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Contributing to CodeIgniter
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CodeIgniter is a community driven project and accepts contributions of code
and documentation from the community. These contributions are made in the form
of Issues or `Pull Requests <http://help.github.com/send-pull-requests/>`_ on
the `EllisLab CodeIgniter repository
<https://github.com/EllisLab/CodeIgniter>`_ on GitHub.

Issues are a quick way to point out a bug. If you find a bug or documentation
error in CodeIgniter then please check a few things first:

- There is not already an open Issue
- The issue has already been fixed (check the develop branch, or look for
  closed Issues)
- Is it something really obvious that you fix it yourself?

Reporting issues is helpful but an even better approach is to send a Pull
Request, which is done by "Forking" the main repository and committing to your
own copy. This will require you to use the version control system called Git.

**********
Guidelines
**********

Before we look into how, here are the guidelines. If your Pull Requests fail
to pass these guidelines it will be declined and you will need to re-submit
when you’ve made the changes. This might sound a bit tough, but it is required
for us to maintain quality of the code-base.

PHP Style
=========

All code must meet the `Style Guide
<http://codeigniter.com/user_guide/general/styleguide.html>`_, which is
essentially the `Allman indent style
<http://en.wikipedia.org/wiki/Indent_style#Allman_style>`_, underscores and
readable operators. This makes certain that all code is the same format as the
existing code and means it will be as readable as possible.

Documentation
=============

If you change anything that requires a change to documentation then you will
need to add it. New classes, methods, parameters, changing default values, etc
are all things that will require a change to documentation. The change-log
must also be updated for every change. Also PHPDoc blocks must be maintained.

Compatibility
=============

CodeIgniter is compatible with PHP 5.2.4 so all code supplied must stick to
this requirement. If PHP 5.3 or 5.4 functions or features are used then there
must be a fallback for PHP 5.2.4.

Branching
=========

CodeIgniter uses the `Git-Flow
<http://nvie.com/posts/a-successful-git-branching-model/>`_ branching model
which requires all pull requests to be sent to the "develop" branch. This is
where the next planned version will be developed. The "master" branch will
always contain the latest stable version and is kept clean so a "hotfix" (e.g:
an emergency security patch) can be applied to master to create a new version,
without worrying about other features holding it up. For this reason all
commits need to be made to "develop" and any sent to "master" will be closed
automatically. If you have multiple changes to submit, please place all
changes into their own branch on your fork.

One thing at a time: A pull request should only contain one change. That does
not mean only one commit, but one change - however many commits it took. The
reason for this is that if you change X and Y but send a pull request for both
at the same time, we might really want X but disagree with Y, meaning we
cannot merge the request. Using the Git-Flow branching model you can create
new branches for both of these features and send two requests.

Signing
=======
You must sign your work, certifying that you either wrote the work or
otherwise have the right to pass it on to an open source project. git makes
this trivial as you merely have to use `--signoff` on your commits to your
CodeIgniter fork.

.. code-block:: bash

	git commit --signoff

or simply

.. code-block:: bash

	git commit -s

This will sign your commits with the information setup in your git config, e.g.

	Signed-off-by: John Q Public <john.public@example.com>

If you are using Tower there is a "Sign-Off" checkbox in the commit window. You 
could even alias git commit to use the -s flag so you don’t have to think about 
it.

By signing your work in this manner, you certify to a "Developer's Certificate 
or Origin". The current version of this certificate is in the :doc:`/DCO` file
in the root of this documentation.