Exception thrown in NSOrderedSet generated accesso

Question

On my Lion app, I have this data model:

The relationship subitems inside Item is ordered.

Xcode 4.1 (build 4B110) has created for me the file Item.h, Item.m, SubItem.h and SubItem.h.

Here is the content (autogenerated) of Item.h:

#import <Foundation/Foundation.h>

#import <CoreData/CoreData.h>

@class SubItem;

@interface Item : NSManagedObject {
@private
}

@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) NSOrderedSet *subitems;
@end

@interface Item (CoreDataGeneratedAccessors)

- (void)insertObject:(SubItem *)value inSubitemsAtIndex:(NSUInteger)idx;
- (void)removeObjectFromSubitemsAtIndex:(NSUInteger)idx;
- (void)insertSubitems:(NSArray *)value atIndexes:(NSIndexSet *)indexes;
- (void)removeSubitemsAtIndexes:(NSIndexSet *)indexes;
- (void)replaceObjectInSubitemsAtIndex:(NSUInteger)idx withObject:(SubItem *)value;
- (void)replaceSubitemsAtIndexes:(NSIndexSet *)indexes withSubitems:(NSArray *)values;
- (void)addSubitemsObject:(SubItem *)value;
- (void)removeSubitemsObject:(SubItem *)value;
- (void)addSubitems:(NSOrderedSet *)values;
- (void)removeSubitems:(NSOrderedSet *)values;

@end

And here is the content (autogenerated) of Item.m:

#import "Item.h"
#import "SubItem.h"

@implementation Item

@dynamic name;
@dynamic subitems;

@end

As you can see, the class Item offers a method called addSubitemsObject:. Unfortunately, when trying to use it in this way:

Item *item = [NSEntityDescription insertNewObjectForEntityForName:@"Item" inManagedObjectContext:self.managedObjectContext];
item.name = @"FirstItem";

SubItem *subItem = [NSEntityDescription insertNewObjectForEntityForName:@"SubItem" inManagedObjectContext:self.managedObjectContext];

[item addSubitemsObject:subItem];

this error appear:

2011-09-12 10:28:45.236 Test[2002:707] *** -[NSSet intersectsSet:]: set argument is not an NSSet

Can you help me?

Update:

After just 1,787 days from my bug report, today (August 1, 2016) Apple wrote me this: "Please verify this issue with the latest iOS 10 beta build and update your bug report at bugreport.apple.com with your results.". Let's hope this is the right time :)

Answer 1

Robert,

I agree your answer will work for this, but keep in mind that there is an automatically created method for adding a whole set of values to a relationship already. Apple's Documentation (as seen here under the "To-many Relationships" section or here under the "Custom To-Many Relationship Accessor Methods" section) implements them this way:

- (void)addEmployees:(NSSet *)value
{
[self willChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueUnionSetMutation
      usingObjects:value];
[[self primitiveEmployees] unionSet:value];
[self didChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueUnionSetMutation
      usingObjects:value];
}

- (void)removeEmployees:(NSSet *)value
{
[self willChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueMinusSetMutation
      usingObjects:value];
[[self primitiveEmployees] minusSet:value];
[self didChangeValueForKey:@"employees"
      withSetMutation:NSKeyValueMinusSetMutation
      usingObjects:value];
}

You could easily compile your set of relationships outside of core data and then add them all at once using this method. It might be less ugly than the method you suggested ;)