Swift actor the most boring data race & race condition example (nonisolated)

actor_race_condition_data_race.swift

import Foundation

class Class {
    var i = 0

    func decrease() {
        i-=1
    }
    
    func increase() {
        i+=1
    }
    
    func log() {
        decrease()
        increase()
        
        print("class i : \(i)")
    }

    func log2() {
        print("class log2")
    }
    
    func log3() {
        print("class log3")
    }
}

actor Actor {
    var i = 0

    func decrease() {
        i-=1
    }
    
    func increase() {
        i+=1
    }
    
    @objc nonisolated func log() {
        Task {
            await isolatedLog()
        }
    }
    
    func isolatedLog() {
        decrease()
        increase()
        
        print("actor i : \(i)")
    }
    
    @objc nonisolated func log2() {
        Task {
            await isolatedLog2()
        }
    }
    
    func isolatedLog2() {
        print("actor log2")
    }
    
    @objc nonisolated func log3() {
        Task {
            await isolatedLog3()
        }
    }
    
    func isolatedLog3() {
        print("actor log3")
    }
}

let actor = Actor()
let `class` = Class()

///
///
/// Data race
///
///

DispatchQueue.concurrentPerform(iterations: 1000) { _ in
    actor.log()
}

// actor i : 0
// actor i : 0
// actor i : 0
// actor i : 0
// actor i : 0
// actor i : 0
// actor i : 0
// actor i : 0
// actor i : 0
// ...
// ..
// .
// actor i : 0

DispatchQueue.concurrentPerform(iterations: 1000) { _ in
    `class`.log()
}

// class i : -3
// class i : -5
// class i : -5
// class i : -2
// class i : -2
// class i : -2
// class i : -5
// class i : 0
// class i : -2
// ...
// ..


///
///
/// Race conditon
///
///

DispatchQueue.concurrentPerform(iterations: 1000) { _ in
    Task {
        await actor.isolatedLog2()
        await actor.isolatedLog3()
    }
}

// actor log2
// actor log3
// actor log2
// actor log3
// actor log2
// actor log3
// actor log2
// actor log3
// ...
// ..
// .
// actor log2
// actor log3

DispatchQueue.concurrentPerform(iterations: 1000) { _ in
    actor.log2()
    actor.log3()
}

// actor log2
// actor log2
// actor log2
// actor log2
// actor log2
// actor log2
// actor log2
// actor log3
// ...


DispatchQueue.concurrentPerform(iterations: 1000) { _ in
    `class`.log2()
    `class`.log3()
}

// class log2
// class log2
// class log2
// class log2
// class log3
// class log2
// class log3
// class log3
// class log2
// class log3
// ...