Using parent NSManagedObjectContexts seems like a pain...

NSManagedObjectContext+ParentContextHelper.m

@implementation NSManagedObjectContext (ParentContextHelper)

/*
 * In sample code I see a lot of stuff like this when dealing with nested (parent) managed object contexts:
 *
 * [moc performBlock:^{
 *   NSError* error = nil;
 *   [moc save:&error];
 *   
 *    [moc.parentContext performBlock:^{
 *      NSError* error = nil;
 *      moc.parentContext save:&error];
 *    }];
 * }];
 *
 * (Example: http://stackoverflow.com/questions/19452487/core-data-parent-context-and-change-propagation)
 *
 * The problem with this is that each context has to know where it is in relation to the 
 * root context (i.e., the one with the persistent store).
 *
 * The approach below seems a bit hacky but I don't (currently) see why it wouldn't work. Is there
 * a better scheme?
 *
 */

- (void)propagateSave:(void (^)(NSError*))completionHandler {
    __weak typeof(self) weakSelf = self;
    [self propagateSave:completionHandler
              withBlock:^(void (^block)(void)){
                  [weakSelf performBlock:block];
              }];
}

- (void)propagateSaveAndWait:(void (^)(NSError*))completionHandler {
    __weak typeof(self) weakSelf = self;
    [self propagateSave:completionHandler
              withBlock:^(void (^block)(void)){
                  [weakSelf performBlockAndWait:block];
              }];
}

- (void)propagateSave:(void (^)(NSError *))completionHandler withBlock:(void (^)(void (^)(void)))blockName {
    __weak typeof(self) weakSelf = self;
    blockName(^{
        NSError* error = nil;
        BOOL retv = [weakSelf save:&error];
        if (retv && weakSelf.parentContext) {
            [weakSelf.parentContext propagateSave:completionHandler
                                        withBlock:blockName];
        }
        else if (completionHandler) {
            completionHandler(error);
        }
    });
}

@end