Best practice to close QUIC stream and delete app object after peer-initiated RESET_STREAM (ngtcp2 + nghttp3)

[yasha-liebes]

Context

1. Client receives RESET_STREAM frame from the server.
2. After handling it, I want:
   • The QUIC stream to be fully closed.
   • My per-stream application object to be destroyed exactly once.
3. I currently:
   • Call nghttp3_conn_shutdown_stream_read(httpconn_, stream_id);
   • Rely on ngtcp2_callbacks.stream_close to delete the per-stream object.

Questions

1. After receiving peer RESET_STREAM, is calling nghttp3_conn_shutdown_stream_read sufficient to drive ngtcp2 to a final stream_close callback, or should I also call one or both of:
   • ngtcp2_conn_shutdown_stream_read(conn, stream_id, app_error_code);
   • ngtcp2_conn_shutdown_stream_write(conn, stream_id, app_error_code);
2. What is the recommended API sequence to guarantee:
   • QUIC stream is closed per ngtcp2.
   • stream_close fires exactly once so I can safely delete my per-stream object.
3. Are there cases where stream_close will not fire after peer RESET_STREAM, and should I add a secondary cleanup path?
4. Should the client send STOP_SENDING in response to a peer RESET_STREAM, or is that unnecessary/incorrect?
5. Any ordering guarantees between nghttp3 events and ngtcp2 stream_close that I should rely on for cleanup?

What I want to confirm

1. The minimal, correct set of calls after peer RESET_STREAM.

[tatsuhiro-t]

RESET_STREAM from a remote endpoint means that it stops sending stream data on that stream, and cancels all unacknowledged data. This is equivalent for the receiver (in this case, client) to call ngtcp2_conn_shutdown_stream_read(), so in this case, you do not need to call ngtcp2_conn_shutdown_stream_read yourself.

If you have not send stream fin to server, you should call ngtcp2_conn_shutdown_stream_write, which will send RESET_STREAM to the remote endpoint. After the packet is acknowledged by the remote endpoint, the stream is closed, and stream_close callback will be invoked.

[yasha-liebes]

Thanks for the answer.