Colorful errors

[Sk7Str1p3]

Summary 💡

Implement colored error and panic reports

Motivation 🔦

As a follow-up to #1634, which added colour to the CLI interface, we should implement something similar for errors and panics. I think this would make them easier to read and more user-friendly.

I came up with 3 options of implementing this:
1). Simply replace anyhow with color-eyre

• pros:
  • easy to drop-in replace anyhow
• cons:
  • bring some odd dependencies (e.g. tracing, backtrace)
  • not that flexible, can be confusing if .context() called many times

2. Add eyre and implement custom error report

• pros:
  • easy to drop-in replace anyhow
  • customisable
• cons:
  • reports are not so detailed, requires many extension traits to get detailed report
  • can be confusing if error has many sources

3. Use miette

• pros:
  • really comprehensive and beatiful error reports
  • derive macros for error types
• cons:
  • probably overkill
  • 2MB built with --release, really big crate

[spenserblack]

Could we just change main to not explicitly return a Result, and instead catch the result and manually add colors?

[Sk7Str1p3]

You suggest something like this?

fn main() {
    if let Err(e) = fallible_main() {
        // print error somehow
        exit(1)
    }
}

fn fallible_main() -> Result<()> {
    // Actual `main` fn
}

It doesn't look like good approach for me. Furthermore, current error handling with anyhow also doesn't seem to be proper solution, since onefetch is a library crate.

[spenserblack]

It doesn't look like good approach for me.

Why not? Pro for me is not needing to pull in a new crate and/or significantly change most of the error handling. What are the cons for you?