# How to contribute

Third-party patches are essential for keeping Puppet great. We simply can't
access the huge number of platforms and myriad configurations for running
Puppet. We want to keep it as easy as possible to contribute changes that
get things working in your environment. There are a few guidelines that we
need contributors to follow so that we can have a chance of keeping on
top of things.

## Puppet Core vs Modules

New functionality is typically directed toward modules to provide a slimmer
Puppet Core, reducing its surface area, and to allow greater freedom for
module maintainers to ship releases at their own cadence, rather than
being held to the cadence of Puppet releases. With Puppet 4's "all in one"
packaging, a list of modules at specific versions will be packaged with the
core so that popular types and providers will still be available as part of
the "out of the box" experience.

Generally, new types and new OS-specific providers for existing types should
be added in modules. Exceptions would be things like new cross-OS providers
and updates to existing core types.

If you are unsure of whether your contribution should be implemented as a
module or part of Puppet Core, you may visit [#puppet-dev on slack](https://puppetcommunity.slack.com/), or ask on
the [puppet-dev mailing list](https://groups.google.com/forum/#!forum/puppet-dev) for advice.

## Getting Started

* Make sure you have a [Jira account](https://tickets.puppetlabs.com).
* Make sure you have a [GitHub account](https://github.com/signup/free).
* Submit a Jira ticket for your issue if one does not already exist.
  * Clearly describe the issue including steps to reproduce when it is a bug.
  * Make sure you fill in the earliest version that you know has the issue.
  * A ticket is not necessary for [trivial changes](https://puppet.com/community/trivial-patch-exemption-policy)
* Fork the repository on GitHub.

## Making Changes

* Create a topic branch from where you want to base your work.
  * This is usually the master branch.
  * Only target release branches if you are certain your fix must be on that
    branch.
  * To quickly create a topic branch based on master, run `git checkout -b
    fix/master/my_contribution master`. Please avoid working directly on the
    `master` branch.
* Make commits of logical and atomic units.
* Check for unnecessary whitespace with `git diff --check` before committing.
* Make sure your commit messages are in the proper format. If the commit
  addresses an issue filed in the
  [Puppet Jira project](https://tickets.puppetlabs.com/browse/PUP), start
  the first line of the commit with the issue number in parentheses.

  ```
      (PUP-1234) Make the example in CONTRIBUTING imperative and concrete

      Without this patch applied the example commit message in the CONTRIBUTING
      document is not a concrete example. This is a problem because the
      contributor is left to imagine what the commit message should look like
      based on a description rather than an example. This patch fixes the
      problem by making the example concrete and imperative.

      The first line is a real-life imperative statement with a ticket number
      from our issue tracker. The body describes the behavior without the patch,
      why this is a problem, and how the patch fixes the problem when applied.
  ```
* Make sure you have added the necessary tests for your changes.
* Run _all_ the tests to assure nothing else was accidentally broken. First
  install all the test dependencies with `bundle install --path .bundle`. Then
  either run all the tests serially with `bundle exec rspec spec` or in parallel
  with `bundle exec rake parallel:spec[process_count]`

## Writing Translatable Code

We use [gettext tooling](https://github.com/puppetlabs/gettext-setup-gem) to
extract user-facing strings and pull in translations based on the user's locale
at runtime. In order for this tooling to work, all user-facing strings must be
wrapped in the `_()` translation function, so they can be extracted into files
for the translators.

When adding user-facing strings to your work, follow these guidelines:

* Use full sentences. Strings built up out of concatenated bits are hard to translate.
* Use string formatting instead of interpolation. Use the hash format and give good names to the placeholder values that can be used by translators to understand the meaning of the formatted values.
  For example: `_('Creating new user %{name}.') % { name: user.name }`
* Use `n_()` for pluralization. (see gettext gem docs linked above for details)

It is the responsibility of contributors and code reviewers to ensure that all
user-facing strings are marked in new PRs before merging.

## Making Trivial Changes

For [changes of a trivial nature](https://puppet.com/community/trivial-patch-exemption-policy), it is not always necessary to create a new
ticket in Jira. In this case, it is appropriate to start the first line of a
commit with one of  `(docs)`, `(maint)`, or `(packaging)` instead of a ticket
number.

If a Jira ticket exists for the documentation commit, you can include it
after the `(docs)` token.

```
    (docs)(DOCUMENT-000) Add docs commit example to CONTRIBUTING

    There is no example for contributing a documentation commit
    to the Puppet repository. This is a problem because the contributor
    is left to assume how a commit of this nature may appear.

    The first line is a real-life imperative statement with '(docs)' in
    place of what would have been the PUP project ticket number in a
    non-documentation related commit. The body describes the nature of
    the new documentation or comments added.
```

For commits that address trivial repository maintenance tasks or packaging
issues, start the first line of the commit with `(maint)` or `(packaging)`,
respectively.

## Submitting Changes

* Sign the [Contributor License Agreement](http://links.puppet.com/cla).
* Push your changes to a topic branch in your fork of the repository.
* Submit a pull request to the repository in the puppetlabs organization.
* Update your Jira ticket to mark that you have submitted code and are ready
  for it to be reviewed (Status: Ready for Merge).
  * Include a link to the pull request in the ticket.
* The core team looks at Pull Requests on a regular basis in a weekly triage
  meeting that we hold in a public Google Hangout. The hangout is announced in
  the weekly status updates that are sent to the puppet-dev list. Notes are
  posted to the [Puppet Community community-triage
  repo](https://github.com/puppet-community/community-triage/tree/master/core/notes)
  and include a link to a YouTube recording of the hangout.
* After feedback has been given we expect responses within two weeks. After two
  weeks we may close the pull request if it isn't showing any activity.

## Revert Policy

By running tests in advance and by engaging with peer review for prospective
changes, your contributions have a high probability of becoming long lived
parts of the the project. After being merged, the code will run through a
series of testing pipelines on a large number of operating system
environments. These pipelines can reveal incompatibilities that are difficult
to detect in advance.

If the code change results in a test failure, we will make our best effort to
correct the error. If a fix cannot be determined and committed within 24 hours
of its discovery, the commit(s) responsible _may_ be reverted, at the
discretion of the committer and Puppet maintainers. This action would be taken
to help maintain passing states in our testing pipelines.

The original contributor will be notified of the revert in the Jira ticket
associated with the change. A reference to the test(s) and operating system(s)
that failed as a result of the code change will also be added to the Jira
ticket. This test(s) should be used to check future submissions of the code to
ensure the issue has been resolved.

### Summary

* Changes resulting in test pipeline failures will be reverted if they cannot
  be resolved within one business day.

## Additional Resources

* [Puppet community guidelines](https://puppet.com/community/community-guidelines)
* [Bug tracker (Jira)](https://tickets.puppetlabs.com)
* [Contributor License Agreement](http://links.puppet.com/cla)
* [General GitHub documentation](https://help.github.com/)
* [GitHub pull request documentation](https://help.github.com/articles/creating-a-pull-request/)
* #puppet-dev IRC channel on freenode.org ([Archive](https://botbot.me/freenode/puppet-dev/))
* [puppet-dev mailing list](https://groups.google.com/forum/#!forum/puppet-dev)
* [Community PR Triage notes](https://github.com/puppet-community/community-triage/tree/master/core/notes)