UIAlertController crashes (SIGABRT) when adding second action

Question

I see a very strange behavior in one of my apps since a few days. A UIAlertController crashes as soon as I add a second action. Here is the code>

let alertController = UIAlertController.init(title: title, message: message, preferredStyle: .Alert)

for  action in actions
{
    alertController.addAction(action)
}

actions is an array containing UIAlertAction elements, in my case 2. I already tried reordering the actions to see if there was a problem with a specific UIAlertAction object, but no, the app always crashes when adding the second action. I create them like this:

let cancelAction = UIAlertAction.init(title: "Cancel", style: .Cancel)
{ (action:UIAlertAction!) -> Void in
    print("User cancelled action");
}

Edit: here is how I create the array:

showAlertView("Proceed", message: proceedMessage, actions: [cancelAction, proceedAction])

Edit end

Most of this code comes from the Apple tutorials with little changes. The debugger is immediately jumping to the class AppDelegate: ... line with no other information then SIGABRT and in the crash logs I see this:

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note:  EXC_CORPSE_NOTIFY
Triggered by Thread:  0

Filtered syslog:
None found

Last Exception Backtrace:
0   CoreFoundation                  0x1832c6db0 __exceptionPreprocess + 124
1   libobjc.A.dylib                 0x18292bf80 objc_exception_throw + 56
2   CoreFoundation                  0x1832c6c80 +[NSException raise:format:arguments:] + 108
3   Foundation                      0x183c4c154 -[NSAssertionHandler   handleFailureInMethod:object:file:lineNumber:description:] + 112
4   UIKit                           0x188897c24 -[UIAlertController addAction:] + 220
5   MyApp                           0x10007bb60 0x10006c000 + 64352
6   MyApp                           0x10007b648 0x10006c000 + 63048
7   MyApp                           0x10007929c 0x10006c000 + 53916
8   MyApp                           0x100079554 0x10006c000 + 54612
9   UIKit                           0x1886de1a8 -[UIApplication _handleNonLaunchSpecificActions:forScene:withTransitionContext:completion:] + 2676
10  UIKit                           0x1886cbf84 -[UIApplication workspace:didReceiveActions:] + 136
11  FrontBoardServices              0x184c677ac __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 36
12  FrontBoardServices              0x184c67618 -[FBSSerialQueue _performNext] + 168
13  FrontBoardServices              0x184c679c8 -[FBSSerialQueue _performNextFromRunLoopSource] + 56
14  CoreFoundation                  0x18327d09c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
15  CoreFoundation                  0x18327cb30 __CFRunLoopDoSources0 + 540
16  CoreFoundation                  0x18327a830 __CFRunLoopRun + 724
17  CoreFoundation                  0x1831a4c50 CFRunLoopRunSpecific + 384
18  GraphicsServices                0x184a8c088 GSEventRunModal + 180
19  UIKit                           0x18848e088 UIApplicationMain + 204
20  MyApp                           0x10007d984 0x10006c000 + 72068
21  libdyld.dylib                   0x182d428b8 start + 4

Does anybody have any idea? The strangest thing is, that the same code worked a couple of days ago. As I have a lot of problems with Xcode 7.3 after upgrading from Yosemite to El Capitan (basically it's almost unusable and constantly crashing) I re-installed it recently. But the code is the same...

Best regrads Bjoern

Julejulee

Why you use for loop in actions? – Anse

You should show how the actions array is created. – Isolt

Have you tried running a clean before building? I've had situations where, for whatever reason, some piece of code hasn't been recompiled that should be after changing it and that causes these kinds of crash. – Oxyhydrogen

Try adding a breakpoint on Objective-C exceptions in the Breakpoint Navigator. It might give a better description of the error in the debug console window. – Drees

@Phillip Unfortunately, the Objective-C breakpoint reveals no further information. In fact the debugger stops three times at the line with .addAction, then it shows the SIGABRT. @Oxyhydrogen I did a Clean as well as uninstalling and re-installing the app. Nothing worked so far. – Julejulee

@PhillipMills The last step before SIGABRT is 0x188897c24 <+220>: mov x0, x24 – Julejulee

@IyyappanRavi I use a function to dynamically create the UIAlertController, so I don't know how many actions there will be. But even if I call addAction() directly, without the loop, the app crashes on the second addAction call. – Julejulee

Answer 1

My guess is that you set style: .Cancel on more than 1 action.

Aerotherapeutics

Yes, this caused the problem. Is this documented somewhere? – Julejulee