Swift - release build crashes unless I turn off optimization

Question

This is on XCode 6.2.

If I run the app in release mode it will crash, but with optimizations off it does not crash. The code looks straightforward. I have programmed Obj

Answer 1

I had a similar scenario. Since I believe most people coming to this question are looking more for insight on what potentially causes this, I'll share what happened with my code.

I am using ReactiveCocoa in my project, and I set up a reactive signal to be fired anytime I had a UIView's selected stated change. It was custom view that mimics a button, but is actually derived from UIView. In this block, I was then setting all of the other button-like views in my view to have their selected states set to NO.

Without optimizations, this was executing fine. With optimizations, it descended into an infinite loop. Weird, eh?

In short, in my scenario, I changed this code:

[allButtons makeObjectsPerformSelector:@selector(setSelected:) withObject:@(NO)];

to this

for(MyButtonLikeView* button in allButtons) {
    if(button.selected) {
        button.selected = NO;
    }
}

I know this isn't likely going to be a solution to your problem. But I hope it's useful.

In summary, use your debugger and be on the lookout for code that is correct in Debug, but may suddenly stop working in Release.