F12: a third NR==FNR survived at the focus-filter join in plan() (fp_names
x pf), next to two comments that already state this file's rule -- never
by NR==FNR. Measured before fixing: unlike the two prior instances, this
join has no third file whose lookup table a misroute could corrupt, and
FOCUS_SLUGS is provably a subset of what focus_slugs() finds in the same
$RECORDS focus_declares() re-checks -- so fp_names cannot be empty while
the filter applies, and even forced empty the old and new form produce
identical output. No reachable defect to pin behaviourally; the fix closes
the file's own stated invariant instead. Pinned structurally in selftest
section 21: no live NR==FNR outside a comment, with a known-positive
control proving the filter can still find one.
board-selftest: 239/239 (was 237). coord/route/orders/guard unchanged and
green (220/69/99/40), npm test 11/11.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016YkJ1rKh5YNfVUr5UDKpfh
Kjell Tore Guttormsen
2928c28044