The "Switch User" sub-menu is missing on a multi-user system

Environment:

• gnome-shell-3.28
• accountsservice-0.6.49

Description:

Log into a multi user system you will find the "Switch User" sub-menu of SystemIndicator(upper right corner of gnome-shell) is missing.

But it can be activated when:

• A new user is created via g-c-c but it will disappear after a reboot or relogin
• The gsettings value of "disable-user-swithching" is turned on then off
• Lock then unlock the screen

My findings

I added some print sentences for gnome-shell and found that the default value of _userManager.can_switch() in systemActions.js (on a multi user system) is false while it should be true. Then I tried to downgrade libaccountsservice from 0.6.49 to 0.6.45 and the issue is resolved.

The version bump of libaccountsservice brings in some changes which causes this issue, but I'm not sure if it should be fixed by the gnome-shell side or accountsservice side?

suspected commit

• The default behavior of act_user_manager_get_default() was changed by: lib: only track users after act_user_manager_list_users

Downstream bugs

• brc#1576903 Switch User menu item is missing
• brc#1597350 - Switch User is missing in System Menu
• boo#1100041 - The "switch user" disappeared from control center on Tumbleweed gnome