A fix for a bug in -countForFetchRequest: in iOS versions prior to 4.0. If you have multiple stores at the base of your CoreData stack, it would throw an exception. The fix below swaps out the faulty version with one which directs the request at the corre

gistfile1.m

@interface NSManagedObjectContext (AQFixedCountForFetchRequestOnIOS32)
@end

@implementation NSManagedObjectContext (AQFixedCountForFetchRequestOnIOS32)

+ (void) load
{
	// +load gets called per-category, unlike +initialize
	if ( [[[UIDevice currentDevice] systemVersion] compare: @"4.0" options: NSNumericSearch] == NSOrderedAscending )
	{
		// swap the broken method with our fixed version
		Method brokenMethod = class_getInstanceMethod(self, @selector(countForFetchRequest:error:));
		Method fixedMethod = class_getInstanceMethod(self, @selector(ipad32_fixed_countForFetchRequest:error:));
		method_exchangeImplementations(brokenMethod, fixedMethod);
	}
}

- (NSUInteger) ipad32_fixed_countForFetchRequest: (NSFetchRequest *) request error: (NSError **) error
{
	NSManagedObjectModel * model = [[self persistentStoreCoordinator] managedObjectModel];
	
	for ( NSPersistentStore * store in [[self persistentStoreCoordinator] persistentStores] )
	{
		if ( [[model entitiesForConfiguration: [store configurationName]] containsObject: [request entity]] )
		{
			[request setAffectedStores: [NSArray arrayWithObject: store]];
			break;
		}
	}
	
	// remember: the implementation was *swapped*
	return ( [self ipad32_fixed_countForFetchRequest: request error: error] );
}

@end