impl std::error::Error for argonautica-rs error type

[kellenff]

It'd be great if I could use argonautica errors with snafu, which requires that errors embedded in custom error types implement std::error::Error.

I haven't found any reference to this yet, so I hope this isn't a duplicate feature request. I'm happy to look into writing a PR for this, as well.

[agaviria]

I wonder if the following std::error::Error implementation is suffice?

use std::err::Error as StdError;

impl StdError for Error {
    fn display(&self) -> &str {
        match *self {
            ErrorKind::AdditionalDataTooLongError(ref s) => s.display(),
            ErrorKind::BackendEncodeError(ref s) => s.display(),
            ErrorKind::BackendUnsupportedError(ref s) => s.display(),
            ErrorKind::Base64DecodeError(ref s) => s.display(),
            ErrorKind::Bug(ref s) => s.display(),
            ErrorKind::HashDecodeError(ref s) => s.display(),
            ErrorKind::HashEncodeError(ref s) => s.display(),
            ErrorKind::HashLenTooShortError(ref s) => s.display(),
            ErrorKind::HashMissingError(ref s) => s.display(),
            ErrorKind::IterationsTooFewError(ref s) => s.display(),
            ErrorKind::LanesTooFewError(ref s) => s.display(),
            ErrorKind::LanesTooManyError(ref s) => s.display(),
            ErrorKind::MemoryAllocationError(ref s) => s.display(),
            ErrorKind::MemorySizeInvalidError(ref s) => s.display(),
            ErrorKind::MemorySizeTooSmallError(ref s) => s.display(),
            ErrorKind::OsRngError(ref s) => s.display(),
            ErrorKind::PasswordImmutableError(ref s) => s.display(),
            ErrorKind::PasswordMissingError(ref s) => s.display(),
            ErrorKind::PasswordTooLongError(ref s) => s.display(),
            ErrorKind::PasswordTooShortError(ref s) => s.display(),
            ErrorKind::SaltTooLongError(ref s) => s.display(),
            ErrorKind::SaltTooShortError(ref s) => s.display(),
            ErrorKind::SecretKeyImmutableError(ref s) => s.display(),
            ErrorKind::SecretKeyMissingError(ref s) => s.display(),
            ErrorKind::SecretKeyTooLongError(ref s) => s.display(),
            ErrorKind::ThreadError(ref s) => s.display(),
            ErrorKind::ThreadsTooFewError(ref s) => s.display(),
            ErrorKind::ThreadsTooManyError(ref s) => s.display(),
            ErrorKind::Utf8EncodeError(ref s) => s.display(),
            ErrorKind::VariantEncodeError(ref s) => s.display(),
            ErrorKind::VersionEncodeError(ref s) => s.display(),
            _ => __Nonexhaustive,
        }
    }
}

Unfortunately, I'm encountering a build error so I cannot test if this works.

error: failed to run custom build command for `argonautica v0.2.1 (/Users/ag/rust/argonautica/argonautica-rs)`

Caused by:

process didn't exit successfully: `/Users/ag/rust/argonautica/target/debug/build/argonautica-eab0f3f8753de6f4/build-script-build` (exit code: 1)
 --- stderr
 Error: Os { code: 2, kind: NotFound, message: "No such file or directory" }

[meh]

Any update on this? It's very annoying right now to bubble up errors from argonautica with stuff like anyhow because of this.

[ManevilleF]

using the crate thiserror the Error implementation could be quite easy

[ManevilleF]

If someone know why my pull request (https://github.com/bcmyers/argonautica/pull/38) is failing : https://travis-ci.org/github/bcmyers/argonautica/jobs/761279238 I'd like some help.

For some reason, and I think it might come from the build script, the thiserror crate is not found