Hacking on Pyramid
==================

Here are some guidelines for hacking on Pyramid.

Using a Development Checkout
----------------------------

You'll have to create a development environment to hack on Pyramid, using a
Pyramid checkout.  You can either do this by hand, or if you have ``tox``
installed (it's on PyPI), you can use tox to set up a working development
environment.  Each installation method is described below.

By Hand
+++++++

- While logged into your GitHub account, navigate to the Pyramid repo on
  GitHub.
  
  https://github.com/Pylons/pyramid

- Fork and clone the Pyramid repository to your GitHub account by clicking
  the "Fork" button.

- Clone your fork of Pyramid from your GitHub account to your local computer,
  substituting your account username and specifying the destination as
  "hack-on-pyramid".

   $ cd ~
   $ git clone git@github.com:USERNAME/pyramid.git hack-on-pyramid
   $ cd hack-on-pyramid
   # Configure remotes such that you can pull changes from the Pyramid
   # repository into your local repository.
   $ git remote add upstream https://github.com/Pylons/pyramid.git
   # fetch and merge changes from upstream into master
   $ git fetch upstream
   $ git merge upstream/master

Now your local repo is set up such that you will push changes to your GitHub
repo, from which you can submit a pull request.

- Create a virtualenv in which to install Pyramid:

   $ cd ~/hack-on-pyramid
   $ virtualenv -ppython2.7 env

  Note that very old versions of virtualenv (virtualenv versions below, say,
  1.10 or thereabouts) require you to pass a ``--no-site-packages`` flag to
  get a completely isolated environment.

  You can choose which Python version you want to use by passing a ``-p``
  flag to ``virtualenv``.  For example, ``virtualenv -ppython2.7``
  chooses the Python 2.7 interpreter to be installed.

  From here on in within these instructions, the ``~/hack-on-pyramid/env``
  virtual environment you created above will be referred to as ``$VENV``.
  To use the instructions in the steps that follow literally, use the
  ``export VENV=~/hack-on-pyramid/env`` command.

- Install ``setuptools-git`` into the virtualenv (for good measure, as we're
  using git to do version control):

   $ $VENV/bin/easy_install setuptools-git

- Install Pyramid from the checkout into the virtualenv using ``setup.py
  dev``.  ``setup.py dev`` is an alias for "setup.py develop" which also
  installs testing requirements such as nose and coverage.  Running
  ``setup.py dev`` *must* be done while the current working directory is the
  ``pyramid`` checkout directory:

   $ cd ~/hack-on-pyramid
   $ $VENV/bin/python setup.py dev

- Optionally create a new Pyramid project using ``pcreate``:

  $ cd $VENV
  $ bin/pcreate -s starter starter

- ...and install the new project (also using ``setup.py develop``) into the
  virtualenv:

  $ cd $VENV/starter
  $ $VENV/bin/python setup.py develop

Using Tox
+++++++++

Alternatively, if you already have ``tox`` installed, there is an easier
way to get going.

- Create a new directory somewhere and ``cd`` to it:

   $ mkdir ~/hack-on-pyramid
   $ cd ~/hack-on-pyramid

- Check out a read-only copy of the Pyramid source:

   $ git clone git://github.com/Pylons/pyramid.git .

  (alternately, create a writeable fork on GitHub and check that out).

Since Pyramid is a framework and not an application, it can be
convenient to work against a sample application, preferably in its own
virtualenv. A quick way to achieve this is to (ab-)use ``tox``
(http://tox.readthedocs.org/en/latest/) with a custom configuration
file that's part of the checkout:

  tox -c hacking-tox.ini

This will create a python-2.7 based virtualenv named ``env27`` (Pyramid's
``.gitconfig` ignores all top-level folders that start with ``env`` specifically
for this use case) and inside that a simple pyramid application named
``hacking`` that you can then fire up like so:

  cd env27/hacking
  ../bin/python setup.py develop
  ../bin/pserve development.ini

Adding Features
---------------

In order to add a feature to Pyramid:

- The feature must be documented in both the API and narrative
  documentation (in ``docs/``).

- The feature must work fully on the following CPython versions: 2.6, 2.7, 3.2,
  3.3, 3.4, and 3.5 on both UNIX and Windows.

- The feature must work on the latest version of PyPy and PyPy3.

- The feature must not cause installation or runtime failure on App Engine.
  If it doesn't cause installation or runtime failure, but doesn't actually
  *work* on these platforms, that caveat should be spelled out in the
  documentation.

- The feature must not depend on any particular persistence layer
  (filesystem, SQL, etc).

- The feature must not add unnecessary dependencies (where
  "unnecessary" is of course subjective, but new dependencies should
  be discussed).

The above requirements are relaxed for scaffolding dependencies.  If a
scaffold has an install-time dependency on something that doesn't work on a
particular platform, that caveat should be spelled out clearly in *its*
documentation (within its ``docs/`` directory).

Coding Style
------------

- PEP8 compliance.  Whitespace rules are relaxed: not necessary to put
  2 newlines between classes.  But 79-column lines, in particular, are
  mandatory.  See
  http://docs.pylonsproject.org/en/latest/community/codestyle.html for more
  information.

- Please do not remove trailing whitespace.  Configure your editor to reduce
  diff noise. See https://github.com/Pylons/pyramid/issues/788 for more.

Running Tests
--------------

- To run all tests for Pyramid on a single Python version, run ``nosetests``
  from your development virtualenv (See *Using a Development Checkout* above).

- To run individual tests (i.e. during development) you can use a regular
  expression with the ``-t`` parameter courtesy of the `nose-selecttests
  <https://pypi.python.org/pypi/nose-selecttests/>`_ plugin that's been
  installed (along with nose itself) via ``python setup.py dev``. The
  easiest usage is to simply provide the verbatim name of the test you're
  working on.

- To run the full set of Pyramid tests on all platforms, install ``tox``
  (http://codespeak.net/~hpk/tox/) into a system Python.  The ``tox`` console
  script will be installed into the scripts location for that Python.  While
  ``cd``'ed to the Pyramid checkout root directory (it contains ``tox.ini``),
  invoke the ``tox`` console script.  This will read the ``tox.ini`` file and
  execute the tests on multiple Python versions and platforms; while it runs,
  it creates a virtualenv for each version/platform combination.  For
  example::

   $ sudo /usr/bin/easy_install tox
   $ cd ~/hack-on-pyramid/
   $ /usr/bin/tox

- The tests can also be run using ``pytest`` (http://pytest.org/).  This is
  intended as a convenience for people who are more used or fond of ``pytest``.
  Run the tests like so::

   $ $VENV/bin/easy_install pytest
   $ $VENV/bin/py.test --strict pyramid/

- Functional tests related to the "scaffolds" (starter, zodb, alchemy) which
  create a virtualenv, install the scaffold package and its dependencies, start
  a server, and hit a URL on the server can be run like so::

   $ ./scaffoldtests.sh

  Alternately::

   $ tox -e{py26,py27,py32,py33,py34,py35,pypy,pypy3}-scaffolds,

Test Coverage
-------------

- The codebase *must* have 100% test statement coverage after each commit.  You
  can test coverage via ``./coverage.sh`` (which itself just executes ``tox
  -epy2-cover,py3-cover,coverage``).

Documentation Coverage and Building HTML Documentation
------------------------------------------------------

If you fix a bug, and the bug requires an API or behavior modification, all
documentation in this package which references that API or behavior must be
changed to reflect the bug fix, ideally in the same commit that fixes the bug
or adds the feature.  To build and review docs, use the following steps.

1. In the main Pyramid checkout directory, run ``./builddocs.sh`` (which just
   turns around and runs ``tox -e docs``)::

    $ ./builddocs.sh

2. Open the ``docs/_build/html/index.html`` file to see the resulting HTML
   rendering.

Change Log
----------

- Feature additions and bugfixes must be added to the ``CHANGES.txt``
  file in the prevailing style.  Changelog entries should be long and
  descriptive, not cryptic.  Other developers should be able to know
  what your changelog entry means.

