Causes issues passing descriptors to subprocesses

[donatj]

I had an issue reported to my package donatj/mock-webserver that turned out to be caused by this package.

donatj/mock-webserver#59 (comment)

After poking @sigma-z's example a bit, I've determined there's some sort of problem with this using this library AND generating file descriptors that can be passed to sub processes with proc_open.

I've boiled an example of the problem down to:

<?php

require __DIR__ . '/vendor/autoload.php';

DG\BypassFinals::enable();

$stdin   = fopen('php://stdin', 'rb');
$stdoutf = tempnam(sys_get_temp_dir(), 'dgb.test');

$descriptorSpec = [
	0 => $stdin,
	1 => [ 'file', $stdoutf, 'a' ],
];

$fullCmd = 'echo "This should come LAST in the output"';
$process = proc_open($fullCmd, $descriptorSpec, $pipes);

sleep(1);

echo "=== Text should come AFTER this line not before... reading from {$stdoutf} ===\n";
echo file_get_contents($stdoutf);

If you run this, you get something like

dup2: Bad file descriptor
This should come LAST in the output
=== Text should come AFTER this line not before... reading from <path> ===

If you comment out the line DG\BypassFinals::enable(); though you get the expected

=== Text should come AFTER this line not before... reading from /private/var/folders/dr/cpm01_51333c1px2yzc8qr9xq1kth0/T/dgb.testx1XyaY ===
This should come LAST in the output

It's failing to either create or pass the file descriptor to the subprocess.

I seem to be able to solve it on my site by replacing the line

	1 => [ 'file', $stdoutf, 'a' ],

with

	1 => fopen($stdoutf, 'wb'),

and I very well might do that but I still think this likely calls for some investigation

[dg]

Thanks for the detailed description. The stream functionality is magic for me, so I don't quite know what to do with it, just experimenting. Could you verify that this solves the problem? 2cb1b3c

[sigma-z]

@dg I checked your fix and cannot confirm that it works. The error stays the same. :(

[dg]

I have no idea what to do…

[sigma-z]

@dg I am sorry. I tried to debug the code, but could not find anything of help. Maybe it is a bug in PHP itself. I am not deep in the php stream wrapper functionality and can not help here. :(

[dg]

I think the problem is the missing implementation of NativeWrapper::stream_cast(). But I have no idea how to implement it. And I couldn't find any documentation.