NSFetchedResultsController does not see inserts (or updates)

Question

I have a very basic NSFetchedResultsController that shows the data to the user in a UITableView, allows the user to add a new entity and so forth.

However, whenever I add a new entity, my app crashes (or sometimes just warns) with the following message:

CoreData: error: Serious application error.  An exception was caught from the delegate of NSFetchedResultsController during a call to -controllerDidChangeContent:.  Invalid update: invalid number of sections.  The number of sections contained in the table view after the update (3) must be equal to the number of sections contained in the table view before the update (2), plus or minus the number of sections inserted or deleted (0 inserted, 0 deleted). with userInfo (null)

Notice that even thought the numberOfRows have been updated from 2 to 3, the insertion/deletion thing still says (0 inserted, 0 deleted). So my best understanding is that the NSFetchedResultsController is not noticing the changes or something.

My code for NSFetchedResultsController is:

func fetch(frcToFetch: NSFetchedResultsController) {

    do {
        try frcToFetch.performFetch()
    } catch {
        return
    }
}

func fetchRequest() -> NSFetchRequest {

    // Initialize Fetch Request
    let fetchRequest = NSFetchRequest(entityName: "ItemInfo")

    // Add Sort Descriptors
    let nameSortDescriptor = NSSortDescriptor(key: "iName", ascending: true)
    fetchRequest.sortDescriptors = [nameSortDescriptor]

    return fetchRequest
}


func getFRC() -> NSFetchedResultsController {

    if let context = self.context{
        fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest(), managedObjectContext: context, sectionNameKeyPath: "iName.stringGroupByFirstInitial", cacheName: nil)
        fetchedResultsController.delegate = self
    }
    return fetchedResultsController
}

func controllerWillChangeContent(controller: NSFetchedResultsController) {
    tableView.beginUpdates()
}

func controllerDidChangeContent(controller: NSFetchedResultsController) {
    tableView.endUpdates()
}

func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
    switch (type) {
    case .Insert:
        if let indexPath = newIndexPath {
            tableView.insertRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        }
        break;
    case .Delete:
        if let indexPath = indexPath {
            tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        }
        break;
    case .Update:
        if let indexPath = indexPath {
            let cell = tableView.cellForRowAtIndexPath(indexPath)! as UITableViewCell
            configureCell(cell, atIndexPath: indexPath)
        }
        break;
    case .Move:
        if let indexPath = indexPath {
            tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        }

        if let newIndexPath = newIndexPath {
            tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Fade)
        }
        break;
    }
}

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    if let sections = fetchedResultsController.sections {
        return sections.count
    }

    return 0
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    if let sections = fetchedResultsController.sections {
        let sectionInfo = sections[section]
        return sectionInfo.numberOfObjects
    }

    return 0
}

And the code to insert new record is:

let entity: NSEntityDescription.entityForName("ItemInfo", inManagedObjectContext: self.context!)!

let record = NSManagedObject(entity: entity, insertIntoManagedObjectContext: self.context!)

record.setValue(name, forKey: "iName")
record.setValue(self.billingMode.text, forKey: "iBillingMode")

do {
            // Save Record
            try record.managedObjectContext?.save()
            try self.context!.save()
            // Dismiss View Controller
            dismissViewControllerAnimated(true, completion: nil)

        } catch {
            let saveError = error as NSError
            print("\(saveError), \(saveError.userInfo)")

            // Show Alert View
            showAlertWithTitle("Unexpected Error", message: "Your data could not be saved. Please try again later.", cancelButtonTitle: "Done")
        }

Note that the self.context variable is passed from the actual or master view controller that has the NSFetchedResultsController.

Answer 1

Note that the problem is with the number of sections not the number of rows. You need to implement:

(void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo