This is an imported issue, original reference WP-188, created on 25 Nov 2014.

The problem is that when we use Symfony\Filesystem as a Composer package and some other plugin decides to do the same but in a different version, strange things might happen.

This is unfortunately probably problem on the PHP level because it doesn't allow two versions of the same class in memory at the same time. Considered solutions:

• In RequirementsChecker, check that no other plugin uses "our" libraries in incompatible versions
• At least write some docs about it