EXC_BAD_ACCESS when calling managedObjectContext save

Question

Occasionally I get this error:

EXC_BAD_ACCESS Code: KERN_INVALID_ADDRESS at 0x13421772123

It happens on the save: line below (in a CoreDataController singleton class)

    NSError *error = nil;
    NSManagedObjectContext *managedObjectContext = self.managedObjectContext;

    if (managedObjectContext != nil) {
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        }
    }

I know this isn't a lot of code to go from, but from experience is there common cause to this, and any way to prevent this from crashing the app?

Answer 1

if managedObjectContext is the main context, then you should call it in main thread, try wrap it with following code, incase you call it in a background thread

NSManagedObjectContext *managedObjectContext = self.managedObjectContext;

if (managedObjectContext != nil) {
    [managedObjectContext performBlockAndWait:^{
        NSError *error = nil;
        if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        }
    }];
}