What causes "No session selected." in Hmbown/CodeWhale?

Type the session id shown in the prompt and press Enter.

No session selected.

Error message

No session selected.

What it means

When resuming a session interactively, the CLI reads a session id from stdin; if the user presses enter without typing anything, the empty selection aborts with this error instead of launching the TUI with an invalid session.

Solutions

Type the session id shown in the prompt and press Enter.
Find a valid session id first (e.g. via the session listing command) and resume non-interactively: `codewhale resume <session-id>`.
If running non-interactively, pipe the session id: `echo <session-id> | codewhale ...`.

Example fix

null

Defensive patterns

Strategy: validation

Validate before calling

if session_id.trim().is_empty() {
    eprintln!("no session id supplied; run 'codewhale resume <session-id>'");
} else {
    run_tui_in_process(cli, resolved_runtime, vec!["resume".into(), session_id.trim().into()])?;
}

Try / catch

match result {
    Err(e) if e.to_string() == "No session selected." => {
        eprintln!("selection was empty — pass a session id explicitly");
    }
    Err(e) => return Err(e),
    Ok(()) => {}
}

Prevention

List sessions first and resume by explicit id rather than relying on the interactive prompt.
In non-interactive contexts, always pipe or pass the session id; stdin may be EOF.
Trim and validate user input before forwarding it to resume.

When it happens

Trigger: The session-selection prompt read an empty line from stdin (io::stdin().read_line) and `input.trim()` was empty before `run_tui_in_process` is called with `resume <session_id>`.

Common situations: User hit Enter at the selection prompt without typing a session id; stdin was EOF/closed (piped or non-interactive) so read_line returned zero bytes; script driving the CLI omitted the input.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of Hmbown/CodeWhale@73e0f67d83 (2026-09-22). Data as JSON: /api/errors/8c3a01cfb832ec5a. Report an issue: GitHub.

Appendix: source

Thrown at crates/cli/src/lib.rs:5296

            0
        } else {
            1
        })
    }

    println!();
    println!("Windows note: enter a session id or prefix from the list above.");
    println!("You can also run `codewhale resume --last` to skip this prompt.");
    print!("Session id/prefix (Enter to cancel): ");
    io::stdout().flush()?;

    let mut input = String::new();
    io::stdin()
        .read_line(&mut input)
        .context("failed to read session selection")?;
    let session_id = input.trim();
    if session_id.is_empty() {
        bail!("No session selected.");
    }

    run_tui_in_process(
        cli,
        resolved_runtime,
        vec!["resume".to_string(), session_id.to_string()],
    )
}

fn should_pick_resume_in_dispatcher(passthrough: &[String], is_windows: bool) -> bool {
    is_windows && passthrough == ["resume"]
}

fn run_tui_in_process(
    cli: &Cli,
    resolved_runtime: &ResolvedRuntimeOptions,
    passthrough: Vec<String>,
) -> Result<()> {

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