FB7867609.md

FB7867609

Consider the following code:

class ViewModel: ObservableObject {
  @Published private(set) var value = 0
}

let vm = ViewModel()

// vm.value = 42 // <- This fails since value is private

Just(42).assign(to: vm.$value) // this compiles

print(vm.value) // and changes the private value

It is unexpected that you can use the assign(to:) method on publisher to circumvent access modifiers on a class, allowing you to change private fields.

I understand why this is possible (due to how property wrappers work), but it is incredibly subtle and gives an escape hatch to break encapsulation of the class.