[SR-8232] Leak when storing optional URL

[swift-ci]

Previous ID	SR-8232
Radar	rdar://problem/42086749
Original Reporter	damiandudycz (JIRA User)
Type	Bug
Status	Resolved
Resolution	Cannot Reproduce

Attachment: Download

Environment

Xcode 10, iOS 12, Swift 4.2

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, 4.2Regression, Leak
Assignee	None
Priority	Medium

md5: 5d2a2fd97aae3377acab62a62ee39f43

Issue Description:

When you store optional URL in some class, then this URL causes leak. Please see simple code below. Leaks appear in libswiftCore and in CoreFoundation. This only happens on real device - not in simulator.

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        let url = URL(string: "http://google.com/asd")
        print(url)
        t = Test(url: url!)
    }

    var t: Test?

}

class Test {
    let url: URL!
    init(url: URL) {
        self.url = url
    }
}

[belkadan]

This sounds like something we fixed already with resilience. @slavapestov, @mikeash, do either of you remember something like this?

[slavapestov]

I seem to recall an issue where false leaks were reported but I don't remember any more details.

[belkadan]

Better make sure it's tracked.

@swift-ci create

[slavapestov]

I only see the false leak on iOS 11, and not iOS 12 beta 5. damiandudycz (JIRA User) are you still seeing this with latest Xcode/iOS?

[slavapestov]

I suspect it was a mismatch between Swift and the remote mirrors library on the device. This explains why it worked in the simulator as well, because there we use Swift's copy of the library.

Please re-open if you believe otherwise.