ios - Referring to weak self inside a nested block

Question

Suppose I already create a weak self using

__weak typeof(self) weakSelf = self;
[self doABlockOperation:^{
        ...
}];

Inside that block, if I nest another block:

[weakSelf doAnotherBlockOperation:^{
    [weakSelf doSomething];
}

will it create a retain cycle? Do I need to create another weak reference to the weakSelf?

__weak typeof(self) weakerSelf = weakSelf;
[weakSelf doAnotherBlockOperation:^{
    [weakerSelf doSomething];
}

question from:https://stackoverflow.com/questions/17104634/referring-to-weak-self-inside-a-nested-block

Answer 1

Your code will work fine: the weak reference will not cause a retain cycle as you explicitly instruct ARC not to increase the retainCount of your weak object. For best practice, however, you should create a strong reference of your object using the weak one. This won't create a retain cycle either as the strong pointer within the block will only exist until the block completes (it's only scope is the block itself).

__weak typeof(self) weakSelf = self;
[self doABlockOperation:^{
    __strong typeof(weakSelf) strongSelf = weakSelf;
    if (strongSelf) {
        ...
    }
}];