ngtcp2 — Field section that blocks until the encoder stream catches up

Inconclusive

The run did not exercise this test: the client advertised SETTINGS_QPACK_MAX_TABLE_CAPACITY of 0 and SETTINGS_QPACK_BLOCKED_STREAMS of 0, which forbid the server's encoder from using the dynamic table at all.

The run did not establish what this client does here — either it was never put in the situation, or its answer admits more than one reading. Not a failure, and never counted as one.

What was measured

Client

ngtcp2 — ngtcp2 + nghttp3 (direct), 3c23148

Test

Field section that blocks until the encoder stream catches up — h-qpack-blocked-stream

Clause

RFC 9204 §2.1.2, §2.2.1 (MUST)

Class

interoperability — Correctly decoded something valid but demanding.

Required behaviour

Hold the field section, apply the insertions when they arrive on the encoder stream, and complete the request. §2.2.1 makes a section whose Required Insert Count exceeds the decoder's Insert Count a blocked stream — something to be waited on, not an error. Only run when the client advertised both a table capacity and at least one blocked stream; §2.1.2 forbids the encoder from blocking more streams than the decoder promised to support, so a client that permits none cannot be tested on this.

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-qpack-blocked-stream"]'