JSON stringify returning invalid token `inf`

[richard-powers]

Zig Version

0.14.0

Steps to Reproduce and Observed Behavior

Min. repro:

const std = @import("std");

test {
    const foo = .{
        .a = std.math.inf(f32),
    };
    const str = try std.json.stringifyAlloc(std.testing.allocator, foo, .{});
    defer std.testing.allocator.free(str);
    std.log.warn("{s}", .{str});
}

The output: {"a":inf}

inf is not a valid token in JSON. In my opinion, a parsing error should be thrown in cases with infinite values.

Expected Behavior

An error should be returned, instead of malformed json.

[bradcypert]

I’d be interested in attempting to fix this!

[bradcypert]

Put together a small PR to test out the issue and provide a possible solution! I hope it helps! :)

[martindrlik]

You can do the same as JSON.stringify.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

The numbers Infinity and NaN, as well as the value null, are all considered null. (But unlike the values in the previous point, they would never be omitted.)

Output would be {"a":null}.

[nektro]

JS succeed and marshals as null
Go fails and returns an error

[bradcypert]

From RFC-7159: https://datatracker.ietf.org/doc/html/rfc7159#section-6

Numeric values that cannot be represented in the grammar below (such as Infinity and NaN) are not permitted.