Unexplained `capturing self strongly` warning

Question

I have a number of methods in blocks, firing one inside the next, in order to sync some data with a web service. Most of these behave completely fine, but one method won't let me mention self after it's been called, giving me a capturing self strongly in this block is likely to lead to a retain cycle warning.

Here's what I mean:

[self deleteEntriesCorrespondingToDeletedNotesInNotebook:notebook success:^{
    [self deleteNotesToMatchDeletedEntriesWithCompletion:^{
       [self deleteResourcesToMatchDeletedMediaItemsWithCompletion:^{
           [self addOrUpdateEntriesCorrespondingToUpdatedNotesInNotebook:notebook success:^{
               //Anything calling a property or self after this point is a problem and gives the warning
               [self addOrUpdateNotesCorrespondingToUpdatedEntriesWithCompletion:^{

               }];
           }failure:^{

           }];
       }];
   }];
}failure:^{

}];

Any ideas why only items passed this point have a problem with this? If I replace the method before it with another similar method, there isn't a problem. The problem is only existent after addOrUpdateEntriesCorrespondingToUpdatedNotesInNotebook: is used.

Answer 1

[self deleteEntriesCorrespondingToDeletedNotesInNotebook:notebook success:^{
    [self deleteNotesToMatchDeletedEntriesWithCompletion:^{  //this line here and the rest in your downward loop

dont use self. Instead do this before the first line

__typeof__(self) __weak _weakSelf = self; and then from second line onwards, replace self with weakSelf

try this. cheers

Answer 2

All of your methods could "behave fine" or create a retain cycle, depending on what they do with the completion block.

As explained here: Blocks retain cycle from naming convention? , the clang compiler uses naming conventions to decide whether to emit a warning or not: All methods add... and set... (but not addOperationWithBlock !) cause a warning, other methods don't.