Crashing on setValue:forKey: - ios

Question

Crashlytics reported a crash in my app, and I have no idea of what is happening.
Here is the stacktrace:
Thread : Fatal Exception: NSInternalInconsistencyException
0 CoreFoundation 0x30080e83 __exceptionPreprocess + 130
1 libobjc.A.dylib 0x3a3dd6c7 objc_exception_throw + 38
2 CoreData 0x2fdcf941 -[NSSQLiteStatement cachedSQLiteStatement]
3 CoreData 0x2fdcf18d -[NSSQLiteConnection prepareSQLStatement:] + 52
4 CoreData 0x2fde8edf -[NSSQLChannel selectRowsWithCachedStatement:] + 58
5 CoreData 0x2fea8e1f newFetchedRowsForFetchPlan_MT + 910
6 CoreData 0x2fde8949 -[NSSQLCore fetchRowForObjectID:] + 1180
7 CoreData 0x2fde8311 -[NSSQLCore newValuesForObjectWithID:withContext:error:] + 256
8 CoreData 0x2fde762b _PFFaultHandlerLookupRow + 398
9 CoreData 0x2fde7193 _PF_FulfillDeferredFault + 218
10 CoreData 0x2fdf6449 _PF_ManagedObject_WillChangeValueForKeyIndex + 68
11 CoreData 0x2fdf636b _sharedIMPL_setvfk_core + 110
12 CoreData 0x2fe1995d _PF_Handler_Public_SetProperty + 92
13 CoreData 0x2fe1e2a9 -[NSManagedObject setValue:forKey:] + 124
14 Application 0x0004dc45 -[DateFormatter storeValue:error:] (DateFormatter.m:65)
15 Application 0x0004ee17 -[Formatter storeValue:inObject:] (Formatter.m:176)
16 Application 0x0002b5c5 -[NSManagedObject(App) setValuesForKeysWithReceivedDictionary:] (NSManagedObject+App.m:320)
17 Application 0x0002b8f3 -[NSManagedObject(App) setValuesForKeysWithReceivedDictionary:] (NSManagedObject+App.m:377)
18 Application 0x0006352d -[ODataGetOperation processResult:] (ODataGetOperation.m:220)
19 Application 0x0004420b -[ODataOperation connectionDidFinishLoading:] (ODataOperation.m:741)
20 Foundation 0x309bb47f __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 54
21 Foundation 0x309bb3c1 -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 204
22 Foundation 0x309bb2dd -[NSURLConnectionInternal _withActiveConnectionAndDelegate:] + 60
23 CFNetwork 0x2fceaf8f ___ZN27URLConnectionClient_Classic26_delegate_didFinishLoadingEU13block_pointerFvvE_block_invoke + 74
24 CFNetwork 0x2fce9b8f ___ZN27URLConnectionClient_Classic18_withDelegateAsyncEPKcU13block_pointerFvP16_CFURLConnectionPK33CFURLConnectionClientCurrent_VMaxE_block_invoke_2 + 54
25 CFNetwork 0x2fd1b337 ___ZNK17CoreSchedulingSet13_performAsyncEPKcU13block_pointerFvvE_block_invoke + 18
26 CoreFoundation 0x2ffb3ea1 CFArrayApplyFunction + 36
27 CFNetwork 0x2fc81e05 RunloopBlockContext::perform() + 164
28 CFNetwork 0x2fc81cd5 MultiplexerSource::perform() + 220
29 CFNetwork 0x2fc81b65 MultiplexerSource::_perform(void*) + 48
30 CoreFoundation 0x3004bf1f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 14
31 CoreFoundation 0x3004b3e7 __CFRunLoopDoSources0 + 206
32 CoreFoundation 0x30049bd7 __CFRunLoopRun + 630
33 CoreFoundation 0x2ffb4471 CFRunLoopRunSpecific + 524
34 CoreFoundation 0x2ffb4253 CFRunLoopRunInMode + 106
35 Foundation 0x309a2697 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 254
36 Application 0x00043b4b -[ODataOperation send] (ODataOperation.m:548)
37 Application 0x0004277f -[ODataOperation operationWillStartPreparingData] (ODataOperation.m:131)
38 Foundation 0x30a5396d __NSOQSchedule_f + 60
39 libdispatch.dylib 0x3a8c64b7 _dispatch_async_redirect_invoke + 110
40 libdispatch.dylib 0x3a8c77d9 _dispatch_root_queue_drain + 224
41 libdispatch.dylib 0x3a8c79c5 _dispatch_worker_thread2 + 56
42 libsystem_pthread.dylib 0x3a9f1dff _pthread_wqthread + 298
43 libsystem_pthread.dylib 0x3a9f1cc4 start_wqthread + 8
And there is the last method that calls setValue:forKey: in an NSManagedObject subclass
- (BOOL)storeValue:(void *)theValue error:(NSError **)theError
{
NSString * value = (__bridge NSString *)theValue;
NSString * errorMessage = nil;
if (![value length] && !isOptional)
errorMessage = [NSString stringWithFormat: NSLocalizedString(#"Value cannot be nil or empty (Date) for field %#", #""), varName];
else
{
NSDate * date = nil;
if ([value length])
{
date = [NSDate dateWithISO8601: value];
if (!date)
errorMessage = [NSString stringWithFormat: NSLocalizedString(#"Invalid date %# for field %#", #""), theValue, varName];
}
if (IvarAddress)
*((__strong NSDate **) IvarAddress) = date;
else
[currentObject setValue: date forKey: varName];
}
if (errorMessage)
{
if (theError)
*theError = [NSError errorWithDomain: AppDomain code: NSFormattingError userInfo: #{ NSLocalizedDescriptionKey: errorMessage }];
#ifdef DEBUG
NSLog(#"Formatter error: %#", errorMessage);
#endif
return NO;
}
return YES;
}
I am completely open to any suggestion :)
Update : The key exists, and the value being set is an NSDate so it's an attribute of the NSManagedObject, not a relationship.
Update 2 :
I also have another crash with that method (stack trace is not exactly the same) :
Thread : Fatal Exception: NSInternalInconsistencyException
0 CoreFoundation 0x30080e83 __exceptionPreprocess + 130
1 libobjc.A.dylib 0x3a3dd6c7 objc_exception_throw + 38
2 CoreData 0x2fddfacb -[NSSQLCore _obtainOpenChannel] + 234
3 CoreData 0x2fea8ded newFetchedRowsForFetchPlan_MT + 860
4 CoreData 0x2fde8949 -[NSSQLCore fetchRowForObjectID:] + 1180
5 CoreData 0x2fde8311 -[NSSQLCore newValuesForObjectWithID:withContext:error:] + 256
6 CoreData 0x2fde762b _PFFaultHandlerLookupRow + 398
7 CoreData 0x2fde7193 _PF_FulfillDeferredFault + 218
8 CoreData 0x2fdf6449 _PF_ManagedObject_WillChangeValueForKeyIndex + 68
9 CoreData 0x2fdf636b _sharedIMPL_setvfk_core + 110
10 CoreData 0x2fe1995d _PF_Handler_Public_SetProperty + 92
11 CoreData 0x2fe1e2a9 -[NSManagedObject setValue:forKey:] + 124
12 Application 0x000fcc45 -[DateFormatter storeValue:error:] (DateFormatter.m:65)
13 Application 0x000fde17 -[Formatter storeValue:inObject:] (Formatter.m:176)
14 Application 0x000da5c5 -[NSManagedObject(App) setValuesForKeysWithReceivedDictionary:] (NSManagedObject+.m:320)
15 Application 0x000da8f3 -[NSManagedObject(App) setValuesForKeysWithReceivedDictionary:] (NSManagedObject+.m:377)
16 Application 0x0011252d -[ODataGetOperation processResult:] (ODataGetOperation.m:220)
17 Application 0x000f320b -[ODataOperation connectionDidFinishLoading:] (ODataOperation.m:741)
18 Foundation 0x309bb47f __65-[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:]_block_invoke + 54
19 Foundation 0x309bb3c1 -[NSURLConnectionInternal _withConnectionAndDelegate:onlyActive:] + 204
20 Foundation 0x309bb2dd -[NSURLConnectionInternal _withActiveConnectionAndDelegate:] + 60
The exception message also is different :
_obtainOpenChannel -- NSSQLCore 0x15ef3780: no database channel is available
But I think they are two related issues.

Answer 1

So I finally found the reasons which were all related to multithreading/concurrency issues. Basically updating the same objects on two threads at the same time..
The recently added core data debug flags (-com.apple.CoreData.ConcurrencyDebug 1) were used to figure out what was happening.