[wtfishackernews]

For json marshalling, I would defer to the underlying type's marshalling if it's present, and return `null` otherwise.

[shhsshs]

I think this is appropriate in some cases but not others. For example how does the JSON value distinguish between `Some(null)` and `None`?

[dialogbox]

IMO using Optional type means the inner value must be not null. And if it's Some(null), it should mean exactly same as None.

[uryga]

distinguishing `Some(null)` and `None` is often considered a feature of Optional ;)

to use a tired example: when getting a value out of a map via some `myMap.get(key)`, you may want to distinguish "not present" = `None` and "present, with value null" = `Some(null)`

the right solution is to just not have nulls in the first place, then there's no problem ;)

[alophawen]

(Assuming we are discussing the Option type from rust)

Some(null) is not a valid result.

The whole point of the Option type is to let you know:

a) we got a result: Some(value)

b) there is no result: None

[andrewjf]

It's trivial to store a null pointer in an Option::Some().

  struct Foo;
  
  fn main() {
      let option_with_null: Option<*const Foo> = Some(std::ptr::null());
  
      dbg!(option_with_null);
      dbg!(option_with_null.is_none());
  }

Output:

  [src/main.rs:6] option_with_null = Some(
      0x0000000000000000,
  )
  [src/main.rs:7] option_with_null.is_none() = false

https://play.rust-lang.org/?version=stable&mode=debug&editio...

[alophawen]

As the creator of the function, you should try to adhere to the conventions and not try to break them.

[andrewjf]

I don't disagree, but:

> Some(null) is not a valid result.

It is a valid result. Null pointer and Option::None are still different things, is all.