We've got a slightly old version of Assetic in composer, and it should be updated.
More importantly, Assetic has a ton of dependencies without which we cannot use most of its filters (e.g., css minification, js minification, css/js preprocessing, etc.). I believe because of how Symfony is expected to work, these dependencies are listed in its
require-dev block, not
require, which means we haven't already pulled them in.
This patch adds some of those dependencies - specifically, one that should let us compress css and js entirely in PHP. We should do this, then remove them later if we decide we don't want them, in order to simplify work over in .