'Can't answer a question unless a user TTY'

yarn version: 1.15.2 node version: 10.15.1 OS: Win10/Fedora 29

What is the current behavior? When i try to spawn a subprocess in node via child_process i got error 'Can't answer a question unless a user TTY'. It Only happens in case of package version conflicts and user inpute expected.

If the current behavior is a bug, please provide the steps to reproduce. Example code:

const spawn = require("child_process").spawn; const express = require("express"); const app = express(); const expressWs = require("express-ws")(app); app.use(express.static(${__dirname}));

expressWs.app.ws("/shell", ws => {

const shell = spawn("yarn.cmd", ["add", "pkgName"], { stdio: ["pipe", "pipe", "pipe"] });

shell.stdout.on("data", data => { ws.send(data.toString()); });

shell.stderr.on("data", data => { ws.send(data.toString()); });

ws.on("message", msg => { shell.stdin.write(msg); }); });

app.listen(3000);

Temporal solution for me was to comment lines in ConsoleReporter

if (!process.stdout.isTTY) {
       return (_promise || _load_promise()).default.reject(new Error("Can't answer a question unless a user TTY"));
     }