========================
Django's release process
========================

.. _official-releases:

Official releases
=================

Since version 1.0, Django's release numbering works as follows:

* Versions are numbered in the form ``A.B`` or ``A.B.C``.

* ``A`` is the *major version* number, which is only incremented for major
  changes to Django, and these changes are not necessarily
  backwards-compatible. That is, code you wrote for Django 1.2 may break
  when we release Django 2.0.

* ``B`` is the *minor version* number, which is incremented for large yet
  backwards compatible changes.  Code written for Django 1.2 will continue
  to work under Django 1.3. Exceptions to this rule will be listed in the
  release notes.

* ``C`` is the *micro version* number, which is incremented for bug and
  security fixes. A new micro-release will be 100% backwards-compatible with
  the previous micro-release. The only exception is when a security issue
  can't be fixed without breaking backwards-compatibility. If this happens,
  the release notes will provide detailed upgrade instructions.

* In some cases, we'll make alpha, beta, or release candidate releases.
  These are of the form ``A.B alpha/beta/rc N``, which means the ``Nth``
  alpha/beta/release candidate of version ``A.B``.

In Subversion, each Django release will be tagged under ``tags/releases``.  If
it's necessary to release a bug fix release or a security release that doesn't
come from the trunk, we'll copy that tag to ``branches/releases`` to make the
bug fix release.

Major releases
--------------

Major releases (1.0, 2.0, etc.) will happen very infrequently (think "years",
not "months"), and will probably represent major, sweeping changes to Django.

Minor releases
--------------

Minor release (1.1, 1.2, etc.) will happen roughly every nine months -- see
`release process`_, below for details.

.. _internal-release-deprecation-policy:

These releases will contain new features, improvements to existing features, and
such. A minor release may deprecate certain features from previous releases. If a
feature in version ``A.B`` is deprecated, it will continue to work in version
``A.B+1``. In version ``A.B+2``, use of the feature will raise a
``DeprecationWarning`` but will continue to work. Version ``A.B+3`` will
remove the feature entirely.

So, for example, if we decided to remove a function that existed in Django 1.0:

* Django 1.1 will contain a backwards-compatible replica of the function
  which will raise a ``PendingDeprecationWarning``. This warning is silent
  by default; you need to explicitly turn on display of these warnings.

* Django 1.2 will contain the backwards-compatible replica, but the warning
  will be promoted to a full-fledged ``DeprecationWarning``. This warning is
  *loud* by default, and will likely be quite annoying.

* Django 1.3 will remove the feature outright.

Micro releases
--------------

Micro releases (1.0.1, 1.0.2, 1.1.1, etc.) will be issued at least once half-way
between minor releases, and probably more often as needed.

These releases will be 100% compatible with the associated minor release, unless
this is impossible for security reasons. So the answer to "should I upgrade to
the latest micro release?" will always be "yes."

Each minor release of Django will have a "release maintainer" appointed. This
person will be responsible for making sure that bug fixes are applied to both
trunk and the maintained micro-release branch. This person will also work with
the release manager to decide when to release the micro releases.

Supported versions
==================

At any moment in time, Django's developer team will support a set of releases to
varying levels:

* The current development trunk will get new features and bug fixes
  requiring major refactoring.

* Patches applied to the trunk will also be applied to the last minor
  release, to be released as the next micro release, when they fix critical
  problems:

  * Security issues.

  * Data-loss bugs.

  * Crashing bugs.

  * Major functionality bugs in newly-introduced features.

  The rule of thumb is that fixes will be backported to the last minor
  release for bugs that would have prevented a release in the first place.

* Security fixes will be applied to the current trunk and the previous two
  minor releases.

* Documentation fixes generally will be more freely backported to the last
  release branch, at the discretion of the committer, and they don't need to
  meet the "critical fixes only" bar. That's because it's highly advantageous
  to have the docs for the last release be up-to-date and correct, and the
  downside of backporting (risk of introducing regressions) is much less of a
  concern.

As a concrete example, consider a moment in time halfway between the release of
Django 1.3 and 1.4. At this point in time:

* Features will be added to development trunk, to be released as Django 1.4.

* Critical bug fixes will be applied to a ``1.3.X`` branch, and released as
  1.3.1, 1.3.2, etc.

* Security fixes will be applied to trunk, a ``1.3.X`` branch and a
  ``1.2.X`` branch. They will trigger the release of ``1.3.1``, ``1.2.1``,
  etc.

* Documentation fixes will be applied to trunk, and, if easily backported, to
  the ``1.3.X`` branch.

.. _lts-releases:

Long-term support (LTS) releases
================================

Additionally, the Django team will occasionally designate certain releases
to be "Long-term support" (LTS) releases. LTS releases will get security fixes
applied for a guaranteed period of time, typically 3+ years, regardless of
the pace of releases afterwards.

The follow releases have been designated for long-term support:

    * Django 1.4, supported until at least March 2015.

.. _release-process:

Release process
===============

Django uses a time-based release schedule, with minor (i.e. 1.1, 1.2, etc.)
releases every nine months, or more, depending on features.

After each release, and after a suitable cooling-off period of a few weeks, the
core development team will examine the landscape and announce a timeline for the
next release. Most releases will be scheduled in the 6-9 month range, but if we
have bigger features to development we might schedule a longer period to allow
for more ambitious work.

Release cycle
-------------

Each release cycle will be split into three periods, each lasting roughly
one-third of the cycle:

Phase one: feature proposal
~~~~~~~~~~~~~~~~~~~~~~~~~~~

The first phase of the release process will be devoted to figuring out what
features to include in the next version. This should include a good deal of
preliminary work on those features -- working code trumps grand design.

At the end of part one, the core developers will propose a feature list for the
upcoming release. This will be broken into:

* "Must-have": critical features that will delay the release if not finished
* "Maybe" features: that will be pushed to the next release if not finished
* "Not going to happen": features explicitly deferred to a later release.

Anything that hasn't got at least some work done by the end of the first third
isn't eligible for the next release; a design alone isn't sufficient.

Phase two: development
~~~~~~~~~~~~~~~~~~~~~~

The second third of the release schedule is the "heads-down" working period.
Using the roadmap produced at the end of phase one, we'll all work very hard to
get everything on it done.

Longer release schedules will likely spend more than a third of the time in this
phase.

At the end of phase two, any unfinished "maybe" features will be postponed until
the next release. Though it shouldn't happen, any "must-have" features will
extend phase two, and thus postpone the final release.

Phase two will culminate with an alpha release.

Phase three: bugfixes
~~~~~~~~~~~~~~~~~~~~~

The last third of a release is spent fixing bugs -- no new features will be
accepted during this time. We'll release a beta release about halfway through,
and an rc complete with string freeze two weeks before the end of the schedule.

Bug-fix releases
----------------

After a minor release (e.g. 1.1), the previous release will go into bug-fix
mode.

A branch will be created of the form ``branches/releases/1.0.X`` to track
bug-fixes to the previous release. Critical bugs fixed on trunk must
*also* be fixed on the bug-fix branch; this means that commits need to cleanly
separate bug fixes from feature additions. The developer who commits a fix to
trunk will be responsible for also applying the fix to the current bug-fix
branch.  Each bug-fix branch will have a maintainer who will work with the
committers to keep them honest on backporting bug fixes.

How this all fits together
--------------------------

Let's look at a hypothetical example for how this all first together. Imagine,
if you will, a point about halfway between 1.1 and 1.2. At this point,
development will be happening in a bunch of places:

* On trunk, development towards 1.2 proceeds with small additions, bugs
  fixes, etc. being checked in daily.

* On the branch "branches/releases/1.1.X", fixes for critical bugs found in
  the 1.1 release are checked in as needed. At some point, this branch will
  be released as "1.1.1", "1.1.2", etc.

* On the branch "branches/releases/1.0.X", security fixes are made if
  needed and released as "1.0.2", "1.0.3", etc.

* On feature branches, development of major features is done. These
  branches will be merged into trunk before the end of phase two.
