问题
I have a very odd error with Core Data. I have a Recipe class that has a many to many relationship to an Ingredient class.
When I try to add an Ingredient to the Recipe on a RecipeViewController, everything works fine until I save the context. Thats when things go horribly wrong.
I get an error on my RecipesTableViewController (which has a NSFetchedResultsController and implements NSFetchedResultsControllerDelegate). The
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
method gets called and then I get an exception:
CoreData: error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[KCGIngredient sectionOffset]: unrecognized selector sent to instance 0x7bf83d50 with userInfo (null)
I have no idea what this sectionOffset message is and couldn't find it in the documentation. This happens after NSFetchResultsController gets the _postprocessInsertedObjects: message.
I'm assuming this sectionOffset message was intended to an instance of NSFetchedResultsController, but I have no idea how it ended up being sent to a model object.
EDIT:
Actually, I checked it out and apparently sectionOffset is not a method of NSFetchedResultsController.
This test fails miserably:
XCTAssertTrue([NSFetchedResultsController instancesRespondToSelector:@selector(sectionOffset)]);
What on Earth is going on? I already tried everything,s o if you can shed some light, I'd really appreciate it.
来源：https://stackoverflow.com/questions/29829792/serious-application-error-model-object-getting-nsfetchedresultscontroller-messa