An error happened when asking for payload, try again later.

Error message

An error happened when asking for payload, try again later.

What it means

In h3i's interactive prompt, prompt_grease sends a GREASE frame and panics if the inquire Text prompt for the payload returns an error. Inquire's prompt() errors when the user cancels (ESC/Ctrl-C) or the terminal is not interactive.

Solutions

Enter a payload string instead of cancelling the prompt.
Run h3i interactively in a real TTY (docker run -it, no stdin redirection).
Replace the expect with ? so cancellation gracefully aborts the prompt flow.

Example fix

// before
.prompt().expect("An error happened when asking for payload, try again later.");
// after
.prompt()?;

Defensive patterns

Strategy: try-catch

Validate before calling

if !atty::is(atty::Stream::Stdin) {
    eprintln!("interactive prompts require a TTY");
    std::process::exit(1);
}

Try / catch

let payload = Text::new("payload:").prompt()
    .map_err(|e| { eprintln!("payload prompt cancelled: {e}"); e })?;

Prevention

Run h3i interactively with a real terminal (docker -it).
Avoid piping stdin into interactive prompt mode.
Handle InquireError::OperationCanceled as a graceful skip.

When it happens

Trigger: Pressing ESC or Ctrl-C at the 'payload:' prompt; running the interactive h3i prompt in a non-TTY environment (piped stdin, CI).

Common situations: Piping input into h3i instead of using a terminal; aborting the prompt mid-flow; running inside a Docker container without -t.

Related errors

AI-assisted analysis of cloudflare/quiche@9f96daa2c2 (2026-09-08). Data as JSON: /api/errors/296a0eccc347ca0a. Report an issue: GitHub.

Appendix: source

Thrown at h3i/src/prompts/h3/mod.rs:421

    let fin_stream = prompt_fin_stream()?;

    let action = Action::SendFrame {
        stream_id,
        fin_stream,
        frame: quiche::h3::frame::Frame::GoAway { id },
        expected_result: Default::default(),
    };

    Ok(action)
}

fn prompt_grease() -> InquireResult<Action> {
    let stream_id = h3::prompt_control_stream_id()?;
    let raw_type = quiche::h3::grease_value();
    let payload = Text::new("payload:")
        .prompt()
        .expect("An error happened when asking for payload, try again later.");

    let fin_stream = prompt_fin_stream()?;

    let action = Action::SendFrame {
        stream_id,
        fin_stream,
        frame: quiche::h3::frame::Frame::Unknown {
            raw_type,
            payload: payload.into(),
        },
        expected_result: Default::default(),
    };

    Ok(action)
}

fn prompt_extension() -> InquireResult<Action> {
    let stream_id = h3::prompt_control_stream_id()?;

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