casefold and NFKC do not commute and neither is a fixpoint of the other, so a
single NFKC(casefold(...)) pass left normalize_id(s) != normalize_id(s.casefold())
for some combining-mark sequences (e.g. Greek ypogegrammeni U+0345 + a combining
accent): pre-casefolding turned U+0345 into iota, which NFKC then composed with
the accent into a form the single pass never saw. Iterate casefold-then-NFKC to
a bounded fixpoint (casefold first, on the raw input) so the result is stable
regardless of prior casefolds. No churn: letter/digit-bearing ids and every
CONTRACT_CASE are byte-identical; idempotency, word-only, and the Turkish (#2614)
cases still hold. Adds a deterministic regression pin so the fix does not rely on
hypothesis re-drawing the codepoints.
This was a pre-existing latent bug (present in released 0.9.45), surfaced by the
hypothesis property test; ids.py was untouched by the PRs landed alongside it.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
safishamsi
0929519ec1