The Active Support library has always (or, close enough to always) allowed us to cherry-pick specific extensions/behaviors, to load only strictly needed dependencies. That is, rather than loading the entirety of the library, we can load just the bits and pieces we need. This helps keep the amount of things loaded in memory smaller, and faster by doing less work. It can also aide in understanding by making more explicit the dependencies some code relies on.
I’ve been using this technique for years, and it’s been solid. Until today, while working on a Rails 7 code base, when I started seeing an error:
uninitialized constant ActiveSupport::IsolatedExecutionState (NameError)
As it happens, what I’d been doing for years worked, but more by accident than design. Active Support 7 has fixed the glitch.