Wrong float values via `findCustomMessageOption`

I ran into a float decoding issue with the output of findCustomMessageOption() when generating code for float validation rules as defined here:

https://github.com/bufbuild/protoc-gen-validate/blob/main/tests/harness/cases/numbers.proto#L8

The value 1.23 in that float.const option is turned into 1.2300000190734863 once it reaches my protoplugin code generator here.

As seen here (in the output): https://github.com/fubhy/protobuf-zod/blob/main/packages/protoc-gen-validate-zod/tests/harness/cases/numbers_zod.ts#L47-L51

Is that a known issue or am I doing sth. wrong or is there a bug with that? I can dig deeper myself if nothing comes to mind right away but I thought I’d ask first …

[smaye81]

Yeah meant to respond. After some investigation to verify we are parsing these correctly, this actually is expected just by the nature of precision with floating-point in JavaScript. There’s really not much we can do to alleviate it, since it’s part of the language itself.

[fubhy]

I guess it boils down to this …

const view = new DataView(new ArrayBuffer(16));
view.setFloat32(0, 1.23, true);
view.getFloat32(0, true); // 1.2300000190734863

Which, I guess, is expected.