Millised põhjused muudavad Unowned kasutamise teatud olukordades vähem eelistatavaks?

The use of unowned in iOS (Swift) is less recommended in situations where there is a risk that the object referenced by unowned may be deallocated before the reference is used. Unlike weak, unowned is not optional and does not become nil when the object is deallocated, so accessing such a reference after deallocation will lead to a runtime error.

Reasons to avoid unowned:

• If the object's lifecycle does not guarantee that the reference will always be valid.
• In complex mutual references, where the order of object deallocation is unclear.

In such cases, it is better to use weak, which automatically becomes nil, preventing unexpected crashes.

Example:

class A {
    unowned var b: B
    init(b: B) { self.b = b }
}

class B {
    var a: A?
}

If the B object is deallocated before A, accessing b in A will cause an error.