get mercurial (hg) current version on a repo (last tag and rev number)

version.py

# -*- coding: utf-8 -*-
"""get version number from dvcs
"""

from subprocess import Popen, PIPE


def get_hg_version():
    """uses mercurial to get last tag and last revision number

    if repo has just been tagged, return 'lasttag'
    if not, return 'lasttag-lastrevnum'
    """
    try:
        p = Popen(["hg", "log", "--limit", "1",
                   "--template", "{latesttag};{rev}"],
                  stdout=PIPE, stderr=PIPE)
        p.stderr.close()
        line = p.stdout.readlines()[0]
        latest_tag, latest_rev = line.strip().split(';')

        p = Popen(["hg", "log", "--limit", "1",
                   "-r", '"%s"' % latest_tag,
                   "--template", "{rev}"],
                  stdout=PIPE, stderr=PIPE)
        p.stderr.close()
        line = p.stdout.readlines()[0]
        latest_tag_rev = line.strip()

        if int(latest_tag_rev) == int(latest_rev) - 1:
            # here our version has just been tagged,
            # return only version number
            return latest_tag
        else:
            # we have commits since last tag, return tag-commit
            return "%s-%s" % (latest_tag, latest_rev)
    except:
        return None

if __name__ == '__main__':
    print get_hg_version()