Waybar vanished after a logout→login (no reboot): the bar's systemd user
service landed in `failed`. HM's Hyprland integration cycles
hyprland-session.target on every launch (exec-once stop && start), which
re-pulls WantedBy units — including waybar.service — very early, before
Hyprland's IPC socket is ready. Waybar's hyprland/workspaces & window
modules can't connect, so it exits non-zero and is never retried. A cold
boot's extra latency hid the race, so it only bit on warm relogins. The
non-IPC session services (swaync/hypridle/hyprsunset) survive the same
cycling fine, which is why night-light kept working.
Launch waybar from Hyprland's own exec-once instead (systemd.enable =
false). exec-once entries are dispatched once the compositor is up, so the
IPC socket is ready — the same reliable pattern awww-daemon, the wallpaper
sync and the keyboard watcher already use across relogins. Since the unit
no longer exists to be restarted on a home-manager switch, nudge the
running bar to re-read its rebuilt config/style with SIGUSR2 from
nomarchy-theme-sync so theme switches still reapply the bar live.
Found on the Latitude 5410 hardware sweep (systemctl --user status showed
waybar.service loaded/failed; manual start worked).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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