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196 lines
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196 lines
8.3 KiB
Plaintext
============================================
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Django 1.5 release notes - UNDER DEVELOPMENT
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============================================
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These release notes cover the `new features`_, as well
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as some `backwards incompatible changes`_ you'll want to be aware of
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when upgrading from Django 1.4 or older versions. We've also dropped some
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features, which are detailed in :doc:`our deprecation plan
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</internals/deprecation>`, and we've `begun the deprecation process for some
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features`_.
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.. _`new features`: `What's new in Django 1.5`_
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.. _`backwards incompatible changes`: `Backwards incompatible changes in 1.5`_
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.. _`begun the deprecation process for some features`: `Features deprecated in 1.5`_
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Python compatibility
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====================
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Django 1.5 has dropped support for Python 2.5. Python 2.6 is now the minimum
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required Python version. Django is tested and supported on Python 2.6 and
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2.7.
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This change should affect only a small number of Django users, as most
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operating-system vendors today are shipping Python 2.6 or newer as their default
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version. If you're still using Python 2.5, however, you'll need to stick to
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Django 1.4 until you can upgrade your Python version. Per :doc:`our support policy
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</internals/release-process>`, Django 1.4 will continue to receive security
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support until the release of Django 1.6.
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Django 1.5 does not run on a Jython final release, because Jython's latest release
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doesn't currently support Python 2.6. However, Jython currently does offer an alpha
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release featuring 2.7 support.
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What's new in Django 1.5
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========================
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Support for saving a subset of model's fields
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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The method :meth:`Model.save() <django.db.models.Model.save()>` has a new
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keyword argument ``update_fields``. By using this argument it is possible to
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save only a select list of model's fields. This can be useful for performance
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reasons or when trying to avoid overwriting concurrent changes.
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See the :meth:`Model.save() <django.db.models.Model.save()>` documentation for
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more details.
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Caching of related model instances
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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When traversing relations, the ORM will avoid re-fetching objects that were
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previously loaded. For example, with the tutorial's models::
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>>> first_poll = Poll.objects.all()[0]
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>>> first_choice = first_poll.choice_set.all()[0]
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>>> first_choice.poll is first_poll
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True
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In Django 1.5, the third line no longer triggers a new SQL query to fetch
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``first_choice.poll``; it was set by the second line.
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For one-to-one relationships, both sides can be cached. For many-to-one
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relationships, only the single side of the relationship can be cached. This
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is particularly helpful in combination with ``prefetch_related``.
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``{% verbatim %}`` template tag
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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To make it easier to deal with javascript templates which collide with Django's
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syntax, you can now use the :ttag:`verbatim` block tag to avoid parsing the
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tag's content.
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Retrieval of ``ContentType`` instances associated with proxy models
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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The methods :meth:`ContentTypeManager.get_for_model() <django.contrib.contenttypes.models.ContentTypeManager.get_for_model()>`
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and :meth:`ContentTypeManager.get_for_models() <django.contrib.contenttypes.models.ContentTypeManager.get_for_models()>`
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have a new keyword argument – respectively ``for_concrete_model`` and ``for_concrete_models``.
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By passing ``False`` using this argument it is now possible to retreive the
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:class:`ContentType <django.contrib.contenttypes.models.ContentType>`
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associated with proxy models.
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Minor features
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~~~~~~~~~~~~~~
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Django 1.5 also includes several smaller improvements worth noting:
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* The template engine now interprets ``True``, ``False`` and ``None`` as the
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corresponding Python objects.
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* :mod:`django.utils.timezone` provides a helper for converting aware
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datetimes between time zones. See :func:`~django.utils.timezone.localtime`.
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* The generic views support OPTIONS requests.
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* Management commands do not raise ``SystemExit`` any more when called by code
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from :ref:`call_command <call-command>`. Any exception raised by the command
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(mostly :ref:`CommandError <ref-command-exceptions>`) is propagated.
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* The dumpdata management command outputs one row at a time, preventing
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out-of-memory errors when dumping large datasets.
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* In the localflavor for Canada, "pq" was added to the acceptable codes for
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Quebec. It's an old abbreviation.
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* The :ref:`receiver <connecting-receiver-functions>` decorator is now able to
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connect to more than one signal by supplying a list of signals.
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Backwards incompatible changes in 1.5
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=====================================
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.. warning::
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In addition to the changes outlined in this section, be sure to review the
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:doc:`deprecation plan </internals/deprecation>` for any features that
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have been removed. If you haven't updated your code within the
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deprecation timeline for a given feature, its removal may appear as a
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backwards incompatible change.
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Context in year archive class-based views
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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For consistency with the other date-based generic views,
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:class:`~django.views.generic.dates.YearArchiveView` now passes ``year`` in
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the context as a :class:`datetime.date` rather than a string. If you are
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using ``{{ year }}`` in your templates, you must replace it with ``{{
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year|date:"Y" }}``.
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``next_year`` and ``previous_year`` were also added in the context. They are
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calculated according to ``allow_empty`` and ``allow_future``.
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OPTIONS, PUT and DELETE requests in the test client
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Unlike GET and POST, these HTTP methods aren't implemented by web browsers.
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Rather, they're used in APIs, which transfer data in various formats such as
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JSON or XML. Since such requests may contain arbitrary data, Django doesn't
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attempt to decode their body.
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However, the test client used to build a query string for OPTIONS and DELETE
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requests like for GET, and a request body for PUT requests like for POST. This
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encoding was arbitrary and inconsistent with Django's behavior when it
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receives the requests, so it was removed in Django 1.5.
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If you were using the ``data`` parameter in an OPTIONS or a DELETE request,
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you must convert it to a query string and append it to the ``path`` parameter.
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If you were using the ``data`` parameter in a PUT request without a
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``content_type``, you must encode your data before passing it to the test
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client and set the ``content_type`` argument.
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String types of hasher method parameters
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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If you have written a :ref:`custom password hasher <auth_password_storage>`,
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your ``encode()``, ``verify()`` or ``safe_summary()`` methods should accept
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Unicode parameters (``password``, ``salt`` or ``encoded``). If any of the
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hashing methods need byte strings, you can use the
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:func:`~django.utils.encoding.smart_str` utility to encode the strings.
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Validation of previous_page_number and next_page_number
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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When using :doc:`object pagination </topics/pagination>`,
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the ``previous_page_number()`` and ``next_page_number()`` methods of the
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:class:`~django.core.paginator.Page` object did not check if the returned
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number was inside the existing page range.
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It does check it now and raises an :exc:`InvalidPage` exception when the number
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is either too low or too high.
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Behavior of autocommit database option on PostgreSQL changed
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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PostgreSQL's autocommit option didn't work as advertised previously. It did
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work for single transaction block, but after the first block was left the
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autocommit behavior was never restored. This bug is now fixed in 1.5. While
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this is only a bug fix, it is worth checking your applications behavior if
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you are using PostgreSQL together with the autocommit option.
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Features deprecated in 1.5
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==========================
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``django.utils.simplejson``
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Since Django 1.5 drops support for Python 2.5, we can now rely on the
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:mod:`json` module being in Python's standard library -- so we've removed
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our own copy of ``simplejson``. You can safely change any use of
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:mod:`django.utils.simplejson` to :mod:`json`.
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``itercompat.product``
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~~~~~~~~~~~~~~~~~~~~~~
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The :func:`~django.utils.itercompat.product` function has been deprecated. Use
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the built-in :func:`itertools.product` instead.
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