The client completed its request and closed without objecting, and the anomaly was on the control stream — a unidirectional stream nothing obliges it to read on any schedule. Accepting the violation and never reaching the stream look the same from here. The one signal that separates reading from receiving is a flow-control credit grant, and a receiver grants credit only as its consumption approaches the window it advertised, so a client with a large window reads everything sent and says nothing. Not a judgement withheld — a distinction this vantage point cannot draw for this client. The client process had already exited 1553ms in, before this test's reaction point at never observed, so the silence after that is not evidence either way.
The suite could not establish what this client does here. That is a shortcoming of the run rather than anything about the client, and every one of these is on our list to remove.
What was measured
- Client
- xquic — Alibaba xquic + BoringSSL, 2060a44
- Test
- SETTINGS_H3_DATAGRAM with a value that is neither 0 nor 1 —
h-datagram-setting-invalid - Clause
- RFC 9297 §2.1.1 (MUST)
- Class
- correctness — Rejected something invalid, with the code the RFC names.
- Required behaviour
- Close the connection with H3_SETTINGS_ERROR. Unusually for a setting, RFC 9297 pins down the invalid-value case rather than leaving it open: the value "MUST be either 0 or 1", and if one "is received with a value that is neither 0 nor 1, the receiver MUST terminate the connection with error H3_SETTINGS_ERROR". This is the setting that gates HTTP Datagrams and so WebTransport, which means a client that implements either has real parsing behind it rather than an ignored identifier.
- Measured
- 2026-10-27
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=$(curl -sX POST https://conformance.pqcrypta.com/session | jq -r .id)
# then drive xquic at the test URL and read the verdict:
curl -s https://conformance.pqcrypta.com/report/$SESSION.json | jq '.results["h-datagram-setting-invalid"]'