mirror of https://github.com/django/django.git
120 lines
4.6 KiB
Plaintext
120 lines
4.6 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 Jython, because Jython doesn't currently offer any
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version compatible with Python 2.6.
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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 when 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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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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* 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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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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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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