Q: why does Option::get() may return null?

[nzour]

Just noticed that Option::get() may return null value.
Are there any specific reasons for this behavior?

I mean, there are other implementations of Option and non of them do return null value.

Java

public T get() {
    if (value == null) {
        throw new NoSuchElementException("No value present");
    }

    return value;
}

Scala

def get: Nothing = throw new NoSuchElementException("None.get")

Rust

pub fn unwrap(self) -> T {
    match self {
        Some(val) => val,
        None => panic!("called `Option::unwrap()` on a `None` value"),
    }
}

Maybe there is a contract for Option to have that kind of behavior?

[whsv26]

There are cases like Option<non-empty-list<int>>. You would expect to use $nonEmptyListOption->getOrElse([]), but getOrElse signature is

   /**
     * @psalm-param A $fallback
     * @psalm-return A
     */
    public function getOrElse(mixed $fallback): mixed

And psalm will issue an error cause of [] is not non-empty-list. In this case it's convenient to use $nonEmptyListOption->get() ?? []

[whsv26]

In scala getOrElse default value type is supertype of option value type, but I don't see a way to implement this in psalm.

final def getOrElse[B >: A](default: => B): B

[nzour]

Got it, thanks for replying