django/docs/internals/contributing.txt

======================
Contributing to Django
======================

If you think working *with* Django is fun, wait until you start working *on*
it. We're passionate about helping Django users make the jump to contributing
members of the community, so there are many ways you can help Django's
development:

    * Blog about Django.  We syndicate all the Django blogs we know about on
      the `community page`_; contact jacob@jacobian.org if you've got a blog
      you'd like to see on that page.

    * Report bugs and request features in our `ticket tracker`_.  Please read
      `Reporting bugs`_, below, for the details on how we like our bug reports
      served up.

    * Submit patches for new and/or fixed behavior.  Please read `Submitting
      patches`_, below, for details on how to submit a patch. If you're looking
      for an easy way to start contributing to Django have a look at the
      `easy-pickings`_ tickets.

    * Join the `django-developers`_ mailing list and share your ideas for how
      to improve Django.  We're always open to suggestions, although we're
      likely to be skeptical of large-scale suggestions without some code to
      back it up.

    * Triage patches that have been submitted by other users. Please read
      `Ticket triage`_ below, for details on the triage process.

That's all you need to know if you'd like to join the Django development
community. The rest of this document describes the details of how our community
works and how it handles bugs, mailing lists, and all the other minutiae of
Django development.

.. seealso::

    This document contains specific details for contributing to
    Django. However, many new contributors find this guide confusing
    or intimidating at first. For a simpler introduction
    to becoming a contributor please see the :doc:`/howto/contribute` guide.

.. _reporting-bugs:

Reporting bugs
==============

Well-written bug reports are *incredibly* helpful. However, there's a certain
amount of overhead involved in working with any bug tracking system so your
help in keeping our ticket tracker as useful as possible is appreciated.  In
particular:

    * **Do** read the :doc:`FAQ </faq/index>` to see if your issue might
      be a well-known question.

    * **Do** `search the tracker`_ to see if your issue has already been filed.

    * **Do** ask on `django-users`_ *first* if you're not sure if what you're
      seeing is a bug.

    * **Do** write complete, reproducible, specific bug reports. Include as
      much information as you possibly can, complete with code snippets, test
      cases, etc. This means including a clear, concise description of the
      problem, and a clear set of instructions for replicating the problem.
      A minimal example that illustrates the bug in a nice small test case
      is the best possible bug report.

    * **Don't** use the ticket system to ask support questions.  Use the
      `django-users`_ list, or the `#django`_ IRC channel for that.

    * **Don't** use the ticket system to make large-scale feature requests.
      We like to discuss any big changes to Django's core on the
      `django-developers`_ list before actually working on them.

    * **Don't** reopen issues that have been marked "wontfix". This mark
      means that the decision has been made that we can't or won't fix
      this particular issue.  If you're not sure why, please ask
      on `django-developers`_.

    * **Don't** use the ticket tracker for lengthy discussions, because they're
      likely to get lost. If a particular ticket is controversial, please move
      discussion to `django-developers`_.

    * **Don't** post to django-developers just to announce that you have filed
      a bug report. All the tickets are mailed to another list
      (`django-updates`_), which is tracked by developers and interested
      community members; we see them as they are filed.

.. _django-updates: http://groups.google.com/group/django-updates

.. _reporting-security-issues:

Reporting security issues
=========================

Report security issues to security@djangoproject.com. This is a private list
only open to long-time, highly trusted Django developers, and its archives are
not publicly readable.

In the event of a confirmed vulnerability in Django itself, we will take the
following actions:

    * Acknowledge to the reporter that we've received the report and that a
      fix is forthcoming. We'll give a rough timeline and ask the reporter
      to keep the issue confidential until we announce it.

    * Halt all other development as long as is needed to develop a fix,
      including patches against the current and two previous releases.

    * Determine a go-public date for announcing the vulnerability and the fix.
      To try to mitigate a possible "arms race" between those applying the
      patch and those trying to exploit the hole, we will not announce
      security problems immediately.

    * Pre-notify everyone we know to be running the affected version(s) of
      Django. We will send these notifications through private e-mail
      which will include documentation of the vulnerability, links to the
      relevant patch(es), and a request to keep the vulnerability
      confidential until the official go-public date.

    * Publicly announce the vulnerability and the fix on the pre-determined
      go-public date. This will probably mean a new release of Django, but
      in some cases it may simply be patches against current releases.

Submitting patches
==================

We're always grateful for patches to Django's code. Indeed, bug reports
with associated patches will get fixed *far* more quickly than those
without patches.

"Claiming" tickets
------------------

In an open-source project with hundreds of contributors around the world, it's
important to manage communication efficiently so that work doesn't get
duplicated and contributors can be as effective as possible. Hence, our policy
is for contributors to "claim" tickets in order to let other developers know
that a particular bug or feature is being worked on.

If you have identified a contribution you want to make and you're capable of
fixing it (as measured by your coding ability, knowledge of Django internals
and time availability), claim it by following these steps:

    * `Create an account`_ to use in our ticket system.

    * If a ticket for this issue doesn't exist yet, create one in our
      `ticket tracker`_.

    * If a ticket for this issue already exists, make sure nobody else has
      claimed it. To do this, look at the "Assigned to" section of the ticket.
      If it's assigned to "nobody," then it's available to be claimed.
      Otherwise, somebody else is working on this ticket, and you either find
      another bug/feature to work on, or contact the developer working on the
      ticket to offer your help.

    * Log into your account, if you haven't already, by clicking "Login" in the
      upper right of the ticket page.

    * Claim the ticket by clicking the radio button next to "Accept ticket"
      near the bottom of the page, then clicking "Submit changes."

If you have an account but have forgotten your password, you can reset it
using the `password reset page`_.

.. _Create an account: http://www.djangoproject.com/accounts/register/
.. _password reset page: http://www.djangoproject.com/accounts/password/reset/

Ticket claimers' responsibility
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Once you've claimed a ticket, you have a responsibility to work on that ticket
in a reasonably timely fashion. If you don't have time to work on it, either
unclaim it or don't claim it in the first place!

If there's no sign of progress on a particular claimed ticket for a week or
two, another developer may ask you to relinquish the ticket claim so that it's
no longer monopolized and somebody else can claim it.

If you've claimed a ticket and it's taking a long time (days or weeks) to code,
keep everybody updated by posting comments on the ticket. If you don't provide
regular updates, and you don't respond to a request for a progress report,
your claim on the ticket may be revoked. As always, more communication is
better than less communication!

Which tickets should be claimed?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Of course, going through the steps of claiming tickets is overkill in some
cases. In the case of small changes, such as typos in the documentation or
small bugs that will only take a few minutes to fix, you don't need to jump
through the hoops of claiming tickets. Just submit your patch and be done with
it.

Patch style
-----------

    * Make sure your code matches our `coding style`_.

    * Submit patches in the format returned by the ``svn diff`` command.
      An exception is for code changes that are described more clearly in
      plain English than in code. Indentation is the most common example; it's
      hard to read patches when the only difference in code is that it's
      indented.

      Patches in ``git diff`` format are also acceptable.

    * When creating patches, always run ``svn diff`` from the top-level
      ``trunk`` directory -- i.e., the one that contains ``django``, ``docs``,
      ``tests``, ``AUTHORS``, etc. This makes it easy for other people to
      apply your patches.

    * Attach patches to a ticket in the `ticket tracker`_, using the "attach
      file" button. Please *don't* put the patch in the ticket description
      or comment unless it's a single line patch.

    * Name the patch file with a ``.diff`` extension; this will let the ticket
      tracker apply correct syntax highlighting, which is quite helpful.

    * Check the "Has patch" box on the ticket details. This will make it
      obvious that the ticket includes a patch, and it will add the ticket to
      the `list of tickets with patches`_.

    * The code required to fix a problem or add a feature is an essential part
      of a patch, but it is not the only part. A good patch should also include
      a regression test to validate the behavior that has been fixed
      (and prevent the problem from arising again).

    * If the code associated with a patch adds a new feature, or modifies
      behavior of an existing feature, the patch should also contain
      documentation.

Non-trivial patches
-------------------

A "non-trivial" patch is one that is more than a simple bug fix. It's a patch
that introduces Django functionality and makes some sort of design decision.

If you provide a non-trivial patch, include evidence that alternatives have
been discussed on `django-developers`_. If you're not sure whether your patch
should be considered non-trivial, just ask.

Ticket triage
=============

Unfortunately, not all bug reports in the `ticket tracker`_ provide all
the `required details`_. A number of tickets have patches, but those patches
don't meet all the requirements of a `good patch`_.

One way to help out is to *triage* bugs that have been reported by other
users. The core team--as well as many community members--work on this
regularly, but more help is always appreciated.

Most of the workflow is based around the concept of a ticket's "triage stage".
This stage describes where in its lifetime a given ticket is at any time.
Along with a handful of flags, this field easily tells us what and who each
ticket is waiting on.

Since a picture is worth a thousand words, let's start there:

.. image:: _images/djangotickets.png
   :height: 451
   :width: 590
   :alt: Django's ticket workflow

We've got two roles in this diagram:

    * Core developers: people with commit access who are responsible for
      making the big decisions, writing large portions of the code and
      integrating the contributions of the community.

    * Ticket triagers: anyone in the Django community who chooses to
      become involved in Django's development process. Our Trac installation
      is :ref:`intentionally left open to the public
      <the-spirit-of-contributing>`, and anyone can triage tickets.
      Django is a community project, and we encourage `triage by the
      community`_.

Second, note the five triage stages:

    1. A ticket starts as "Unreviewed", meaning that nobody has examined
       the ticket.

    2. "Design decision needed" means "this concept requires a design
       decision," which should be discussed either in the ticket comments or on
       `django-developers`_. The "Design decision needed" step will generally
       only be used for feature requests. It can also be used for issues
       that *might* be bugs, depending on opinion or interpretation. Obvious
       bugs (such as crashes, incorrect query results, or non-compliance with a
       standard) skip this step and move straight to "Accepted".

    3. Once a ticket is ruled to be approved for fixing, it's moved into the
       "Accepted" stage. This stage is where all the real work gets done.

    4. In some cases, a ticket might get moved to the "Someday/Maybe" state.
       This means the ticket is an enhancement request that we might consider
       adding to the framework if an excellent patch is submitted. These
       tickets are not a high priority.

    5. If a ticket has an associated patch (see below), it will be reviewed
       by the community. If the patch is complete, it'll be marked as "ready
       for checkin" so that a core developer knows to review and commit the
       patch.

The second part of this workflow involves a set of flags the describe what the
ticket has or needs in order to be "ready for checkin":

    "Has patch"
        This means the ticket has an associated patch_. These will be
        reviewed to see if the patch is "good".

    "Needs documentation"
        This flag is used for tickets with patches that need associated
        documentation. Complete documentation of features is a prerequisite
        before we can check them into the codebase.

    "Needs tests"
        This flags the patch as needing associated unit tests. Again, this is a
        required part of a valid patch.

    "Patch needs improvement"
        This flag means that although the ticket *has* a patch, it's not quite
        ready for checkin. This could mean the patch no longer applies
        cleanly, there is a flaw in the implementation, or that the code
        doesn't meet our standards.

A ticket can be resolved in a number of ways:

    "fixed"
        Used by the core developers once a patch has been rolled into
        Django and the issue is fixed.

    "invalid"
        Used if the ticket is found to be incorrect. This means that the
        issue in the ticket is actually the result of a user error, or
        describes a problem with something other than Django, or isn't
        a bug report or feature request at all (for example, some new users
        submit support queries as tickets).

    "wontfix"
        Used when a core developer decides that this request is not
        appropriate for consideration in Django. This is usually chosen after
        discussion in the ``django-developers`` mailing list. Feel free to
        start or join in discussions of "wontfix" tickets on the mailing list,
        but please do not reopen tickets closed as "wontfix" by core
        developers.

    "duplicate"
        Used when another ticket covers the same issue. By closing duplicate
        tickets, we keep all the discussion in one place, which helps everyone.

    "worksforme"
        Used when the ticket doesn't contain enough detail to replicate
        the original bug.

If you believe that the ticket was closed in error -- because you're
still having the issue, or it's popped up somewhere else, or the triagers have
made a mistake -- please reopen the ticket and provide further information.
Please do not reopen tickets that have been marked as "wontfix" by core
developers.

.. _required details: `Reporting bugs`_
.. _good patch: `Patch style`_
.. _triage by the community: `Triage by the general community`_
.. _patch: `Submitting patches`_

Triage by the general community
-------------------------------

Although the core developers make the big decisions in the ticket triage
process, there's a lot that general community members can do to help the
triage process. In particular, you can help out by:

    * Closing "Unreviewed" tickets as "invalid", "worksforme" or "duplicate."

    * Promoting "Unreviewed" tickets to "Design decision needed" if a design
      decision needs to be made, or "Accepted" in case of obvious bugs.

    * Correcting the "Needs tests", "Needs documentation", or "Has patch"
      flags for tickets where they are incorrectly set.

    * Adding the `easy-pickings`_ keyword to tickets that are small and
      relatively straightforward.

    * Checking that old tickets are still valid. If a ticket hasn't seen
      any activity in a long time, it's possible that the problem has been
      fixed but the ticket hasn't yet been closed.

    * Contacting the owners of tickets that have been claimed but have not
      seen any recent activity. If the owner doesn't respond after a week
      or so, remove the owner's claim on the ticket.

    * Identifying trends and themes in the tickets. If there a lot of bug
      reports about a particular part of Django, it may indicate we should
      consider refactoring that part of the code. If a trend is emerging,
      you should raise it for discussion (referencing the relevant tickets)
      on `django-developers`_.

However, we do ask the following of all general community members working in
the ticket database:

    * Please **don't** close tickets as "wontfix." The core developers will
      make the final determination of the fate of a ticket, usually after
      consultation with the community.

    * Please **don't** promote your own tickets to "Ready for checkin". You
      may mark other people's tickets which you've reviewed as "Ready for
      checkin", but you should get at minimum one other community member to
      review a patch that you submit.

    * Please **don't** reverse a decision that has been made by a core
      developer. If you disagree with a decision that has been made,
      please post a message to `django-developers`_.

    * If you're unsure if you should be making a change, don't make the change
      but instead leave a comment with your concerns on the ticket, or
      post a message to `django-developers`_. It's okay to be unsure, but
      your input is still valuable.

.. _contributing-translations:

Submitting and maintaining translations
=======================================

Various parts of Django, such as the admin site and validation error messages,
are internationalized. This means they display different text depending on a
user's language setting. For this, Django uses the same internationalization
infrastructure available to Django applications described in the
:doc:`i18n documentation</topics/i18n/index>`.

These translations are contributed by Django users worldwide. If you find an
incorrect translation or want to discuss specific translations, go to the
`translation team`_ page for that language. If you would like to help out
with translating or add a language that isn't yet translated, here's what
to do:

    * Join the `Django i18n mailing list`_ and introduce yourself.

    * Make sure you read the notes about :ref:`specialties-of-django-i18n`.

    * Signup at `Transifex`_ and visit the `Django project page`_.

    * On the "`Translation Teams`_" page, choose the language team you want
      to work with, **or** -- in case the language team doesn't exist yet --
      request a new team by clicking on the "Request a new team" button
      and select the appropriate language.

    * Then, click the "Join this Team" button to become a member of this team.
      Every team has at least one coordinator who is responsible to review
      your membership request. You can of course also contact the team
      coordinator to clarify procedual problems and handle the actual
      translation process.

    * Once you are a member of a team choose the translation resource you
      want update on the team page. For example the "core" resource refers
      to the translation catalogue that contains all non-app translations.
      Each of the contrib apps also have a resource (prefixed with "contrib-").

      .. note::
         For more information about how to use Transifex, see the
         `Transifex Help`_

    * Optionally, review and update the ``conf/locale/<locale>/formats.py``
      file to describe the date, time and numbers formatting particularities
      of your locale. These files aren't covered by the use of Transifex and
      require a patch against the Django source tree, just as a code change
      would:

      * Create a diff against the current Subversion trunk.

      * Open a ticket in Django's ticket system, set its ``Component`` field
        to ``Translations``, and attach the patch to it. See
        :ref:`format-localization` for details.

.. _Django i18n mailing list: http://groups.google.com/group/django-i18n/
.. _Transifex: http://www.transifex.net/
.. _Django project page: http://www.transifex.net/projects/p/django/
.. _translation teams: http://www.transifex.net/projects/p/django/teams/
.. _translation team: http://www.transifex.net/projects/p/django/teams/
.. _Transifex Help: http://help.transifex.net/

Submitting javascript patches
=============================

.. versionadded:: 1.2

Django's admin system leverages the jQuery framework to increase the
capabilities of the admin interface. In conjunction, there is an emphasis on
admin javascript performance and minimizing overall admin media file size.
Serving compressed or "minified" versions of javascript files is considered
best practice in this regard.

To that end, patches for javascript files should include both the original
code for future development (e.g. "foo.js"), and a compressed version for
production use (e.g. "foo.min.js"). Any links to the file in the codebase
should point to the compressed version.

To simplify the process of providing optimized javascript code, Django
includes a handy script which should be used to create a "minified" version.
This script is located at ``/contrib/admin/media/js/compress.py``.

Behind the scenes, ``compress.py`` is a front-end for Google's
`Closure Compiler`_ which is written in Java. However, the Closure Compiler
library is not bundled with Django directly, so those wishing to contribute
complete javascript patches will need to download and install the library
independently.

The Closure Compiler library requires Java version 6 or higher (Java 1.6 or
higher on Mac OS X). Note that Mac OS X 10.5 and earlier did not ship with Java
1.6 by default, so it may be necessary to upgrade your Java installation before
the tool will be functional. Also note that even after upgrading Java, the
default `/usr/bin/java` command may remain linked to the previous Java
binary, so relinking that command may be necessary as well.

Please don't forget to run ``compress.py`` and include the ``diff`` of the
minified scripts when submitting patches for Django's javascript.

.. _Closure Compiler: http://code.google.com/closure/compiler/

Django conventions
==================

Various Django-specific code issues are detailed in this section.

Use of ``django.conf.settings``
-------------------------------

Modules should not in general use settings stored in ``django.conf.settings``
at the top level (i.e. evaluated when the module is imported). The explanation
for this is as follows:

Manual configuration of settings (i.e. not relying on the
``DJANGO_SETTINGS_MODULE`` environment variable) is allowed and possible as
follows::

    from django.conf import settings

    settings.configure({}, SOME_SETTING='foo')

However, if any setting is accessed before the ``settings.configure`` line,
this will not work. (Internally, ``settings`` is a ``LazyObject`` which
configures itself automatically when the settings are accessed if it has not
already been configured).

So, if there is a module containing some code as follows::

    from django.conf import settings
    from django.core.urlresolvers import get_callable

    default_foo_view = get_callable(settings.FOO_VIEW)

...then importing this module will cause the settings object to be configured.
That means that the ability for third parties to import the module at the top
level is incompatible with the ability to configure the settings object
manually, or makes it very difficult in some circumstances.

Instead of the above code, a level of laziness or indirection must be used,
such as `django.utils.functional.LazyObject``, ``django.utils.functional.lazy``
or ``lambda``.

Coding style
============

Please follow these coding standards when writing code for inclusion in Django:

    * Unless otherwise specified, follow :pep:`8`.

      You could use a tool like `pep8.py`_ to check for some problems in this
      area, but remember that PEP 8 is only a guide, so respect the style of
      the surrounding code as a primary goal.

    * Use four spaces for indentation.

    * Use underscores, not camelCase, for variable, function and method names
      (i.e. ``poll.get_unique_voters()``, not ``poll.getUniqueVoters``).

    * Use ``InitialCaps`` for class names (or for factory functions that
      return classes).

    * Mark all strings for internationalization; see the :doc:`i18n
      documentation </topics/i18n/index>` for details.

    * In docstrings, use "action words" such as::

          def foo():
              """
              Calculates something and returns the result.
              """
              pass

      Here's an example of what not to do::

          def foo():
              """
              Calculate something and return the result.
              """
              pass

    * Please don't put your name in the code you contribute. Our policy is to
      keep contributors' names in the ``AUTHORS`` file distributed with Django
      -- not scattered throughout the codebase itself. Feel free to include a
      change to the ``AUTHORS`` file in your patch if you make more than a
      single trivial change.

Template style
--------------

    * In Django template code, put one (and only one) space between the curly
      brackets and the tag contents.

      Do this:

      .. code-block:: html+django

          {{ foo }}

      Don't do this:

      .. code-block:: html+django

          {{foo}}

View style
----------

    * In Django views, the first parameter in a view function should be called
      ``request``.

      Do this::

          def my_view(request, foo):
              # ...

      Don't do this::

          def my_view(req, foo):
              # ...

Model style
-----------

    * Field names should be all lowercase, using underscores instead of
      camelCase.

      Do this::

          class Person(models.Model):
              first_name = models.CharField(max_length=20)
              last_name = models.CharField(max_length=40)

      Don't do this::

          class Person(models.Model):
              FirstName = models.CharField(max_length=20)
              Last_Name = models.CharField(max_length=40)

    * The ``class Meta`` should appear *after* the fields are defined, with
      a single blank line separating the fields and the class definition.

      Do this::

          class Person(models.Model):
              first_name = models.CharField(max_length=20)
              last_name = models.CharField(max_length=40)

              class Meta:
                  verbose_name_plural = 'people'

      Don't do this::

          class Person(models.Model):
              first_name = models.CharField(max_length=20)
              last_name = models.CharField(max_length=40)
              class Meta:
                  verbose_name_plural = 'people'

      Don't do this, either::

          class Person(models.Model):
              class Meta:
                  verbose_name_plural = 'people'

              first_name = models.CharField(max_length=20)
              last_name = models.CharField(max_length=40)

    * The order of model inner classes and standard methods should be as
      follows (noting that these are not all required):

        * All database fields
        * Custom manager attributes
        * ``class Meta``
        * ``def __unicode__()``
        * ``def __str__()``
        * ``def save()``
        * ``def get_absolute_url()``
        * Any custom methods

    * If ``choices`` is defined for a given model field, define the choices as
      a tuple of tuples, with an all-uppercase name, either near the top of the
      model module or just above the model class. Example::

          GENDER_CHOICES = (
              ('M', 'Male'),
              ('F', 'Female'),
          )

Documentation style
===================

We place a high importance on consistency and readability of documentation.
(After all, Django was created in a journalism environment!)

How to document new features
----------------------------

We treat our documentation like we treat our code: we aim to improve it as
often as possible. This section explains how writers can craft their
documentation changes in the most useful and least error-prone ways.

Documentation changes come in two forms:

    * General improvements -- Typo corrections, error fixes and better
      explanations through clearer writing and more examples.

    * New features -- Documentation of features that have been added to the
      framework since the last release.

Our policy is:

    **All documentation of new features should be written in a way that clearly
    designates the features are only available in the Django development
    version. Assume documentation readers are using the latest release, not the
    development version.**

Our preferred way for marking new features is by prefacing the features'
documentation with: ".. versionadded:: X.Y", followed by an optional one line
comment and a mandatory blank line.

General improvements, or other changes to the APIs that should be emphasized
should use the ".. versionchanged:: X.Y" directive (with the same format as the
``versionadded`` mentioned above.

There's a full page of information about the :doc:`Django documentation
system </internals/documentation>` that you should read prior to working on the
documentation.

Guidelines for reST files
-------------------------

These guidelines regulate the format of our reST documentation:

    * In section titles, capitalize only initial words and proper nouns.

    * Wrap the documentation at 80 characters wide, unless a code example
      is significantly less readable when split over two lines, or for another
      good reason.

Commonly used terms
-------------------

Here are some style guidelines on commonly used terms throughout the
documentation:

    * **Django** -- when referring to the framework, capitalize Django. It is
      lowercase only in Python code and in the djangoproject.com logo.

    * **e-mail** -- it has a hyphen.

    * **MySQL**

    * **PostgreSQL**

    * **Python** -- when referring to the language, capitalize Python.

    * **realize**, **customize**, **initialize**, etc. -- use the American
      "ize" suffix, not "ise."

    * **SQLite**

    * **subclass** -- it's a single word without a hyphen, both as a verb
      ("subclass that model") and as a noun ("create a subclass").

    * **Web**, **World Wide Web**, **the Web** -- note Web is always
      capitalized when referring to the World Wide Web.

    * **Web site** -- use two words, with Web capitalized.

Django-specific terminology
---------------------------

    * **model** -- it's not capitalized.

    * **template** -- it's not capitalized.

    * **URLconf** -- use three capitalized letters, with no space before
      "conf."

    * **view** -- it's not capitalized.

Committing code
===============

Please follow these guidelines when committing code to Django's Subversion
repository:

    * For any medium-to-big changes, where "medium-to-big" is according to your
      judgment, please bring things up on the `django-developers`_ mailing list
      before making the change.

      If you bring something up on `django-developers`_ and nobody responds,
      please don't take that to mean your idea is great and should be
      implemented immediately because nobody contested it. Django's lead
      developers don't have a lot of time to read mailing-list discussions
      immediately, so you may have to wait a couple of days before getting a
      response.

    * Write detailed commit messages in the past tense, not present tense.

          * Good: "Fixed Unicode bug in RSS API."
          * Bad: "Fixes Unicode bug in RSS API."
          * Bad: "Fixing Unicode bug in RSS API."

    * For commits to a branch, prefix the commit message with the branch name.
      For example: "magic-removal: Added support for mind reading."

    * Limit commits to the most granular change that makes sense. This means,
      use frequent small commits rather than infrequent large commits. For
      example, if implementing feature X requires a small change to library Y,
      first commit the change to library Y, then commit feature X in a separate
      commit. This goes a *long way* in helping all core Django developers
      follow your changes.

    * Separate bug fixes from feature changes.

      Bug fixes need to be added to the current bugfix branch (e.g. the
      ``1.0.X`` branch) as well as the current trunk.

    * If your commit closes a ticket in the Django `ticket tracker`_, begin
      your commit message with the text "Fixed #abc", where "abc" is the number
      of the ticket your commit fixes. Example: "Fixed #123 -- Added support
      for foo". We've rigged Subversion and Trac so that any commit message
      in that format will automatically close the referenced ticket and post a
      comment to it with the full commit message.

      If your commit closes a ticket and is in a branch, use the branch name
      first, then the "Fixed #abc." For example:
      "magic-removal: Fixed #123 -- Added whizbang feature."

      For the curious: We're using a `Trac post-commit hook`_ for this.

      .. _Trac post-commit hook: http://trac.edgewall.org/browser/trunk/contrib/trac-post-commit-hook

    * If your commit references a ticket in the Django `ticket tracker`_ but
      does *not* close the ticket, include the phrase "Refs #abc", where "abc"
      is the number of the ticket your commit references. We've rigged
      Subversion and Trac so that any commit message in that format will
      automatically post a comment to the appropriate ticket.

Reverting commits
-----------------

Nobody's perfect; mistakes will be committed. When a mistaken commit is
discovered, please follow these guidelines:

    * Try very hard to ensure that mistakes don't happen. Just because we
      have a reversion policy doesn't relax your responsibility to aim for
      the highest quality possible. Really: double-check your work before
      you commit it in the first place!

    * If possible, have the original author revert his/her own commit.

    * Don't revert another author's changes without permission from the
      original author.

    * If the original author can't be reached (within a reasonable amount
      of time -- a day or so) and the problem is severe -- crashing bug,
      major test failures, etc -- then ask for objections on django-dev
      then revert if there are none.

    * If the problem is small (a feature commit after feature freeze,
      say), wait it out.

    * If there's a disagreement between the committer and the
      reverter-to-be then try to work it out on the `django-developers`_
      mailing list. If an agreement can't be reached then it should
      be put to a vote.

    * If the commit introduced a confirmed, disclosed security
      vulnerability then the commit may be reverted immediately without
      permission from anyone.

    * The release branch maintainer may back out commits to the release
      branch without permission if the commit breaks the release branch.

.. _unit-tests:

Unit tests
==========

Django comes with a test suite of its own, in the ``tests`` directory of the
Django tarball. It's our policy to make sure all tests pass at all times.

The tests cover:

    * Models and the database API (``tests/modeltests/``).
    * Everything else in core Django code (``tests/regressiontests``)
    * Contrib apps (``django/contrib/<contribapp>/tests``, see below)

We appreciate any and all contributions to the test suite!

The Django tests all use the testing infrastructure that ships with Django for
testing applications. See :doc:`Testing Django applications </topics/testing>`
for an explanation of how to write new tests.

.. _running-unit-tests:

Running the unit tests
----------------------

Quickstart
~~~~~~~~~~

Running the tests requires a Django settings module that defines the
databases to use. To make it easy to get started. Django provides a
sample settings module that uses the SQLite database. To run the tests
with this sample ``settings`` module, ``cd`` into the Django
``tests/`` directory and run:

.. code-block:: bash

    ./runtests.py --settings=test_sqlite

If you get an ``ImportError: No module named django.contrib`` error,
you need to add your install of Django to your ``PYTHONPATH``. For
more details on how to do this, read `Pointing Python at the new
Django version`_ below.

Using another ``settings`` module
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The included settings module allows you to run the test suite using
SQLite. If you want to test behavior using a different database (and
if you're proposing patches for Django, it's a good idea to test
across databases), you may need to define your own settings file.

To run the tests with different settings, ``cd`` to the ``tests/`` directory
and type:

.. code-block:: bash

    ./runtests.py --settings=path.to.django.settings

The :setting:`DATABASES` setting in this test settings module needs to define
two databases:

    * A ``default`` database. This database should use the backend that
      you want to use for primary testing

    * A database with the alias ``other``. The ``other`` database is
      used to establish that queries can be directed to different
      databases. As a result, this database can use any backend you
      want. It doesn't need to use the same backend as the ``default``
      database (although it can use the same backend if you want to).

If you're using a backend that isn't SQLite, you will need to provide other
details for each database:

    * The :setting:`USER` option for each of your databases needs to
      specify an existing user account for the database.

    * The :setting:`PASSWORD` option needs to provide the password for
      the :setting:`USER` that has been specified.

    * The :setting:`NAME` option must be the name of an existing database to
      which the given user has permission to connect. The unit tests will not
      touch this database; the test runner creates a new database whose name is
      :setting:`NAME` prefixed with ``test_``, and this test database is
      deleted when the tests are finished. This means your user account needs
      permission to execute ``CREATE DATABASE``.

You will also need to ensure that your database uses UTF-8 as the default
character set. If your database server doesn't use UTF-8 as a default charset,
you will need to include a value for ``TEST_CHARSET`` in the settings
dictionary for the applicable database.

Running only some of the tests
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Django's entire test suite takes a few minutes to run. To run a subset of the
unit tests, append the names of the test modules to the ``runtests.py``
command line.

As an example, if you'd like to only run tests for generic relations and
internationalization, type:

.. code-block:: bash

    ./runtests.py --settings=path.to.settings generic_relations i18n

See the list of directories in ``tests/modeltests`` and
``tests/regressiontests`` for module names.

If you just want to run a particular class of tests, you can specify a list of
paths to individual test classes. For example, to run the ``TranslationTests``
of the ``i18n`` module, type:

.. code-block:: bash

    ./runtests.py --settings=path.to.settings i18n.TranslationTests

You can specify an individual test like this:

.. code-block:: bash

    ./runtests.py --settings=path.to.settings i18n.TranslationTests.test_lazy_objects

Running all the tests
~~~~~~~~~~~~~~~~~~~~~

If you want to run the full suite of tests, you'll need to install a number of
dependencies:

    *  PyYAML_
    *  Markdown_
    *  Textile_
    *  Docutils_
    *  setuptools_
    *  memcached_, plus a :ref:`supported Python binding <memcached>`
    *  gettext_ (:ref:`gettext_on_windows`)

If you want to test the memcached cache backend, you will also need to define
a :setting:`CACHES` setting that points at your memcached instance.

Each of these dependencies is optional. If you're missing any of them, the
associated tests will be skipped.

.. _PyYAML: http://pyyaml.org/wiki/PyYAML
.. _Markdown: http://pypi.python.org/pypi/Markdown/1.7
.. _Textile: http://pypi.python.org/pypi/textile
.. _docutils: http://pypi.python.org/pypi/docutils/0.4
.. _setuptools: http://pypi.python.org/pypi/setuptools/
.. _memcached: http://www.danga.com/memcached/
.. _gettext: http://www.gnu.org/software/gettext/manual/gettext.html

Contrib apps
------------

Tests for apps in ``django/contrib/`` go in their respective directories under
``django/contrib/``, in a ``tests.py`` file. (You can split the tests over
multiple modules by using a ``tests`` directory in the normal Python way.)

For the tests to be found, a ``models.py`` file must exist (it doesn't
have to have anything in it). If you have URLs that need to be
mapped, put them in ``tests/urls.py``.

To run tests for just one contrib app (e.g. ``markup``), use the same
method as above::

    ./runtests.py --settings=settings markup

Requesting features
===================

We're always trying to make Django better, and your feature requests are a key
part of that. Here are some tips on how to most effectively make a request:

    * Request the feature on `django-developers`_, not in the ticket tracker;
      it'll get read more closely if it's on the mailing list.

    * Describe clearly and concisely what the missing feature is and how you'd
      like to see it implemented. Include example code (non-functional is OK)
      if possible.

    * Explain *why* you'd like the feature. In some cases this is obvious, but
      since Django is designed to help real developers get real work done,
      you'll need to explain it, if it isn't obvious why the feature would be
      useful.

As with most open-source projects, code talks. If you are willing to write the
code for the feature yourself or if (even better) you've already written it,
it's much more likely to be accepted.  If it's a large feature that might need
multiple developers we're always happy to give you an experimental branch in
our repository; see below.

Branch policy
=============

In general, the trunk must be kept stable. People should be able to run
production sites against the trunk at any time. Additionally, commits to trunk
ought to be as atomic as possible -- smaller changes are better. Thus, large
feature changes -- that is, changes too large to be encapsulated in a single
patch, or changes that need multiple eyes on them -- must happen on dedicated
branches.

This means that if you want to work on a large feature -- anything that would
take more than a single patch, or requires large-scale refactoring -- you need
to do it on a feature branch. Our development process recognizes two options
for feature branches:

    1. Feature branches using a distributed revision control system like
       Git_, Mercurial_, Bazaar_, etc.

       If you're familiar with one of these tools, this is probably your best
       option since it doesn't require any support or buy-in from the Django
       core developers.

       However, do keep in mind that Django will continue to use Subversion for
       the foreseeable future, and this will naturally limit the recognition of
       your branch. Further, if your branch becomes eligible for merging to
       trunk you'll need to find a core developer familiar with your DVCS of
       choice who'll actually perform the merge.

       If you do decided to start a distributed branch of Django and choose to
       make it public, please add the branch to the `Django branches`_ wiki
       page.

    2. Feature branches using SVN have a higher bar. If you want a branch
       in SVN itself, you'll need a "mentor" among the :doc:`core committers
       </internals/committers>`. This person is responsible for actually
       creating the branch, monitoring your process (see below), and
       ultimately merging the branch into trunk.

       If you want a feature branch in SVN, you'll need to ask in
       `django-developers`_ for a mentor.

.. _git: http://git-scm.com/
.. _mercurial: http://mercurial.selenic.com/
.. _bazaar: http://bazaar.canonical.com/
.. _django branches: http://code.djangoproject.com/wiki/DjangoBranches

Branch rules
------------

We've got a few rules for branches born out of experience with what makes a
successful Django branch.

DVCS branches are obviously not under central control, so we have no way of
enforcing these rules. However, if you're using a DVCS, following these rules
will give you the best chance of having a successful branch (read: merged back
to trunk).

Developers with branches in SVN, however, **must** follow these rules. The
branch mentor will keep on eye on the branch and **will delete it** if these
rules are broken.

    * Only branch entire copies of the Django tree, even if work is only
      happening on part of that tree. This makes it painless to switch to a
      branch.

    * Merge changes from trunk no less than once a week, and preferably every
      couple-three days.

      In our experience, doing regular trunk merges is often the difference
      between a successful branch and one that fizzles and dies.

      If you're working on an SVN branch, you should be using `svnmerge.py`_
      to track merges from trunk.

    * Keep tests passing and documentation up-to-date. As with patches,
      we'll only merge a branch that comes with tests and documentation.

.. _svnmerge.py: http://www.orcaware.com/svn/wiki/Svnmerge.py

Once the branch is stable and ready to be merged into the trunk, alert
`django-developers`_.

After a branch has been merged, it should be considered "dead"; write access to
it will be disabled, and old branches will be periodically "trimmed." To keep
our SVN wrangling to a minimum, we won't be merging from a given branch into
the trunk more than once.

Using branches
--------------

To use a branch, you'll need to do two things:

    * Get the branch's code through Subversion.

    * Point your Python ``site-packages`` directory at the branch's version of
      the ``django`` package rather than the version you already have
      installed.

Getting the code from Subversion
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To get the latest version of a branch's code, check it out using Subversion:

.. code-block:: bash

    svn co http://code.djangoproject.com/svn/django/branches/<branch>/

...where ``<branch>`` is the branch's name. See the `list of branch names`_.

Alternatively, you can automatically convert an existing directory of the
Django source code as long as you've checked it out via Subversion. To do the
conversion, execute this command from within your ``django`` directory:

.. code-block:: bash

    svn switch http://code.djangoproject.com/svn/django/branches/<branch>/

The advantage of using ``svn switch`` instead of ``svn co`` is that the
``switch`` command retains any changes you might have made to your local copy
of the code. It attempts to merge those changes into the "switched" code. The
disadvantage is that it may cause conflicts with your local changes if the
"switched" code has altered the same lines of code.

(Note that if you use ``svn switch``, you don't need to point Python at the new
version, as explained in the next section.)

.. _list of branch names: http://code.djangoproject.com/browser/django/branches

Pointing Python at the new Django version
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Once you've retrieved the branch's code, you'll need to change your Python
``site-packages`` directory so that it points to the branch version of the
``django`` directory. (The ``site-packages`` directory is somewhere such as
``/usr/lib/python2.4/site-packages`` or
``/usr/local/lib/python2.4/site-packages`` or ``C:\Python\site-packages``.)

The simplest way to do this is by renaming the old ``django`` directory to
``django.OLD`` and moving the trunk version of the code into the directory
and calling it ``django``.

Alternatively, you can use a symlink called ``django`` that points to the
location of the branch's ``django`` package. If you want to switch back, just
change the symlink to point to the old code.

A third option is to use a `path file`_ (``<something>.pth``) which should
work on all systems (including Windows, which doesn't have symlinks
available). First, make sure there are no files, directories or symlinks named
``django`` in your ``site-packages`` directory. Then create a text file named
``django.pth`` and save it to your ``site-packages`` directory. That file
should contain a path to your copy of Django on a single line and optional
comments. Here is an example that points to multiple branches. Just uncomment
the line for the branch you want to use ('Trunk' in this example) and make
sure all other lines are commented::

    # Trunk is a svn checkout of:
    #   http://code.djangoproject.com/svn/django/trunk/
    #
    /path/to/trunk

    # <branch> is a svn checkout of:
    #   http://code.djangoproject.com/svn/django/branches/<branch>/
    #
    #/path/to/<branch>

    # On windows a path may look like this:
    # C:/path/to/<branch>

If you're using Django 0.95 or earlier and installed it using
``python setup.py install``, you'll have a directory called something like
``Django-0.95-py2.4.egg`` instead of ``django``. In this case, edit the file
``setuptools.pth`` and remove the line that references the Django ``.egg``
file. Then copy the branch's version of the ``django`` directory into
``site-packages``.

.. _path file: http://docs.python.org/library/site.html

How we make decisions
=====================

Whenever possible, we strive for a rough consensus. To that end, we'll often
have informal votes on `django-developers`_ about a feature. In these votes we
follow the voting style invented by Apache and used on Python itself, where
votes are given as +1, +0, -0, or -1.  Roughly translated, these votes mean:

    * +1: "I love the idea and I'm strongly committed to it."

    * +0: "Sounds OK to me."

    * -0: "I'm not thrilled, but I won't stand in the way."

    * -1: "I strongly disagree and would be very unhappy to see the idea turn
      into reality."

Although these votes on django-developers are informal, they'll be taken very
seriously. After a suitable voting period, if an obvious consensus arises
we'll follow the votes.

However, consensus is not always possible. If consensus cannot be reached, or
if the discussion towards a consensus fizzles out without a concrete decision,
we use a more formal process.

Any core committer (see below) may call for a formal vote using the same
voting mechanism above. A proposition will be considered carried by the core
team if:

    * There are three "+1" votes from members of the core team.

    * There is no "-1" vote from any member of the core team.

    * The BDFLs haven't stepped in and executed their positive or negative
      veto.

When calling for a vote, the caller should specify a deadline by which
votes must be received. One week is generally suggested as the minimum
amount of time.

Since this process allows any core committer to veto a proposal, any "-1"
votes (or BDFL vetos) should be accompanied by an explanation that explains
what it would take to convert that "-1" into at least a "+0".

Whenever possible, these formal votes should be announced and held in
public on the `django-developers`_ mailing list. However, overly sensitive
or contentious issues -- including, most notably, votes on new core
committers -- may be held in private.

Commit access
=============

Django has two types of committers:

Core committers
    These are people who have a long history of contributions to Django's
    codebase, a solid track record of being polite and helpful on the
    mailing lists, and a proven desire to dedicate serious time to Django's
    development. The bar is high for full commit access.

Partial committers
    These are people who are "domain experts." They have direct check-in access
    to the subsystems that fall under their jurisdiction, and they're given a
    formal vote in questions that involve their subsystems. This type of access
    is likely to be given to someone who contributes a large subframework to
    Django and wants to continue to maintain it.

    Partial commit access is granted by the same process as full
    committers. However, the bar is set lower; proven expertise in the area
    in question is likely to be sufficient.

Decisions on new committers will follow the process explained above in `how
we make decisions`_.

To request commit access, please contact an existing committer privately.
Public requests for commit access are potential flame-war starters, and
will be ignored.

.. _community page: http://www.djangoproject.com/community/
.. _ticket tracker: http://code.djangoproject.com/newticket
.. _django-developers: http://groups.google.com/group/django-developers
.. _search the tracker: http://code.djangoproject.com/search
.. _django-users: http://groups.google.com/group/django-users
.. _`#django`: irc://irc.freenode.net/django
.. _list of tickets with patches: http://code.djangoproject.com/query?status=new&status=assigned&status=reopened&has_patch=1&order=priority
.. _pep8.py: http://pypi.python.org/pypi/pep8/
.. _i18n branch: http://code.djangoproject.com/browser/django/branches/i18n
.. _`tags/releases`: http://code.djangoproject.com/browser/django/tags/releases
.. _`easy-pickings`: http://code.djangoproject.com/query?status=new&status=assigned&status=reopened&keywords=~easy-pickings&order=priority