Why when saving an NSINteger to NSSNumber results in NSNumber having random weird result

Question

item.itemId is in coredata as an NSNumber and itemModel.itemID is a NSInteger. When saving itemModel.itemId to the itemId in core data it prints out -31016 for item.ItemID and 100056 for the NSInteger.

The following two lines prints out -31016 100056.

item.itemId = [NSNumber numberWithInteger:itemModel.itemId];
NSLog(@"%@ %ld",item.itemId,(long)itemModel.itemId);

ItemId is model i've created and itemId is declared like this.

@property (assign, nonatomic) NSInteger itemId

The value for itemID is set like this coming from the server as an integer.

self.itemId = [attributes[@"Id"] integerValue];

Answer 1

Your Core Data attribute is problaby defined as Integer 16. In that case, all values stored in the Core Data object are (silently) truncated to 16-bit. In your example:

100056 = 0x186D8

is truncated to

-31016 = 0x86D8

Changing the attribute to Integer 32 or Integer 64 should solve the problem.