Running lifecycle scripts might hang on Windows

[segrey]

Do you want to request a feature or report a bug?
Bug

What is the current behavior?

A lifecycle script run by yarn might hang on Windows if the script accesses process.stdin.

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

Let's consider the example project:

// starter.js
const exec = require('child_process').exec;
var yarn = exec('yarn run app');

yarn.stdout.on('data', function(data) {
    process.stdout.write('yarn: ' + data);
});

yarn.stderr.on('data', function(data) {
    process.stdout.write('yarn: ' + data);
});

yarn.on('close', function(code) {
    process.stdout.write('yarn process finished with exit code ' + code);
});

// package.json
{
  "scripts": {
    "app": "node child.js"
  }
}

// child.js
console.log('child: accessing process.stdin');
console.log('child: done successfully ' + process.stdin);

Sometimes running node starter.js in cmd.exe results in printing these lines and hanging

yarn: yarn: yarn run v0.18.1
yarn: yarn: $ node child.js 
yarn: child: accessing process.stdin

What is the expected behavior?

node starter.js should print these lines and exit

yarn: yarn: yarn run v0.18.1
yarn: yarn: $ node child.js 
yarn: child: accessing process.stdin
yarn: child: done successfully [object Object]
yarn: yarn: Done in 0.17s.
yarn process finished with exit code 0

Please mention your node.js, yarn and operating system version.
yarn 0.18.1, 0.19.0
node 7.4.0
OS Windows 10

Though it's a node.js bug (nodejs/node#10836), it'd be nice if yarn could omit accessing process.stdin entirely when running any lifecycle script. That would fix this issue as well. Currently, process.stdin is accessed in lib/reporters/base-reporter.js (https://github.com/yarnpkg/yarn/blob/v0.20.0-0/src/reporters/base-reporter.js#L55), but not used afterwards.

[rally25rs]

Closing this as it is a Node/Win issue.