[Next] Add system reboot ability to mintUpdate when reboot is needed

[timfeierabend]

Implements fix for #749

Rationale:

When a kernel update is installed, users need to reboot their system outside of mintUpdate. This adds a way for users to reboot their system from within mintUpdate.

Reboot button will present a yes/no modal dialog asking for confirmation of reboot. This can be tweaked as needed.

Before:

After:

Note: screenshots below were created from manually after temporarily disabling reboot_required condition check to trigger the infobar.

[clefebvre]

Marking as Next because it's too late to get in 22.1.

I'm not mad about the confirmation dialog... the DE is much better at handling this kind of things. For instance, cinnamon-session-quit will monitor and warn about session idlers (i.e. opened unsaved documents etc..).

We might be able to call for a reboot via systemd and have the DE dialog triggered instead of calling reboot directly.

[timfeierabend]

Thanks for pointing me to cinnamon-session-quit. Looks like it uses D-Bus to tell Cinnamon to reboot. Both MATE (org.gnome.SessionManager) and XFCE (org.xfce.SessionManager) also have D-Bus reboot capabilities. Instead of using reboot/systemctl reboot to initiate the reboot process, I'll re-write this to send the reboot message via D-Bus to the DE's session manager. That way it'll mimic the behavior as if the user initiated the reboot via the DE's menu.

[mtwebster]

Why not just run cinnamon-session-quit --reboot directly?

[clefebvre]

Yeah either way, as long as it works everywhere.

[timfeierabend]

@mtwebster That's ultimately what I ended up doing instead of re-inventing wheels. Cinnamon and XFCE had apps that trigger a reboot in their respective session. MATE's mate-session-save doesn't have a reboot option, so I ended up using dbus-send to trigger the reboot.

[timfeierabend]

Cinnamon session end:

MATE session end:

XFCE doesn't perform the same check when you go to reboot, even from the main menu, so the reboot button immediately reboots the machine without any dialog.