While trying out phpvirtualbox on a server running PHP 8.0.3, I ran into problems with the file selection dialog when trying to attach an ISO file.

This was due to the following error which showed up in the error logs:

PHP Fatal error:  Cannot redeclare getdir() in /usr/share/webapps/phpvirtualbox/endpoints/jqueryFileTree.php on line 224

getdir() seems to be a built-in function in PHP, so I wonder how this worked before.

The easiest fix is to rename getdir() function to something else.

Then another error showed up:

PHP Fatal error:  Uncaught TypeError: count(): Argument #1 ($var) must be of type Countable|array, null given in /usr/share/webapps/phpvirtualbox/endpoints/jqueryFileTree.php:256

For PHP versions >= 7.30 the fix is to use is_countable() instead of count().

With those fixes, directory selection is working now.