Comment 2 for bug 654878

apt_pkg is correct, and we use it reasonably correctly. Except for this bit here:

    def _checkVersion(self, proposed_version, archive_version, filename):
        """Check if the proposed version is higher than the one in archive."""
        if apt_pkg.VersionCompare(proposed_version, archive_version) < 0:
            self.reject("%s: Version older than that in the archive. %s <= %s"
                        % (filename, proposed_version, archive_version))

If the versions are equal, it will return 0 and the check will pass. An upload with the same version string will be rejected in the file conflict check, but an upload with an equal (but not byte-identical) version string will be let through.