I am having the same issue described at this address http://www.cocoabuilder.com/archive/cocoa/288659-iphone-nsmanagedobjectcontext-save-doesn-crash-but-breaks-on-objc-excep
Recently I ran into the same issue: app crashing without any log, when trying to save managedObjectContext.
In my case there was a completely different cause from mentioned above:
Make sure you do not have DB Manager open on your mac, that could be locking the persistent data store.
This will (apparently) also kill the Core Date stack, without throwing any visible errors in code or in log.
Turned out I had some unsaved changes, which made the DB Manager lock the store. Closing the DB Manager fixed the issue. Simple and stupid error, but took me hours to figure out.
I happened to meet this problem, and after long time debug I found it's because of a duplicate declaration of the NSError* error, may you had another NSError* error in the outer scope, like:
NSError* error = nil;
Some code
if (!error)
{
NSError* error = nil;
// your code
}
Then the error will be nil although in fact there is a exception.
I had a similar problem, eventually it turned out to be because of an observer of NSManagedObjectContextDidSaveNotification that was deallocated without removing itself from the notification center. It seems that the CoreData exception "hides" the unknown selector exception that is raised when the notification center tries notifying whatever object occupies the memory freed by the registered (but deallocated) observer.
Looking at this answer reveals that CoreData internally uses exceptions to manage their program flow. Thats why the debugger breaks at objc_exception_throw. As far as I know there is no way to disable this.
EDIT: Since then, there is now a solution to ignore these exceptions: Ignore certain exceptions when using Xcode's All Exceptions breakpoint
BTW: Do not check on error
but use the returned BOOL
value to ensure success of your save call. The correct way of doing this would be:
NSError *error = nil;
BOOL success = [self.managedObjectContext save:&error];
if (!success) {
NSLog(@"Error : %@",error);
}