Node child_process spawn hangs when calling git shortlog -sn

My Scenario

In my node application I'm using child_process.spawn to query information from the current repository

I've built a small function to return a promise which resolves with the response from the command:

const spawn = require('child_process').spawn;

const gitExec = command => (
  new Promise((resolve, reject) => {
    const thread = spawn('git', command);
    const stdOut = [];
    const stdErr = [];

    thread.stdout.on('data', (data) => {
      stdOut.push(data.toString('utf8'));
    });

    thread.stderr.on('data', (data) => {
      stdErr.push(data.toString('utf8'));
    });

    thread.on('close', () => {
      if (stdErr.length) {
        reject(stdErr.join(''));
        return;
      }
      resolve(stdOut.join());
    });
  })
);

module.exports = gitExec;

Calling git branchworks just as expected:

gitExec(['branch'])
.then((branchInfo) => {
  console.log(branchInfo);
})

(as expected) results in

    * develop
      feature/forever
      feature/sourceconfig
      feature/testing
      master

From my understanding this proves the method I'm using to actually be working.

When calling git shortlog -sn the spawned process "hangs" and does not resolve in anything

gitExec(['shortlog', '-sn'])
.then((shortlogInfo) => {
  console.log(shortlogInfo);
})

Calling git shortlog -sn via commandline i geht the expected result:

   154  Andreas Gack
    89  Some other dude
     6  Whoever else

My (so far unsuccessfull) tries

using spawnSync (while changing my gitExec function to acommodate the syncronous approach) returns an object as documented - so the process seems to actually exit - but the relevant props of the object output stdout and stderr are all empty.
The status of the object is 0 which indicates the command to execute successfully

I've read about having to redefine the maxBuffer in the spawn options, but neither setting it to a (ridiculously) high value nor a very small value does make a difference in the syncronous or asynchronous approach.

Setting the shell option to true also does not make a difference in all of the above scenarios.

The issue occurrs on my Win10x64 as well as on MacOs running node v6.9.x or 7.x

Also calling the alias git log --pretty=short does not provide a result

My Actual Question

• Has anyone yet managed to successfully query git shortlog -sn via child_process.spawn?
• Does anyone know a module for Node which allows querying the current local git-repository?

I somehow think the two commands git branch and git shortlog internally handle their output in a different way.

I'd be happy to create an issue on their github page, but I actually don't know how to identify the actual root-cause of that problem.

Any further input is much appreciated!

via Andreas Gack