When should forced value extraction be used in Swift?

Forced unwrapping of optional types (using !) should be used very rarely and only in cases where you are absolutely sure that the optional contains a non-nil value.

Main use cases:

1. Testing and prototyping: For quick concept checks when it is not critical if the application crashes with nil.
2. Explicit false state: When nil of a forcibly unwrapped optional indicates a critical logic error that should be immediately detected (e.g., configuration failure or incorrect data state). Such errors are better handled more gracefully in production.
3. forceUnwrap during debugging: Sometimes used during debugging to quickly check a value, but this is a temporary solution.

Example (extremely cautious use):

// Example when you are *absolutely* sure that the nib file exists
class MyViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        // If MyView.xib does not exist, the app will crash.
        // This is DANGEROUS code in production!
        let myView = Bundle.main.loadNibNamed("MyView", owner: self, options: nil)![0] as! UIView
        view.addSubview(myView)
    }
}

Do not use forced unwrapping in the following cases:

• When there are doubts about the presence of a value.
• For handling potential user input or external data sources.
• In most production code where app crashes are unacceptable.

Preferred alternatives:

• if let or guard let for conditional unwrapping.
• nil-coalescing operator (??) to provide a default value.
• Optional chaining (?.) for conditional method calls or property access.