Awesome Apple Bugs

A list of awesome bugs with SwiftUI, Swift, etc. Includes code examples and possible workarounds to help developers navigate common pitfalls.

Contents (tags):

• UI Frameworks
  • SwiftUI
  • UIKit
• Swift
• Xcode
• SwiftData
• OS
  • iOS
  • iPadOS
  • macOS
  • watchOS
  • tvOS
  • visionOS
• Overview
• Contributing

UI Frameworks

SwiftUI

• Memory leak when applying .searchable and .refreshable modifiers together on a ScrollView.
• Button action is not canceled during scrolling in a sheet and is executed after scrolling completes.
• Gesture issue: .updating block is not called on LongPressGesture.
• Gesture issue: when DragGesture is added as a .highPriorityGesture to a List or ScrollView, scrolling stops working.
• NavigationStack issue: popping back programmatically doesn't work when using .navigationDestination(isPresented:).
• NavigationStack issue: when clearing a path, it does not go back if there was a transition with an active .searchable.
• Sheet issue: .presentationDetents is ignored if the sheet is reopened after a short period.
• Sheet issue: if you have multiple .sheets open, when you restore the state, not all of them will be presented, and after that .sheet won't be open even manually until you close the previous one.
• NavigationSplitView issue: toolbar items disappear after the app goes to the background and then returns to the foreground.
• TabView issue: wrong tab displayed after rotation when using .page style.
• @State issue: the same variable is shared between different scenes.
• PhaseAnimator crash: when closing the presented view or popping the pushed view on which it is (or 100% CPU load iOS 17.0).
• Alert issue: .default and .cancel buttons are recolored if alert in a NavigationStack that has .tint applied (or higher up the Views tree).
• Animation glitch on drag and drop action.

UIKit

• Life cycle of controllers when the new one is immediately pushed with animation: true.
• UIBezierPath issue: cornerRadius is incorrect for roundedRect when it exceeds ~65.5% of half of min(width, height).
• Navigation title is displayed in quotation marks " " if a whitespace is specified as the title.

Swift

• Crash occurs when using a typed throws in a closure variable within an ObservableObject.
• Crash in Swift 6 language mode when using the closure-based version of the UNUserNotificationCenter.requestAuthorization function.
• Compilation error if Observable class name is Member.
• Compilation error when passing a function isolated to an actor as an argument.

Xcode

• Compilation error if Observable class name is Member.
• Compilation error when passing a function isolated to an actor as an argument.
• Entry macro issue: generated variable defaultValue is a computed property if the variable type is explicitly specified, but a stored property if the variable type is not specified explicitly.

SwiftData

• SwiftData crash: deleting the element will result in a crash in the standard template.

OS

iOS

• Memory leak when applying .searchable and .refreshable modifiers together on a ScrollView.
• Crash occurs when using a typed throws in a closure variable within an ObservableObject.
• Crash in Swift 6 language mode when using the closure-based version of the UNUserNotificationCenter.requestAuthorization function.
• Button action is not canceled during scrolling in a sheet and is executed after scrolling completes.
• Gesture issue: .updating block is not called on LongPressGesture.
• Gesture issue: when DragGesture is added as a .highPriorityGesture to a List or ScrollView, scrolling stops working.
• NavigationStack issue: popping back programmatically doesn't work when using .navigationDestination(isPresented:).
• NavigationStack issue: when clearing a path, it does not go back if there was a transition with an active .searchable.
• Sheet issue: .presentationDetents is ignored if the sheet is reopened after a short period.
• Sheet issue: if you have multiple .sheets open, when you restore the state, not all of them will be presented, and after that .sheet won't be open even manually until you close the previous one.
• TabView issue: wrong tab displayed after rotation when using .page style.
• @State issue: the same variable is shared between different scenes.
• PhaseAnimator crash: when closing the presented view or popping the pushed view on which it is (or 100% CPU load iOS 17.0).
• Alert issue: .default and .cancel buttons are recolored if alert in a NavigationStack that has .tint applied (or higher up the Views tree).
• UIBezierPath issue: cornerRadius is incorrect for roundedRect when it exceeds ~65.5% of half of min(width, height).
• Animation glitch on drag and drop action.
• Navigation title is displayed in quotation marks " " if a whitespace is specified as the title.

iPadOS

• Crash occurs when using a typed throws in a closure variable within an ObservableObject.
• Crash in Swift 6 language mode when using the closure-based version of the UNUserNotificationCenter.requestAuthorization function.
• Gesture issue: .updating block is not called on LongPressGesture.
• Gesture issue: when DragGesture is added as a .highPriorityGesture to a List or ScrollView, scrolling stops working.
• NavigationSplitView issue: toolbar items disappear after the app goes to the background and then returns to the foreground.
• TabView issue: wrong tab displayed after rotation when using .page style.
• @State issue: the same variable is shared between different scenes.
• PhaseAnimator crash: when closing the presented view or popping the pushed view on which it is (or 100% CPU load iOS 17.0).
• SwiftData crash: deleting the element will result in a crash in the standard template.
• Alert issue: .default and .cancel buttons are recolored if alert in a NavigationStack that has .tint applied (or higher up the Views tree).
• UIBezierPath issue: cornerRadius is incorrect for roundedRect when it exceeds ~65.5% of half of min(width, height).
• Navigation title is displayed in quotation marks " " if a whitespace is specified as the title.

macOS

• @State issue: the same variable is shared between different scenes.

watchOS

• Crash occurs when using a typed throws in a closure variable within an ObservableObject.
• @State issue: the same variable is shared between different scenes.

tvOS

• @State issue: the same variable is shared between different scenes.

visionOS

• Crash occurs when using a typed throws in a closure variable within an ObservableObject.
• @State issue: the same variable is shared between different scenes.

Overview

Memory leak when applying .searchable and .refreshable modifiers together on a ScrollView.

A video demonstrating how it behaves on iOS 17.2 without a memory leak and on iOS 18.2 with a memory leak.

demo.mp4

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Crash in Swift 6 language mode when using the closure-based version of the UNUserNotificationCenter.requestAuthorization function.

Images with the result.

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Button action is not canceled during scrolling in a sheet and is executed after scrolling completes.

A video demonstrating how it works on iOS 17 and iOS 18.

gestures.mp4

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Gesture issue: .updating block is not called on LongPressGesture.

A video demonstrating how it behaves on iOS 18 and iOS 17.

gesture_updating.mp4

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Gesture issue: when DragGesture is added as a .highPriorityGesture to a List or ScrollView, scrolling stops working.

A video demonstrating how it behaves on iOS 17 and iOS 18.

drag_high_priority_gesture.mp4

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NavigationStack issue: popping back programmatically doesn't work when using .navigationDestination(isPresented:).

A video demonstrating how it behaves on iOS 16 and iOS 17.

1732264172150-ezgif.com-gif-to-mp4-converter.mp4

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NavigationStack issue: when clearing a path, it does not go back if there was a transition with an active .searchable.

A video demonstrating how it behaves on iOS 17 and iOS 18.

1731658771630-ezgif.com-gif-to-mp4-converter.mp4

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Sheet issue: .presentationDetents is ignored if the sheet is reopened after a short period.

A video demonstrating how it behaves on iOS 18.

sheet_detents.mp4

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Sheet issue: if you have multiple .sheets open, when you restore the state, not all of them will be presented, and after that .sheet won't be open even manually until you close the previous one.

A video demonstrating how it behaves.

sheet_restoration.mp4

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Life cycle of controllers when the new one is immediately pushed with animation: true.

Comparison images on iOS 18 and earlier.

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Crash occurs when using a typed throws in a closure variable within an ObservableObject.

Video showing how it works up to but not including iOS 18.0.

typedthrows.mp4

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Compilation error if Observable class name is Member.

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Compilation error when passing a function isolated to an actor as an argument.

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NavigationSplitView issue: toolbar items disappear after the app goes to the background and then returns to the foreground.

A video demonstrating how it behaves on iOS 18.

1730448296047.mp4

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Entry macro issue: generated variable defaultValue is a computed property if the variable type is explicitly specified, but a stored property if the variable type is not specified explicitly.

Image comparing the code generated by the macro

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• TabView issue: wrong tab displayed after rotation when using .page style.

A video demonstrating how it behaves on iOS 15.

tabview_tab_roatation.mp4

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@State issue: the same variable is shared between different scenes.

A video demonstrating how it behaves on iPadOS 17.4 and 17.5.

state.mp4

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• PhaseAnimator crash: when closing the presented view or popping the pushed view on which it is (or 100% CPU load iOS 17.0).

A video demonstrating how it behaves on iOS 17.2.

phaseanimator_crash.mp4

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Alert issue: .default and .cancel buttons are recolored if alert in a NavigationStack that has .tint applied (or higher up the Views tree).

Video showing how it works on iOS 18.1 and iOS 18.2.

alert_buttons_tint.mp4

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SwiftData crash: deleting the element will result in a crash in the standard template.

A video demonstrating how it behaves on iPadOS 17.5.

swift_data_crash.mp4

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• UIBezierPath issue: cornerRadius is incorrect for roundedRect when it exceeds ~65.5% of half of min(width, height).

A video demonstrating how it behaves on iOS 18.

uibezierpath_cornerradius.mp4

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Animation glitch on drag and drop action.

A video showing how it works on iOS 18.0.

1736496554750-ezgif.com-gif-to-mp4-converter.mp4

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Navigation title is displayed in quotation marks " " if a whitespace is specified as the title.

Comparison images on iOS 18 and earlier storyboard/code.

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Contributing

Contributions welcome! See the guidelines.