Restkit addFetchRequestBlock不会删除对象

Question

我有这段代码：

-(void)fetchCategoriesOnCompletion:(myCompletion) compblock{
    Mapper *mapper = [Mapper new];
    RKManagedObjectStore *store = [[ASLDataModel sharedDataModel] objectStore];
    NSManagedObjectContext *context = store.mainQueueManagedObjectContext;
    RKObjectManager *objectManager = [mapper mapReisCategorie];

    NSString *urlString = [NSString stringWithFormat:@"/webservice/category/get/apikey/%@/language/%@",apikey,language];

    [objectManager addFetchRequestBlock:^NSFetchRequest *(NSURL *URL) {
        RKPathMatcher *pathMatcher = [RKPathMatcher pathMatcherWithPattern:[NSString stringWithFormat:@"webservice/category/get/apikey/%@/language/%@",apikey,language]];

        NSDictionary *argsDict = nil;
        BOOL match = [pathMatcher matchesPath:[URL relativePath] tokenizeQueryStrings:NO parsedArguments:&argsDict];
        if (match) {
            NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Reiscategorie"];
            return fetchRequest;
        }

        return nil;
    }];

    NSURLRequest *request = [objectManager requestWithObject:nil method:RKRequestMethodGET path:urlString parameters:nil];
    NSLog(@"REQUEST URL IS %@",request.URL);

    RKManagedObjectRequestOperation *operation = [objectManager managedObjectRequestOperationWithRequest:request managedObjectContext:context success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
        NSError *error = nil;
        BOOL success = [context  save:&error];
        if (!success) RKLogWarning(@"Failed saving managed object context: %@", error);
        NSError *saveError = nil;
        compblock(YES);
    } failure:nil];

    [objectManager enqueueObjectRequestOperation:operation];
}

这应该删除核心数据中我没有从JSON返回的对象。它曾经工作，但突然间没有？ restkit有什么变化吗？