According to the doc:
The value returned is the same as the value returned in the kEventParamKeyCode when using Carbon Events.
So where can I find kEventParamKeyCode?
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I found a similar problem here https://developer.apple.com/forums/thread/764777 and I could solve my problem by wrapping the call to requestAutomaticPassPresentationSuppression in a call to DispatchQueue.global().async.
But my question is if this is really how things should work. Even with strict concurrency warnings in Swift 6 I don't get any warnings. Just a runtime crash.
How are we supposed to find these problems? Couldn't the compiler assist with a warning/error.
Why does the compiler make the assumptions it does about the method that is declared like this:
@available(iOS 9.0, *)
open class func requestAutomaticPassPresentationSuppression(responseHandler: @escaping (PKAutomaticPassPresentationSuppressionResult) -> Void) -> PKSuppressionRequestToken
Now that we have migrated to Swift 6 our code base contains a bunch of unknown places where it will crash as above.
Using the DebugDescription macro to display an optional value produces a “String interpolation produces a debug description for an optional value” build warning.
For example:
@DebugDescription
struct MyType: CustomDebugStringConvertible {
let optionalValue: String?
public var debugDescription: String {
"Value: \(optionalValue)"
}
}
The DebugDescription macro does not allow (it is an error)
"Value: \(String(describing: optionalValue))"
or
"Value: \(optionalValue ?? "nil")"
because “Only references to stored properties are allowed.”
Is there a way to reconcile these?
I have a build log full of these warnings, obscuring real issues.
I was trying to evaulate
let myTuple = ("blue", false)
let otherTuple = ("blue", true)
if myTuple < otherTuple {
print("yes it evaluates")
}
Ans I got
/tmp/S9jAk7P7KW/main.swift:5:12: error: binary operator '<' cannot be applied to two '(String, Bool)' operands
if myTuple < otherTuple {
My question is why there is no compile time issue in first place where the declaration is
let myTuple = ("blue", false)
~~~~~~
something like above
After swapping the -objectAtIndex: method using method_exchangeImplementations, it will cause continuous memory growth.
Connect the iPhone and run the provided project.
Continuously tap the iPhone screen.
Observe Memory; it will keep growing.
Sample code
Topic:
Programming Languages
SubTopic:
General
Tags:
Objective-C Runtime
Xcode Sanitizers and Runtime Issues
Foundation
Title
Why doesn’t this async function see external changes to an inout Bool in Release builds (but works in Debug)?
Body
I have a small helper function that waits for a Bool flag to become true with a timeout:
public func test(binding value: inout Bool, timeout maximum: Int) async throws {
var count = 0
while value == false {
count += 1
try await Task.sleep(nanoseconds: 0_100_000_000)
if value == true {
return
}
if count > (maximum * 10) {
return
}
}
}
I call like this:
var isVPNConnected = false
adapter.start(tunnelConfiguration: tunnelConfiguration) { [weak self] adapterError in
guard let self = self else { return }
if let adapterError = adapterError {
} else {
isVPNConnected = true
}
completionHandler(adapterError)
}
try await waitUntilTrue(binding: &isVPNConnected, timeout: 10)
What I expect:
test should keep looping until flag becomes true (or the timeout is hit).
When the second task sets flag = true, the first task should see that change and return.
What actually happens:
In Debug builds this behaves as expected: when the second task sets flag = true, the loop inside test eventually exits.
In Release builds the function often never sees the change and gets stuck until the timeout (or forever, depending on the code). It looks like the while value == false condition is using some cached value and never observes the external write.
So my questions are:
Is the compiler allowed to assume that value (the inout Bool) does not change inside the loop, even though there are await suspension points and another task is mutating the same variable?
Is this behavior officially “undefined” because I’m sharing a plain Bool across tasks without any synchronization (actors / locks / atomics), so the debug build just happens to work?
What is the correct / idiomatic way in Swift concurrency to implement this kind of “wait until flag becomes true with timeout” pattern?
Should I avoid inout here completely and use some other primitive (e.g. AsyncStream, CheckedContinuation, Actor, ManagedAtomic, etc.)?
Is there any way to force the compiler to re-read the Bool from memory each iteration, or is that the wrong way to think about it?
Environment (if it matters):
Swift: [fill in your Swift version]
Xcode: [fill in your Xcode version]
Target: iOS / macOS [fill in as needed]
Optimization: default Debug vs. Release settings
I’d like to understand why Debug vs Release behaves differently here, and what the recommended design is for this kind of async waiting logic in Swift.
AsyncStream { continuation in
Task {
let response = await getResponse()
continuation.yield(response)
continuation.finish()
}
}
In this WWDC video https://developer.apple.com/videos/play/wwdc2025/231/ at 8:20 the presenter mentions that if the "Task gets cancelled, the Task inside the function will automatically get cancelled too". The documentation does not mention anything like this.
From my own testing on iOS 18.5, this is not true.
NSPredicate(format: "SELF MATCHES %@", "^[0-9A-Z]+$").evaluate(with: "126𝒥ℰℬℬ𝒢𝒦𝒮33")
Returns true, and I don't know why. 𝒥ℰℬℬ𝒢𝒦𝒮 is not between 0-9 and A-Z, and why it returns true? How to avoid similar problem like this when using NSPredicate?
Hello,
Please can you tell me how to create an array of dictionaries? This code below should create 4 dictionaries in an array, but I'm getting these errors:
For line "var output = [id: "testID", name: "testName"]":
cannot find 'name' in scope
Type '(any AnyObject).Type'
cannot conform to 'Hashable'
For line "return output":
Type '(any AnyObject).Type' cannot conform to 'Hashable'
var quotes: [(id: String, name: String)] {
var output = [[(id: String, name: String)]] ()
for i in 1...4 {
var output = [id: "testID", name: "testName"]
}
return output
}
Topic:
Programming Languages
SubTopic:
Swift
I'm having trouble dealing with concurrency with the SFAuthorizationPluginView. Does anybody know how this can be solved?
https://developer.apple.com/documentation/securityinterface/sfauthorizationpluginview
The crux of it is:
If I inherit an object as part of an API, and the API is preconcurrency, and thus is nonisolated (but in reality is @MainActor), how do I return a @MainActor GUI element?
https://developer.apple.com/documentation/securityinterface/sfauthorizationpluginview/firstresponder()
The longer story:
I made my view class inherit SFAuthorizationPluginView.
The API is preconcurrency (but not marked as preconcurrency)
I started using concurrency in my plugin to retrieve data over XPC. (https://developer.apple.com/documentation/xpc/xpcsession + https://developer.apple.com/documentation/swift/withcheckedthrowingcontinuation(isolation:function:_:))
Once I retrieve the data over XPC, I need to post it on GUI, hence I've set my view class as @MainActor in order to do the thread switch.
Swift compiler keeps complaining:
override func firstResponder() -> NSResponder? {
return usernameField
}
"Main actor-isolated property 'usernameField' can not be referenced from a nonisolated context; this is an error in the Swift 6 language mode"
override func firstResponder() -> NSResponder? {
MainActor.assumeIsolated {
return usernameField
}
}
"Sending 'self' risks causing data races; this is an error in the Swift 6 language mode"
I think fundamentally, the API is forcing me to give away a @MainActor variable through a nonisolated function, and there is no way to shut up the compiler.
I've tried @preconcurrency and it has no effect as far as I can tell. I've also tried marking the function explicitly as nonisolated.
The rest of the API are less problematic, but returning a GUI variable is exceptionally difficult.
Given the below code with Swift 6 language mode, Xcode 16.2
If running with iOS 18+: the app crashes due to _dispatch_assert_queue_fail
If running with iOS 17 and below: there is a warning: warning: data race detected: @MainActor function at Swift6Playground/PublishedValuesView.swift:12 was not called on the main thread
Could anyone please help explain what's wrong here?
import SwiftUI
import Combine
@MainActor
class PublishedValuesViewModel: ObservableObject {
@Published var count = 0
@Published var content: String = "NA"
private var cancellables: Set<AnyCancellable> = []
func start() async {
let publisher = $count
.map { String(describing: $0) }
.removeDuplicates()
for await value in publisher.values {
content = value
}
}
}
struct PublishedValuesView: View {
@ObservedObject var viewModel: PublishedValuesViewModel
var body: some View {
Text("Published Values: \(viewModel.content)")
.task {
await viewModel.start()
}
}
}
Consider this simple miniature of my iOS Share Extension:
import SwiftUI
import Photos
class ShareViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
if let itemProviders = (extensionContext?.inputItems.first as? NSExtensionItem)?.attachments {
let hostingView = UIHostingController(rootView: ShareView(extensionContext: extensionContext, itemProviders: itemProviders))
hostingView.view.frame = view.frame
view.addSubview(hostingView.view)
}
}
}
struct ShareView: View {
var extensionContext: NSExtensionContext?
var itemProviders: [NSItemProvider]
var body: some View {
VStack{}
.task{
await extractItems()
}
}
func extractItems() async {
guard let itemProvider = itemProviders.first else { return }
guard itemProvider.hasItemConformingToTypeIdentifier(UTType.url.identifier) else { return }
do {
guard let url = try await itemProvider.loadItem(forTypeIdentifier: UTType.url.identifier) as? URL else { return }
try await downloadAndSaveMedia(reelURL: url.absoluteString)
extensionContext?.completeRequest(returningItems: [])
}
catch {}
}
}
On the line 34
guard let url = try await itemProvider.loadItem
...
I get these warnings:
Passing argument of non-sendable type '[AnyHashable : Any]?' outside of main actor-isolated context may introduce data races; this is an error in the Swift 6 language mode
1.1. Generic enum 'Optional' does not conform to the 'Sendable' protocol (Swift.Optional)
Passing argument of non-sendable type 'NSItemProvider' outside of main actor-isolated context may introduce data races; this is an error in the Swift 6 language mode
2.2. Class 'NSItemProvider' does not conform to the 'Sendable' protocol (Foundation.NSItemProvider)
How to fix them in Xcode 16?
Please provide a solution which works, and not the one which might (meaning you run the same code in Xcode, add your solution and see no warnings).
I tried
Decorating everything with @MainActors
Using @MainActor in the .task
@preconcurrency import
Decorating everything with @preconcurrency
Playing around with nonisolated
Hello,
While watching WWDC25: Code-along: Elevate an app with Swift concurrency at timestamp 25:48, I noticed something in the slide/diagram that might be incorrect.
The diagram shows ExtractSticker twice, but based on the code context and spoken explanation, I think it was meant to be ExtractSticker and ExtractColor.
Reasoning:
The surrounding code and narration describe the use of async let and a Sendable Data object.
From the flow, one task extracts a sticker while the other extracts a color, so it seems like the diagram is inconsistent.
I do understand that with @concurrent, having two ExtractSticker operations on the same Data is technically possible (with two concurrent process executing their respective ExtractSticker) — but that would be a different meaning than what the talk was describing.
Since concurrency is already a subtle and error-prone topic, I thought it was worth pointing this out. If I’m mistaken, I’d love clarification. Otherwise, this could be a small correction to keep things aligned and clearer for everyone.
Minor point overall, but Swift 6’s concurrency model is doing a fantastic job at helping us write safer code—so thank you to the team for that!
(Attaching screenshots for reference)
I am currently studying the Accelerate library by referring to Apple documentation.
Here is the link to the referenced document:
https://developer.apple.com/documentation/accelerate/veclib/vforce
When I executed the sample code provided at the bottom of the document, I found a case where the results were different.
let n = 10_000
let x = (0..<n).map { _ in
Float.random(in: 1 ... 10_000)
}
let y = x.map {
return sqrt($0)
}
and
let y = [Float](unsafeUninitializedCapacity: n) { buffer, initializedCount in
vForce.sqrt(x,
result: &buffer)
initializedCount = n
}
The code below is provided to observe the issue described above.
import Accelerate
Task {
let n = 1//10_000
let x = (0..<n).map { _ in
Float(6737.015)//Float.random(in: 1 ... 10_000)
}
let y = x.map {
return sqrt($0)
}
try? await Task.sleep(nanoseconds: 1_000_000_000)
let z = [Float](unsafeUninitializedCapacity: n) { buffer, initializedCount in
vForce.sqrt(x, result: &buffer)
initializedCount = n
}
}
For a value of 6737.015 when calculating the square root:
Using the sqrt(_:) function gives the result 82.07932,
While using the vForce.sqrt(_:result:) function gives the result 82.07933.
Using a calculator, the value comes out as 82.07932139, which shows that the result from vForce is incorrect.
Could you explain the reason behind this difference?
var testTwo: Double = 0
testDouble = 80
testTwo = 200
var testThree: Int = 0
testThree = Int(testTwo/testDouble)
var testDate: Date = .now
var dateComponent = DateComponents()
dateComponent.day = testThree
var newDate: Date = Calendar.current.date(byAdding: dateComponentwith a thread error , to: testDate)!
This code works in a playground. However, when I try to use it in Xcode for my app it fails with the following error:
Thread 1: Fatal error: Double value cannot be converted to Int because it is either infinite or NaN
I printed the value being converted to Int and it was not NAN or infinite.
I'm trying to use FormatStyle from Foundation to format numbers when printing a vector structure. See code below.
import Foundation
struct Vector<T> {
var values: [T]
subscript(item: Int) -> T {
get { values[item] }
set { values[item] = newValue }
}
}
extension Vector: CustomStringConvertible {
var description: String {
var desc = "( "
desc += values.map { "\($0)" }.joined(separator: " ")
desc += " )"
return desc
}
}
extension Vector {
func formatted<F: FormatStyle>(_ style: F) -> String where F.FormatInput == T, F.FormatOutput == String {
var desc = "( "
desc += values.map { style.format($0) }.joined(separator: " ")
desc += " )"
return desc
}
}
In the example below, the vector contains a mix of integer and float literals. The result is a vector with a type of Vector<Double>. Since the values of the vector are inferred as Double then I expect the print output to display as decimal numbers. However, the .number formatted output seems to ignore the vector type and print the values as a mix of integers and decimals. This is fixed by explicitly providing a format style with a fraction length. So why is the .formatted(.number) method ignoring the vector type T which is Double in this example?
let vec = Vector(values: [-2, 5.5, 100, 19, 4, 8.37])
print(vec)
print(vec.formatted(.number))
print(vec.formatted(.number.precision(.fractionLength(1...))))
( -2.0 5.5 100.0 19.0 4.0 8.37 ) // correct output that uses all Double types
( -2 5.5 100 19 4 8.37 ) // wrong output that uses Int and Double types
( -2.0 5.5 100.0 19.0 4.0 8.37 ) // correct output that uses all Double types
I am writing a SPM based project for MacOS. In this project? I need to access MacOS Keychain.
I am write a swift test built by SPM testTarget(). I can see it generates a bundle ./.build/x86_64-apple-macosx/debug/MyProjectTests.xctest with an executable:
% file ./.build/x86_64-apple-macosx/debug/MyProjectPackageTests.xctest/Contents/MacOS/MyProjectPackageTests
./.build/x86_64-apple-macosx/debug/MyProjectPackageTests.xctest/Contents/MacOS/MyProjectPackageTests: Mach-O 64-bit bundle x86_64
This bundle file cannot be executed. How can I execute its tests?
I tried with xcodebuild test-without-building -xctestrun ./.build/x86_64-apple-macosx/debug/MyProjectPackageTests.xctest -destination 'platform=macOS' without any chance.
Obviously the next question is can I 'simply' add entitlement to this bundle with codesign to fix my enttilement error.
My error when running the test is A required entitlement isn't present.
Hello,
I have a json array showing in Xcode debugger (from the line "print(dataString)"):
Optional("[{\"id\":\"8e8tfdcssu4u2hn7a71tkveahjhn8xghqcfkwf1bzvtrw5nu0b89w\",\"name\":\"Ameliana\",\"country\":\"France\",\"type\":\"Private\\/Corporate\",\"overallrecsit\":\"Positive\",\"dlastupd\":\"1741351633\",\"doverallrecsit\":\"1546848000\"},{\"id\":\"z69718a1a5z2y5czkwrhr1u37h7h768v05qr3pf1fegh4r4yrt5a68\",\"name\":\"Timberland\",\"country\":\"Switzerland\",\"type\":\"Charter\",\"overallrecsit\":\"Negative\",\"dlastupd\":\"1741351615\",\"doverallrecsit\":\"1740434582\"},
But my JSON decoder is throwing the catch error "Error in JSON parsing"
This is the code:
super.viewDidLoad()
let urlString = "https://www.pilotjobsnetwork.com/service_ios.php"
let url = URL(string: urlString)
guard url != nil else {
return
}
let session = URLSession.shared
let dataTask = session.dataTask(with: url!) { (data, response, error) in
var dataString = String(data: data!, encoding: String.Encoding.utf8)
print(dataString)
if error == nil && data != nil {
// Parse JSON
let decoder = JSONDecoder()
do {
let newsFeed = try decoder.decode(NewsFeed.self, from: data!)
print(newsFeed)
print(error)
}
catch{
print("Error in JSON parsing")
}
}
}
// Make the API Call
dataTask.resume()
}
And this is my Codable file NewsFeed.swift:
struct NewsFeed: Codable {
var id: String
var name: String
var country: String
var type: String
var overallrecsit: String
var dlastupd: String
var doverallrecsit: String
}
Please do you know why the parsing may be failing? Is it significant that in the debugging window the JSON is displaying backslashes before the quotation marks?
Thank you for any pointers :-)
Hello,
Please see the test project at https://we.tl/t-aWAu7kk9lD
I have a json array showing in Xcode debugger (from the line "print(dataString)"):
Optional("[{\"id\":\"8e8tcssu4u2hn7a71tkveahjhn8xghqcfkwf1bzvtrw5nu0b89w\",\"name\":\"Test name 0\",\"country\":\"Test country 0\",\"type\":\"Test type 0\",\"situation\":\"Test situation 0\",\"timestamp\":\"1546848000\"},{\"id\":\"z69718a1a5z2y5czkwrhr1u37h7h768v05qr3pf1h4r4yrt5a68\",\"name\":\"Test name 1\",\"country\":\"Test country 1\",\"type\":\"Test type 1\",\"situation\":\"Test situation 1\",\"timestamp\":\"1741351615\"},{\"id\":\"fh974sv586nhyysbhg5nak444968h7hgcgh6yw0usbvcz9b0h69\",\"name\":\"Test name 2\",\"country\":\"Test country 2\",\"type\":\"Test type 2\",\"situation\":\"Test situation 2\",\"timestamp\":\"1741351603\"},{\"id\":\"347272052385993\",\"name\":\"Test name 3\",\"country\":\"Test country 3\",\"type\":\"Test type 3\",\"situation\":\"Test situation 3\",\"timestamp\":\"1741351557\"}]")
But my JSON decoder is throwing a catch error
Line 57, Error in JSON parsing
typeMismatch(Swift.Dictionary<Swift.String, Any>, Swift.DecodingError.Context(codingPath: [], debugDescription: "Expected to decode Dictionary<String, Any> but found an array instead.", underlyingError: nil))
This is the code:
let urlString = "https://www.notafunnyname.com/jsonmockup.php"
let url = URL(string: urlString)
guard url != nil else {
return
}
let session = URLSession.shared
let dataTask = session.dataTask(with: url!) { (data, response, error) in
var dataString = String(data: data!, encoding: String.Encoding.utf8)
print(dataString)
if error == nil && data != nil {
// Parse JSON
let decoder = JSONDecoder()
do {
let newsFeed = try decoder.decode(NewsFeed.self, from: data!)
print("line 51")
print(newsFeed)
print(error)
}
catch{
print("Line 57, Error in JSON parsing")
print(error)
}
}
}
// Make the API Call
dataTask.resume()
}
And this is my Codable file NewsFeed.swift:
struct NewsFeed: Codable {
var id: String
var name: String
var country: String
var type: String
var situation: String
var timestamp: String
}
Please do you know how to resolve the typeMismatch error?
Topic:
Programming Languages
SubTopic:
Swift
I ran into a problem, I have a recursive function in which Data type objects are temporarily created, because of this, the memory expands until the entire recursion ends. It would just be fixed using autoreleasepool, but it can't be used with async await, and I really don't want to rewrite the code for callbacks. Is there any option to use autoreleasepool with async await functions? (I Googled one option, that the Task already contains its own autoreleasepool, and if you do something like that, it should work, but it doesn't, the memory is still growing)
func autoreleasepool<Result>(_ perform: @escaping () async throws -> Result) async throws -> Result {
try await Task {
try await perform()
}.value
}