Hi, after a recent update, I am having the same authentication
issue with the brightness helper on the Mate desktop:
Authentication is needed to run
/gnu/store/ra8zy...-mate-power-manager-1.28.1/sbin/
mate-power-backlight-helper as the super user.
As noted previously on this bug report, the polkit
org.mate.power.policy file refers to an absolute store path.
But I think ultimately the problem may have to do with the fact that
mate-power-manager APPEARS TWICE in the system closure:
$ guix gc -R /gnu/store/2zf16...-system | grep mate-power
/gnu/store/ra8zy...-mate-power-manager-1.28.1
/gnu/store/a14gf...-mate-power-manager-1.28.1
The brightness function keys and the power-manager itself
attempt to invoke the 'ra8zy' path (and it's also in the
profile's sbin), but the polkit policy file permits only the 'a14gf'
path:
$ readlink -f (which mate-power-backlight-helper)
/gnu/store/ra8zy...-mate-power-manager-1.28.1/sbin/mate-power-backlight-helper
$ pkexec /gnu/store/a14gf...-mate-power-manager-1.28.1/sbin/\
mate-power-backlight-helper --set-brightness 340
# Works perfectly
$ pkexec /gnu/store/ra8zy...-mate-power-manager-1.28.1/sbin/\
mate-power-backlight-helper --set-brightness 340
# Authentication error, same as pressing brightness buttons
Looking at gnu/services/desktop.scm and gnu/packages/mate.scm,
it's unclear to me why mate-polkit-extension would end up with a
different hash for mate-power-manager than the profile does.
The effect may be reproducible just from packages, without
needing to troubleshoot the services or system. What happens if
we build mate-power-manager vs the mate union package:
$ guix build mate-power-manager
/gnu/store/a14gf...-mate-power-manager-1.28.1
That's the one in polkit.
$ guix gc -R (guix build mate) | grep mate-power
/gnu/store/ra8zy...-mate-power-manager-1.28.1
And that's the one in the profile.
Why are they different? Does it have to do with using
union-build? Apparently a similar duplication happens with xfce,
though I don't know if it leads to the same authentication
errors:
$ guix gc -R /gnu/store/2zf16...-system | grep xfce4-power
/gnu/store/8mqna...-xfce4-power-manager-4.20.0
/gnu/store/jrflf...-xfce4-power-manager-4.20.0
The exact store paths used in these examples should be
reproducible from the following minimal configuration and
relatively recent commit:
;;; BEGIN configuration.scm
(use-modules
(gnu bootloader)
(gnu bootloader grub)
(gnu system file-systems)
(gnu services desktop))
(operating-system
(host-name "mate-power-bug")
(bootloader (bootloader-configuration (bootloader grub-bootloader)))
(file-systems
(cons (file-system
(mount-point "/")
(device "/dev/sda1")
(type "ext4"))
%base-file-systems))
(services
(cons (service mate-desktop-service-type)
%desktop-services)))
;; END configuration.scm
$ guix time-machine -q --commit=ed5988f0d2cf14e3cc35a32e6ad91d7cbf535e2f\
-- system build configuration.scm
/gnu/store/2zf16...-system
