Error return type of TryFrom<Vec<u8>> for PrivateKeyDer<'_> doesn't impl std::error::Error

[paulcdejean]

I tried the following:

    let key = PrivateKeyDer::try_from(std::fs::read(key)?)?;

And I get the error:

? couldn't convert the error: str: std::error::Error is not satisfied
the question mark operation (?) implicitly performs a conversion on the error value using the From trait
required for &str to implement std::error::Error
required for anyhow::Error to implement From<&str>

Unfortunately &str doesn't impl core::error::Error, so using it as the error return type in a try_from can cause users of the library some difficulty. It would be better to instead return a type that impls core::error::Error in the error value.

[paulcdejean]

Example of a workaround:

PrivateKeyDer::try_from(std::fs::read(key)?).map_err(anyhow::Error::msg)?;

[djc]

We can't change this backward compatibly and I don't think it's important enough to do a 2.0 just for this. So we can consider this if we ever decide we want to do 2.0 for other reasons.

Meanwhile, there's an impl From<&str> for Box<dyn Error + Send + Sync + 'static> that you can use if you don't want to rely on anyhow.