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rails latest stable - Superclass: ObjectSpace::WeakMap

On MRI `ObjectSpace::WeakMap` keys are weak references. So we can simply use WeakMap as a `Set`.

On TruffleRuby `ObjectSpace::WeakMap` keys are strong references. So we use `object_id` as a key and the actual object as a value.

JRuby for now doesn’t have Class#descendant, but when it will, it will likely have the same WeakMap semantic than Truffle so we future proof this as much as possible.

Files

  • activesupport/lib/active_support/descendants_tracker.rb