=====================
Contribution Guide
=====================

Contributions are highly welcomed and appreciated.  Every little help counts,
so do not hesitate! You can make a high impact on ``climpred`` just by using
it and reporting `issues <https://github.com/pangeo-data/climpred/issues>`__.

The following sections cover some general guidelines
regarding development in ``climpred`` for maintainers and contributors.

Please also review our `Code of Conduct <code_of_conduct.html>`__.

Nothing here is set in stone and can't be changed.
Feel free to suggest improvements or changes in the workflow.


.. _submitfeedback:

Feature requests and feedback
-----------------------------

We are eager to hear about your requests for new features and any suggestions
about the API, infrastructure, and so on. Feel free to submit these as
`issues <https://github.com/pangeo-data/climpred/issues/new>`__ with the label
``"feature request"``.

Please make sure to explain in detail how the feature should work and keep the
scope as narrow as possible. This will make it easier to implement in small
PRs.


.. _reportbugs:

Report bugs
-----------

Report bugs for ``climpred`` in the
`issue tracker <https://github.com/pangeo-data/climpred/issues>`_ with the
label "bug".

If you are reporting a bug, please include:

* Any details about your local setup that might be helpful in troubleshooting,
  specifically the Python interpreter version, installed libraries, and
  ``climpred`` version.
* Detailed steps to reproduce the bug.

If you can write a demonstration test that currently fails but should pass,
that is a very useful commit to make as well, even if you cannot fix the bug
itself.


.. _fixbugs:

Bug Fix
-------

Look through the
`GitHub issues for bugs <https://github.com/pangeo-data/climpred/labels/bug>`_.

Talk to developers to find out how you can fix specific bugs.


Write documentation
-------------------

``climpred`` could always use more documentation.  What exactly is needed?

* More complementary documentation.  Have you perhaps found something unclear?
* Example notebooks with different Earth System Models, lead times, etc. --
  they're all very appreciated.

You can also edit documentation files directly in the GitHub web interface,
without using a local copy.  This can be convenient for small fixes.

Our documentation is written in reStructuredText. You can follow our
conventions in already written documents. Some helpful guides are located
`rst-quickref <http://docutils.sourceforge.net/docs/user/rst/quickref.html>`__
and
`rst-cheatsheet <https://github.com/ralsina/rst-cheatsheet/blob/master/rst-cheatsheet.rst>`__.

.. note::
    Build the documentation locally with the following command:

    .. code:: bash

        $ conda env update -f ci/requirements/climpred-dev.yml
        $ cd docs
        $ make html

    The built documentation should be available in the ``docs/build/``.

If you need to add new functions to the API, run
``sphinx-autogen -o api api.rst`` from the ``docs/source`` directory after
adding functions to ``api.rst``.

 .. _`pull requests`:
 .. _pull-requests:

Preparing Pull Requests
-----------------------

#. Fork the `climpred GitHub repository <https://github.com/pangeo-data/climpred>`__.
   It's fine to use ``climpred`` as your fork repository name because it will
   live under your user.

#. Clone your fork locally using `git <https://git-scm.com/>`_, connect your
   repository to the upstream (main project), and create a branch::

    $ git clone git@github.com:YOUR_GITHUB_USERNAME/climpred.git
    $ cd climpred
    $ git remote add upstream git@github.com:pangeo-data/climpred.git

    # now, to fix a bug or add feature create your own branch off "main":

    $ git checkout -b your-bugfix-feature-branch-name main

   If you need some help with Git, follow this quick start
   `guide <https://git.wiki.kernel.org/index.php/QuickStart>`_.

#. Install dependencies into a new
   `conda <https://conda.io/projects/conda/en/latest/user-guide/getting-started.html>`_
   environment::

    $ conda env create -f ci/requirements/climpred-dev.yml
    $ conda activate climpred-dev

#. Make an editable install of ``climpred`` by running::

    $ pip install -e .

#. Install `pre-commit <https://pre-commit.com>`_ and its hook on the
   ``climpred`` repo::

     $ pip install --user pre-commit
     $ pre-commit install

   ``pre-commit`` automatically beautifies the code, makes it more
   maintainable and catches syntax errors. Afterwards ``pre-commit`` will run
   whenever you commit.

   Now you have an environment called ``climpred-dev`` that you can work in.
   You’ll need to make sure to activate that environment next time you want
   to use it after closing the terminal or your system.

   You can now edit your local working copy and run/add tests as necessary.
   Please try to follow
   `PEP-8 <https://www.python.org/dev/peps/pep-0008/#naming-conventions>`_ for
   naming. When committing, ``pre-commit`` will modify the files as
   needed, or will generally be quite clear about what you need to do to pass
   the commit test.

   ``pre-commit`` also runs::

    * `mypy <http://mypy-lang.org/>`_ for static type checking on
      `type hints <https://docs.python.org/3/library/typing.html>`_.
    * `isort <https://pycqa.github.io/isort/>`_ sorting imports
    * `black <https://black.readthedocs.io/en/stable/>`_ code formatting
    * `flake8 <https://flake8.pycqa.org/en/latest/>`_ code linting
    * `blackdoc <https://blackdoc.readthedocs.io/en/latest/>`_ docstring code
      formatter


#. Break your edits up into reasonably sized commits::

    $ git commit -a -m "<commit message>"
    $ git push -u

#. Run all tests

   Once commits are pushed to ``origin``, GitHub Actions runs continuous
   integration of all tests on all new commits. However, you are already
   run tests locally::

    $ pytest climpred

   Check that `doctests <https://docs.pytest.org/en/stable/doctest.html>`_ are
   passing::

    $ pytest --doctest-modules climpred --ignore climpred/tests

   Check that your contribution is covered by tests and therefore increases
   the overall test coverage::

    $ coverage run --source climpred -m py.test
    $ coverage report
    $ coveralls

   Please stick to
   `xarray <http://xarray.pydata.org/en/stable/contributing.html>`_'s testing
   recommendations.

#. Running the performance test suite

   If you considerably changed to core of code of ``climpred``, it is worth
   considering whether your code has introduced performance regressions.
   ``climpred`` has a suite of benchmarking tests using
   `asv <https://asv.readthedocs.io/en/stable/>`_
   to enable easy monitoring of the performance of critical ``climpred``
   operations. These benchmarks are all found in the ``asv_bench`` directory.

   If you need to run a benchmark, change your directory to ``asv_bench/`` and
   run::

      $ asv continuous -f 1.1 upstream/main HEAD

   You can replace ``HEAD`` with the name of the branch you are working on,
   and report benchmarks that changed by more than 10%.
   The command uses ``conda`` by default for creating the benchmark
   environments.

   Running the full benchmark suite can take up to half an hour and use up a
   few GBs of RAM. Usually it is sufficient to paste only a subset of the
   results into the pull request to show that the committed changes do not
   cause unexpected performance regressions.
   If you want to only run a specific group of tests from a file, you can do it
   using ``.`` as a separator. For example::

      $ asv continuous -f 1.1 upstream/main HEAD -b benchmarks_PredictionEnsemble.GenerateHindcastEnsembleSmall.time_bootstrap

   will only run the ``time_bootstrap`` benchmark of class
   ``GenerateHindcastEnsembleSmall`` defined in ``benchmarks_PredictionEnsemble.py``.


#. Create a new changelog entry in `CHANGELOG.rst <CHANGELOG.html>`_:

   The entry should be entered as:

   ``<description>`` (``:pr:`#<pull request number>```) ```<author's names>`_``

   where ``<description>`` is the description of the PR related to the change
   and ``<pull request number>`` is the pull request number and
   ``<author's names>`` are your first and last names.

   Add yourself to list of authors at the end of `CHANGELOG.rst <CHANGELOG.html>`_ file if
   not there yet, in alphabetical order.

#. Add yourself to the `contributors <https://climpred.readthedocs.io/en/latest/contributors.html>`_ list via ``docs/source/contributors.rst``.

#. Finally, submit a `Pull Request <https://docs.github.com/en/github/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests>`_ through the GitHub website using this data::

    head-fork: YOUR_GITHUB_USERNAME/climpred
    compare: your-branch-name

    base-fork: pangeo-data/climpred
    base: main

Note that you can create the ``Pull Request`` while you're working on this.
The PR will update as you add more commits. ``climpred`` developers and
contributors can then review your code and offer suggestions.