vcversioner 0.13.0.2

Use version control tags to discover version numbers

vcversioner

Elevator pitch: you can write a setup.py with no version information specified, and vcversioner will find a recent, properly-formatted git tag and extract a version from it.

It’s much more convenient to be able to use your version control system’s tagging mechanism to derive a version number than to have to duplicate that information all over the place. I eventually ended up copy-pasting the same code into a couple different setup.py files just to avoid duplicating version information. But, copy-pasting is dumb and unit testing setup.py files is hard. This code got factored out into vcversioner.

Basic usage

vcversioner installs itself as a setuptools hook, which makes its use exceedingly simple:

from setuptools import setup

setup(
    # [...]
    setup_requires=['vcversioner'],
    vcversioner={},
)

The presence of a vcversioner argument automagically activates vcversioner and updates the project’s version. The parameter to the vcversioner argument can also be a dict of keyword arguments which find_version will be called with.

To allow tarballs to be distributed without requiring a .git directory, vcversioner will also write out a file named (by default) version.txt. Then, if there is no git or git is unable to find any version information, vcversioner will read version information from the version.txt file. However, this file needs to be included in a distributed tarball, so the following line should be added to MANIFEST.in:

include version.txt

This isn’t necessary if setup.py will always be run from a git checkout, but otherwise is essential for vcversioner to know what version to use.

The name version.txt also can be changed by specifying the version_file parameter. For example:

from setuptools import setup

setup(
    # [...]
    setup_requires=['vcversioner'],
    vcversioner={
        'version_file': 'custom_version.txt',
    },
)

Non-hook usage

It’s not necessary to depend on vcversioner; while pip will take care of dependencies automatically, sometimes having a self-contained project is simpler. vcversioner is a single file which is easy to add to a project. Simply copy the entire vcversioner.py file adjacent to the existing setup.py file and update the usage slightly:

from setuptools import setup
import vcversioner

setup(
    # [...]
    version=vcversioner.find_version().version,
)

This is necessary because the vcversioner distutils hook won’t be available.

Version modules

setup.py isn’t the only place that version information gets duplicated. By generating a version module, the __init__.py file of a package can import version information. For example, with a package named spam:

from setuptools import setup

setup(
    # [...]
    setup_requires=['vcversioner'],
    vcversioner={
        'version_module_paths': ['spam/_version.py'],
    },
)

This will generate a spam/_version.py file that defines __version__ and __sha__. Then, in spam/__init__.py:

from spam._version import __version__, __sha__

Since this acts like (and is) a regular python module, changing MANIFEST.in is not required.

Customizing git commands

vcversioner by default executes git describe --tags --long to get version information. This command will output a string that describes the current commit, using all tags (as opposed to just unannotated tags), and always output the long format (1.0-0-gdeadbeef instead of just 1.0 if the current commit is tagged).

However, sometimes this isn’t sufficient. If someone wanted to only use annotated tags, the git command could be amended like so:

from setuptools import setup

setup(
    # [...]
    setup_requires=['vcversioner'],
    vcversioner={
        'git_args': ['git', 'describe', '--long'],
    },
)

The git_args parameter must always be a list of strings, which will not be interpreted by the shell. This is the same as what subprocess.Popen expects.

Development versions

vcversioner can also automatically make a version that corresponds to a commit that isn’t itself tagged. Following PEP 386, this is done by adding a .dev suffix to the version specified by a tag on an earlier commit. For example, if the current commit is three revisions past the 1.0 tag, the computed version will be 1.0.dev3.

This behavior can be disabled by setting the include_dev_version parameter to False. In that case, the aforementioned untagged commit’s version would be just 1.0.

Sphinx documentation

Sphinx documentation is yet another place where version numbers get duplicated. Fortunately, since sphinx configuration is python code, vcversioner can be used there too. Assuming vcversioner is installed system-wide, this is quite easy. Simply change your conf.py to include:

import vcversioner
version = release = vcversioner.find_version().version

If your current working directory while building documentation is not your project root, this will make a duplicate version.txt file in the documentation directory. In this case, it might be preferable to call find_version with version_file=None or version_file='../version.txt'.

If vcversioner is bundled with your project instead of relying on it being installed, you might have to add the following to your conf.py before import vcversioner:

import sys, os
sys.path.insert(0, os.path.abspath('..'))

This line, or something with the same effect, is sometimes already present when using the sphinx autodoc extension.

Read the Docs

Using vcversioner is even possible when building documentation on Read the Docs. If vcversioner is bundled with your project, nothing further needs to be done. Otherwise, you need to tell Read the Docs to install vcversioner before it builds the documentation. This means using a requirements.txt file.

If your project is already set up to install dependencies with a requirements.txt file, add vcversioner to it. Otherwise, create a requirements.txt file. Assuming your documentation is in a docs subdirectory of the main project directory, create docs/requirements.txt containing a vcversioner line.

Then, make the following changes to your project’s configuration: (Project configuration is edited at e.g. https://readthedocs.org/dashboard/vcversioner/edit/)

• Check the checkbox under Use virtualenv.

• If there was no requirements.txt previously, set the Requirements file to the newly-created one, e.g. docs/requirements.txt.