Disallow serde serialize/deserialize unsigned integer types

[zonyitoo]

• Disallow u16, u32 and u64 to be serialize to / deserialize from BSON

[kyeah]

Should we replace these with functions that users can refer to, so people can still keep the original functionality if necessary?

// something like this -- pseudocode!

#[inline]
fn serialize_u64_into_f64(serializer: Encoder, value: u64) -> EncoderResult<Bson> {
    serializer.serialize_f64(value as f64)
}

#[derive(Serialize, Debug)]
struct Thing {
    #[serde(serialize_with = "bson::encoder::serialize_u64_into_f64")]
    s: u64,
}

reference

[zonyitoo]

Hmm, maybe. But I don't think it is correct to serialize u64 to f64.

It is reasonable to do this for compatibility.

[zonyitoo]

Added backward compatibility support mod u2f

#[test]
fn test_compat_u2f() {
    #[derive(Serialize, Deserialize, Eq, PartialEq, Debug)]
    struct Foo {
        #[serde(with = "bson::compat::u2f")]
        x: u32
    }

    let foo = Foo { x: 20 };
    let b = bson::to_bson(&foo).unwrap();
    assert_eq!(b, Bson::Document(doc! { "x" => (Bson::FloatingPoint(20.0)) }));

    let de_foo = bson::from_bson::<Foo>(b).unwrap();
    assert_eq!(de_foo, foo);
}

[kyeah]

nice, LGTM. unfortunate that we don't have a changelog to document this 😅 Maybe we should add a section in the README to document the fact that mongodb doesn't support unsigned integers, and this module is provided for serialization compatibility.

[zonyitoo]

@kyeah How about this?

[kyeah]

some small grammatical comments but looks good otherwise. Thanks for adding it!

[kyeah]

"In the BSON specification, unsigned integer types are unsupported; for example"...

[kyeah]

we => we've

[kyeah]

uses => use

"the bson::compat::u2f::serialize and bson::compat::u2f::deserialize methods"

[zonyitoo]

Already done.

[kyeah]

awesome, LGTM!

[zonyitoo]

Already published to crates.io.