Xcode doesn't show the line that causes a crash

objective-c ios xcode cocoa-touch nsexception
JonasG picture JonasG · Oct 9, 2011 · Viewed 45k times · Source

Every time my app crashes Xcode highlights the UIApicationMain() call in the main() function as the line that caused the crash. In some cases that used to be normal (segmentation fault for example) but the crash I am trying to deal with is a simple SIGABRT with detailed information logged in the console:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary setObject:forKey:]: attempt to insert nil value (key: Date)'

Xcode used to show the line just right with older SDKs but since i upgraded to Xocde 4.2 that changed. It is pretty obvious that Xcode knows exactly what caused the crash (or could know), but its still not showing the actual line. Is there any fix or workaround for this?

Answer

Carter picture Carter · Oct 9, 2011

You should also ensure that you have breakpoints set for all exceptions. This will cause Xcode to stop at the line where the exception is occurring. Do the following [in Xcode 4]:

  1. In the Project Navigator on the left side of Xcode, click on the breakpoint navigator (almost all the way to the right hand side of the top button bar. The icon looks like a fat right arrow).

  2. At the bottom of the navigator, click the "+" button.

  3. Click "Add Exception Breakpoint".

  4. A new breakpoint will be created. It should be configured as needed but you can tweak its behavior.

  5. Run your project and reproduce the exception.

Also you mentioned that you linked to some 3rd party libraries/frameworks. If the exception is occurring within those frameworks then you are going to have a hard time since the code is compiled and Xcode can't actually show you the line that caused the exception. If this is the case and you are certain you are using the libraries correctly, then you should file a bug report to the maintainers of those libraries.

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