# Hacking

Want to fix a bug in Pootle? Want to change the behaviour of an existing feature or add new ones? This section is all about hacking on Pootle, so if you are interested on the topic, keep reading.

## Before doing anything

Before starting any actual work on the source code, make sure that:

- There is nobody working on the bug you are trying to fix. See the existing bug reports and the existing pull requests. In the situation where somebody else is working on a fix, you can always offer your help.
- If you plan to develop a new feature and want to include it upstream, please first discuss it with the developers on IRC or in the translate-pootle mailing list so that it doesn’t interfere in current development plans. Also note that adding new features is relatively easy, but keeping them updated is harder.

## Setting up the development environment

The minimum software packages you need for setting up a development environment include git and a Python interpreter along with the pip installer. Consult the specifics for your operating system in order to get each package installed successfully.

Once you have the basic requirements in place, you will need to install Pootle’s dependencies, which come in shape of Python packages. Instead of installing them system-wide, we recommend using virtualenv (and virtualenvwrapper for easing the management of multiple virtualenvs). This way you can install all the dependencies at specific versions without interfering with system-wide packages. You can test on different Python/Django versions in parallel as well.

### Detailed setup

For installing the dependencies in an isolated environment, we will use virtualenv – more specifically virtualenvwrapper, which eases the process of managing and switching between multiple virtual environments. Installing virtualenwrapper will pull in virtualenv as a dependency.

    $ sudo pip install virtualenvwrapper

virtualenvwrapper will need to be configured in order to specify where to store the created environments.

    $ export WORKON_HOME=~/envs
    $ mkdir -p $WORKON_HOME
    $ source /usr/local/bin/virtualenvwrapper.sh  # Or /usr/bin/virtualenvwrapper.sh

Note

You may want to add the above-mentioned commands in your `.bashrc` file (or whatever file your shell uses for initializing user customizations).

Now the commands provided virtualenv and virtualenvwrapper are available, so we can start creating our virtual environment.

    $ mkvirtualenv <env-name>

Replace `<env-name>` with a meaningful name that describes the environment you are creating. mkvirtualenv accepts any options that virtualenv accepts. We could for example specify to use the Python 2.6 interpreter by passing the `-p python2.6` option.

Note

After running mkvirtualenv, the newly created environment is activated. To deactivate it just run:

    (env-name) $ deactivate

To activate a virtual environment again simply run:

    $ workon <env-name>

Time to clone Pootle’s source code repository. The main repository lives under translate/pootle in GitHub. If you have a GitHub account, the best idea is to fork the main repository and to clone your own fork for hacking. Once you know which way you want to continue forward, just move to a directory where you want to keep the development files and run git clone by passing the repository’s URL.

    (env-name) $ git clone https://github.com/translate/pootle.git

This will create a directory named `pootle` where you will find all the files that constitute Pootle’s source code.

Note

If you have a GitHub account, fork the main `translate/pootle` repository and replace the repository URL by your own fork.

Before running the development server, it’s necessary to install the software dependencies/requirements by using pip. For this matter there are some pip requirements files within the `requirements` directory. We will install the requirements defined in `requirements/dev.txt`, which apart from the minimum will pull in some extras that will ease the development process.

    (env-name) $ cd pootle
    (env-name) $ pip install -r requirements/dev.txt

Note

Some dependencies might need to build or compile source code in languages other than Python. You may need to install extra packages on your system in order to complete the build process and the installation of the required packages.

With all the dependencies installed within the virtual environment, Pootle is almost ready to run. In development environments you will want to use settings that vastly differ from those used in production environments.

For that purpose there is a sample configuration file with settings adapted for development scenarios, `pootle/settings/90-dev-local.conf.sample`. Copy this file and rename it by removing the .sample extension:

    (env-name) $ cp pootle/settings/90-dev-local.conf.sample pootle/settings/90-dev-local.conf

Note

To learn more about how settings work in Pootle head over the Settings section in the documentation.

Once the configuration is in place, you’ll need to setup the database schema and add initial data.

    (env-name) $ python manage.py syncdb --noinput
    (env-name) $ python manage.py migrate
    (env-name) $ python manage.py initdb

Finally, just run the development server.

    (env-name) $ python manage.py runserver

Once all is done, you can start the development server anytime by enabling the virtual environment (using the workon command) and running the manage.py runserver command.

Happy hacking!!

## Workflow

Any time you want to fix a bug or work on a new feature, create a new local branch:

    $ git checkout -b <my_new_branch>

Then safely work there, create the needed commits and once the work is ready for being incorporated upstream, either:

- Push the changes to your own GitHub fork and send us a pull request, or
- Create a patch against the `HEAD` of the `master` branch using git diff or git format-patch and attach it to the affected bug.

## Commits

When creating commits take into account the following:

What to commit

  As far as possible, try to commit individual changes in individual commits. Where different changes depend on each other, but are related to different parts of a problem / solution, try to commit them in quick succession.

  If a change in the code requires some change in the documentation then all those changes must be in the same commit.

  If code and documentation changes are unrelated then it is recommended to put them in separate commits, despite that sometimes it is acceptable to mix those changes in the same commit, for example cleanups changes both in code and documentation.

Commit messages

  Begin the commit message with a single short (less than 50 character) line summarizing the change, followed by a blank line and then a more thorough (and sometimes optional) description.

      Cleanups

  Another example:

      Factor out common behavior for whatever

      These reduces lines of code to maintain, and eases a lot the maintenance
      work.

      Also was partially reworked to ease extending it in the future.

  If your change fixes a bug in Bugzilla, mention the bug number. This way the bug is automatically closed after merging the commit.

      Docs: Update code for this thing

      Now the docs are exact and represent the actual behavior introduced in
      commits ef4517ab and abc361fd.

      Fixes bug #2399

  If you are reverting a previous commit, mention the sha1 revision that is being reverted.

      Revert "Fabric: Cleanup to use the new setup command"

      This reverts commit 5c54bd4.