What causes "unable to read from stdin for confirmation" in getzola/zola?

Provide input on stdin (pipe a line such as 'y' or run interactively) so lines().next() returns Some.

unable to read from stdin for confirmation

Error message

unable to read from stdin for confirmation

What it means

read_line in src/prompt.rs reads a single line from stdin to confirm an interactive prompt. It panics/aborts with this anyhow error when stdin yields no line at all — i.e. the stream is closed (EOF) or the read fails with an I/O error. The library throws it because a confirmation prompt cannot proceed without user input.

Source

Thrown at src/prompt.rs:15

use std::io::{self, BufRead, Write};

use url::Url;

use errors::{Result, anyhow};

/// Wait for user input and return what they typed
fn read_line() -> Result<String> {
    let stdin = io::stdin();
    let stdin = stdin.lock();
    let mut lines = stdin.lines();
    lines
        .next()
        .and_then(|l| l.ok())
        .ok_or_else(|| anyhow!("unable to read from stdin for confirmation"))
}

/// Ask a yes/no question to the user
pub fn ask_bool(question: &str, default: bool) -> Result<bool> {
    print!("{} {}: ", question, if default { "[Y/n]" } else { "[y/N]" });
    let _ = io::stdout().flush();
    let input = read_line()?;

    match &*input {
        "y" | "Y" | "yes" | "YES" | "true" => Ok(true),
        "n" | "N" | "no" | "NO" | "false" => Ok(false),
        "" => Ok(default),
        _ => {
            println!("Invalid choice: '{input}'");
            ask_bool(question, default)
        }
    }
}

View on GitHub (pinned to 61d3082821)

Solutions

Provide input on stdin (pipe a line such as 'y' or run interactively) so lines().next() returns Some.
Check for a non-interactive flag (e.g. --force / --yes) to skip confirmation prompts entirely.
In CI, use the tool's non-interactive mode instead of relying on a TTY prompt.
If embedding, ensure stdin is not closed/consumed before the prompt runs.

Example fix

// before
echo -n | myapp deploy   # stdin at EOF -> error
// after
yes | myapp deploy       # or: myapp deploy --yes

Defensive patterns

Strategy: try-catch

Validate before calling

// Rust: probe stdin before prompting
use std::io::IsTerminal;
fn stdin_usable() -> bool { !std::io::stdin().is_terminal() || atty_ok() } // or check !stdin is at EOF via a peek
if std::io::stdin().read_line(&mut probe).is_ok() && !probe.is_empty() { /* safe to prompt */ }

Type guard

fn stdin_has_input() -> bool {
    use std::io::IsTerminal;
    std::io::stdin().is_terminal() // false in CI/piped-EOF contexts -> skip prompting
}

Try / catch

match ask_bool("continue?", true) {
    Ok(v) => /* proceed with v */,
    Err(e) if e.to_string().contains("unable to read from stdin") => /* assume default / skip prompt */,
    Err(e) => return Err(e),
}

Prevention

Run interactive commands in a real TTY or pipe explicit answers (yes | cmd).
Use the tool's non-interactive flag (--yes/--force) in CI.
Never pipe input shorter than the number of prompts.
Detect non-interactive environments early (isatty) and avoid prompts.

When it happens

Trigger: Calling ask_bool or ask_url when stdin is closed, exhausted (e.g. stdin already consumed to EOF by an earlier read or piped input), or the underlying read returns an I/O error.

Common situations: Running the CLI non-interactively (CI pipelines, cron) with stdin at EOF or </dev/null; piping input that runs out of lines before the prompt; a terminal/PTY that detaches mid-run.

Related errors

AI-assisted analysis of getzola/zola@61d3082821 (2026-09-03). Data as JSON: /api/errors/0af5da855ad6d887. Report an issue: GitHub.