.. _internals-svn:

=================================
The Django source code repository
=================================


When deploying a Django application into a real production
environment, you will almost always want to use `an official packaged
release of Django`_. However, if you'd like to try out in-development
code from an upcoming release or contribute to the development of
Django, you'll need to obtain a checkout from Django's source code
repository. This document covers the way the code repository is laid
out and how to work with and find things in it.


.. _an official packaged release of Django: http://www.djangoproject.com/download/


High-level overview
===================

The Django source code repository uses `Subversion`_ to track changes
to the code over time, so you'll need a copy of the Subversion client
(a program called ``svn``) on your computer, and you'll want to
familiarize yourself with the basics of how Subversion
works. Subversion's web site offers downloads for various operating
systems, and `a free online book`_ is available to help you get up to
speed with using Subversion.

The Django Subversion repository is located online at
`code.djangoproject.com/svn <http://code.djangoproject.com/svn/>`_. `A
friendly Web-based interface for browsing the code`_ is also
available, though when using Subversion you'll always want to use the
repository address instead. At the top level of the repository are two
directories: ``django`` contains the full source code for all Django
releases, while ``djangoproject.com`` contains the source code and
templates for the `djangoproject.com <http://www.djangoproject.com/>`_
web site. For trying out in-development Django code, or contributing
to Django, you'll always want to check out code from some location in
the ``django`` directory.

Inside the ``django`` directory, Django's source code is organized
into three areas:

* ``branches`` contains branched copies of Django's code, which are
  (or were) maintained for various purposes. Some branches exist to
  provide a place to develop major or experimental new features
  without affecting the rest of Django's code, while others serve to
  provide bug fixes or support for older Django releases.

* ``tags`` contains snapshots of Django's code at various important
  points in its history; mostly these are the exact revisions from
  which packaged Django releases were produced.

* ``trunk`` contains the main in-development code which will become
  the next packaged release of Django, and is where most development
  activity is focused.


.. _Subversion: http://subversion.tigris.org/
.. _a free online book: http://svnbook.red-bean.com/
.. _A friendly web-based interface for browsing the code: http://code.djangoproject.com/browser/


Working with Django's trunk
===========================

If you'd like to try out the in-development code for the next release
of Django, or if you'd like to contribute to Django by fixing bugs or
developing new features, you'll want to get the code from trunk. You
can get a complete copy of this code (a "Subversion checkout") by
typing::

    svn co http://code.djangoproject.com/svn/django/trunk/

Note that this will get *all* of Django: in addition to the top-level
``django`` module containing Python code, you'll also get a copy of
Django's documentation, unit-test suite, packaging scripts and other
miscellaneous bits. Django's code will be present in your checkout as
a directory named ``django``.

To try out the in-development trunk code with your own applications,
simply place the directory containing your checkout on your Python
import path. Then ``import`` statements which look for Django will find
the ``django`` module within your checkout.

If you're going to be working on Django's code (say, to fix a bug or
develop a new feature), you can probably stop reading here and move
over to :ref:`the documentation for contributing to Django
<internals-contributing>`, which covers things like the preferred
coding style and how to generate and submit a patch.


Branches
========

Django uses branches for two main purposes:

1. Development of major or experimental features, to keep them from
   affecting progress on other work in trunk.

2. Security and bug-fix support for older releases of Django, during
   their support lifetimes.


Feature-development branches
----------------------------

Feature-development branches tend by their nature to be
temporary. Some produce successful features which are merged back into
Django's trunk to become part of an official release, but others do
not; in either case there comes a time when the branch is no longer
being actively worked on by any developer. At this point the branch is
considered closed.

Unfortunately, Subversion has no standard way of indicating this. As a
workaround, branches of Django which are closed and no longer
maintained are moved into the directory ``django/branches/attic``.

For reference, the following are branches whose code eventually became
part of Django itself, and so are no longer separately maintained:

* ``boulder-oracle-sprint``: Added support for Oracle databases to
  Django's object-relational mapper. This has been part of Django
  since the 1.0 release.

* ``gis``: Added support for geographic/spatial queries to Django's
  object-relational mapper. This has been part of Django since the 1.0
  release, as the bundled application ``django.contrib.gis``.

* ``i18n``: Added :ref:`internationalization support <topics-i18n>` to
  Django. This has been part of Django since the 0.90 release.

* ``magic-removal``: A major refactoring of both the internals and
  public APIs of Django's object-relational mapper. This has been part
  of Django since the 0.95 release.

* ``multi-auth``: A refactoring of :ref:`Django's bundled
  authentication framework <topics-auth>` which added support for
  :ref:`authentication backends <authentication-backends>`. This has
  been part of Django since the 0.95 release.

* ``new-admin``: A refactoring of :ref:`Django's bundled
  administrative application <ref-contrib-admin>`. This became part of
  Django as of the 0.91 release, but was superseded by another
  refactoring (see next listing) prior to the Django 1.0 release.

* ``newforms-admin``: The second refactoring of Django's bundled
  administrative application. This became part of Django as of the 1.0
  release, and is the basis of the current incarnation of
  ``django.contrib.admin``.

* ``queryset-refactor``: A refactoring of the internals of Django's
  object-relational mapper. This became part of Django as of the 1.0
  release.

* ``unicode``: A refactoring of Django's internals to consistently use
  Unicode-based strings in most places within Django and Django
  applications. This became part of Django as of the 1.0 release.

Additionally, the following branches are closed, but their code was
never merged into Django and the features they aimed to implement
were never finished:

* ``full-history``

* ``generic-auth``

* ``multiple-db-support``

* ``per-object-permissions``

* ``schema-evolution``

* ``schema-evolution-ng``

* ``search-api``

* ``sqlalchemy``

All of the above-mentioned branches now reside in
``django/branches/attic``.


Support and bugfix branches
---------------------------

In addition to fixing bugs in current trunk, the Django project
provides official bug-fix support for the most recent released version
of Django, and security support for the two most recently-released
versions of Django. This support is provided via branches in which the
necessary bug or security fixes are applied; the branches are then
used as the basis for issuing bugfix or security releases.

As of the Django 1.0 release, these branches can be found in the
repository in the directory ``django/branches/releases``, and new branches
will be created there approximately one month after each new Django
release. For example, shortly after the release of Django 1.0, the
branch ``django/branches/releases/1.0.X`` was created to receive bug
fixes, and shortly after the release of Django 1.1 the branch
``django/branches/releases/1.1.X`` was created.

Prior to the Django 1.0 release, these branches were maintaind within
the top-level ``django/branches`` directory, and so the following
branches exist there and provided support for older Django releases:

* ``0.90-bugfixes``

* ``0.91-bugfixes``

* ``0.95-bugfixes``

* ``0.96-bugfixes``

Official support for those releases has expired, and so they no longer
receive direct maintenance from the Django project. However, the
branches continue to exist and interested community members have
occasionally used them to provide unofficial support for old Django
releases.


Tags
====

The directory ``django/tags`` within the repository contains complete
copies of the Django source code as it existed at various points in
its history. These "tagged" copies of Django are *never* changed or
updated; new tags may be added as needed, but once added they are
considered read-only and serve as useful guides to Django's
development history.

Within ``django/tags/releases`` are copies of the code which formed each
packaged release of Django, and each tag is named with the version
number of the release to which it corresponds. So, for example,
``django/tags/releases/1.1`` is a complete copy of the code which was
packaged as the Django 1.1 release.

Within ``django/tags/notable_moments`` are copies of the Django code from
points which do not directly correspond to releases, but which are
nonetheless important historical milestones for Django
development. The current "notable moments" marked there are:

* ``ipo``: Django's code as it existed at the moment Django was first
  publicly announced in 2005.

* ``pre-magic-removal``: The state of Django's code just before the
  merging of the ``magic-removal`` branch (described above), which
  significantly updated Django's object-relational mapper.

* ``pre-newforms-admin``: The state of Django's code just before the
  merging of the ``newforms-admin`` branch (see above), which
  significantly updated Django's bundled administrative application.

* Tags corresponding to each of the alpha, beta and release-candidate
  packages in the run up to the Django 1.0 release.
