Hi There,
I have a iOS App which has been published and purely managing data by SwiftData. I use following simple codes everywhere in Views:
...
@Query var items: [Item]
....
if let firstItem = items.first( where: {...}) {
...
Then I encountered crash at Query that _items.wrapperdValue has some errors.
Then I tried to split first(where...) into ordinary way:
let filteredItems = items.filter(...)
if let firstItem = filteredItems.first {
...
It runs OK.
Is it a bug in SwiftData in 18.2 or I missed some steps to facilitate SwiftData macros?
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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()
}
}
}
iOS18.2 / iPhone 16pro / Xcode 16.2
'traitCollectionDidChange'
This function has been deprecated since ios17.
However, in ios18, when I changed the app to the background state or changed it to the foreground state again, it was confirmed that the function worked.
It hasn't been confirmed in ios17, but why is it only confirmed in ios18?
iOS18.2 / iPhone16 pro / xcode16.2
'traitCollectionDidChange'
This function has been deprecated in iOS17.
However, when I debugged it, I confirmed that it is not called on iOS17, but it is called on iOS18.2.
What is the reason?
I just added a .systemLarge widget to my app, but I can't get Links to work. I want the user to be able to tap one of the four rows in my widget - like the EmojiRangers example - but I can't get it to work.
I watched a Developer video from WWDC20: https://developer.apple.com/videos/play/wwdc2020/10036?time=223
The guy, Izzy, 'simply' embeds an HStack in a Link, and hey presto! It all works. But that doesn't happen for me. There's clearly some code in the background that runs.
I already have .widgetURL working for .systemSmall and .systemMedium widgets, and I don't need to use Links on those two types. Those work by sending a URL to .onOpenURL { incomingURL in ... All good there, no issues.
I've wrapped each row in the large widget in a Link with the URL of something like myappurlscheme://widgetTapped/widgetId (it's the same url as that used in the small and medium widgets). I build & run. I tap a row. It doesn't act as though a row is tappable (it doesn't go slightly transparent), and just opens the app without hitting .onOpenURL or anything else. Nothing in my scene delegate is triggered. Is there a specific delegate method that gets called? Do I need to set up some awful intents?
I'm not using any sort of NavigationStack here; that model doesn't fit my app.
Any ideas? Thanks.
"the compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions" ...... it killing me !!!!
I'm primarily an AppleScript writer and only a novice programmer, using ChatGPT to help me with the legwork. It has helped me to write a functioning app that builds a menu structure based on the scripts I have in the Scripts directory used in the script menu and then runs the applescripts. When I distribute the app to my desktop and run it, the scripts that access other apps, like InDesign will cause it to launch, but not actually do anything. I included the ids for each app in the entitlements dictionary and have given the app full disk access in system settings, but it's not functioning as I'd expect.
I know there are apps like Alfred that allow you to run scripts from a keystroke, but I'm building this for others I work with so they can also access info about each script, what it does, and how to use it from the menu, as well as key commands to run them.
Not sure what else to say, but if this sounds like a simple fix to anyone, please let me know.
A program I wrote in Swift that uploads and downloads to a private database in iCloud is failing for downloads since the the 15.2 update.
It still works for uploads. I.e., I can download uploads made from the program under 15.2 on another computer running the same program under 15.1
The Fetch operation does not return an error, but the returnRecord is empty!
I do get the error below after the fact of the failure, don't know if it's related.
"ViewBridge to RemoteViewService Terminated: Error Domain=com.apple.ViewBridge Code=18 "(null)" UserInfo={com.apple.ViewBridge.error.hint=this process disconnected remote view controller -- benign unless unexpected, com.apple.ViewBridge.error.description=NSViewBridgeErrorCanceled}"
To be clear, I assume I do have access to the database since it works for upload under 15.2, as well as upload and download under 15.1, and from a very similar program on my iPhone (which I haven't updated yet!)
Questions? Comments?
Thanks!
Topic:
Programming Languages
SubTopic:
Swift
I have an xcode project which has both cpp and swift code. In one of my usecase I am passing primitive type variables from swift to cpp by reference( primitives types list here as per the new cpp-swift interop documentation)
swift code:
// primitive check code:Bool
var x : Bool = true
// When we are passing a variable as a Reference, we need to use explicitly use'&'
student.PassBoolAsReferenceType (&x) // interop call to cpp code
print (x)
Cpp code:
void
Student::PassBoolAsReferenceType(bool &pValue) noexcept
{
std::cout << pValue << std::endl;
pValue = false;
}
The above code fails during compilation with no clear error message "Command SwiftCompile failed with a nonzero exit code"
However, all the other primitive types that I tested worked for the above code like Int, Float, Double etc. Only the Bool interop fails. Can someone explain why is it not possible for bool? I m using the new interop introduced in swift 5.9.
On iOS 18 some string functions return incorrect values in some cases.
Found problems on replacingOccurrences() and split() functions, but there may be others.
In the results of these functions in some cases a character is left in the result string when it shouldn't.
This did not happen on iOS17 and older versions.
I created a very simple Test Project to reproduce the problem.
If I run these tests on iOS17 or older the tests succeed.
If I run these tests on iOS18 the tests fail.
test_TestStr1() function shows a problem in replacingOccurrences() directly using strings.
test_TestStr2() function shows a problem in split() that seems to happen only when bridging from NSString to String.
import XCTest
final class TestStrings18Tests: XCTestCase {
override func setUpWithError() throws {
// Put setup code here. This method is called before the invocation of each test method in the class.
}
override func tearDownWithError() throws {
// Put teardown code here. This method is called after the invocation of each test method in the class.
}
func test_TestStr1()
{
let str1 = "_%\u{7}1\u{7}_";
let str2 = "%\u{7}1\u{7}";
let str3 = "X";
let str4 = str1.replacingOccurrences(of: str2, with: str3);
//This should be true
XCTAssertTrue(str4 == "_X_");
}
func test_TestStr2()
{
let s1 = "TVAR(6)\u{11}201\"Ã\"\u{11}201\"A\"";
let s2 = s1.components(separatedBy: "\u{11}201");
let t1 = NSString("TVAR(6)\u{11}201\"Ã\"\u{11}201\"A\"") as String;
let t2 = t1.components(separatedBy: "\u{11}201");
XCTAssertTrue(s2.count == t2.count);
let c = s2.count
//This should be True
XCTAssertTrue(s2[0] == t2[0]);
}
}
Topic:
Programming Languages
SubTopic:
Swift
I noticed that when I enter the fully immersive view and then click the X button below the window, the immersive space remains active, and the only way to dismiss it is to click the digital crown. On other apps (Disney+ for example), closing out of the main window while in immersive mode also closes out the immersive space. I tried applying an onDisappear modifier to the the Modules view with a dismissImmersiveSpace, but that doesn't appear to do anything.
Any help would be appreciated.
I've been searching all over the web trying to find the proper way to get all records created by a specific user in CloudKit.
I am able to get the correct id using:
guard let userRecordID = try? await container.userRecordID() else { return }
I can see that the id returned is associated with records in my CloudKit dashboard. So I would expect that the following would get those records:
let predicate = NSPredicate(format: "%K == %@", #keyPath(CKRecord.creatorUserRecordID), userRecordID)
let query = CKQuery(recordType: "CKUser", predicate: predicate)
But instead when I use that query it returns nothing. It is successful but with nothing returned...
Any ideas why this would be happening?
P.S. I have also tried constructing the predicate using the reference, but I get the same result - success with no results.
P.S.2 Also worth mentioning that I am trying to get the results from the public database and I have set my CKContainer to the correct container id.
I get this red warning in Xcode every time my app is syncing to the iCloud. My model has only basic types and enum that conform to Codable so i'm not sure what is the problem.
App is working well, synchronization works. But the warning doesn't look good.
Maybe someone has idea how to debug it.
Hi
In C#, one can define associated functions by the following.
Notice that "Declarations DE" is a reference to a function in another C# project file. This lets the compiler know that there are other references in the project.
Likewise, "Form_Load" is the entry point of the code, similar to "main" in C. Any calls to related functions can be made in this section, to the functions that have been previously defined above.
So I set out trying to find similar information about SwiftUI, and found several, but only offer partial answers to my questions.
The YouTube video...
Extracting functions and subviews in SwiftUI | Bootcamp #20 - YouTube
... goes into some of the details, but still leaves me hanging.
Likewise...
SOLVED: Swift Functions In Swift UI – SwiftUI – Hacking with Swift forums
... has further information, but nothing concrete that I am looking for.
Now in the SwiftUI project, I tried this...
The most confusing thing for me, is where is "main"?
I found several examples that call functions from the structure shown above, BUT I have no reason as to why.
So one web example on StackOverFlow called the function from position 1. That did not work.
Position 2 worked to call the function at position 3, but really, why?
All this activity brings up a lot of questions for me, such as:
Does SwiftUI need function callouts similar to C#, and they are called out even before running "main". I seem to recall Borland Delphi being this way as well.
How does SwiftUI make references to other classes (places where other functions are stored in separate files)?
Does SwiftUI actually make use of "main" in the normal sense, i.e. similar to C, C#, Rust and so on?
I did notice that once a SwiftUI function is called, it makes reference to data being passed very similar to other languages, at least for the examples I found.
Note that I looked at official SwiftUI documentation, but did not come across information that answers the above.
Topic:
Programming Languages
SubTopic:
Swift
Hey everyone,
I’m learning async/await and trying to fetch an image from a URL off the main thread to avoid overloading it, while updating the UI afterward. Before starting the fetch, I want to show a loading indicator (UI-related work). I’ve implemented this in two different ways using Task and Task.detached, and I have some doubts:
Is using Task { @MainActor the better approach?
I added @MainActor because, after await, the resumed execution might not return to the Task's original actor. Is this the right way to ensure UI updates are done safely?
Does calling fetchImage() on @MainActor force it to run entirely on the main thread?
I used an async data fetch function (not explicitly marked with any actor). If I were to use a completion handler instead, would the function run on the main thread?
Is using Task.detached overkill here?
I tried Task.detached to ensure the fetch runs on a non-main actor. However, it seems to involve unnecessary actor hopping since I still need to hop back to the main actor for UI updates. Is there any scenario where Task.detached would be a better fit?
class ViewController : UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
//MARK: First approch
Task{@MainActor in
showLoading()
let image = try? await fetchImage() //Will the image fetch happen on main thread?
updateImageView(image:image)
hideLoading()
}
//MARK: 2nd approch
Task{@MainActor in
showLoading()
let detachedTask = Task.detached{
try await self.fetchImage()
}
updateImageView(image:try? await detachedTask.value)
hideLoading()
}
}
func fetchImage() async throws -> UIImage {
let url = URL(string: "https://via.placeholder.com/600x400.png?text=Example+Image")!
//Async data function call
let (data, response) = try await URLSession.shared.data(from: url)
guard let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 else {
throw URLError(.badServerResponse)
}
guard let image = UIImage(data: data) else {
throw URLError(.cannotDecodeContentData)
}
return image
}
func showLoading(){
//Show Loader handling
}
func hideLoading(){
//Hides the loader
}
func updateImageView(image:UIImage?){
//Image view updated
}
}
https://developer.apple.com/forums/thread/768776
Swift concurrency is an important part of my day-to-day job. I created the following document for an internal presentation, and I figured that it might be helpful for others.
If you have questions or comments, put them in a new thread here on DevForums. Use the App & System Services > Processes & Concurrency topic area and tag it with both Swift and Concurrency.
Share and Enjoy
—
Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"
Swift Concurrency Proposal Index
This post summarises the Swift Evolution proposals that went into the Swift concurrency design. It covers the proposal that are implemented in Swift 6.2, plus a few additional ones that aren’t currently available.
The focus is here is the Swift Evolution proposals. For general information about Swift concurrency, see the documentation referenced by Concurrency Resources.
Swift 6.0
The following Swift Evolution proposals form the basis of the Swift 6.0 concurrency design.
SE-0176 Enforce Exclusive Access to Memory
link: SE-0176
notes: This defines the “Law of Exclusivity”, a critical foundation for both serial and concurrent code.
SE-0282 Clarify the Swift memory consistency model ⚛︎
link: SE-0282
notes: This defines Swift’s memory model, that is, the rules about what is and isn’t allowed when it comes to concurrent memory access.
SE-0296 Async/await
link: SE-0296
introduces: async functions, async, await
SE-0297 Concurrency Interoperability with Objective-C
link: SE-0297
notes: Specifies how Swift imports an Objective-C method with a completion handler as an async method. Explicitly allows @objc actors.
SE-0298 Async/Await: Sequences
link: SE-0298
introduces: AsyncSequence, for await syntax
notes: This just defines the AsyncSequence protocol. For one concrete implementation of that protocol, see SE-0314.
SE-0300 Continuations for interfacing async tasks with synchronous code
link: SE-0300
introduces: CheckedContinuation, UnsafeContinuation
notes: Use these to create an async function that wraps a legacy request-reply concurrency construct.
SE-0302 Sendable and @Sendable closures
link: SE-0302
introduces: Sendable, @Sendable closures, marker protocols
SE-0304 Structured concurrency
link: SE-0304
introduces: unstructured and structured concurrency, Task, cancellation, CancellationError, withTaskCancellationHandler(…), sleep(…), withTaskGroup(…), withThrowingTaskGroup(…)
notes: For the async let syntax, see SE-0317. For more ways to sleep, see SE-0329 and SE-0374. For discarding task groups, see SE-0381.
SE-0306 Actors
link: SE-0306
introduces: actor syntax
notes: For actor-isolated parameters and the nonisolated keyword, see SE-0313. For global actors, see SE-0316. For custom executors and the Actor protocol, see SE-0392.
SE-0311 Task Local Values
link: SE-0311
introduces: TaskLocal
SE-0313 Improved control over actor isolation
link: SE-0313
introduces: isolated parameters, nonisolated
SE-0314 AsyncStream and AsyncThrowingStream
link: SE-0314
introduces: AsyncStream, AsyncThrowingStream, onTermination
notes: These are super helpful when you need to publish a legacy notification construct as an async stream. For a simpler API to create a stream, see SE-0388.
SE-0316 Global actors
link: SE-0316
introduces: GlobalActor, MainActor
notes: This includes the @MainActor syntax for closures.
SE-0317 async let bindings
link: SE-0317
introduces: async let syntax
SE-0323 Asynchronous Main Semantics
link: SE-0323
SE-0327 On Actors and Initialization
link: SE-0327
notes: For a proposal to allow access to non-sendable isolated state in a deinitialiser, see SE-0371.
SE-0329 Clock, Instant, and Duration
link: SE-0329
introduces: Clock, InstantProtocol, DurationProtocol, Duration, ContinuousClock, SuspendingClock
notes: For another way to sleep, see SE-0374.
SE-0331 Remove Sendable conformance from unsafe pointer types
link: SE-0331
SE-0337 Incremental migration to concurrency checking
link: SE-0337
introduces: @preconcurrency, explicit unavailability of Sendable
notes: This introduces @preconcurrency on declarations, on imports, and on Sendable protocols. For @preconcurrency conformances, see SE-0423.
SE-0338 Clarify the Execution of Non-Actor-Isolated Async Functions
link: SE-0338
note: This change has caught a bunch of folks by surprise and there’s a discussion underway as to whether to adjust it.
SE-0340 Unavailable From Async Attribute
link: SE-0340
introduces: noasync availability kind
SE-0343 Concurrency in Top-level Code
link: SE-0343
notes: For how strict concurrency applies to global variables, see SE-0412.
SE-0374 Add sleep(for:) to Clock
link: SE-0374
notes: This builds on SE-0329.
SE-0381 DiscardingTaskGroups
link: SE-0381
introduces: DiscardingTaskGroup, ThrowingDiscardingTaskGroup
notes: Use this for task groups that can run indefinitely, for example, a network server.
SE-0388 Convenience Async[Throwing]Stream.makeStream methods
link: SE-0388
notes: This builds on SE-0314.
SE-0392 Custom Actor Executors
link: SE-0392
introduces: Actor protocol, Executor, SerialExecutor, ExecutorJob, assumeIsolated(…)
notes: For task executors, a closely related concept, see SE-0417. For custom isolation checking, see SE-0424.
SE-0395 Observation
link: SE-0395
introduces: Observation module, Observable
notes: While this isn’t directly related to concurrency, it’s relationship to Combine, which is an important exising concurrency construct, means I’ve included it in this list.
SE-0401 Remove Actor Isolation Inference caused by Property Wrappers
link: SE-0401, commentary
availability: upcoming feature flag: DisableOutwardActorInference
SE-0410 Low-Level Atomic Operations ⚛︎
link: SE-0410
introduces: Synchronization module, Atomic, AtomicLazyReference, WordPair
SE-0411 Isolated default value expressions
link: SE-0411, commentary
SE-0412 Strict concurrency for global variables
link: SE-0412
introduces: nonisolated(unsafe)
notes: While this is a proposal about globals, the introduction of nonisolated(unsafe) applies to “any form of storage”.
SE-0414 Region based Isolation
link: SE-0414, commentary
notes: To send parameters and results across isolation regions, see SE-0430.
SE-0417 Task Executor Preference
link: SE-0417, commentary
introduces: withTaskExecutorPreference(…), TaskExecutor, globalConcurrentExecutor
notes: This is closely related to the custom actor executors defined in SE-0392.
SE-0418 Inferring Sendable for methods and key path literals
link: SE-0418, commentary
availability: upcoming feature flag: InferSendableFromCaptures
notes: The methods part of this is for “partial and unapplied methods”.
SE-0420 Inheritance of actor isolation
link: SE-0420, commentary
introduces: #isolation, optional isolated parameters
notes: This is what makes it possible to iterate over an async stream in an isolated async function.
SE-0421 Generalize effect polymorphism for AsyncSequence and AsyncIteratorProtocol
link: SE-0421, commentary
notes: Previously AsyncSequence used an experimental mechanism to support throwing and non-throwing sequences. This moves it off that. Instead, it uses an extra Failure generic parameter and typed throws to achieve the same result. This allows it to finally support a primary associated type. Yay!
SE-0423 Dynamic actor isolation enforcement from non-strict-concurrency contexts
link: SE-0423, commentary
introduces: @preconcurrency conformance
notes: This adds a number of dynamic actor isolation checks (think assumeIsolated(…)) to close strict concurrency holes that arise when you interact with legacy code.
SE-0424 Custom isolation checking for SerialExecutor
link: SE-0424, commentary
introduces: checkIsolation()
notes: This extends the custom actor executors introduced in SE-0392 to support isolation checking.
SE-0430 sending parameter and result values
link: SE-0430, commentary
introduces: sending
notes: Adds the ability to send parameters and results between the isolation regions introduced by SE-0414.
SE-0431 @isolated(any) Function Types
link: SE-0431, commentary, commentary
introduces: @isolated(any) attribute on function types, isolation property of functions values
notes: This is laying the groundwork for SE-NNNN Closure isolation control. That, in turn, aims to bring the currently experimental @_inheritActorContext attribute into the language officially.
SE-0433 Synchronous Mutual Exclusion Lock 🔒
link: SE-0433
introduces: Mutex
SE-0434 Usability of global-actor-isolated types
link: SE-0434, commentary
availability: upcoming feature flag: GlobalActorIsolatedTypesUsability
notes: This loosen strict concurrency checking in a number of subtle ways.
Swift 6.1
Swift 6.1 has the following additions.
Vision: Improving the approachability of data-race safety
link: vision
SE-0442 Allow TaskGroup’s ChildTaskResult Type To Be Inferred
link: SE-0442, commentary
notes: This represents a small quality of life improvement for withTaskGroup(…) and withThrowingTaskGroup(…).
SE-0449 Allow nonisolated to prevent global actor inference
link: SE-0449, commentary
notes: This is a straightforward extension to the number of places you can apply nonisolated.
Swift 6.2
Xcode 26 beta has two new build settings:
Approachable Concurrency enables the following feature flags: DisableOutwardActorInference, GlobalActorIsolatedTypesUsability, InferIsolatedConformances, InferSendableFromCaptures, and NonisolatedNonsendingByDefault.
Default Actor Isolation controls SE-0466
Swift 6.2, still in beta, has the following additions.
SE-0371 Isolated synchronous deinit
link: SE-0371, commentary
introduces: isolated deinit
notes: Allows a deinitialiser to access non-sendable isolated state, lifting a restriction imposed by SE-0327.
SE-0457 Expose attosecond representation of Duration
link: SE-0457
introduces: attoseconds, init(attoseconds:)
SE-0461 Run nonisolated async functions on the caller’s actor by default
link: SE-0461
availability: upcoming feature flag: NonisolatedNonsendingByDefault
introduces: nonisolated(nonsending), @concurrent
notes: This represents a significant change to how Swift handles actor isolation by default, and introduces syntax to override that default.
SE-0462 Task Priority Escalation APIs
link: SE-0462
introduces: withTaskPriorityEscalationHandler(…)
notes: Code that uses structured concurrency benefits from priority boosts automatically. This proposal exposes APIs so that code using unstructured concurrency can do the same.
SE-0463 Import Objective-C completion handler parameters as @Sendable
link: SE-0463
notes: This is a welcome resolution to a source of much confusion.
SE-0466 Control default actor isolation inference
link: SE-0466, commentary
availability: not officially approved, but a de facto part of Swift 6.2
introduces: -default-isolation compiler flag
notes: This is a major component of the above-mentioned vision document.
SE-0468 Hashable conformance for Async(Throwing)Stream.Continuation
link: SE-0468
notes: This is an obvious benefit when you’re juggling a bunch of different async streams.
SE-0469 Task Naming
link: SE-0469
introduces: name, init(name:…)
SE-0470 Global-actor isolated conformances
link: SE-0470
availability: upcoming feature flag: InferIsolatedConformances
introduces: @SomeActor protocol conformance
notes: This is particularly useful when you want to conform an @MainActor type to Equatable, Hashable, and so on.
SE-0471 Improved Custom SerialExecutor isolation checking for Concurrency Runtime
link: SE-0471
notes: This is a welcome extension to SE-0424.
SE-0472 Starting tasks synchronously from caller context
link: SE-0472
introduces: immediate[Detached](…), addImmediateTask[UnlessCancelled](…),
notes: This introduces the concept of an immediate task, one that initially uses the calling execution context. This is one of those things where, when you need it, you really need it. But it’s hard to summary when you might need it, so you’ll just have to read the proposal (-:
In Progress
The proposals in this section didn’t make Swift 6.2.
SE-0406 Backpressure support for AsyncStream
link: SE-0406
availability: returned for revision
notes: Currently AsyncStream has very limited buffering options. This was a proposal to improve that. This feature is still very much needed, but the outlook for this proposal is hazy. My best guess is that something like this will land first in the Swift Async Algorithms package. See this thread.
SE-NNNN Closure isolation control
link: SE-NNNN
introduces: @inheritsIsolation
availability: not yet approved
notes: This aims to bring the currently experimental @_inheritActorContext attribute into the language officially. It’s not clear how this will play out given the changes in SE-0461.
Revision History
2025-09-02 Updated for the upcoming release Swift 6.2.
2025-04-07 Updated for the release of Swift 6.1, including a number of things that are still in progress.
2024-11-09 First post.
This is not a question but more of a hint where I was having trouble with. In my SwiftData App I wanted to move from Swift 5 to Swift 6, for that, as recommended, I stayed in Swift 5 language mode and set 'Strict Concurrency Checking' to 'Complete' within my build settings.
It marked all the places where I was using predicates with the following warning:
Type '' does not conform to the 'Sendable' protocol; this is an error in the Swift 6 language mode
I had the same warnings for SortDescriptors.
I spend quite some time searching the web and wrapping my head around how to solve that issue to be able to move to Swift 6. In the end I found this existing issue in the repository of the Swift Language https://github.com/swiftlang/swift/issues/68943. It says that this is not a warning that should be seen by the developer and in fact when turning Swift 6 language mode on those issues are not marked as errors.
So if anyone is encountering this when trying to fix all issues while staying in Swift 5 language mode, ignore those, fix the other issues and turn on Swift 6 language mode and hopefully they are gone.
We are getting a crash _dispatch_assert_queue_fail when the cancellationHandler on NSProgress is called.
We do not see this with iOS 17.x, only on iOS 18. We are building in Swift 6 language mode and do not have any compiler warnings.
We have a type whose init looks something like this:
init(
request: URLRequest,
destinationURL: URL,
session: URLSession
) {
progress = Progress()
progress.kind = .file
progress.fileOperationKind = .downloading
progress.fileURL = destinationURL
progress.pausingHandler = { [weak self] in
self?.setIsPaused(true)
}
progress.resumingHandler = { [weak self] in
self?.setIsPaused(false)
}
progress.cancellationHandler = { [weak self] in
self?.cancel()
}
When the progress is cancelled, and the cancellation handler is invoked. We get the crash. The crash is not reproducible 100% of the time, but it happens significantly often. Especially after cleaning and rebuilding and running our tests.
* thread #4, queue = 'com.apple.root.default-qos', stop reason = EXC_BREAKPOINT (code=1, subcode=0x18017b0e8)
* frame #0: 0x000000018017b0e8 libdispatch.dylib`_dispatch_assert_queue_fail + 116
frame #1: 0x000000018017b074 libdispatch.dylib`dispatch_assert_queue + 188
frame #2: 0x00000002444c63e0 libswift_Concurrency.dylib`swift_task_isCurrentExecutorImpl(swift::SerialExecutorRef) + 284
frame #3: 0x000000010b80bd84 MyTests`closure #3 in MyController.init() at MyController.swift:0
frame #4: 0x000000010b80bb04 MyTests`thunk for @escaping @callee_guaranteed @Sendable () -> () at <compiler-generated>:0
frame #5: 0x00000001810276b0 Foundation`__20-[NSProgress cancel]_block_invoke_3 + 28
frame #6: 0x00000001801774ec libdispatch.dylib`_dispatch_call_block_and_release + 24
frame #7: 0x0000000180178de0 libdispatch.dylib`_dispatch_client_callout + 16
frame #8: 0x000000018018b7dc libdispatch.dylib`_dispatch_root_queue_drain + 1072
frame #9: 0x000000018018bf60 libdispatch.dylib`_dispatch_worker_thread2 + 232
frame #10: 0x00000001012a77d8 libsystem_pthread.dylib`_pthread_wqthread + 224
Any thoughts on why this is crashing and what we can do to work-around it? I have not been able to extract our code into a simple reproducible case yet. And I mostly see it when running our code in a testing environment (XCTest). Although I have been able to reproduce it running an app a few times, it's just less common.
Hello Everyone,
I have a use case where I wanted to interpret the "Data" object received as a part of my NWConnection's recv call. I have my interpretation logic in cpp so in swift I extract the pointer to the raw bytes from Data and pass it to cpp as a UnsafeMutableRawPointer.
In cpp it is received as a void * where I typecast it to char * to read data byte by byte before framing a response.
I am able to get the pointer of the bytes by using
// Swift Code
// pContent is the received Data
if let content = pContent, !content.isEmpty {
bytes = content.withUnsafeBytes { rawBufferPointer in
guard let buffer = rawBufferPointer.baseAddress else {
// return with null data.
}
// invoke cpp method to interpret data and trigger response.
}
// Cpp Code
void InterpretResponse (void * pDataPointer, int pDataLength) {
char * data = (char *) pDataPointer;
for (int iterator = 0; iterator < pDataLength; ++iterator )
{
std::cout << data<< std::endl;
data++;
}
}
When I pass this buffer to cpp, I am unable to interpret it properly.
Can someone help me out here?
Thanks :)
Harshal
Hey all!
in my personal quest to make future proof apps moving to Swift 6, one of my app has a problem when setting an artwork image in MPNowPlayingInfoCenter
Here's what I'm using to set the metadata
func setMetadata(title: String? = nil, artist: String? = nil, artwork: String? = nil) async throws {
let defaultArtwork = UIImage(named: "logo")!
var nowPlayingInfo = [
MPMediaItemPropertyTitle: title ?? "***",
MPMediaItemPropertyArtist: artist ?? "***",
MPMediaItemPropertyArtwork: MPMediaItemArtwork(boundsSize: defaultArtwork.size) { _ in
defaultArtwork
}
] as [String: Any]
if let artwork = artwork {
guard let url = URL(string: artwork) else { return }
let (data, response) = try await URLSession.shared.data(from: url)
guard (response as? HTTPURLResponse)?.statusCode == 200 else { return }
guard let image = UIImage(data: data) else { return }
nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { _ in
image
}
}
MPNowPlayingInfoCenter.default().nowPlayingInfo = nowPlayingInfo
}
the app crashes when hitting
MPMediaItemPropertyArtwork: MPMediaItemArtwork(boundsSize: defaultArtwork.size) { _ in
defaultArtwork
}
or
nowPlayingInfo[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(boundsSize: image.size) { _ in
image
}
commenting out these two make the app work again.
Again, no clue on why.
Thanks in advance