fix(systemd): use absolute %h/.nix-profile/bin paths in user units

The previous environment.d fix was insufficient: even with the nix profile
on the --user manager's PATH (confirmed via `systemctl --user
show-environment`), bare-name ExecStart= still fails 203/EXEC. systemd's
--user manager does not resolve a bare ExecStart binary against the
imported/environment.d PATH.

Invoke each unit's main binary by absolute path %h/.nix-profile/bin/<name>
(waybar, swayidle, swayrd, inhibridge, wl-paste, wob). %h expands to $HOME
at unit load. Secondary lookups those binaries/scripts perform (cliphist,
swaymsg, playerctl) still rely on PATH, which environment.d provides — so
that file stays, with its comment corrected to reflect this split.

1 files changed, 15 insertions, 17 deletions

diff --git a/dot_config/environment.d/10-nix-profile-path.conf b/dot_config/environment.d/10-nix-profile-path.conf
index 2e396d7..61d6402 100644
--- a/dot_config/environment.d/10-nix-profile-path.conf
+++ b/dot_config/environment.d/10-nix-profile-path.conf
@@ -1,22 +1,20 @@
 # Prepend the Nix home-profile (and ~/.local/bin) to the systemd *user*
-# manager's PATH at manager startup, before any unit in sway-session.target
-# launches.
+# manager's environment PATH, so it is inherited by every service process.
 #
-# Why this exists: most user-leaf tools (waybar, swayidle, swayr, mako,
-# cliphist, inhibridge, wob, …) were migrated from pacman (/usr/bin) to the
-# Nix home profile (~/.nix-profile/bin) and their .service units reference
-# them by *bare* name, relying on $PATH resolution (see nix/host.nix). The
-# systemd user manager does NOT source ~/.zprofile, so without this its PATH
-# is only /usr/local/bin:/usr/bin:/bin and every bare-name ExecStart fails
-# with status=203/EXEC.
+# Scope of this file: it fixes PATH for *child-process* lookups made BY the
+# services — e.g. wl-paste spawning `cliphist store`, swayidle running
+# `swaymsg`/`playerctl`, and helper scripts (display-watcher.sh,
+# on-battery-suspend) that call nix tools by bare name. The systemd user
+# manager does NOT source ~/.zprofile, so without this its PATH is only
+# /usr/local/bin:/usr/bin:/bin and those bare-name lookups fail.
 #
-# The sway config also runs `systemctl --user import-environment PATH`, but
-# that is a fire-and-forget `exec` that races with
-# `systemctl --user start sway-session.target`; if the start wins, the units
-# launch with the default PATH. environment.d is read deterministically at
-# manager start (before any unit), so it closes that race independently of
-# the live session.
+# It does NOT fix systemd's own ExecStart= binary resolution: systemd's
+# --user manager does not resolve a bare ExecStart name against this
+# (imported/environment.d) PATH, so those would still fail 203/EXEC. For
+# that reason the units under dot_config/systemd/user/ invoke their main
+# binary by absolute path (%h/.nix-profile/bin/<name>); this file only
+# covers the secondary PATH lookups those binaries/scripts perform.
 #
-# Note: environment.d is only re-read on a fresh user manager (login/boot) or
-# after `systemctl --user daemon-reexec`; it is not picked up mid-session.
+# Note: environment.d is only re-read on a fresh user manager (login/boot)
+# or after `systemctl --user daemon-reexec`; it is not picked up mid-session.
 PATH=${HOME}/.nix-profile/bin:${HOME}/.local/bin:${PATH}