iOS Project throws unhandled exception after Xcode upgrade

Question

I'm working on a PhoneGap application. The app itself seems to have handled iOS 9 fine, because it's still working, but the transition to the new Xcode has introduced a new exception that wasn't happening under the old version of Xcode.

I'm getting the following exception text:

2015-10-12 13:40:58.434 <AppName>[29769:897739] -[__NSDictionaryI length]:      unrecognized selector sent to instance 0x7ff0295c95d0
2015-10-12 13:40:58.445 <AppName>[29769:897739] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSDictionaryI length]: unrecognized selector sent to instance 0x7ff0295c95d0'
*** First throw call stack:
(
0   CoreFoundation                      0x000000010d24bf65 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x000000011061fdeb objc_exception_throw + 48
2   CoreFoundation                      0x000000010d25458d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3   CoreFoundation                      0x000000010d1a1f7a ___forwarding___ + 970
4   CoreFoundation                      0x000000010d1a1b28 _CF_forwarding_prep_0 + 120
5   UIKit                               0x000000010d857011 -[UILabel _ensureBaselineMetricsReturningBounds] + 153
6   UIKit                               0x000000010d85725e -[UILabel _firstBaselineOffsetFromTop] + 36
7   UIKit                               0x000000010de7d0c3 -[UIView(AdditionalLayoutSupport) nsli_lowerAttribute:intoExpression:withCoefficient:forConstraint:onBehalfOfLayoutGuide:] + 1560
8   UIKit                               0x000000010de7ca8f -[UIView(AdditionalLayoutSupport) nsli_lowerAttribute:intoExpression:withCoefficient:forConstraint:] + 74
9   Foundation                          0x00000001101f3bd8 lower_1_attribute + 158
10  Foundation                          0x00000001101f36ec -[NSLayoutConstraint _lowerIntoExpression:reportingConstantIsRounded:] + 102
11  Foundation                          0x00000001101e98f1 -[NSLayoutConstraint _addToEngine:integralizationAdjustment:mutuallyExclusiveConstraints:] + 96
12  UIKit                               0x000000010de79213 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 504
13  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
14  UIKit                               0x000000010de79637 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
15  UIKit                               0x000000010de78fd3 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 646
16  UIKit                               0x000000010de79640 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
17  UIKit                               0x000000010de78d08 -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 242
18  UIKit                               0x000000010de790fc __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 225
19  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
20  UIKit                               0x000000010de79637 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
21  UIKit                               0x000000010de78fd3 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 646
22  UIKit                               0x000000010de79640 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
23  UIKit                               0x000000010de78d08 -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 242
24  UIKit                               0x000000010d6b2fef -[UIScrollView _switchToLayoutEngine:] + 107
25  UIKit                               0x000000010de790fc __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 225
26  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
27  UIKit                               0x000000010de79637 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
28  UIKit                               0x000000010de78fd3 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 646
29  UIKit                               0x000000010de79640 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
30  UIKit                               0x000000010de78d08 -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 242
31  UIKit                               0x000000010de790fc __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 225
32  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
33  UIKit                               0x000000010de79637 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
34  UIKit                               0x000000010de78fd3 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 646
35  UIKit                               0x000000010de79640 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
36  UIKit                               0x000000010de78d08 -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 242
37  UIKit                               0x000000010de790fc __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 225
38  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
39  UIKit                               0x000000010de79637 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
40  UIKit                               0x000000010de78fd3 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 646
41  UIKit                               0x000000010de79640 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
42  UIKit                               0x000000010de78d08 -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 242
43  UIKit                               0x000000010de790fc __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke_2 + 225
44  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
45  UIKit                               0x000000010de79637 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 58
46  UIKit                               0x000000010de78fd3 __57-[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:]_block_invoke + 646
47  UIKit                               0x000000010de79640 -[UIView(AdditionalLayoutSupport) _withAutomaticEngineOptimizationDisabledIfEngineExists:] + 67
48  UIKit                               0x000000010de78d08 -[UIView(AdditionalLayoutSupport) _switchToLayoutEngine:] + 242
49  UIKit                               0x000000010d6980dc __45-[UIView(Hierarchy) _postMovedFromSuperview:]_block_invoke + 113
50  Foundation                          0x00000001101f723a -[NSISEngine withBehaviors:performModifications:] + 155
51  UIKit                               0x000000010d698024 -[UIView(Hierarchy) _postMovedFromSuperview:] + 575
52  UIKit                               0x000000010d6a5ac3 -[UIView(Internal) _addSubview:positioned:relativeTo:] + 1967
53  UIKit                               0x000000010d8e7695 -[_UIAlertControllerPresentationController presentationTransitionWillBegin] + 208
54  UIKit                               0x000000010d75999c __71-[UIPresentationController _initViewHierarchyForPresentationSuperview:]_block_invoke + 2044
55  UIKit                               0x000000010d7575c5 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke + 309
56  UIKit                               0x000000010d6044be _runAfterCACommitDeferredBlocks + 317
57  UIKit                               0x000000010d6167ee _cleanUpAfterCAFlushAndRunDeferredBlocks + 95
58  UIKit                               0x000000010d6224e6 _afterCACommitHandler + 90
59  CoreFoundation                      0x000000010d1779d7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
60  CoreFoundation                      0x000000010d177947 __CFRunLoopDoObservers + 391
61  CoreFoundation                      0x000000010d16d59b __CFRunLoopRun + 1147
62  CoreFoundation                      0x000000010d16ce98 CFRunLoopRunSpecific + 488
63  GraphicsServices                    0x0000000111d12ad2 GSEventRunModal + 161
64  UIKit                               0x000000010d5f8676 UIApplicationMain + 171
65  <AppName>                          0x000000010cd9c061 main + 65
66  libdyld.dylib                       0x0000000110ff192d start + 1
67  ???                                 0x0000000000000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

Looking at the code, it shows me the following as the source of the exception:

int main(int argc, char* argv[])
{
    @autoreleasepool {
        int retVal = UIApplicationMain(argc, argv, nil, @"AppDelegate");
        return retVal;
    }       
}

With the exception coming out of the UIApplicationMain() call. Following the stack trace further down just takes me into assembly code, which appears to be Apple libraries.

I'm basically certain that the code problem has nothing to do with the UIApplicationMain() call directly, and is probably something else in the project file that is broken, but I can't get a lead to track down this bug for the life of me.

If I load this same project in Xcode 6.0 or 6.3 (the other two versions I've tried), no exception is thrown at this point. Even the compiled app on the store, when tested in iOS 9, doesn't seem to have this problem. So far, the problem only seems to occur when running the app in debug mode via Xcode 7.0.

Config.xml specifies to build this with phonegap-version 3.5, but I've tried other versions up to the very most recent, and all of them have this problem.

I've been trying to solve this problem for two days now, but I'm making no progress because I just can't get a handhold on what might have gone wrong. Everything I end up checking seems fine, and yet this error emerges from somewhere. I feel like this has to be a case where something is configured wrong somewhere, and so it blows up inside Apple's code wherever the misconfigured piece is finally being used, but I have absolutely no clue as to what. I'm stumped. Does anyone have any useful information that might be able to help me out?

UPDATE: I finally found it. Tucked into the debug output was a line I was overlooking:

 NSURLSession/NSURLConnection HTTP load failed (kCFStreamErrorDomainSSL, -9802

That led me to this question here on SO. As it turns out, that was the actual root cause of my problem. This also explained why the application was working fine in production on actual devices, and why old Xcode was just fine. The web request being made was being made against HTTPS in production, but the servers for development were HTTP instead. Thus, the production version of the app was fine, and the development version of the app was fine in old Xcode (where there was no ATS), but the development version of the app compiled against the new iOS 9 Xcode was throwing the exception.

I was so busy looking at the big exception and some other major items in that debug output that I missed the key line that was tucked between other items.

What happens when you run the app with an exception breakpoint? https://developer.apple.com/library/ios/recipes/xcode_help-breakpoint_navigator/articles/adding_an_exception_breakpoint.html — Caleb Kleveter, Oct 12 '15 at 21:44
Pretty much the same thing. It still stops and points me at the same UIApplicationMain() line, and the last part of the stack trace that doesn't seem to deal with exception handling is: `[UILabel _ensureBaselineMetricsReturningBounds] + 153` The further up items in the exception trace are: `__forwarding_prep_0___ ___forwarding___ -[NSObject(NSObject) doesNotRecognizeSelector:] objc_exception_throw` If I continue past, it catches one more exception, which pushes those items in the stack down for: ` __cxa_throw` Sorry, I keep hitting enter and not shift+enter. — AggravatedDeveloper, Oct 12 '15 at 22:02

score 3 · Accepted Answer · answered Oct 13 '15 at 04:00

3

the transition to the new Xcode has introduced a new exception

New versions of Xcode usually come with new frameworks. It's not so much that Xcode itself is causing the exception, but rather that something your code does was allowed before but throws an exception in the latest version of the framework.

From the stack trace it's pretty clear that the exception occurs while the auto layout system is doing its thing. Take a look at your storyboard and see if there are any layout issues that need to be resolved. Also, look at the console for messages -- there's usually a clue there as to what caused the exception.

answered Oct 13 '15 at 04:00

Caleb

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1

There was a message in the console that I had somehow been overlooking, which led me to my solution. Thanks. – AggravatedDeveloper Oct 13 '15 at 17:18
1

I had similar issue after xcode 8 to xcode 9 upgrade. I realized one of my storyboards had the build target of iOS 11, and the min deployment target of the whole project was iOS 10. We saw these exceptions on iOS 10 devices. Theory is that it might have occurred since iOS 11 might have introduced a new method unavailable to iOS 10 which led to the doesNotRecognizeSelector exception on iOS 10 devices. – Rushabh Nov 16 '17 at 23:21

iOS Project throws unhandled exception after Xcode upgrade

1 Answers1