CODEWITHSUNDEEP
swift
Yuriy Fedchenko
Yuriy Fedchenko

Reputation: 33

Closure stored in class property

Don't understand why compiler make the error on this code snippet 

class Addr {

    var num: Int = 0
    lazy var increment: (Int) -> () = {[unowned self] value in
        self.num += value
        print(self.num)
    }
    deinit {
        print("deinit")
    }
}

do {
    let object = Addr().increment(5) // ERROR
}

Of course, i can change in capture list [unowned self] to [weak self] but I try to understand why this code not working. Why is the obeject is deinit before the call of the property. Will be thanked for the advanced explanation of this mechanism.

Upvotes: 0

Views: 125

Answers (1)

David Pasztor
David Pasztor

Reputation: 54805

The issue is that since you are not storing a reference to the Addr object, it gets deallocated immediately, even before increment would be called on it.

Storing Addr in a variable and then calling increment on the variable solves the issue.

let object = Addr()
object.increment(5)

Upvotes: 1

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