={...})`` now allows you to escape a literal ``%s`` sequence
using ``%%s``.
* :doc:`Custom Lookups</howto/custom-lookups>` can now be registered using
a decorator pattern.
* The new :attr:`Transform.bilateral <django.db.models.Transform.bilateral>`
attribute allows creating bilateral transformations. These transformations
are applied to both ``lhs`` and ``rhs`` when used in a lookup expression,
providing opportunities for more sophisticated lookups.
* SQL special characters (\, %, _) are now escaped properly when a pattern
lookup (e.g. ``contains``, ``startswith``, etc.) is used with an ``F()``
expression as the right-hand side. In those cases, the escaping is performed
by the database, which can lead to somewhat complex queries involving nested
``REPLACE`` function calls.
* You can now refresh model instances by using :meth:`Model.refresh_from_db()
<django.db.models.Model.refresh_from_db>`.
* You can now get the set of deferred fields for a model using
:meth:`Model.get_deferred_fields() <django.db.models.Model.get_deferred_fields>`.
* Model field ``default``’s are now used when primary key field's are set to
``None``.
Signals
~~~~~~~
* Exceptions from the ``(receiver, exception)`` tuples returned by
:meth:`Signal.send_robust() <django.dispatch.Signal.send_robust>` now have
their traceback attached as a ``__traceback__`` attribute.
* The ``environ`` argument, which contains the WSGI environment structure from
the request, was added to the :data:`~django.core.signals.request_started`
signal.
* You can now import the :func:`~django.test.signals.setting_changed` signal
from ``django.core.signals`` to avoid loading ``django.test`` in non-test
situations. Django no longer does so itself.
System Check Framework
~~~~~~~~~~~~~~~~~~~~~~
* :attr:`~django.core.checks.register` can now be used as a function.
Templates
~~~~~~~~~
* :tfilter:`urlize` now supports domain-only links that include characters after
the top-level domain (e.g. ``djangoproject.com/`` and
``djangoproject.com/download/``).
* :tfilter:`urlize` doesn't treat exclamation marks at the end of a domain or
its query string as part of the URL (the URL in e.g. ``'djangoproject.com!``
is ``djangoproject.com``)
* Added a :class:`locmem.Loader <django.template.loaders.locmem.Loader>`
class that loads Django templates from a Python dictionary.
* The :ttag:`now` tag can now store its output in a context variable with the
usual syntax: ``{% now 'j n Y' as varname %}``.
Requests and Responses
~~~~~~~~~~~~~~~~~~~~~~
* ``WSGIRequest`` now respects paths starting with ``//``.
* The :meth:`HttpRequest.build_absolute_uri()
<django.http.HttpRequest.build_absolute_uri>` method now handles paths
starting with ``//`` correctly.
* If :setting:`DEBUG` is ``True`` and a request raises a
:exc:`~django.core.exceptions.SuspiciousOperation`, the response will be
rendered with a detailed error page.
* The ``query_string`` argument of :class:`~django.http.QueryDict` is now
optional, defaulting to ``None``, so a blank ``QueryDict`` can now be
instantiated with ``QueryDict()`` instead of ``QueryDict(None)`` or
``QueryDict('')``.
* The ``GET`` and ``POST`` attributes of an :class:`~django.http.HttpRequest`
object are now :class:`~django.http.QueryDict`\s rather than dictionaries,
and the ``FILES`` attribute is now a ``MultiValueDict``.
This brings this class into line with the documentation and with
``WSGIRequest``.
* The :attr:`HttpResponse.charset <django.http.HttpResponse.charset>` attribute
was added.
* ``WSGIRequestHandler`` now follows RFC in converting URI to IRI, using
``uri_to_iri()``.
* The :meth:`HttpRequest.get_full_path()
<django.http.HttpRequest.get_full_path>` method now escapes unsafe characters
from the path portion of a Uniform Resource Identifier (URI) properly.
* :class:`~django.http.HttpResponse` now implements a few additional methods
like :meth:`~django.http.HttpResponse.getvalue` so that instances can be used
as stream objects.
* The new :meth:`HttpResponse.setdefault()
<django.http.HttpResponse.setdefault>` method allows setting a header unless
it has already been set.
* You can use the new :class:`~django.http.FileResponse` to stream files.
* The :func:`~django.views.decorators.http.condition` decorator for
conditional view processing now supports the ``If-unmodified-since`` header.
Tests
~~~~~
* The :class:`RequestFactory.trace() <django.test.RequestFactory>`
and :class:`Client.trace() <django.test.Client.trace>` methods were
implemented, allowing you to create ``TRACE`` requests in your tests.
* The ``count`` argument was added to
:meth:`~django.test.SimpleTestCase.assertTemplateUsed`. This allows you to
assert that a template was rendered a specific number of times.
* The new :meth:`~django.test.SimpleTestCase.assertJSONNotEqual` assertion
allows you to test that two JSON fragments are not equal.
* Added options to the :djadmin:`test` command to preserve the test database
(:option:`--keepdb <test --keepdb>`), to run the test cases in reverse order
(:option:`--reverse <test --reverse>`), and to enable SQL logging for failing
tests (:option:`--debug-sql <test --debug-sql>`).
* Added the :attr:`~django.test.Response.resolver_match` attribute to test
client responses.
* Added several settings that allow customization of test tablespace parameters
for Oracle: :setting:`DATAFILE`, :setting:`DATAFILE_TMP`,
:setting:`DATAFILE_MAXSIZE` and :setting:`DATAFILE_TMP_MAXSIZE`.
* The :func:`~django.test.override_settings` decorator can now affect the
master router in :setting:`DATABASE_ROUTERS`.
* Added test client support for file uploads with file-like objects.
* A shared cache is now used when testing with an SQLite in-memory database when
using Python 3.4+ and SQLite 3.7.13+. This allows sharing the database
between threads.
Validators
~~~~~~~~~~
* :class:`~django.core.validators.URLValidator` now supports IPv6 addresses,
unicode domains, and URLs containing authentication data.
.. _backwards-incompatible-1.8:
Backwards incompatible changes in 1.8
=====================================
.. warning::
In addition to the changes outlined in this section, be sure to review the
:ref:`deprecation plan <deprecation-removed-in-1.8>` for any features that
have been removed. If you haven't updated your code within the
deprecation timeline for a given feature, its removal may appear as a
backwards incompatible change.
Related object operations are run in a transaction
--------------------------------------------------
Some operations on related objects such as
:meth:`~django.db.models.fields.related.RelatedManager.add()` or direct
assignment ran multiple data modifying queries without wrapping them in
transactions. To reduce the risk of data corruption, all data modifying methods
that affect multiple related objects (i.e. ``add()``, ``remove()``,
``clear()``, and direct assignment) now perform their data modifying queries
from within a transaction, provided your database supports transactions.
This has one backwards incompatible side effect, signal handlers triggered from
these methods are now executed within the method's transaction and any
exception in a signal handler will prevent the whole operation.
.. _unsaved-model-instance-check-18:
Assigning unsaved objects to relations raises an error
------------------------------------------------------
.. note::
To more easily allow in-memory usage of models, this change was reverted in
Django 1.8.4 and replaced with a check during ``model.save()``. For example::
>>> book = Book.objects.create(name="Django")
>>> book.author = Author(name="John")
>>> book.save()
Traceback (most recent call last):
...
ValueError: save() prohibited to prevent data loss due to unsaved related object 'author'.
A similar check on assignment to reverse one-to-one relations was removed
in Django 1.8.5.
Assigning unsaved objects to a :class:`~django.db.models.ForeignKey`,
:class:`~django.contrib.contenttypes.fields.GenericForeignKey`, and
:class:`~django.db.models.OneToOneField` now raises a :exc:`ValueError`.
Previously, the assignment of an unsaved object would be silently ignored.
For example::
>>> book = Book.objects.create(name="Django")
>>> book.author = Author(name="John")
>>> book.author.save()
>>> book.save()
>>> Book.objects.get(name="Django")
>>> book.author
>>>
Now, an error will be raised to prevent data loss::
>>> book.author = Author(name="john")
Traceback (most recent call last):
...
ValueError: Cannot assign "<Author: John>": "Author" instance isn't saved in the database.
If you require allowing the assignment of unsaved instances (the old behavior)
and aren't concerned about the data loss possibility (e.g. you never save the
objects to the database), you can disable this check by using the
``ForeignKey.allow_unsaved_instance_assignment`` attribute. (This attribute was
removed in 1.8.4 as it's no longer relevant.)
Management commands that only accept positional arguments
---------------------------------------------------------
If you have written a custom management command that only accepts positional
arguments and you didn't specify the ``args`` command variable, you might get
an error like ``Error: unrecognized arguments: ...``, as variable parsing is
now based on :py:mod:`argparse` which doesn't implicitly accept positional
arguments. You can make your command backwards compatible by simply setting the
``args`` class variable. However, if you don't have to keep compatibility with
older Django versions, it's better to implement the new
:meth:`~django.core.management.BaseCommand.add_arguments` method as described
in :doc:`/howto/custom-management-commands`.
Custom test management command arguments through test runner
------------------------------------------------------------
The method to add custom arguments to the ``test`` management command through
the test runner has changed. Previously, you could provide an ``option_list``
class variable on the test runner to add more arguments (à la
:py:mod:`optparse`). Now to implement the same behavior, you have to create an
``add_arguments(cls, parser)`` class method on the test runner and call
``parser.add_argument`` to add any custom arguments, as parser is now an
:py:class:`argparse.ArgumentParser` instance.
Model check ensures auto-generated column names are within limits specified by database
---------------------------------------------------------------------------------------
A field name that's longer than the column name length supported by a database
can create problems. For example, with MySQL you'll get an exception trying to
create the column, and with PostgreSQL the column name is truncated by the
database (you may see a warning in the PostgreSQL logs).
A model check has been introduced to better alert users to this scenario before
the actual creation of database tables.
If you have an existing model where this check seems to be a false positive,
for example on PostgreSQL where the name was already being truncated, simply
use :attr:`~django.db.models.Field.db_column` to specify the name that's being
used.
The check also applies to the columns generated in an implicit
``ManyToManyField.through`` model. If you run into an issue there, use
:attr:`~django.db.models.ManyToManyField.through` to create an explicit model
and then specify :attr:`~django.db.models.Field.db_column` on its column(s)
as needed.
Query relation lookups now check object types
---------------------------------------------
Querying for model lookups now checks if the object passed is of correct type
and raises a :exc:`ValueError` if not. Previously, Django didn't care if the
object was of correct type; it just used the object's related field attribute
(e.g. ``id``) for the lookup. Now, an error is raised to prevent incorrect
lookups::
>>> book = Book.objects.create(name="Django")
>>> book = Book.objects.filter(author=book)
Traceback (most recent call last):
...
ValueError: Cannot query "<Book: Django>": Must be "Author" instance.
``select_related()`` now checks given fields
--------------------------------------------
``select_related()`` now validates that the given fields actually exist.
Previously, nonexistent fields were silently ignored. Now, an error is raised::
>>> book = Book.objects.select_related('nonexistent_field')
Traceback (most recent call last):
...
FieldError: Invalid field name(s) given in select_related: 'nonexistent_field'
The validation also makes sure that the given field is relational::
>>> book = Book.objects.select_related('name')
Traceback (most recent call last):
...
FieldError: Non-relational field given in select_related: 'name'
Default ``EmailField.max_length`` increased to 254
--------------------------------------------------
The old default 75 character ``max_length`` was not capable of storing all
possible RFC3696/5321-compliant email addresses. In order to store all
possible valid email addresses, the ``max_length`` has been increased to 254
characters. You will need to generate and apply database migrations for your
affected models (or add ``max_length=75`` if you wish to keep the length on
your current fields). A migration for
:attr:`django.contrib.auth.models.User.email` is included.
Support for PostgreSQL versions older than 9.0
----------------------------------------------
The end of upstream support periods was reached in July 2014 for PostgreSQL 8.4.
As a consequence, Django 1.8 sets 9.0 as the minimum PostgreSQL version it
officially supports.
This also includes dropping support for PostGIS 1.3 and 1.4 as these versions
are not supported on versions of PostgreSQL later than 8.4.
Django also now requires the use of Psycopg2 version 2.4.5 or higher (or 2.5+
if you want to use :mod:`django.contrib.postgres`).
Support for MySQL versions older than 5.5
-----------------------------------------
The end of upstream support periods was reached in January 2012 for MySQL 5.0
and December 2013 for MySQL 5.1. As a consequence, Django 1.8 sets 5.5 as the
minimum MySQL version it officially supports.
Support for Oracle versions older than 11.1
-------------------------------------------
The end of upstream support periods was reached in July 2010 for Oracle 9.2,
January 2012 for Oracle 10.1, and July 2013 for Oracle 10.2. As a consequence,
Django 1.8 sets 11.1 as the minimum Oracle version it officially supports.
Specific privileges used instead of roles for tests on Oracle
-------------------------------------------------------------
Earlier versions of Django granted the CONNECT and RESOURCE roles to the test
user on Oracle. These roles have been deprecated, so Django 1.8 uses the
specific underlying privileges instead. This changes the privileges required
of the main user for running tests (unless the project is configured to avoid
creating a test user). The exact privileges required now are detailed in
:ref:`Oracle notes <oracle-notes>`.
``AbstractUser.last_login`` allows null values
----------------------------------------------
The :attr:`AbstractUser.last_login <django.contrib.auth.models.User.last_login>`
field now allows null values. Previously, it defaulted to the time when the user
was created which was misleading if the user never logged in. If you are using
the default user (:class:`django.contrib.auth.models.User`), run the database
migration included in ``contrib.auth``.
If you are using a custom user model that inherits from ``AbstractUser``,
you'll need to run :djadmin:`makemigrations` and generate a migration for your
app that contains that model. Also, if wish to set ``last_login`` to ``NULL``
for users who haven't logged in, you can run this query::
from django.db import models
from django.contrib.auth import get_user_model
from django.contrib.auth.models import AbstractBaseUser
UserModel = get_user_model()
if issubclass(UserModel, AbstractBaseUser):
UserModel._default_manager.filter(
last_login=models.F('date_joined')
).update(last_login=None)
:mod:`django.contrib.gis`
-------------------------
* Support for GEOS 3.1 and GDAL 1.6 has been dropped.
* Support for SpatiaLite < 2.4 has been dropped.
* GIS-specific lookups have been refactored to use the
:class:`django.db.models.Lookup` API.
* The default ``str`` representation of
:class:`~django.contrib.gis.geos.GEOSGeometry` objects has been changed from
WKT to EWKT format (including the SRID). As this representation is used in
the serialization framework, that means that ``dumpdata`` output will now
contain the SRID value of geometry objects.
Priority of context processors for ``TemplateResponse`` brought in line with ``render``
---------------------------------------------------------------------------------------
The :class:`~django.template.response.TemplateResponse` constructor is designed to be a
drop-in replacement for the :func:`~django.shortcuts.render` function. However,
it had a slight incompatibility, in that for ``TemplateResponse``, context data
from the passed in context dictionary could be shadowed by context data returned
from context processors, whereas for ``render`` it was the other way
around. This was a bug, and the behavior of ``render`` is more appropriate,
since it allows the globally defined context processors to be overridden locally
in the view. If you were relying on the fact context data in a
``TemplateResponse`` could be overridden using a context processor, you will
need to change your code.
Overriding ``setUpClass`` / ``tearDownClass`` in test cases
-----------------------------------------------------------
The decorators :func:`~django.test.override_settings` and
:func:`~django.test.modify_settings` now act at the class level when used as
class decorators. As a consequence, when overriding ``setUpClass()`` or
``tearDownClass()``, the ``super`` implementation should always be called.
Removal of ``django.contrib.formtools``
---------------------------------------
The formtools contrib app has been moved to a separate package and the
relevant documentation pages have been updated or removed.
The new package is available `on GitHub`_ and on PyPI.
.. _on GitHub: https://github.com/django/django-formtools/
Database connection reloading between tests
-------------------------------------------
Django previously closed database connections between each test within a
``TestCase``. This is no longer the case as Django now wraps the whole
``TestCase`` within a transaction. If some of your tests relied on the old
behavior, you should have them inherit from ``TransactionTestCase`` instead.
Cleanup of the ``django.template`` namespace
--------------------------------------------
If you've been relying on private APIs exposed in the ``django.template``
module, you may have to import them from ``django.template.base`` instead.
Also private APIs ``django.template.base.compile_string()``,
``django.template.loader.find_template()``, and
``django.template.loader.get_template_from_string()`` were removed.
``model`` attribute on private model relations
----------------------------------------------
In earlier versions of Django, on a model with a reverse foreign key
relationship (for example), ``model._meta.get_all_related_objects()`` returned
the relationship as a ``django.db.models.related.RelatedObject`` with the
``model`` attribute set to the source of the relationship. Now, this method
returns the relationship as ``django.db.models.fields.related.ManyToOneRel``
(private API ``RelatedObject`` has been removed), and the ``model`` attribute
is set to the target of the relationship instead of the source. The source
model is accessible on the ``related_model`` attribute instead.
Consider this example from the tutorial in Django 1.8::
>>> p = Poll.objects.get(pk=1)
>>> p._meta.get_all_related_objects()
[<ManyToOneRel: polls.choice>]
>>> p._meta.get_all_related_objects()[0].model
<class 'polls.models.Poll'>
>>> p._meta.get_all_related_objects()[0].related_model
<class 'polls.models.Choice'>
and compare it to the behavior on older versions::
>>> p._meta.get_all_related_objects()
[<RelatedObject: polls:choice related to poll>]
>>> p._meta.get_all_related_objects()[0].model
<class 'polls.models.Choice'>
To access the source model, you can use a pattern like this to write code that
will work with both Django 1.8 and older versions::
for relation in opts.get_all_related_objects():
to_model = getattr(relation, 'related_model', relation.model)
Also note that ``get_all_related_objects()`` is deprecated in 1.8.
Database backend API
--------------------
The following changes to the database backend API are documented to assist
those writing third-party backends in updating their code:
* ``BaseDatabaseXXX`` classes have been moved to ``django.db.backends.base``.