Issuing

Issue is a small but detailed error wrapper that can be handled by upstream code and can be built from other types.

The problem it solves

Easy, fast reporting to the user via a CLI with enough information.

Usage

This type is not meant to be used by ordinary people writing code, but by library backends defining custom errors:

use libutils_issue::Issue;

enum MyError {
    FirstCause,
    SecondCause
}

impl Into<Issue> for MyError {
    fn into(self) -> Issue {
        return match self {
            MyError::FirstCause => Issue {name: "error 1", ..},
            MyError::SecondCause => Issue {name: "error 2", ..}
        }
    }
}

Then, libraries might use it in two ways:

• By returning it to the user on Result<Type, Issue> with standard try-trait workflow,
• By submitting it to a type that implements SystemIO (see systemio for that)

When to use it

This error type is meant to be used for errors whose failure might interest the user. Common examples are:

• A file doesn't exist
• The input wasn't correct
• Couldn't fetch

Examples for instances in which you should not use it:

• The program internals failed

For that second case, you should likely use .unwrap() or .expect(&'static str) instead.