pep426ver.py

import re

PEP426_VERSION_RE = re.compile('^(\d+\.\d+(\.\d+)*)((a|b|c|rc)(\d+))?'
                               '(\.(post)(\d+))?(\.(dev)(\d+))?$')

def pep426_key(s):
    s = s.strip()
    m = PEP426_VERSION_RE.match(s)
    if not m:
        raise ValueError('Not a valid version: %s' % s)
    groups = m.groups()
    nums = tuple(int(v) for v in groups[0].split('.'))
    while len(nums) > 2 and nums[-1] == 0:
        nums = nums[:-1]

    pre = groups[3:5]
    post = groups[6:8]
    dev = groups[9:11]
    if pre == (None, None):
        pre = ()
    else:
        pre = pre[0], int(pre[1])
    if post == (None, None):
        post = ()
    else:
        post = post[0], int(post[1])
    if dev == (None, None):
        dev = ()
    else:
        dev = dev[0], int(dev[1])
    if not pre:
        # either before pre-release, or final release and after
        if not post and dev:
            # before pre-release
            pre = ('a', -1) # to sort before a0
        else:
            pre = ('z',)    # to sort after all pre-releases
    # now look at the state of post and dev.
    if not post:
        post = ('a',)
    if not dev:
        dev = ('final',)
    return nums, pre, post, dev

if __name__ == '__main__':
    import unittest

    class PEP426VersionTestCase(unittest.TestCase):
        def test_sorting(self):
            versions = (
                '1.0.dev456',
                '1.0a1',
                '1.0a2.dev456',
                '1.0a12.dev456',
                '1.0a12',
                '1.0b1.dev456',
                '1.0b2',
                '1.0b2.post345.dev456',
                '1.0b2.post345',
                '1.0c1.dev456',
                '1.0c1',
                '1.0rc1',
                '1.0',
                '1.0.post345.dev456',
                '1.0.post345',
                '1.1.dev1',
            )

            n = len(versions)
            for i in range(n - 1):
                s1 = versions[i]
                s2 = versions[i + 1]
                v1 = pep426_key(s1)
                v2 = pep426_key(s2)
                self.assertLess(v1, v2)

        def test_equivalence(self):
            versions = (
                '1.0',
                '1.0.0',
                '1.0.0.0',
            )
            n = len(versions)
            for i in range(n - 1):
                s1 = versions[i]
                s2 = versions[i + 1]
                v1 = pep426_key(s1)
                v2 = pep426_key(s2)
                self.assertEqual(v1, v2)

        def test_invalid(self):
            self.assertRaises(ValueError, pep426_key, '1')
            self.assertRaises(ValueError, pep426_key, '')
            self.assertRaises(ValueError, pep426_key, 'A')
            self.assertRaises(ValueError, pep426_key, '1,0')
            self.assertRaises(ValueError, pep426_key, '1.0.2.')
            self.assertRaises(ValueError, pep426_key, '1.0dev1')
            self.assertRaises(ValueError, pep426_key, '1.0post2')
            self.assertRaises(ValueError, pep426_key, '1.0d1')
            self.assertRaises(ValueError, pep426_key, '1.0a')
            self.assertRaises(ValueError, pep426_key, '1.0-d1')


    unittest.main()