bug#36878: guix system reconfigure broken

[Robert Vollmert]

Hi,

it appears that commit 5c8c8c455420af27189d6045b3599fe6e27ad012

  guix system: Reimplement 'reconfigure’.

breaks guix system reconfigure. In particular, after reconfiguring,
shepherd doesn’t know about the updated versions of services.

The usual output below is missing; after reverting the commit it’s
fine again.

guix system: loading new services: …
To complete the upgrade, run 'herd restart SERVICE' to stop,
upgrade, and restart each service that was not automatically restarted.
shepherd: Evaluating user expression (let* ((services (map primitive-load (?))) 
# ?) ?).
shepherd: Service user-homes has been started.
shepherd: Service term-auto could not be started.
bootloader successfully installed on '/dev/sda’

I see that some system tests for “guix system reconfigure” were added
after this change. Might I suggest adding them before the change next
time around, and making sure they pass both before and after?

Cheers
Robert