Nate Stedman

In Swift code, there’s a potential strong reference leak hiding in nested closures:

foo({
    bar({ [weak self] in
        self?.baz()
    })
})

This code seems okay, since only bar refers to self, which is captured weakly. However, that’s not actually the case! foo captures self strongly. Instead:

foo({ [weak self] in
    bar({ [weak self] in
        self?.baz()
    })
})

Will work correctly. There is a proposal to change this.