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.
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❌ Could not find email_ai.py in the app bundle. Available files: []
The error above is what I’m encountering.
I’ve placed the referenced file both in the project directory and inside the app. However, every time I remove and reinsert the file into the folder within the app, it prompts me to designate the targets—I select all, but this doesn’t resolve the issue.
I’m unsure how to properly reference the file so that it is recognised and included in the bundle. Any guidance would be greatly appreciated.
this is my build phase:
#!/bin/sh
set -x # Prints each command before running it (for debugging)
pwd # Shows the current working directory
echo "$SRCROOT" # Shows what Xcode thinks is the project root
ls -l "$SRCROOT/EmailAssistant/EmailAssistant/PythonScripts" # Lists files in the script folder
export PYTHONPATH="/Users/caesar/.pyenv/versions/3.11.6/bin"
/Users/caesar/.pyenv/versions/3.11.6/bin/python3 "$SRCROOT/EmailAssistant/EmailAssistant/PythonScripts/email_ai.py"
echo "Script completed."
Considering below dummy codes:
@MainActor var globalNumber = 0
@MainActor
func increase(_ number: inout Int) async {
// some async code excluded
number += 1
}
class Dummy: @unchecked Sendable {
@MainActor var number: Int {
get { globalNumber }
set { globalNumber = newValue }
}
@MainActor
func change() async {
await increase(&number) //Actor-isolated property 'number' cannot be passed 'inout' to 'async' function call
}
}
I'm not really trying to make an increasing function like that, this is just an example to make everything happen. As for why number is a computed property, this is to trigger the actor-isolated condition (otherwise, if the property is stored and is a value type, this condition will not be triggered).
Under these conditions, in function change(), I got the error: Actor-isolated property 'number' cannot be passed 'inout' to 'async' function call.
My question is: Why Actor-isolated property cannot be passed 'inout' to 'async' function call? What is the purpose of this design? If this were allowed, what problems might it cause?
Hi, I'm relatively new to iOS development and kindly ask for some feedback on a strategy to achieve this desired behavior in my app.
My Question:
What would be the best strategy for sound effect playback when an app is in the background with precise timing? Is this even possible?
Context:
I created a basic countdown timer app (targeting iOS 17 with Swift/SwiftUI.). Countdown sessions can last up to 30-60 mins. When the timer is started it progresses through a series of sub-intervals and plays a short sound for each one. I used AVAudioPlayer and everything works fine when the app is in the foreground. I'm considering switching to AVAudioEngine b/c precise timing is very important and the AIs tell me this would have better precision.
I'm already setting "App plays audio or streams audio/video using AirPlay" in my Plist, and have configured:
AVAudioSession.sharedInstance().setCategory(.playback, mode: .default, options: .mixWithOthers)
Curiously, when testing on my iPhone 13 mini, sounds sometimes still play when the app is in the background, but not always.
What I've considered:
Background Tasks: Would they make any sense for this use-case? Seems like not if the allowed time is short & limited by the system.
Pre-scheduling all Sounds: Not sure this would even work and seems like a lot of memory would be needed (could be hundreds of intervals).
ActivityKit Alerts: works but with a ~50ms delay which is too long for my purposes.
Pre-Render all SFX to 1 large audio file: Seems like a lot of work and processing time and probably not worth it. I hope there's a better solution.
I'd really appreciate any feedback.
Hi all,
I am trying to use this guide to link directly to symbols in my documentation. But I am unable to get it to link to an Objective-C enum case. For example
``EnumNameType/EnumNameMyCase``
does not create a link. It works fine for method names, etc. I have tried all of the combinations I can think of, but I can't get it to work.
Any help is much appreciated!
I have the following TaskExecutor code in Swift 6 and is getting the following error:
//Error
Passing closure as a sending parameter risks causing data races between main actor-isolated code and concurrent execution of the closure.
May I know what is the best way to approach this?
This is the default code generated by Xcode when creating a Vision Pro App using Metal as the Immersive Renderer.
Renderer
@MainActor
static func startRenderLoop(_ layerRenderer: LayerRenderer, appModel: AppModel) {
Task(executorPreference: RendererTaskExecutor.shared) { //Error
let renderer = Renderer(layerRenderer, appModel: appModel)
await renderer.startARSession()
await renderer.renderLoop()
}
}
final class RendererTaskExecutor: TaskExecutor {
private let queue = DispatchQueue(label: "RenderThreadQueue", qos: .userInteractive)
func enqueue(_ job: UnownedJob) {
queue.async {
job.runSynchronously(on: self.asUnownedSerialExecutor())
}
}
func asUnownedSerialExecutor() -> UnownedTaskExecutor {
return UnownedTaskExecutor(ordinary: self)
}
static let shared: RendererTaskExecutor = RendererTaskExecutor()
}
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
}
Everyone knows that dictionaries in swift are unordered collections, there is no problem with that.
I've noticed some behavior that I can't explain and hope someone can help me.
The first variant
We have a very simple code:
struct Test {
let dict = [1: “1”, 2: “2”, 3: “3”, 4: “4”, 5: “5”]
func test() {
for i in dict {
print(i)
}
}
}
If you call test() several times in a row, the output to the console on my computer looks something like this:
(key: 5, value: “5”)
(key: 1, value: “1”)
(key: 2, value: “2”)
(key: 3, value: “3”)
(key: 4, value: “4”)
(key: 2, value: “2”)
(key: 3, value: “3”)
(key: 1, value: “1”)
(key: 4, value: “4”)
(key: 5, value: “5”)
(key: 1, value: “1”)
(key: 3, value: “3”)
(key: 2, value: “2”)
(key: 5, value: “5”)
(key: 4, value: “4”)
At each new for loop we get a random order of elements
It seemed logical to me, because a dictionary is an unordered collection and this is correct behavior.
However
The second variant
the same code on my colleague's computer, but in the console we see something like this:
(key: 2, value: “2”)
(key: 3, value: “3”)
(key: 1, value: “1”)
(key: 4, value: “4”)
(key: 5, value: “5”)
(key: 2, value: “2”)
(key: 3, value: “3”)
(key: 1, value: “1”)
(key: 4, value: “4”)
(key: 5, value: “5”)
(key: 2, value: “2”)
(key: 3, value: “3”)
(key: 1, value: “1”)
(key: 4, value: “4”)
(key: 5, value: “5”)
always, within the same session, we get the same order in print(i)
We didn't use Playground, within which there may be differences, but a real project.
swift version 5+
we tested on Xcode 14+, 15+ (at first I thought it was because the first version had 14 and the second version had 15, but then a third colleague with Xcode 15 had the behavior from the first scenario)
we did a lot of checks, several dozens of times and always got that on one computer random output of items to the console, and in another case disordered only in the first output to the console
Thanks
Can i use c++ library with c library in swift app project
Hello. I want to use a C++ library in my Swift app project.
First, our company has an internal solution library.
When built, it generates a Static Library in '.a' format, and we use it by connecting the library's Header to the App_Bridging_Header.
There's no problem with this part.
However, the new feature now includes C++. It also generates a Static Library in '.a' format.
So, I tried to use the same method and created an App_Bridging_Header. But an error occurs, and I can't proceed.
The first error occurs in the library file:
'iostream' file not found
The second error occurs in the App_Bridging_Header:
failed to emit precompiled header '/Users/kimjitae/Library/Developer/Xcode/DerivedData/ddddd-glmnoqrwdrgarrhjulxjmalpyikr/Build/Intermediates.noindex/PrecompiledHeaders/ddddd-Bridging-Header-swift_3O89L0OXZ0CPD-clang_188AW1HK8F0Q3.pch' for bridging header '/Users/kimjitae/Desktop/enf4/ddddd/ddddd/ddddd-Bridging-Header.h'
Our library is developed in C++ using Xcode, and there's no problem when we run and build just the library project.
The build succeeds, and the '.a' file is generated correctly. However, when we try to connect it with the app, the above problems occur.
Could there be a problem because we also need to use the existing C library alongside this?
The build is successful in an app project created with Objective-C.
Hi, I want to create a dashboard in a app using swift playgrounds with esp 32 and a led. The dashboard should have a toggle switch to toggle the switch state like on/off for the led once i get the basics i want to create a full dashboards with things like gauges, sliders, button and many more. Can someone please help/guide me.
Thanks.
Topic:
Programming Languages
SubTopic:
Swift
I generate images with command line apps in Swift on MacOS. Under the prior Xcode/MacOS my code had been running at the same performance for years. Converting to Swift 6 (no code changes) and running on Sequoia, I noticed a massive slowdown. Running Profile, I tracked it down to allow single line:
var values = ContiguousArray<Double>(repeating: 0.0, count: localData.options.count)
count for my current test case is 4, so its allocating 4 doubles at a time, around 40,000 times in this test. This one line takes 42 seconds out of a run time of 52 seconds. With the profile shown as:
26 41.62 s 4.8% 26.00 ms specialized ContiguousArray.init(_uninitializedCount:)
42 41.57 s 4.8% 42.00 ms _ContiguousArrayBuffer.init(_uninitializedCount:minimumCapacity:)
40730 40.93 s 4.7% 40.73 s _swift_allocObject_
68 68.00 ms 0.0% 68.00 ms std::__1::pair<MallocTypeCacheEntry*, unsigned int> swift::ConcurrentReadableHashMap<MallocTypeCacheEntry, swift::LazyMutex>::find<unsigned int>(unsigned int const&, swift::ConcurrentReadableHashMap<MallocTypeCacheEntry, swift::LazyMutex>::IndexStorage, unsigned long, MallocTypeCacheEntry*)
7 130.00 ms 0.0% 7.00 ms swift::swift_slowAllocTyped(unsigned long, unsigned long, unsigned long long)
which is clearly inside the OS allocator somewhere. What happened? Previously this would have taken closer to 8 seconds or so for the entire run.
I recently submitted my app, Hogs, to the App Store, but it was rejected due to references to non-public symbols:
_lzma_code
_lzma_end
I am using the LZMA compression library in my app, and these functions are part of that implementation. Here's a breakdown of my usage:
Library Used: liblzma (custom wrapper around LZMA functions)
Error Message: "The app references non-public symbols in Payload/Hogs.app/Hogs: _lzma_code, _lzma_end."
Steps I’ve Taken:
I’ve wrapped the LZMA functions in my own functions (my_lzma_code, my_lzma_end) to prevent direct references.
I have checked the build settings and included -lzma in the linker flags.
I’ve tried using a custom framework to encapsulate LZMA, but the issue persists.
I would greatly appreciate any help or suggestions on how to resolve this issue and get my app approved. Is there any workaround or adjustment I can make to avoid using these non-public symbols?
Thank you in advance for your assistance.
Hello,
I have integrated LZMA2 compression into my iOS app, Hogs, and successfully implemented compression. However, when attempting to upload the app for TestFlight, I encountered an error:
"The app references non-public symbols in Payload/Hogs.app/Hogs: _lzma_code, _lzma_end."
These functions are part of the LZMA compression library (specifically LZMA2). Here's a detailed description of the issue:
What I Have Done:
LZMA2 Integration: I integrated LZMA2 compression into the app and created a wrapper around the LZMA functions (_lzma_code, _lzma_end) to prevent direct references.
App Build Configuration:
I ensured the LZMA2 library is linked correctly with the -lzma flag in the linker settings.
I wrapped the LZMA functions in custom functions (my_lzma_code, my_lzma_end) in an attempt to avoid using the non-public symbols directly.
Error Message:
During the app submission process, I received the following error:
"The app references non-public symbols in Payload/Hogs.app/Hogs: _lzma_code, _lzma_end."
Steps Taken to Resolve:
Checked if any LZMA functions were exposed incorrectly.
Ensured that all non-public symbols were properly encapsulated in a wrapper.
Verified linker settings to ensure the proper inclusion of the LZMA2 library.
Request:
Could anyone provide suggestions or best practices to resolve this issue and avoid references to non-public symbols? Should I use a different method for linking LZMA2 or encapsulating these symbols?
Thank You:
I appreciate your help in resolving this issue so I can move forward with submitting the app for TestFlight.
Topic:
Programming Languages
SubTopic:
Swift
Tags:
Swift Packages
Apple Archive
Compression
TestFlight
Issue:
During app execution, the intended method is not being called; instead, the method preceding (written above the intended method) is being executed.
For Example:
//In my case the ViewController class is at 3rd level of inheritance.
class ViewController: UIViewController {
func methodA() {
print("methodA")
}
func methodB() {
print("methodB")
}
}
let vc = ViewController()
vc.methodB()
Output: //"methodA"
Expected: //"methodB"
Observations:
Recent code changes have revealed that enabling the below Swift-6 flag leads to this linking issue. When this flag is commented out, the problem disappears.
.enableUpcomingFeature("InternalImportsByDefault")
Additionally, moving the intended method into an extension of the same class resolves the issue when the flag is enabled.
Conclusion:
To resolve the issue:
Comment out the Swift-6 flag.
Alternatively, move the method into an extension of the same class, which addresses the issue for this specific case.
I had similar issue in other class where it crashes with message "method not found", but actually the method is there. When moving the method into an extension of same class resolve this issue.
Any help is much appreciated.
Thanking you..
I can't find a viable path to call StoreKit from C++ right now and would love some ideas.
I'm implementing the code exactly as shown at 4:09 in
https://developer.apple.com/videos/play/wwdc2023/10172/
However when I add any StoreKit functionality in I immediately get
"Actor isolated structure cannot be exposed in C++"
This makes me think I can't create a StoreKit view and call it from C++? Am I missing a better way? I don't think I can have another structure that holds the storeChooser in it because it will have the same problem (I assume, although I will check). Part of the issue seems to be that my app is C++ so there is no main function called in the swift for me to open this view with either, I was going to use the present function Zoe described (as below).
I've tried a lot of alternative approaches but it seems to be blocking async functions from showing in C++ as well. So I'm not sure how to access the basic product(for:) and purchase(product) functions.
import Foundation
import StoreKit
import SwiftUI
public struct storeChooser: View {
public var productIDs: [String]
public var fetchError: String
//@State //Note this is from the UI
@State public var products: [Product] = []
// @State private var isPresented = true
// weak private var host: UIViewController? = nil
public init() {
productIDs = ["20_super_crystals_v1"]
products = []
self.fetchError = "untried"
}
public var body: some View {
VStack(spacing: 20) {
Text( "Products")
ForEach(self.products) { product in
Button {
//dont do anything yet
} label: {
Text("\(product.displayPrice) - \(product.displayName)")
}
}
}.task {
do {
try await self.loadProducts()
} catch {
print(error)
}
}
}
public func queryProducts() {
Task {
do {
try await self.loadProducts()
} catch {
print(error)
}
}
}
public func getProduct1Name() -> String {
if self.products.count > 0 {
return self.products[0].displayName
} else {
return "empty"
}
}
private func loadProducts() async throws {
self.products = try await Product.products(for: self.productIDs)
}
/* public mutating func present(_ viewController: UIViewController) {
isPresented = true;
let host = UIHostingController(rootView: self)
host.rootView.host = host
viewController.present(host, animated: true)
} */
}
I've narrowed down my question after many rabbit holes - how can C++ code open any view in Swift. I can call functions in swift from C++ (works great), but not async or main actor (or actor at all) functions. And if I'm not mistaken all views are actors if not main actors? When calling from C+ I think its necessary that the first view be the main actor?
I've implemented the code from the WWDC23 C++ interop video (Zoe's image picker) where I made a view in a struct, and just want to call it and let the view do the work.
The compiler immediately gives me 'cannot expose main actors to C++'. If I'm not mistaken, doesn't this block the opening of any kind of swift view from C++? Hopefully I'm missing something obvious, which is likely :)
In Zoe's code was his entry point into the program still Swift and not actually C++ app?
Thanks!
Thanks!
Topic:
Programming Languages
SubTopic:
Swift
We would like to show a user-friendly message but can not.
Description:
When attempting to create a duplicate passkey using the ASAuthrorizationController in iOS, the Face ID authentication times out SDK does not return a timeout specific error. Instead, it directly returns an error stating that duplicate passkey cannot be created.
SDK to first handle the FaceID timeout case and provide a distinct timeout error so we can gracefully manage this scenario before the duplicate passkey validation occurs.
Steps to Reproduce:
Implement passkey creation flow using ASAuthorizationController.
Attempt to register a duplicate passkey (e.g., using the same user ID and challenge).
Let FaceID prompt timeout (do not interact with the authentication prompt).
Topic:
Programming Languages
SubTopic:
Swift
Crashed: com.apple.root.user-initiated-qos.cooperative
0 libswift_Concurrency.dylib 0x67f40 swift_task_create_commonImpl(unsigned long, swift::TaskOptionRecord*, swift::TargetMetadataswift::InProcess const*, void (swift::AsyncContext* swift_async_context) swiftasynccall*, void*, unsigned long) + 528
1 libswift_Concurrency.dylib 0x64d78 swift_asyncLet_begin + 40
2 AAAA 0x47aef28 (1) suspend resume partial function for ActivityContextModule.fetchRecord(startDate:endDate:) + 50786796
3 libswift_Concurrency.dylib 0x60f5c swift::runJobInEstablishedExecutorContext(swift::Job*) + 252
4 libswift_Concurrency.dylib 0x62514 swift_job_runImpl(swift::Job*, swift::SerialExecutorRef) + 144
5 libdispatch.dylib 0x15ec0 _dispatch_root_queue_drain + 392
6 libdispatch.dylib 0x166c4 _dispatch_worker_thread2 + 156
7 libsystem_pthread.dylib 0x3644 _pthread_wqthread + 228
8 libsystem_pthread.dylib 0x1474 start_wqthread + 8
I want to know how to format doubles. In the program I have 4.3333 I just want to print 4 to the screen. I just want to print whole numbers. I'm using Swiftui with xcode. Please help. Thank you.
Topic:
Programming Languages
SubTopic:
Swift
Hi,
I'm struggling to understand using Swift-C++ in the same project. I have an existing code-base that makes heavy use of Swift-Objective-C interoperability.
We make use of swift classes in our project. When I enable swift-objective c interoperability I am running into numerous build errors in the generated bridging header.
I'm trying to understand why these errors exist and what to do to get around them.
I have a project that I've set up with some test code, and I'm running into an error here:
public class Foo {
let name: String
public init(name: String) {
self.name = name
}
}
public class Bar {
let name: String
public init(name : String) {
self.name = name;
}
public func getFoo() -> Foo {
return Foo(name: self.name);
}
}
In the header file:
Unknown type name 'Foo'
SWIFT_INLINE_THUNK Foo getFoo() SWIFT_SYMBOL("s:13ForestBuilder3BarC6getFooAA0E0CyF");
This error goes away if I use structs, but for the purposes of porting my codebase, I'd prefer to use classes. Do classes not play nice here? Or am I misunderstanding something.
Thanks.