Enforce version number at build time.

[Carreau]

Prevent making releases with wrong version number that will confuse pip,
or make sdists to appear more recent than wheels.

cc @gnestor

[gnestor]

Thanks @Carreau! This is very helpful.

[gnestor]

It works!

grant:notebook grant$ python setup.py sdist
Traceback (most recent call last):
  File "setup.py", line 51, in <module>
    from setupbase import (
  File "/Users/grant/Sites/jupyter/notebook/setupbase.py", line 76, in <module>
    raise ValueError('Invalid version number `%s`, please follow pep440 convention or pip will get confused about which package is more recent.' % version)
ValueError: Invalid version number `5.0.0-rc.1`, please follow pep440 convention or pip will get confused about which package is more recent.

Do you think the error message should include a link to the version scheme? https://www.python.org/dev/peps/pep-0440/#version-scheme

[rgbkrk]

😄

[minrk]

If we switch to always building with setuptools, this should also become unnecessary as it will do the check. I've started doing this in most new things, adding only the bdist_egg_disabled. I think we should stop supporting raw distutils install/sdist in general.

[blink1073]

Cough, cough: https://github.com/jupyter/jupyter-packaging

[Carreau]

😄

We know you are a semver guy :-)