Debian 13 | systemd PID 1 | docker exec --user tester | no PAM login

$ id
uid=1000(tester) gid=1000(tester) groups=1000(tester)
[exit 0]

$ sh -c printf "XDG_RUNTIME_DIR=%s\nXDG_CONFIG_HOME=%s\n" "${XDG_RUNTIME_DIR-unset}" "${XDG_CONFIG_HOME-unset}"
XDG_RUNTIME_DIR=unset
XDG_CONFIG_HOME=/home/tester/shell-config
[exit 0]

$ loginctl show-user tester -p Linger -p State
Failed to get user: User ID 1000 is not logged in or lingering
[exit 1]

$ systemctl is-active user@1000.service
inactive
[exit 3]

$ t3 service install
Service installed · t3@0.1.8
Log: /home/tester/.t3/userdata/logs/boot-service.log
Run `t3 up` to choose how your other devices reach it.
[exit 0]

$ t3 service status
T3 Code service
  Status: installed · t3@0.1.8
  Unit: /home/tester/.config/systemd/user/t3code.service
  Logs: /home/tester/.t3/userdata/logs/boot-service.log
[exit 0]

$ loginctl show-user tester -p Linger -p State
State=lingering
Linger=yes
[exit 0]

$ systemctl is-active user@1000.service
active
[exit 0]

$ env XDG_RUNTIME_DIR=/run/user/1000 systemctl --user show t3code.service -p ActiveState -p SubState -p UnitFileState -p FragmentPath
ActiveState=active
SubState=running
FragmentPath=/home/tester/.config/systemd/user/t3code.service
UnitFileState=enabled
[exit 0]

$ sh -c test -f /home/tester/.config/systemd/user/t3code.service && echo "Unit exists in manager config directory"; test ! -f /home/tester/shell-config/systemd/user/t3code.service && echo "No unit in shell-only config directory"
Unit exists in manager config directory
No unit in shell-only config directory
[exit 0]
