How does Ruby manage object lifetime in presence of circular references and root set constraints?

Ruby GC uses reachability analysis from root set, so cycles are safe if unreachable from roots.

Ruby does not rely on reference counting; instead, it uses reachability tracing. Even cyclic structures are collected if not reachable from root set (stack, globals, constants). Mark phase ensures all reachable objects are visited, while sweep phase frees everything else. This avoids classic reference cycle leaks seen in RC systems.