Could anyone give some insights to identify the root cause for this crash?
Fatal Exception: NSInternalInconsistencyException
Layout requested for visible navigation bar, <UINavigationBar: 0x120e74280; frame = (0 0; 430 56); autoresize = W; tintColor = <UIDynamicProviderColor: 0x300488b20; provider = <__NSMallocBlock__: 0x300a60900>>; layer = <CALayer: 0x3000f0380>> delegate=0x1277a4600 standardAppearance=0x302d5c770 scrollEdgeAppearance=0x302d5d500, when the top item belongs to a different navigation bar. topItem = <UINavigationItem: 0x10a7d8500> title='Transfers' style=navigator leftBarButtonItems=0x300690020 rightBarButtonItems=0x300613ff0, navigation bar = <UINavigationBar: 0x11a8ef200; frame = (0 0; 430 44); opaque = NO; autoresize = W; layer = <CALayer: 0x3002a44c0>> delegate=0x1277a0c00, possibly from a client attempt to nest wrapped navigation controllers.
====
Fatal Exception: NSInternalInconsistencyException
0 CoreFoundation 0x827cc __exceptionPreprocess
1 libobjc.A.dylib 0x172e4 objc_exception_throw
2 Foundation 0x80f8d8 _userInfoForFileAndLine
3 UIKitCore 0x2b63e8 -[UINavigationBar layoutSubviews]
4 UIKitCore 0xd688 -[UIView(CALayerDelegate) layoutSublayersOfLayer:]
5 UIKitCore 0x14dc14 -[UINavigationBar layoutSublayersOfLayer:]
6 QuartzCore 0x78c28 CA::Layer::layout_if_needed(CA::Transaction*)
7 QuartzCore 0x787b4 CA::Layer::layout_and_display_if_needed(CA::Transaction*)
8 QuartzCore 0xcf914 CA::Context::commit_transaction(CA::Transaction*, double, double*)
9 QuartzCore 0x4e7c4 CA::Transaction::commit()
10 QuartzCore 0x91a0c CA::Transaction::flush_as_runloop_observer(bool)
11 UIKitCore 0xa3568 _UIApplicationFlushCATransaction
12 UIKitCore 0xa0b64 __setupUpdateSequence_block_invoke_2
13 UIKitCore 0xa09d8 _UIUpdateSequenceRun
14 UIKitCore 0xa0628 schedulerStepScheduledMainSection
15 UIKitCore 0xa159c runloopSourceCallback
16 CoreFoundation 0x56328 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
17 CoreFoundation 0x562bc __CFRunLoopDoSource0
18 CoreFoundation 0x53dc0 __CFRunLoopDoSources0
19 CoreFoundation 0x52fbc __CFRunLoopRun
20 CoreFoundation 0x52830 CFRunLoopRunSpecific
21 GraphicsServices 0x11c4 GSEventRunModal
22 UIKitCore 0x3d2eb0 -[UIApplication _run]
23 UIKitCore 0x4815b4 UIApplicationMain
24 XX 0xa0f64 main + 7 (main.m:7)
25 ??? 0x1abb6eec8 (Missing)
jaletele
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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()
}
}
}