Thank you very much for working on this issue.
I think there might be a problem with your fix, if there is a mail arriving with
more than 1 attachment with invalid filenames. I expect all but the last
processed attachment with invalid filename will be overriden by this fix. I
think this will happen very rarely but maybe it is worth consider this also.
Of course I may be totally wrong with my thoughts as I'm not a programmer and
don't know how gpgol is handling attachments in mails.
kind regards
Helmut Häfner