Crash in UIKeyboardStateManager when repeatedly switching text input focus in WKWebView (hybrid app)
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!