Use setuptools_scm for version management

[diazona]

This is just a proposal, not something we necessarily have to do, but I wanted to get it written down before I forget: I've used setuptools_scm for automatic version management in many of my other projects and I really like the convenience of not having to update the version number manually in files. Should we adopt it here as well?

[redtoad]

I'm in two minds about this. It feels a bit over the top when we only have two places where the version number appears: in setup.py and in CHANGES. However, I have zero experience with setuptools_scm.

[RonnyPfannschmidt]

Im it's maintainer and we use it as part of the release automation in many projects

It's all about having a single source of truth and preventing human error

[diazona]

Oh hey small world, well thank you for all your work on it @RonnyPfannschmidt 😃

Anyway, @redtoad, adopting setuptools_scm would mean we'd no longer record the version number in setup.py, it would be recorded as a Git tag instead. Other than that, there's really no need to think about it. So it's roughly the same amount of work. But I think it's handy to have tags that correspond to releases and we'd get that for free. Plus, we'd get the benefit that every single commit automatically gets its own unique version number which incorporates the commit hash, which is not really a big deal but I've found it to come in handy for preparing one-off packages of unreleased versions for testing.

And to be clear, I'm not suggesting this for the upcoming 0.5.1 release; I thought if we want to make this change, the time to do it would be after that, maybe for version 0.6. I just posted the issue because I didn't want to forget about it.

[coordt]

I have only one question: What does the workflow look like for releasing a new version?

[RonnyPfannschmidt]

In combination with a workflows it's typically tagging a release and pushing the tag