u64 result type is not working as expected in ffi/dlopen

[cztomsik]

if you return u64::MAX from rust and then use dlopen() with { ..., result: u64 } you will get a different value in JS.

It does exactly the same thing if you input it to a deno console but that's probably unrelated:

Deno 1.14.0
exit using ctrl+d or close()
> 18446744073709551615
18446744073709552000
> 

Maybe this is expected behavior but it should be at least documented and I would say it's not terribly useful then for native plugins. Maybe it should return BigInt instead?

rust example:

#[no_mangle]
pub extern "C" fn test_u64() -> u64 {
    u64::MAX
}

deno

const lib = Deno.dlopen(libFile, {
    test_u64: { parameters: [], result: 'u64' }
}
lib.symbols.test_u64() // should return u64::MAX, probably as BigInt but it doesnt

[kevinkassimo]

The internal serdes library serde_v8 forwards all f32/f64/u64 to f64 (normal JS numbers). Opened an issue there: https://github.com/denoland/serde_v8/issues/43

[irbull]

The internal serdes library serde_v8 forwards all f32/f64/u64 to f64 (normal JS numbers). Opened an issue there: denoland/serde_v8#43

It looks like that repository has been archived. There is some good discussion on that thread about opaque pointers. Should that discussion be moved here?

[lucacasonato]

This is now fixed.