Function _legacy_cmpkey

numpy/_utils/_pep440.py:224–248

(version)

def _legacy_cmpkey(version):
    # We hardcode an epoch of -1 here. A PEP 440 version can only have an epoch
    # greater than or equal to 0. This will effectively put the LegacyVersion,
    # which uses the defacto standard originally implemented by setuptools,
    # as before all PEP 440 versions.
    epoch = -1

    # This scheme is taken from pkg_resources.parse_version setuptools prior to
    # its adoption of the packaging library.
    parts = []
    for part in _parse_version_parts(version.lower()):
        if part.startswith("*"):
            # remove "-" before a prerelease tag
            if part < "*final":
                while parts and parts[-1] == "*final-":
                    parts.pop()

            # remove trailing zeros from each series of numeric parts
            while parts and parts[-1] == "00000000":
                parts.pop()

        parts.append(part)
    parts = tuple(parts)

    return epoch, parts


# Deliberately not anchored to the start and end of the string, to make it