I'm not sure if skipping a test is a good idea, but the green bars clearly improve my mood :)

:D
What changed in PHP 7.3? The Filesystem component is supposed to provide one consistent behavior for all versions and OSes. We might want to decide which behavior is the correct one and fix it.

What changed in PHP 7.3?

<?php

// check behavior functions realpath, readlink, and component Symfony Filesystem for windows

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

use Symfony\Component\Filesystem\Filesystem;

$dir = __DIR__ . DIRECTORY_SEPARATOR . 'dir';
mkdir($dir);

$file = $dir . DIRECTORY_SEPARATOR . 'file';
$link1 = $dir . DIRECTORY_SEPARATOR . 'link1';
$link2 = $dir . DIRECTORY_SEPARATOR . 'link2';

touch($file);

symlink($file, $link1);
symlink($link1, $link2);

$fs = new Filesystem();

echo 'PHP: ' . PHP_VERSION . PHP_EOL;
echo 'realpath: ' . realpath($link2) . PHP_EOL;
echo 'readlink: ' . readlink($link2) . PHP_EOL;
echo '$fs->readlink($link2, true): ' . $fs->readlink($link2, true) . PHP_EOL;
echo '$fs->readlink($link2): ' . $fs->readlink($link2) . PHP_EOL;

unlink($file);
unlink($link1);
unlink($link2);
rmdir($dir);

b - before patch, a - after patch

###conclusion:

• realpath() works correctly with PHP 7.4.10, bug report https://www.php.net/ChangeLog-7.php#PHP_7_4
• readlink() works correctly with PHP 7.4.0, bug report n/a

What to do with PHP 7.3.* ?

Correct me, maybe I am confusing or missing something.

how check

set PROJECT_DIR=C:\symfony
set PHPUNIT=%PROJECT_DIR%/phpunit^
    --colors=never^
    --bootstrap %PROJECT_DIR%/vendor\autoload.php^
    --configuration %PROJECT_DIR%/phpunit.xml.dist %PROJECT_DIR%/src/Symfony/Component/Filesystem

FOR %%V IN (
    7.1.3,
    7.1.33,
    7.2.15,
    7.2.34,
    7.3.0,
    7.3.15,
    7.3.27,
    7.3.28,
    7.4.0,
    7.4.9,
    7.4.10,
    7.4.15,
    7.4.16,
    7.4.18,
    8.0.0,
    8.0.1,
    8.0.2,
    8.0.3,
    8.0.5,
    8.0.6
) DO (
    c:\php\%%V\php %PHPUNIT%
    @if errorlevel 1 (
       exit /b
    )
)

Hi @nicolas-grekas, please check my code.

imho need to edit the description, the current one is misleading

"... On Windows systems, readlink() resolves recursively the children links of a link until a final target is found. ... "

https://symfony.com/doc/4.4/components/filesystem.html#readlink

Bug report for PHP7.3.27 https://bugs.php.net/bug.php?id=80993

Answer from php.net

The erroneous readlink() has apparently been fixed inadvertently
when php_sys_readlink() has been refactored[1].

Anyhow, PHP 7.3 is in security mode[2], so unless this would be
regarded as security issue, the fix will not be backported.

[1] <https://github.com/php/php-src/commit/91c905e83c338ef66da824be4f90c1d78d134507>
[2] <https://www.php.net/supported-versions.php>

I think we did everything we could (fixed for 8.0 and >=7.4.10) for behavior our component

Thank you @a1812.