action return incorrect int64_t value

[quocle108]

I expected to receive an action value is -90909090909090909. But the action return the value is -90909090909090910

  [[eosio::action]] int64_t getvalue2() {
        int64_t value = -90909090909090909;
        eosio::print("getvalue2: ", value);
        return value;
  }

You can reproduce this issue through this repo https://github.com/quocle108/return-error

[heifner]

Thanks for the excellent bug report.

[spoonincode]

There appears to be an oversight in fc's json conversion that doesn't stringify small values that can't be represented in a javascript number: -90909090909090909 is smaller than -(2⁵³ - 1)

leap/libraries/libfc/src/io/json.cpp

Lines 620 to 627 in 167bcf7

	case variant::int64_type:
	{
	int64_t i = v.as_int64();
	if( format == json::output_formatting::stringify_large_ints_and_doubles &&
	i > 0xffffffff )
	os << '"'<<v.as_string()<<'"';
	else
	os << i;

This would only be a problem when consuming the JSON returned from a trace via javascript though (i.e. cleos is fine); but that's likely what is happening here since using reporter is using qtest

[quocle108]

This would only be a problem when consuming the JSON returned from a trace via javascript though (i.e. cleos is fine); but that's likely what is happening here since using reporter is using qtest

it might be. Qtest gets the return value from eosjs. And javascript use Number (64-bit Floating Point) to present the number value, so rounding the number might be the issue?

BTW, it should be returned string in both cases even the value i > 0xffffffff or <= 0xffffffff.

[spoonincode]

Right, that number cannot be represented in a javascript primitive type. Just running

let x = -90909090909090909;
console.log(x);

in node,

$ node num.js
-90909090909090910

It would need to be represented as a bigint (or string).