SS4: Uncaught TypeError on dev/build
I updated a project to SilverStripe 4.1 on an older development VM. When running dev/build I got an error:
[Emergency] Uncaught TypeError: Return value of Symfony\Component\Filesystem\Filesystem::toIterable() must be an instance of Symfony\Component\Filesystem\iterable, array returned
This is caused by different PHP-Versions of my host, where I run my composer commands and the VM. Switching to another VM with the same PHP version solved this problem.
Thanks to Kinglozzer on SilverStripe's slack chanel for the fast help.