HostNotFoundError when using symfony/process 3.1 or above

[Athlon1600]

Seems to be similar to this issue: #134

but that fix did not work for me. This is my setup:

composer.json

{
  "require": {
    "symfony/process": "^2.8",
    "knplabs/knp-snappy": "^1.0"
  }
}

test.php

require("vendor/autoload.php");

use Knp\Snappy\Pdf;

$snappy = new Pdf('C:\wkhtmltox\bin\wkhtmltopdf.exe');

header('Content-Type: application/pdf');
header('Content-Disposition: inline; filename="file.pdf"');

echo $snappy->getOutput('http://www.google.com');

works just fine. Now if I were to upgrade to symfony/process 3.1 or above (that's what comes with Laravel), and change nothing else, I get this:

{
  "require": {
    "symfony/process": "^3.1",
    "knplabs/knp-snappy": "^1.0"
  }
}

Fatal error:  Uncaught RuntimeException: The exit status code '1' says something went wrong:
stderr: "Loading pages (1/6)
[>                                                           ] 0%
[======>                                                     ] 10%
Error: Failed to load http://www.google.com/, with network status code 3 and http status code 0 - Host www.google.com not found
Error: Failed loading page http://www.google.com (sometimes it will work just to ignore this error with --load-error-handling ignore)
Exit with code 1 due to network error: HostNotFoundError
"
stdout: ""
command: C:\wkhtmltox\bin\wkhtmltopdf.exe --lowquality "http://www.google.com" "C:\Users\Paul\AppData\Local\Temp\knp_snappy5bf09a493cb1b7.72369057.pdf". in C:\Users\Paul\Desktop\git\vendor\knplabs\knp-snappy\src\Knp\Snappy\AbstractGenerator.php:378
Stack trace:
#0 C:\Users\Paul\Desktop\git\vendor\knplabs\knp-snappy\src\Knp\Snappy\AbstractGenerator.php(177): Knp\Snappy\AbstractGenerator->checkProcessStatus(1, '', 'Loading pages (...', 'C:\\wkht in C:\Users\Paul\Desktop\git\vendor\knplabs\knp-snappy\src\Knp\Snappy\AbstractGenerator.php on line 378

what's the problem? I can't seem to find what has changed between symfony/process versions that broke snappy.
symfony/process@2.8...3.1

I'm using Windows by the way, and I don't know if this same problem exists on Linux platforms....

[Athlon1600]

it's very interesting that it starts working if I manually add 'SystemRoot' env variable when initializing Snappy:

$env = array(
  'SystemRoot' => 'C:\\WINDOWS'
);
	  
$snappy = new Pdf('C:\wkhtmltox\bin\wkhtmltopdf.exe', array(), $env);

^ works

[stale]

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