denoland/deno · error

Failed to create editor.

Error message

Failed to create editor.

What it means

When `deno` starts without a script it builds a line editor (rustyline) for the REPL with list completions, history, and custom key bindings. Editor::with_config() is expected to always succeed; if the underlying terminal cannot be initialized, .expect() panics with 'Failed to create editor.' and the REPL dies at startup.

Source

Thrown at cli/tools/repl/editor.rs:606

#[derive(Clone)]
pub struct ReplEditor {
  inner: Arc<Mutex<Editor<EditorHelper, rustyline::history::FileHistory>>>,
  history_file_path: Option<PathBuf>,
  errored_on_history_save: Arc<AtomicBool>,
  should_exit_on_interrupt: Arc<AtomicBool>,
}

impl ReplEditor {
  pub fn new(
    helper: EditorHelper,
    history_file_path: Option<PathBuf>,
  ) -> Result<Self, AnyError> {
    let editor_config = Config::builder()
      .completion_type(CompletionType::List)
      .build();

    let mut editor =
      Editor::with_config(editor_config).expect("Failed to create editor.");
    editor.set_helper(Some(helper));
    if let Some(history_file_path) = &history_file_path {
      editor.load_history(history_file_path).unwrap_or(());
    }
    editor.bind_sequence(
      KeyEvent(KeyCode::Char('s'), Modifiers::CTRL),
      EventHandler::Simple(Cmd::Newline),
    );
    editor.bind_sequence(
      KeyEvent(KeyCode::Tab, Modifiers::NONE),
      EventHandler::Conditional(Box::new(TabEventHandler)),
    );
    let should_exit_on_interrupt = Arc::new(AtomicBool::new(false));
    editor.bind_sequence(
      KeyEvent(KeyCode::Char('r'), Modifiers::CTRL),
      EventHandler::Conditional(Box::new(ReverseSearchHistoryEventHandler {
        should_exit_on_interrupt: should_exit_on_interrupt.clone(),
      })),

View on GitHub (pinned to 9ad36f7a2c)

Solutions

1. Run the REPL in a real interactive terminal, not with redirected stdin
2. Use `deno run script.ts` or `deno eval "..."` for non-interactive use instead of the REPL
3. Fix TERM (e.g. export TERM=xterm) and install terminfo (ncurses-base / ncurses-term)
4. Pipe scripts explicitly: deno run - < script.ts

Example fix

# before
deno < input.txt   # REPL starts with piped stdin -> editor creation can fail

# after
deno run - < input.txt

if (!Deno.isatty(Deno.stdin.rid)) {
  console.error("no TTY on stdin; use `deno run -` instead of the REPL");
  Deno.exit(1);
}

When it happens

Trigger: Launching the Deno REPL (`deno` or `deno repl`) where terminal setup fails: stdin/stdout not connected to a TTY (piped or closed), a missing or wrong TERM with no terminfo database, or an unsupported console.

Common situations: Accidentally running `deno` in scripts/CI where stdin is /dev/null or a pipe; minimal Docker images without ncurses terminfo; starting the REPL from cron, services, or non-interactive SSH commands.

Related errors

• Failed to create editor.
• ERR_TTY_INIT_FAILED
• ERR_TTY_INIT_FAILED
• REPL thread panicked
• ERR_INVALID_FD

AI-assisted analysis of denoland/deno@9ad36f7a2c (2026-08-20). Data as JSON: /api/errors/5ff9331bd14c9d6e. Report an issue: GitHub.