Throws array access of type bool error in chroot jail

[rgpublic]

_writeHeaderBlock in vendor/pear/archive_tar/archive/tar.php contains:

        if (function_exists('posix_getpwuid')) {
            $userinfo = posix_getpwuid($v_info[4]);
            $groupinfo = posix_getgrgid($v_info[5]);

            $v_uname = $userinfo['name'];
            $v_gname = $groupinfo['name'];
        } else {
            $v_uname = '';
            $v_gname = '';
        }

But posix_getpwuid can in fact return false in a chroot jail. This unfortunately isn't documented here:

https://www.php.net/posix_getpwuid

But someone in the comments writes:

If You are useing kernel security module, such as LIDS, GrSec or Selinux it will work only if '/etc/passwd' is readable for user, under which PHP/Apache runs, otherwice you get FALSE.

In my case it's a chroot jail that's preventing access to /etc/passwd.

It would be nice if v_uname and v_gname could be set to an empty string in this case - just like it's done anyway in the else case.