git_version.py

def git_version(path):
    # Like v1.0.0 or v1.0.0-1-g963fc39.dirty
    git_describe = check_output([
        'git', '-C', path, 'describe', '--tags', '--dirty=.dirty']
    ).decode().strip()
    # Like v1.0.0
    last_tag = check_output([
        'git', '-C', path, 'describe', '--tags', '--abbrev=0']
    ).decode().strip()
    # Strip leading v often used in tag names.
    last_version = last_tag.lstrip('v')
    # Like .dev1+g963fc39.dirty
    diff_to_tag = (
        git_describe[len(last_tag):]
        .replace('-', '.dev', 1)
        .replace('-', '+', 1)
    )
    # Like 1.0.0.dev1+g963fc39.dirty, compatible to PEP440
    return last_version + diff_to_tag