readline: prompt opt-out behavior

• Version: v8.0.0-rc.0
• Platform: Windows 4 x64
• Subsystem: readline

I am not sure if this is a bug or a feature.

Consider this simple echo interface:

'use strict';

const readline = require('readline');

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});

rl.on('line', (line) => {
  console.log(line);
});

It does not use rl.prompt() anywhere and with a common input there will be no default prompt:

However, if a user press DELETE, BACKSPACE or UP button, default prompt immediately and somehow unexpectedly appears shifting the whole line:

This can be prevented by setting the prompt option into the empty line. However, I am not sure if this opt-out rule is an intended behavior.

Start by running the provided readline echo interface on Windows and reproduce the prompt appearing after DELETE, BACKSPACE, or UP. Compare the behavior with an explicitly empty prompt, then inspect the readline input and prompt-handling entry points; done means the opt-out behavior is defined and the unexpected prompt behavior is addressed or documented.