Description

On Unix-like systems, closing a std file handle has the useful property that the next file handle you open will inherit its place. This provides a very simple and effective way to reroute stdin/stdout/stderr during run time.

This has historically also been possible through PHP-CLI scripts, and as a result has become common practice, oft-repeated boilerplate code for using pcntl_fork() in particular, where it is almost always desirable for the forked children to stop using the parent's stdin/stdout/stderr.

This used to be as simple as, for example:

<?php
fclose(STDIN);
fclose(STDOUT);
fclose(STDERR);
$in = fopen('/dev/null', 'r');
$out = fopen('stdout-now-goes-here.txt', 'a');
$err = fopen('stderr-now-goes-here.txt', 'a');

The fix for an unrelated issue in #8575, and unfortunately included in both PHP 8.1.7 and PHP 8.0.20, also makes it impossible for PHP code to willfully close the std file handles anymore. This breaks a whole swath of past code that depended on this functionality, a rather unwelcome and unexpected change for minor releases.

Here's a test:

--TEST--
std handles can be deliberately closed
--SKIPIF--
if (php_sapi_name() != "cli") {
	die("skip CLI only");
}
if (substr(PHP_OS, 0, 3) == 'WIN') {
	die("skip not for Windows");
}
--FILE--
<?php
fclose(STDERR);
var_dump(@fopen('php://stderr', 'a'));
?>
--EXPECT--
bool(false)

With PHP 8.1.7 or 8.0.20 this now results in the following output instead:

resource(5) of type (stream)

3v4l link: https://3v4l.org/OgYWN

PHP Version

PHP 8.1.7

Operating System

Linux, macOS