Trouble getting 'fprintd-service-type' to work

[Mark H Weaver]

Hi Danny,

I see that you're the author of 'fprintd-service-type', added last May
in the following commit:

  commit 7f93bbd5aadf0427190769fba8f478c29e37b4f4
  Author: Danny Milosavljevic <address@hidden>
  Date:   Wed May 30 19:43:48 2018 +0200
  
      services: Add fingerprint identification service.
      
      * gnu/services/authentication.scm: New file.
      * gnu/local.mk (GNU_SYSTEM_MODULES): Add it.
      * doc/guix.texi (Miscellaneous Services): Document it.

Your manual entry for it seems to suggest that:

  (service fprintd-service-type)

is the correct incantation, and yet when I try to build a system with
this service, I see:

  guix system: error: /home/mhw/test-os-config.scm:77:19: no value specified 
for service of type 'fprintd'

Tobias reported seeing the same error, as well as a user on
address@hidden who we're trying to help.

I tried adding:

  (default-value (fprintd-configuration))

to the 'fprintd-service-type' definition, but then I get this:

  guix system: error: #<<fprintd-configuration> ntp: #<package address@hidden 
gnu/packages/freedesktop.scm:1190 396be70>>: invalid G-expression input

and it looks like the 'ntp' field of 'fprintd-configuration' is probably
misnamed.

Did you test this service before pushing it to master?
Does it work for you?

      Thanks,
        Mark