Exception when running on simulator 3.2

Question

Hello,

I'm testing my app on simulator 3.1.3, it runs fine. When it come to simulator 3.2, it crashes right from the beginning:

2010-06-24 16:35:29.208 MyTestApp[6991:207] *** Terminating app due to uncaught exception 'NSGenericException', reason: 'This coder requires that replaced objects be returned from initWithCoder:'
2010-06-24 16:35:29.213 MyTestApp[6991:207] Stack: (
46195275,
2520474889,
46194715,
46194554,
6387912,
6392266,
5568184,
6388086,
6386450,
6392266,
5564974,
5573454,
3555255,
3560368,
3586056,
3567777,
3599431,
52998524,
45735996,
45731912,
3559044,
3591649,
10824,
10678

)

As far as I know, I do not use the "initWithCoder" method (do not really know what this is though).

How can I know where the exception is thrown so I could have a better understanding of what is causing the problem ?

Thanks a lot, Luc

ps: I have added an exception in Breakpoint: objc_exception_throw (with location libobjc.A.dylib, strangely I had to enter the location manually, I expected xcode to find it for me when I added objc_exception_throw). But still the same trace and no more information.

Answer 1

This page should provide some helpful info: Debugging Tips for Objective-C

Of particular interest is the console command info line *. Every one of those numbers listed by the exception log is an address on the stack. Those bottom ones in the 10,000 and below range are usually located in the app's main method, for example. The highest ranged addresses tend to represent the default libraries.

Using the command info line *10678 would likely return some info about a specific line in the main method, which doesn't help very much. Normally the trick is to find the highest address before the default libraries begin. I'm unsure how much this will help your problem in particular, seeing as there's a huge gap between the expected small addresses and the next highest up. In any case, start with the smallest address above the bottom two (3555255 from what I can see in the log you posted) and see if it returns a line from one of your own code files. If it does, check the one above it, and so on until you find the last address from your own code. Hope this helps.

Answer 2

I figured out the reason of this error. I had created an object of type NSDictionnary within IB and it seems it was not the correct way to do this. Instead I have programmatically created this same object in XCode and this works fine. Seems like it was some kind of persistent problem.