ngtcp2 — SETTINGS containing the same identifier twice

Pass

Tolerated it and continued. The specification permits this but does not require it; a client that rejected it would also be conformant.

The client did what the clause requires.

What was measured

Client

ngtcp2 — ngtcp2 + nghttp3 (direct), 3c23148

Test

SETTINGS containing the same identifier twice — h-duplicate-setting

Clause

RFC 9114 §7.2.4 (MAY)

Class

discretionary — The RFC permits either behaviour; the report says which was chosen.

Required behaviour

Either reject with H3_SETTINGS_ERROR or ignore the repeat — the specification says a receiver MAY treat this as an error, so both are conformant.

Measured

2026-09-18

Reproduce it

The suite is the judge, so the reproduction is to point the same client at the same test and let the server report what it saw.

SESSION=$(curl -sX POST https://conformance.pqcrypta.com/session | jq -r .id)
# then drive ngtcp2 at the test URL and read the verdict:
curl -s https://conformance.pqcrypta.com/report/$SESSION.json | jq '.results["h-duplicate-setting"]'