Process suspended when stdout and stderr are redirected and the process is daemonized

[pablopunk]

So trying to fix this issue I found that in this line of term-size stops the execution:

const size = execa.sync('resize', ['-u']).stdout.match(/\d+/g);

Reproduce

With the vendor/resize binary, execute a script:

#!/usr/bin/env node
const path = require('path')
const execa = require('execa')
const size = execa.shellSync(path.join(__dirname, 'resize'), ['-u']).stdout.match(/\d+/g)
console.log(size)

And executing like this:

$ ./index.js >log.txt 2>&1 &
[2] 15736
[2]  + 15736 suspended (tty output)  ./index.js > log.txt 2>&1
$ cat log.txt

$ 

This doesn't happen when you don't run the process in the background (so, without the last &):

$ ./index.js >log.txt 2>&1
$ cat log.txt
[ '111', '25' ]
$

This could be an error in execa or in the resize binary, I have no clue.

[pablopunk]

Okay, I just realized that it says suspended, and I can see the process resize in top with status sleeping:

[sindresorhus]

I looked into this. It's definitely resize's fault, and not execa. Same thing happened with child_process.execFileSync(). From what I could understand, this happens because resize tries to take control of the TTY while in the background, and that's not allowed.

You could do this workaround: http://stackoverflow.com/a/24056296/64949 But I don't consider that a real fix.

I think I've found a solution though, by detecting whether we are in the background or not, and only execute resize when in the foreground:

#!/usr/bin/env node
const path = require('path')
const execa = require('execa')
const resizeBin = path.join(__dirname, 'resize');
const size = execa.shellSync(`case $(ps -o stat= -p $$) in *+*) "${resizeBin}" -u ;; esac`).stdout.match(/\d+/g)
console.log(size)

❯ ./index.js >log.txt 2>&1 &
[21] 34870
[21]    done       ./t.js > log.txt 2>&1

---

// @qix In case you have anything to add.

[dankegel]

See also yeoman/update-notifier#125

npm itself uses update-notifier which uses an old version of boxen which uses an old version of term-size which has the hang bug.

I'm lucky, I can work around it with npm install -g npm@3.10.8, but sure would be nice to not have to.