[DI][4.2] It's a requirement to specify a Metadata Driver and pass it to Doctrine\ORM\Configuration::setMetadataDriverImpl().

**Symfony version(s) affected**: 4.2

This is another report of #28304

The reproducing app is at https://github.com/ro0NL/sf

Running `git apply patch.diff && composer install` (to downgrade to 4.1) solves it.

**EDIT: if you still have this issue, running `composer require symfony/proxy-manager-bridge` should fix it.**