iPhone crash log and how to understand it

Question

This is one crash log I've downloaded from iTunesConnect website.

Incident Identifier: 20D5CB0F-58BE-41E5-B3F6-9BC8091E518C
Hardware Model:      iPhone4,1
Process:         iPill [2006]
Path:            /var/mobile/Applications/4567191D-1013-40F3-A02A-0B3C2552FCD3/iPill.app/iPill
Identifier:      iPill
Version:         ??? (???)
Code Type:       ARM (Native)
Parent Process:  launchd [1]

Date/Time:       2012-07-12 20:59:23.716 +0200
OS Version:      iPhone OS 5.1.1 (9B206)
Report Version:  104

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x00000000, 0x00000000
Crashed Thread:  0

Last Exception Backtrace:
0   CoreFoundation                  0x3558688f __exceptionPreprocess + 163
1   libobjc.A.dylib                 0x3792d259 objc_exception_throw + 33
2   CoreFoundation                  0x354cf9db -[__NSArrayM objectAtIndex:] + 271
3   iPill                           0x0008225b -[ProssimeDosi tableView:cellForRowAtIndexPath:] (ProssimeDosi.m:314)
4   UIKit                           0x3301aefb -[UITableView(UITableViewInternal) _createPreparedCellForGlobalRow:withIndexPath:] + 547
5   UIKit                           0x33019fd9 -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow:] + 1077
6   UIKit                           0x33019763 -[UITableView layoutSubviews] + 207
7   UIKit                           0x32fbdf37 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 183
8   CoreFoundation                  0x354e51fb -[NSObject performSelector:withObject:] + 43
9   QuartzCore                      0x323b5aa5 -[CALayer layoutSublayers] + 217
10  QuartzCore                      0x323b56bd  CA::Layer::layout_if_needed(CA::Transaction*) + 217
11  QuartzCore                      0x323b9843 CA::Context::commit_transaction(CA::Transaction*) + 227
12  QuartzCore                      0x323b957f CA::Transaction::commit() + 315
13  QuartzCore                      0x323b14b9 CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 57
14  CoreFoundation                  0x3555ab1b __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 19
15  CoreFoundation                  0x35558d57 __CFRunLoopDoObservers + 259
16  CoreFoundation                  0x355590b1 __CFRunLoopRun + 761
17  CoreFoundation                  0x354dc4a5 CFRunLoopRunSpecific + 301
18  CoreFoundation                  0x354dc36d CFRunLoopRunInMode + 105
19  GraphicsServices                0x37178439 GSEventRunModal + 137
20  UIKit                           0x32fe8cd5 UIApplicationMain + 1081
21  iPill                           0x000799b7 main (main.m:16)
22  iPill                           0x0007996c 0x78000 + 6508


Thread 0 name:  Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0   libsystem_kernel.dylib          0x35e3c32c __pthread_kill + 8
1   libsystem_c.dylib               0x32988208 pthread_kill + 48
2   libsystem_c.dylib               0x32981298 abort + 88
3   libc++abi.dylib                 0x3593ef64 abort_message + 40
4   libc++abi.dylib                 0x3593c346 _ZL17default_terminatev + 18
5   libobjc.A.dylib                 0x3792d350 _objc_terminate + 140
6   libc++abi.dylib                 0x3593c3be _ZL19safe_handler_callerPFvvE + 70
7   libc++abi.dylib                 0x3593c44a std::terminate() + 14
8   libc++abi.dylib                 0x3593d81e __cxa_rethrow + 82
9   libobjc.A.dylib                 0x3792d2a2 objc_exception_rethrow + 6
10  CoreFoundation                  0x354dc506 CFRunLoopRunSpecific + 398
11  CoreFoundation                  0x354dc366 CFRunLoopRunInMode + 98
12  GraphicsServices                0x37178432 GSEventRunModal + 130
13  UIKit                           0x32fe8cce UIApplicationMain + 1074
14  iPill                           0x000799b0 main (main.m:16)
15  iPill                           0x00079964 0x78000 + 6500

I've pasted only thread 0 because it seems it is the one which crashed. This is all new to me and I have no idea how to interpret this log and solve the problem. I've tested my App on my iPhones 4 and 4s and on a 3GS of a friend of mine and we didn't see any crash. Now I'm getting 1 star reviews from some people saying iPill is crashing a lot. Any help will be really appreciated. Thanks.

Answer 1

Just from this crashlog it looks as if you're having an out-of-bounds problem triggered by line 314 of ProssimeDosi.m due to something requesting more data than is available.

See the accepted answer here for a more elaborate explanation: Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[NSMutableArray objectAtIndex:]: index 1 beyond bounds [0 .. 0]'

Answer 2

I'd say to start in your tables cellForRowAtIndexpath method. I'd hazard a guess that there's an issue with your data model and it's calling data from an array that is empty.