samba - Apr 2014 - Failed to get GUID for printer? (after bug 9900)

Hi team,

Some of the printers served by my Samba+CUPS printserver cannot be used by
Windows clients because of this sort of cryptic error:

printing/nt_printing_ads.c:116(nt_printer_guid_get)
  Failed to get GUID for printer hp1-color
rpc_server/spoolss/srv_spoolss_nt.c:4828(_spoolss_GetPrinter)
 _spoolss_GetPrinter: failed to construct printer info level 7 -
WERR_BADFILE

All affected printers use generic CUPS PS driver for Windows (cupsps6.dll,
etc), and were added by cupsaddsmb to Samba. However, not all printers with
the generic driver are affected.

enumprinters 2 doesn't show any GUIDs for any of the printers. Where does
it look for this GUID, and why would my printer don't have a GUID?

I see that this code was introduced with the fix to the bug 9900. The
behaviour is consistent between Samba 4.1.6 and Samba 3.6.22, both
experience the same issue.

-Alex