result.all is not constant

[ehmicky]

Steps to reproduce:

import { promisify } from 'util'
import execa from 'execa'

(async () => {
  const childProcess = execa('echo', ['test'])
  await promisify(setTimeout)(1e3)

  console.log('all:', (await childProcess).all);
  console.log('all:', (await childProcess).all);
})()

$ node index.js
all: test
all: 

Node v12.4.0
Ubuntu 19.10
Execa 2.0.0

[ehmicky]

I managed to reproduce this bug with this more minimal setup. It's based on what execa is internally doing.

const childProcess = require('child_process');
const getStream = require('get-stream');
const mergeStream = require('merge-stream');

(async () => {
	const {stdout} = childProcess.spawn('echo', ['test']);

	const all = mergeStream();
	all.add(stdout);

	console.log('all:', await getStream(all));
	console.log('all:', await getStream(all));
})();

$ node index.js
all: test

all:

[ehmicky]

PR at #330.