At the end of wrapper setter, I post a notification. The observer receives the notification, naturally starts using the new value. It causes exclusive access violation.
The same patten works perfectly for normal properties.
import Cocoa
class Prefs: NSObject {
static let fooDidChage = Notification.Name("fooDidChange")
static let barDidChage = Notification.Name("barDidChange")
private static var defaults: [String: Any] = [:]
@propertyWrapper
struct UserDefaults<T> {
let key: String
let defaultValue: T
init(key: String, defaultValue: T) {
self.key = key
self.defaultValue = defaultValue
}
var wrappedValue: T {
get {
defaults[key] as? T ?? defaultValue
}
set {
defaults[key] = newValue
NotificationCenter.default.post(name: barDidChage, object: Prefs.self)
}
}
}
static var foo: Int {
get {
defaults["foo"] as? Int ?? 0
}
set {
defaults["foo"] = newValue
NotificationCenter.default.post(name: fooDidChage, object: self)
}
}
@UserDefaults(key: "bar", defaultValue: 0) static var bar: Int
}
NotificationCenter.default.addObserver(forName: Prefs.fooDidChage, object: Prefs.self, queue: .main) { (notif) in
print(notif)
print(Prefs.foo)
}
print(Prefs.foo)
Prefs.foo = 1
// setting->observing->getting foo works. The same should also work for bar.
NotificationCenter.default.addObserver(forName: Prefs.barDidChage, object: Prefs.self, queue: .main) { (notif) in
print(notif)
print(Prefs.bar)
}
print(Prefs.bar)
Prefs.bar = 1 // Simultaneous accesses to 0x1100d9988, but modification requires exclusive access.
beccadax
commented
4 years ago
Additional Detail from JIRA
| | | |------------------|-----------------| |Votes | 0 | |Component/s | | |Labels | Bug | |Assignee | None | |Priority | Medium | md5: dd011de75bdee80984c8950b71db9f7cIssue Description:
At the end of wrapper setter, I post a notification. The observer receives the notification, naturally starts using the new value. It causes exclusive access violation.
The same patten works perfectly for normal properties.