We’re building a hybrid iOS app using Angular (web) rendered inside a WKWebView, hosted by a native Swift app.
Recently, we encountered a crash related to UIKeyboardStateManager in UIKit when switching between text inputs continuously within an Angular screen.
Scenario
- The screen contains several text input fields.
- A “Next” button focuses the next input field programmatically.
- After about 61 continuous input field changes, the app crashes.
It seems like this may be related to UIKit’s internal keyboard management while switching focus rapidly inside a WebView.
crash stack:
Crashed: com.apple.main-thread
0 WebKit 0xfbdad0 <redacted> + 236
1 UIKitCore 0x10b0548 -[UITextInteractionSelectableInputDelegate _moveToStartOfLine:withHistory:] + 96
2 UIKitCore 0xd0fb38 -[UIKBInputDelegateManager _moveToStartOfLine:withHistory:] + 188
3 UIKitCore 0xa16174 __158-[_UIKeyboardStateManager handleMoveCursorToStartOfLine:beforePublicKeyCommands:testOnly:savedHistory:force:canHandleSelectableInputDelegateCommand:keyEvent:]_block_invoke + 52
4 UIKitCore 0xa36ae4 -[_UIKeyboardStateManager performBlockWithTextInputChangesIgnoredForNonMacOS:] + 48
5 UIKitCore 0xa160f0 -[_UIKeyboardStateManager handleMoveCursorToStartOfLine:beforePublicKeyCommands:testOnly:savedHistory:force:canHandleSelectableInputDelegateCommand:keyEvent:] + 440
6 UIKitCore 0xa07010 -[_UIKeyboardStateManager handleKeyCommand:repeatOkay:options:] + 5760
7 UIKitCore 0xa2fb64 -[_UIKeyboardStateManager _handleKeyCommandCommon:options:] + 76
8 UIKitCore 0xa2fb08 -[_UIKeyboardStateManager _handleKeyCommand:] + 20
9 UIKitCore 0xa30684 -[_UIKeyboardStateManager handleKeyEvent:executionContext:] + 2464
10 UIKitCore 0xa2f95c __42-[_UIKeyboardStateManager handleKeyEvent:]_block_invoke + 40
11 UIKitCore 0x4b9460 -[UIKeyboardTaskEntry execute:] + 208
12 UIKitCore 0x4b92f4 -[UIKeyboardTaskQueue continueExecutionOnMainThread] + 356
13 UIKitCore 0x4b8be0 -[UIKeyboardTaskQueue addTask:breadcrumb:] + 120
14 UIKitCore 0x4a9ed0 -[_UIKeyboardStateManager _setupDelegate:delegateSame:hardwareKeyboardStateChanged:endingInputSessionIdentifier:force:delayEndInputSession:] + 3388
15 UIKitCore 0xfa290 -[_UIKeyboardStateManager setDelegate:force:delayEndInputSession:] + 628
16 UIKitCore 0xf617c -[UIKeyboardSceneDelegate _reloadInputViewsForKeyWindowSceneResponder:force:fromBecomeFirstResponder:] + 1140
17 UIKitCore 0xf5c88 -[UIKeyboardSceneDelegate _reloadInputViewsForResponder:force:fromBecomeFirstResponder:] + 88
18 UIKitCore 0x4fe4ac -[UIResponder(UIResponderInputViewAdditions) reloadInputViews] + 84
19 WebKit 0xfbe708 <redacted> + 100
20 WebKit 0xfbf594 <redacted> + 340
21 WebKit 0x8a33d8 <redacted> + 32
22 WebKit 0x8cee04 <redacted> + 144
23 WebKit 0x1c83f0 <redacted> + 22692
24 WebKit 0x73f40 <redacted> + 264
25 WebKit 0x162c7c <redacted> + 40
26 WebKit 0x1623b4 <redacted> + 1608
27 WebKit 0x73298 <redacted> + 268
28 WebKit 0x72e48 <redacted> + 660
29 JavaScriptCore 0xdb00 WTF::RunLoop::performWork() + 524
30 JavaScriptCore 0xd744 WTF::RunLoop::performWork(void*) + 36
31 CoreFoundation 0xf92c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 28
32 CoreFoundation 0xf744 __CFRunLoopDoSource0 + 172
33 CoreFoundation 0xf5a0 __CFRunLoopDoSources0 + 232
34 CoreFoundation 0xff20 __CFRunLoopRun + 840
35 CoreFoundation 0x11adc CFRunLoopRunSpecific + 572
36 GraphicsServices 0x1454 GSEventRunModal + 168
37 UIKitCore 0x135274 -[UIApplication _run] + 816
38 UIKitCore 0x100a28 UIApplicationMain + 336
39 APP1 0xa2ed0 main + 21 (AppDelegate.swift:21)
40 ??? 0x1aa889f08 (シンボルが不足しています)
From reviewing the crash log, it appears that the crash occurs inside UIKeyboardStateManager while handling keyboard or cursor updates.
Questions
- Has anyone seen this specific crash pattern involving UIKeyboardStateManager?
- Are there known UIKit or WebKit bugs related to UIKeyboardStateManager when continuously changing focus between text fields (especially in WKWebView)?
Any insights or workarounds would be greatly appreciated. Thanks!