error-stack: custom exit codes

[gluax]

Feature

I think a great feature to add to the error-stack library would be a method on the report that lets you change the exit code.

Motivation

Depending on the type of application you are writing, an exit code can give a lot of information to the user.

By default, Result types can be returned from the main function and provide an exit code. However, all error-stack errors currently return an exit code of 1.

Implementation

A method, exit_code(&self, code: i32) or could be named attach_exit_code(...) for symmetry, could be added to the Report struct, or maybe the ResultExt trait might be a better place for it.

The following steps would be to use Rust's Termination trait. This method is already implemented on the Result type by default, and error-stack conveniently exposes a Result alias that's more specific. So I believe just adding this trait implementation over the Report type would work, and by default, it could return an exit code of 1 as it currently does. This default behavior also aligns with Rust's errors.

If the idea seems beneficial to the crate, I'd be willing to take a stab at this and open a PR.

[TimDiekmann]

Hi @gluax and thanks for filing this!

I added a few comments to your linked PR 🙂