Looks like deps=high needs some fixing.

regarding this PR, this looks good to me. 👍

With this fix, in Windows system, $caseCheck is set to "0", whereas it should be set to "1" (filesystem is NOT case sensitive) as in previous versions.

@alexchip64 can you detail why it ends up being set to zero in your case?

Because, in my case, the situation of the checking is as follow:

$file = C:\Users\cipriano\Documents\NetBeansProjects\zoe\vendor\symfony\symfony\src\Symfony\Component\Debug\DebugClassLoader.php

$fileTest = C:\USERS\CIPRIANO\DOCUMENTS\NETBEANSPROJECTS\ZOE\VENDOR\SYMFONY\SYMFONY\SRC\SYMFONY\COMPONENT\DEBUG\DEBUGCLASSLOADER.PHP

but

realpath($fileTest) = C:\Users\cipriano\DOCUMENTS\NETBEANSPROJECTS\zoe\vendor\symfony\symfony\src\Symfony\Component\Debug\DebugClassLoader.php

so the check realpath($fileTest) === $file fails.

does it work better if you use strtolower instead of strtoupper?

I've done it, it but final result does not change:

$fileTest = 'c:\users\cipriano\documents\netbeansprojects\zoe\vendor\symfony\symfony\src\symfony\component\debug\debugclassloader.php'

but

realpath($fileTest) = 'C:\Users\cipriano\documents\netbeansprojects\zoe\vendor\symfony\symfony\src\Symfony\Component\Debug\DebugClassLoader.php'

strange... this means it couldn't work previously and caseCheck ended up being 2, not 1, isn't it?

Version 2.8.4 does not work in Windows as I indicated in my #18344, because final value is 2 and Symfony hangs.
Previous versions used different way for checking:

self::$caseCheck = false !== stripos(PHP_OS, 'win') ? (false !== stripos(PHP_OS, 'darwin') ? 2 : 1) : 0;

@alexchip64 PR updated, can you please check the new patch?

Nothing changes.

$test = 'C:\Users\cipriano\Documents\NetBeansProjects\zoe\vendor\symfony\symfony\src\Symfony\Component\Debug\DebugClassLoader.php'

and

$file = 'DebugClassLoader.php'

so the checking:
elseif (substr($test, -strlen($file)) !== $file)

returns false

My bad, it should be === instead of !==. Fixed.

Now it is ok. At least it appears ok for Windows systems.
I've understood what you have done: you ignore the path and focus on the filename only.

Thank you @nicolas-grekas.