Hi:

I have realized that the genre attribute is nil when it is empty. Other
attributes (ext_infos, 'ext' from tracks hash) are assigned the empty
string when they are empty. I think that, in order to be consistent,
genre should also be the empty string.

Perhaps it's more of a bug in some freedb entries than in ruby-freedb.
Quoting from the Appendix B of the Freedb Howto:

    All of the applicable keywords must be present in the file, though
    they may have empty data except for the DISCID and DTITLE keywords.

And some entries lack the keyword DGENRE.

I append a little patch fixing this.

Regards