Retain cycle in MKNetworkOperation completion handler

gistfile1.m

@interface Engine
+ (id)sharedEngine;
- (MKNetworkOperation*)someOperation:(CompletionBlock)block onError:(ErrorBlock)errorBlock;
@end



@interface MyViewController : UITableViewController
@property (nonatomic, strong) MKNetworkOperation* operation;
@end

@implementation MyViewController
@synthesize operation = operation;
- (void)setOperation:(MKNetworkOperation*)operation
{
  if (_operation == operation) return;

  [_operation cancel];
  _operation = operation;
}

- (void)viewDidAppear:(BOOL)animated
{
  self.operation = [[Engine sharedEngine] someOperation:^(NSArray* images)
     {   
        self.flickrImages = images;
        [self.tableView reloadData];//retain cycle here        
     }
     
     onError:^(NSError* error) {                                  
     }];
}

@end

My VC has a strong reference to the operation that in turn copies the completion block that retains `self`, this creates a retain cycle I believe.

A way to break it would be set the operation to nil in `viewDidDisapear:`
- (void)viewDidDisappear:(BOOL)animated
{
  self.operation = nil;
}


or to create a weak reference of self

- (void)viewDidAppear:(BOOL)animated
{
  __weak MyViewController* weakSelf = self;
  self.operation = [[Engine sharedEngine] someOperation:^(NSArray* images)
     {   
        weakSelf.flickrImages = images;
        [weakSelf.tableView reloadData];
     }
     
     onError:^(NSError* error) {                                  
     }];
}