scripts/lib/ratchet.sh: the one implementation of the grandfather/baseline
ratchet mechanics 7 gates hand-roll today — per-consumer parse modes
(raw|cr-strip|strip|trailing-comment), scope-aware changed-file collection
incl. upstream, fail-closed growth guard (comm -13 + intersection authority,
RATCHET_GROWTH_GUARD=off escape for migrated gates), parameterized stale
predicates, generic regenerate (header-fn + LC_ALL=C sorted body), added-hunk
guard with ENVIRON-passed ERE.
tests/scripts/lib/ratchet-difftest.bash: byte-parity differential harness
(stdout, stderr, exit code separately) for the migration slices.
tests/scripts/ratchet-lib.bats: 24 cases — real pinned-shape round-trips per
parse mode, growth rejection, self-allowlist refusal, stale by set-diff and
by predicate, regenerate golden, added-hunk guard, harness smoke.
cli/internal/gates/checks/ratchet_routing_test.go: self-extending FM3 closure —
every check script sourcing the lib must route lib edits via its Match globs.
Pre-mortem: .agents/council/2026-07-10-pre-mortem-ratchet-lib.md (3 rounds).
Lib is FROZEN for the rest of the arc per FM6.
Claude-Session: https://claude.ai/code/session_01RDWPYn4ZS2SyBkcBvAM18u
boshu