The gpgme documentation is unclear about the difference between email and address fields of the gpgme_user_id_t struct.

This makes it difficult for gpgme users to know which field to use.

I did some review and experimentation to try to establish patterns for the differences for GMime's use of gpgme, but it would have been better to have a clearer API in the first place.

for example, sometimes email can be an angle-addr and other times it's an addr-spec -- why is that? email seems to be the empty string when it is blank, but address seems to be NULL when it is blank. is email deprecated and users should prefer address ? Is there some other guidance that would let a library user know what to do?