When introducing this mode, I overlooked the fact that file paths could look like this:

phar:///usr/local/bin/phpunit-5/phpunit/Util/Fileloader.php

In that kind of case, there is not always a way to tell if the deprecation was triggered inside or outside a vendor, so IMO I should add a special case just for phar paths in that method:

Not sure how realpath behave with such paths, BTW

I wonder how / if I'm going to be able to test that though... any ideas?