One needs to have the source code to BOTH examples for this chapter. I can't get the first one to draw the shapes. I get the following error:

CGContextAddLineToPoint: no current point.

Please see below for Errata submitted by author Rob Warner.

Author Comment:

See below for Errata submitted by author Rob Warner.

Author Comment:

Please see below for Errata submitted by author Rob Warner:

Author Comment:

The code gives compiler warnings because its not ARC compatible.

Here is ARC compatible code:

AppDelegate.h
Add #import <CoreData/CoreData.h> before @class
Add following code between last @property line and @end:
@property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
@property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;

- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;

AppDelegate.m
Add following code after last @synthesize line:
@synthesize managedObjectModel = __managedObjectModel;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator;

Add following code between last method and @end:
- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil) {
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}
}

#pragma mark - Core Data stack

// Returns the managed object context for the application.
// If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
- (NSManagedObjectContext *)managedObjectContext
{
if (__managedObjectContext != nil) {
return __managedObjectContext;
}

NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil) {
__managedObjectContext = [[NSManagedObjectContext alloc] init];
[__managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return __managedObjectContext;
}

// Returns the managed object model for the application.
// If the model doesn't already exist, it is created from the application's model.
- (NSManagedObjectModel *)managedObjectModel
{
if (__managedObjectModel != nil) {
return __managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"JSONtester" withExtension:@"momd"];
__managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return __managedObjectModel;
}

// Returns the persistent store coordinator for the application.
// If the coordinator doesn't already exist, it is created and the application's store added to it.
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (__persistentStoreCoordinator != nil) {
return __persistentStoreCoordinator;
}

NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"JSONtester.sqlite"];

NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) {
/*
Replace this implementation with code to handle the error appropriately.

abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.

Typical reasons for an error here include:
* The persistent store is not accessible;
* The schema for the persistent store is incompatible with current managed object model.
Check the error message to determine what the actual problem was.


If the persistent store is not accessible, there is typically something wrong with the file path. Often, a file URL is pointing into the application's resources directory instead of a writeable directory.

If you encounter schema incompatibility errors during development, you can reduce their frequency by:
* Simply deleting the existing store:
[[NSFileManager defaultManager] removeItemAtURL:storeURL error:nil]

* Performing automatic lightweight migration by passing the following dictionary as the options parameter:
[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithBool:YES], NSMigratePersistentStoresAutomaticallyOption, [NSNumber numberWithBool:YES], NSInferMappingModelAutomaticallyOption, nil];

Lightweight migration will only work for a limited set of schema changes; consult "Core Data Model Versioning and Data Migration Programming Guide" for details.

*/
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}

return __persistentStoreCoordinator;
}

#pragma mark - Application's Documents directory

// Returns the URL to the application's Documents directory.
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

Add following code within (void)applicationWillTerminate and (void)applicationDidEnterBackground methods:
[self saveContext];

Rest of example code should work fine.

On figure 3-10, delete rule should be Cascade instead of Nullify.

Chapter 8 Migration using mapping model

I've tried multiple times with the source code provided and each time produces this error when migrating with the mapping model:

Unresolved error Error Domain=NSCocoaErrorDomain Code=134140

reason=Can't find mapping model for migration}

full console output: http://pastebin.com/pUiYAN9E

Using Xcode 4.2.1

I'm concerned about something that you have in "RESPONDING TO DATA CHANGES".

You're pulling out the "configureCell" method to allow it to be called from the FetchedResultsControllerDelegate, but your implementation on page 304 SEEMS to be causing configureCell to be called TWICE. It's called ONCE during the outer [self configureCell:atIndexPath:] call that then calls cellForRowAtIndexPath: which calls configureCell AGAIN.

Granted, it's not a HUGE performance hit, but it seems an odd thing to be holding up as a best practice in a book trying to show folks that are potentially new to CoreData how to use it.

Am I missing something? Thanks in advance for any advice.