setPrimitiveValue forKey does not register a NSManagedObject with changes

Originator:Jake.Kirshner
Number:rdar://15516199 Date Originated:20-Nov-2013 12:22 PM
Status:Open Resolved:
Product:iOS SDK Product Version:7.0.4
Classification:Crash/Hang/Data Loss Reproducible:Always
 
Summary:
I am updating a set of objects using a background NSManagedObjectContext, which I then import into a primary MOC.
when updating a int32_t (or 16-bit) field using setPrimitiveValue forKey where I pass in an NSNumber @(11), the ManagedObject returns the new value properly, but a call to hasChanges returns NO.

Steps to Reproduce:
1) create a bunch of ManagedObjects in a MOC.
2) in a separate thread create a new MOC with the same persistentStoreCoordinator.
3) update an int32_t property in the objects using the new MOC and check the results of the hasChanges method.
4) using NSNotificationCenter import merge the changes in the background MOC into the primary MOC and check the value of the int32_t field you updated.

Expected Results:
i would expect the hasChanges in the managed object to return YES.

Actual Results:
the hasChanges method returns NO.

Regression:
Describe circumstances where the problem occurs or does not occur, such as software versions and/or hardware configurations.

Notes:
Provide additional information, such as references to related problems, workarounds and relevant attachments.

Comments

Works as documented

See: https://developer.apple.com/library/ios/documentation/cocoa/reference/CoreDataFramework/Classes/NSManagedObject_Class/Reference/NSManagedObject.html#//apple_ref/doc/uid/TP30001171-BBCEBFCH

"This method does not invoke the change notification methods (willChangeValueForKey: and didChangeValueForKey:). It is typically used by subclasses that implement custom accessor methods that need direct access to the receiver’s private internal storage. It is also used by the Core Data framework to initialize the receiver with values from a persistent store or to restore a value from a snapshot."

In your scenario you would have to wrap the calls to setPrimitiveValue:forKey: with willChangeValueForKey: and didChangeValueForKey: per the documentation. This is explored in more detail in the programming guide: https://developer.apple.com/library/ios/documentation/cocoa/Conceptual/CoreData/Articles/cdAccessorMethods.html#//apple_ref/doc/uid/TP40002154-SW5

By quellish at Nov. 20, 2013, 8:44 p.m. (reply...)

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