Add support for fallible sanitizers ?

[vic1707]

I have a new type wrapping a std:::fs::PathBuf, I'd like for it to always be an absolute path.
std::fs::canonicalize does exactly that but is fallible (io::Result<Pathbuf>).
Is it feasible to add support for fallible sanitizers? Currently I can work around that limitation by unwraping it but I'm not a fan 😓.

use derive_more::derive::Display;
use nutype::nutype;
use serde::{Deserialize, Serialize};
use std::{fs, io, path::{Path, PathBuf}};

#[nutype(
    derive(
        Debug, Clone, PartialEq, Eq, PartialOrd, Ord,
        Serialize, Deserialize
    ),
    sanitize(with = fs::canonicalize), // Errors since it returns a Result
    validate(with = is_file_and_exists, error = Error)
)]
struct File(PathBuf);

fn is_file_and_exists<P: AsRef<Path>>(path: P) -> Result<(), Error> {
    let path = path.as_ref();
    if !path.exists() {
        return Err(Error::IoError(io::ErrorKind::NotFound.into()));
    }
    if !path.is_file() {
        return Err(Error::NotAFile);
    }
    Ok(())
}

#[derive(Debug, Display, thiserror::Error)]
enum Error {
	#[display("{_0}")]
	IoError(#[from] io::Error),
	#[display("Provided path isn't a file.")]
	NotAFile,
}

[greyblake]

Uh.
The short answer is no, there is no way to support fallible sanitizers, and I don't think it will be supported.
What is more realistically is to support validators that would return a new value in Ok().

But to be honest, I have never thought of the use case like this before.

[vic1707]

Understandable 👌

Would you be open to proposals, I'd like to give it a try to see what it would require ? 🙂

(I have no clue if it's even possible I'm just curious 😁)

[greyblake]

Would you be open to proposals

I am not sure yet. The problem with that is that it will break the conceptual model that exists at the moment.
It will also will require a lot of code changes and breaking the existing API.

Though, I don't wanna stop you from experimenting if you want to, I just don't feel committed to this at the moment.

[greyblake]

Do you have any other potential sanitization functions that could fail?

[vic1707]

Ok no problem 👌

I don't have any other fallible sanitization function in mind at the moment, if I find some I'll tell you