'Never has to master Nix' includes the error messages. The tool grows
validate_state (appearance schema = hard errors; settings.* and
unknown keys = warnings so menu writers and newer schemas keep
working), a read-only `validate` subcommand, and validation BEFORE
every write — an invalid set/apply is refused with the on-disk file
untouched. JSON syntax errors now say line, column, and fix. theme.nix
enforces the same schema at eval time (on the post-defaults state, so
sparse/older files still evaluate) and throws a message naming each
field, its got-value, and the fix paths — the hand-edit escape hatch
no longer ends in a Nix stack trace. Doctor's JSON fix-text points at
validate.
V1: new checks.theme-sync-validate fixture corpus green (good state,
trailing comma, bad hex, bad type, unknown key, refused set with
byte-identical file); negative mkFlake eval of a broken scratch
downstream shows the friendly throw; good-path template-home builds.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The things that actually break user machines, one command (and menu ›
System › Doctor): failed system/user units, disk space (real
filesystems only — fstype allowlist makes it VM/live safe, device
dedupe collapses / and /nix), theme-state.json parses + is
git-tracked, flake dirty/behind as warnings, generation age (profile
symlink mtime — store paths are epoch-1), snapper timeline when
enabled. Read-only by contract; every ✖ prints the one fixing command;
exit 1 on any problem. Ships as pkgs/nomarchy-doctor so the VM check
runs on a minimal node.
Verified: V1 package build (shellcheck-gated) + a real-hardware smoke
that correctly flagged a genuinely failed user unit on the dev box;
V2 green — checks.doctor VM test: induced failed unit flips the sheet
to exit-1 naming the unit and its fix, reset-failed returns healthy.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>