Easiest way to force a crash in Swift

Question

What is the easiest way to force a crash in Swift?

I would like to use only one line of code (something that I can add quickly).

I don't want to use breakpoints, I actually want the app to crash.

Solution 1

Typically you'd use

fatalError()

or

preconditionFailure()

for that.

These do exactly the same: terminating the program, therefore the code after this stamement never gets executed. All of the functions that have this behaviour are annotated with the @noreturn attribute

You can also do something like this:

func getInt() -> Int {
    fatalError()
}

The function is supposed to return an Int, but because the program never gets to that point, you don't have to return anything.

Solution 2

[0][1]

This tries to access second element of a one element array.

Solution 3

You can simply try to access an optional value that has nil value... if you already have a variable declared and it is an optional, just call it (don't forget to unwrap) and it will crash for sure

Solution 4

reversed ranges,

21...3

Thread 1: Fatal error: Can't form Range with upperBound < lowerBound

View more solutions

Comments

[Libor Zapletal]

Could this be in release app? Will it goes through a certification process? I mean of course app can't crash during the process but for me it just checks for exact date (after 2 months from now) and then fatalError is called.

[Kametrixom]

@LiborZapletal You app has to not crash a lot to get accepted, it's better to handle errors when they occur. Your app should only crash when something went terribly wrong

[julien_c]

[][0] is one character shorter 🤓

[Peter DeWeese]

Like the brevity, but it doesn't self document as well as fatalError().

[Mustafa]

While this code may answer the question, it would be better to include some context, explaining how it works and when to use it. Code-only answers are not useful in the long run.

[Sazzad Hissain Khan]

0/1 is three characters shorter 🤓

[RemembranceNN]

@SazzadHissainKhan 0/1 == 0 :-)

[Sazzad Hissain Khan]

@RemembranceNN then compiler should be changed. That’s really a wrong output.

[chadbag]

@SazzadHissainKhan. why is 0/1 wrong output to output 0? I think you mean 1/0.