我知道这是一个泛泛的问题，但我希望有类似经验的人能够了解可能发生的事情。
我们的仅限于iPad的应用程序在上发生了崩溃。它显示 NSInternalInconsistencyException。
无论是在竖屏还是横屏模式下，在许多iPad版本上（如iPad 2、iPad Pro、iPad 4等）都会出现该问题。
我没有在项目中启用自动布局，但它看起来像是一个自动布局问题。
非常难以复制，所以我不能在Xcode上对其进行调试，但我在崩溃分析服务“Crashlytics”上看到了崩溃报告。以下是来自Crashlytics的堆栈跟踪：
Auto layout internal error. Cannot find an outgoing row
head for incoming head <unknown var (bug!) with engine as delegate[...]
Thread : Fatal Exception: NSInternalInconsistencyException
0 CoreFoundation 0x23d4568b __exceptionPreprocess
1 libobjc.A.dylib 0x356c2e17 objc_exception_throw
2 CoreFoundation 0x23d455d1 -[NSException initWithCoder:]
3 Foundation 0x24a873b3 -[NSISEngine minimizeConstantInObjectiveRowWithHead:]
4 Foundation 0x24a86e4d -[NSISEngine optimize]
5 Foundation 0x24a82a53 -[NSISEngine withBehaviors:performModifications:]
6 UIKit 0x27e040bb -[UIView(Hierarchy) _postMovedFromSuperview:]
7 UIKit 0x280fb227 __UIViewWasRemovedFromSuperview
8 UIKit 0x27e02ddb -[UIView(Hierarchy) removeFromSuperview]
9 UIKit 0x282e5fa9 -[UIKeyboardPredictionView setPredictionViewState:animate:notify:]
10 UIKit 0x281e3787 -[UIKeyboardImpl updatePredictionView]
11 UIKit 0x27f155e3 -[UIKeyboardImpl finishLayoutChangeWithArguments:]
12 UIKit 0x27e31437 -[UIKeyboardImpl updateLayout]
13 UIKit 0x27e36077 -[UIKeyboardImpl setDelegate:force:]
14 UIKit 0x27e2f6e1 -[UIPeripheralHost(UIKitInternal) _reloadInputViewsForResponder:]
15 UIKit 0x27e2f20d -[UIResponder(UIResponderInputViewAdditions) reloadInputViews]
16 UIKit 0x27e8d853 -[UIResponder becomeFirstResponder]
17 UIKit 0x27e8db6d -[UIView(Hierarchy) becomeFirstResponder]
18 UIKit 0x27f12289 -[UITextField becomeFirstResponder]
19 UIKit 0x27fbe69f -[UITextInteractionAssistant(UITextInteractionAssistant_Internal) setFirstResponderIfNecessary]
20 UIKit 0x27fbdc75 -[UITextInteractionAssistant(UITextInteractionAssistant_Internal) oneFingerTap:]
21 UIKit 0x28334e27 _UIGestureRecognizerSendTargetActions
22 UIKit 0x27fa2303 _UIGestureRecognizerSendActions
23 UIKit 0x27e3a7af -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:]
24 UIKit 0x28335f2f ___UIGestureRecognizerUpdate_block_invoke809
25 UIKit 0x27dfc287 _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks
26 UIKit 0x27df9e77 _UIGestureRecognizerUpdate
27 UIKit 0x27e386f9 -[UIWindow _sendGesturesForEvent:]
28 UIKit 0x27e37e43 -[UIWindow sendEvent:]
29 UIKit 0x27e097e5 -[UIApplication sendEvent:]
30 UIKit 0x27e07fdf _UIApplicationHandleEventQueue
31 CoreFoundation 0x23d08c3f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
32 CoreFoundation 0x23d0882d __CFRunLoopDoSources0
33 CoreFoundation 0x23d06b9b __CFRunLoopRun
34 CoreFoundation 0x23c5a249 CFRunLoopRunSpecific
35 CoreFoundation 0x23c5a035 CFRunLoopRunInMode
36 GraphicsServices 0x2cd24ad1 GSEventRunModal
37 UIKit 0x27e6f899 UIApplicationMain
38 Mr Appliance 0xcda7b main (main.m:16)
39 libdyld.dylib 0x35e0e873 start
问题在于我不知道代码中发生了什么。堆栈跟踪没有显示崩溃发生的代码位置，只显示了“main.m 16行”，即
return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));。