Unpredictable GPGME bug

[Robert J. Hansen]

Looks like there might be a bug in GPGME (I know, pre-1.0 software with 
bugs--what's the world coming to?).  My C++ bindings for GPGME attempt to 
grab all sorts of string data for a given key, and sometimes it will be 
able to grab a string representation of the algorithm type and other times 
it'll segfault.  The offending snippet of code looks like:

GpgmeKey _key;
std::string _algo;

_algo = gpgme_key_get_string_attr(_key, GPGME_ATTR_ALGO, NULL, 0);

... Maybe one time in ten, that line of code will segfault.  
gpgme_key_get_string_attr apparently returns a NULL pointer, and trying to 
make a C++ std::string out of a NULL pointer is an instant segfault.

This has happened for other string quantities, such as usernames, etc.  
For now, my solution is to assign the result of g_k_g_s_a() to a const 
char*, test the const char* against NULL, and then assign either the const 
char* to _algo or else assign "Unassigned" to _algo.  However, this is 
fairly inelegant given that we could just fix the GPGME code.  :)