Incremental
===========

|gha|
|pypi|
|coverage|

Incremental is a small library that versions your Python projects.

API documentation can be found `here <https://twisted.org/incremental/docs/>`_.

.. contents::

Quick Start
-----------

Using setuptools
~~~~~~~~~~~~~~~~

Add Incremental to your ``pyproject.toml``:

.. code-block:: toml

    [build-system]
    requires = [
        "setuptools",
        "incremental>=24.7.2",  # ← Add incremental as a build dependency
    ]
    build-backend = "setuptools.build_meta"

    [project]
    name = "<projectname>"
    dynamic = ["version"]     # ← Mark the version dynamic
    dependencies = [
        "incremental>=24.7.2",  # ← Depend on incremental at runtime
    ]
    # ...

    [tool.incremental]        # ← Activate Incremental's setuptools plugin

It's fine if the ``[tool.incremental]`` table is empty, but it must be present.

Remove any ``[project] version =`` entry and any ``[tool.setuptools.dynamic] version =`` entry.

Next, `initialize the project`_.

Using Hatchling
~~~~~~~~~~~~~~~

If you're using `Hatchling <https://hatch.pypa.io/>`_ to package your project,
activate Incremental's Hatchling plugin by altering your ``pyproject.toml``:

.. code:: toml

    [build-system]
    requires = [
        "hatchling",
        "incremental>=24.7.2",  # ← Add incremental as a build dependency
    ]
    build-backend = "hatchling.build"

    [project]
    name = "<projectname>"
    dynamic = ["version"]     # ← Mark the version dynamic
    dependencies = [
        "incremental>=24.7.2",  # ← Depend on incremental at runtime
    ]
    # ...

    [tool.hatch.version]
    source = "incremental"    # ← Activate Incremental's Hatchling plugin

Incremental can be configured as usual in an optional ``[tool.incremental]`` table.

The ``hatch version`` command will report the Incremental-managed version.
Use the ``python -m incremental.update`` command to change the version (setting it with ``hatch version`` is not supported).

Next, `initialize the project`_.


Using ``setup.py``
~~~~~~~~~~~~~~~~~~

Incremental may be used from ``setup.py`` instead of ``pyproject.toml``.
Add this to your ``setup()`` call, removing any other versioning arguments:

.. code:: python

   setup(
       use_incremental=True,
       setup_requires=['incremental'],
       install_requires=['incremental'], # along with any other install dependencies
       ...
   }

Then `initialize the project`_.


Initialize the project
~~~~~~~~~~~~~~~~~~~~~~

Install Incremental to your local environment with ``pip install incremental[scripts]``.
Then run ``python -m incremental.update <projectname> --create``.
It will create a file in your package named ``_version.py`` like this:

.. code:: python

   from incremental import Version

   __version__ = Version("<projectname>", 24, 1, 0)
   __all__ = ["__version__"]


Then, so users of your project can find your version, in your root package's ``__init__.py`` add:

.. code:: python

   from ._version import __version__


Subsequent installations of your project will then use Incremental for versioning.



Incremental Versions
--------------------

``incremental.Version`` is a class that represents a version of a given project.
It is made up of the following elements (which are given during instantiation):

- ``package`` (required), the name of the package this ``Version`` represents.
- ``major``, ``minor``, ``micro`` (all required), the X.Y.Z of your project's ``Version``.
- ``release_candidate`` (optional), set to 0 or higher to mark this ``Version`` being of a release candidate (also sometimes called a "prerelease").
- ``post`` (optional), set to 0 or higher to mark this ``Version`` as a postrelease.
- ``dev`` (optional), set to 0 or higher to mark this ``Version`` as a development release.

You can extract a PEP-440 compatible version string by using the ``.public()`` method, which returns a ``str`` containing the full version. This is the version you should provide to users, or publicly use. An example output would be ``"13.2.0"``, ``"17.1.2dev1"``, or ``"18.8.0rc2"``.

Calling ``repr()`` with a ``Version`` will give a Python-source-code representation of it, and calling ``str()`` on a ``Version`` produces a string like ``'[Incremental, version 16.10.1]'``.


Updating
--------

Incremental includes a tool to automate updating your Incremental-using project's version called ``incremental.update``.
It updates the ``_version.py`` file and automatically updates some uses of Incremental versions from an indeterminate version to the current one.
It requires ``click`` from PyPI.

``python -m incremental.update <projectname>`` will perform updates on that package.
The commands that can be given after that will determine what the next version is.

- ``--newversion=<version>``, to set the project version to a fully-specified version (like 1.2.3, or 17.1.0dev1).
- ``--rc``, to set the project version to ``<year-2000>.<month>.0rc1`` if the current version is not a release candidate, or bump the release candidate number by 1 if it is.
- ``--dev``, to set the project development release number to 0 if it is not a development release, or bump the development release number by 1 if it is.
- ``--patch``, to increment the patch number of the release. This will also reset the release candidate number, pass ``--rc`` at the same time to increment the patch number and make it a release candidate.
- ``--post``, to set the project postrelease number to 0 if it is not a postrelease, or bump the postrelease number by 1 if it is. This will also reset the release candidate and development release numbers.

If you give no arguments, it will strip the release candidate number, making it a "full release".

Incremental supports "indeterminate" versions, as a stand-in for the next "full" version. This can be used when the version which will be displayed to the end-user is unknown (for example "introduced in" or "deprecated in"). Incremental supports the following indeterminate versions:

- ``Version("<projectname>", "NEXT", 0, 0)``
- ``<projectname> NEXT``

When you run ``python -m incremental.update <projectname> --rc``, these will be updated to real versions (assuming the target final version is 17.1.0):

- ``Version("<projectname>", 17, 1, 0, release_candidate=1)``
- ``<projectname> 17.1.0rc1``

Once the final version is made, it will become:

- ``Version("<projectname>", 17, 1, 0)``
- ``<projectname> 17.1.0``


.. |coverage| image:: https://codecov.io/gh/twisted/incremental/branch/master/graph/badge.svg?token=K2ieeL887X
.. _coverage: https://codecov.io/gh/twisted/incremental

.. |gha| image:: https://github.com/twisted/incremental/actions/workflows/tests.yaml/badge.svg
.. _gha: https://github.com/twisted/incremental/actions/workflows/tests.yaml

.. |pypi| image:: http://img.shields.io/pypi/v/incremental.svg
.. _pypi: https://pypi.python.org/pypi/incremental