nghttpx and jetty http3 client

[ChGen]

When trying jetty http3 client, I found out that it fails with nghttpx http3 server.
For example, java test below fails for https://nghttp2.org:4433 (or local nghttpx), but will pass for https://http3check.net
However, curl built with http3 support will connect both https://nghttp2.org:4433 and https://http3check.net successfully.

curl -kv --http3 https://nghttp2.org:4433

According to the comment in jetty/jetty.project#10390 , this could be bug in the nghttpx too:

Note that the value sent by nghttp2.org is 4611686018427387903, which is not a "grease" value.
The closes grease value is 0x1F * 148764065110560899 + 0x21 = 4611686018427387902 which is off by 1 with what sent by nghttp2.org, so I guess also nghttp2.org has a bug.

Test code:

    @Test
    public void testConnection_nghttp2() throws Exception {
        final HTTP3Client h3Client = new HTTP3Client();
        final HttpClientTransportOverHTTP3 transport = new HttpClientTransportOverHTTP3(h3Client);
        final HttpClient client = new HttpClient(transport);
        client.start();
        final ContentResponse response = client.GET("https://nghttp2.org:4433"); // will pass for 'https://http3check.net`
        assertEquals(200, response.getStatus());
        client.stop();
    }

[tatsuhiro-t]

Greasing is done for settings ID, not value.
4611686018427387903 is a valid value for SETTINGS_MAX_FIELD_SECTION_SIZE. That is the maximum value that can be expressed in 62-bit unsigned integer.
I think jetty should try to convert it to 64-bit integer rather than int (which I assume 32-bit integer which is too small).

[tatsuhiro-t]

Closing because this is not a bug on our side.