Better default error for `var(...)`

[clifton]

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: EnvVar(NotPresent)'

I was looking into mapping the error and adding context (eg, "missing VAR_XYZ"), but it would be a breaking API change. Any suggestions for how to structure that change?

[allan2]

This is a great idea that is definitely worth implementing. I opened a discussion (#25) for this.

Maybe something like this?

// dotenvy::Error
enum Error {
    LineParse(String, usize),
    Io(Error),
    EnvVar(VarError, String),  // name is here
}

This is just a suggestion. It could be possible that the name information could be used for other variants like LineParse, I am not sure yet.

[clifton]

Great, thanks