systemd 254: systemctl return code change after polkit authentication rework

[Romain Naour <romain.naour@xxxxxxxx>]

Hello,

I noticed a change in the return code of systemctl command between systemd 253
and 254 when the polkit authentication is refused:

/bin/systemctl restart systemd-timesyncd.service

The return code changed from 1 to 4. The Buildroot Polkit test case
"TestPolkitSystemd" expected 1 as return code [1].

The service log is not the same either:

systemd v253:
Failed to restart systemd-timesyncd.service: Interactive authentication required.

systemd v254:
Failed to restart systemd-timesyncd.service: Access denied

git bisect report this commit:
https://github.com/systemd/systemd/commit/959301cf9f42418314abf027183dc25c08731b82

>From the PR (to get more context):
https://github.com/systemd/systemd/pull/26365

I'm not sure if it's expected or not.

Is the systemctl return code is considered "stable" over systemd releases?

[1] https://gitlab.com/buildroot.org/buildroot/-/jobs/4768561464 (TestPolkitSystemd)

Thoughts?

Best regards,
Romain