Print a backtrace/spantrace to debug logs not to stderr

[gibfahn]

Print a backtrace/spantrace to debug logs not to stderr

[gibfahn]

I tried a few more things, and as far as I can tell:

A spantrace is mostly useful if you have #[instrument] calls in all your functions. Setting this up means the compact tracing logs start including the function name in them (with as far as I can tell no way to disable it). So avoiding this for now.

A backtrace is more likely to be what I want, but the RUST_BACKTRACE style env vars are only checked at color_eyre setup (config), so changing them later doesn't do anything.

I think what I want is something like this:

    if std::env::var("RUST_BACKTRACE").is_err() {
        std::env::set_var("RUST_BACKTRACE", "1");
    }

    // Rest of program execution goes here.

    // Print the backtrace.
    debug!("Run result: {result}");
    if let Err(report) = result.as_mut() {
        if let Some(handler) = report.handler_mut().downcast_mut::<color_eyre::Handler>() {
            if let Some(backtrace) = handler.backtrace_mut() {
                // Remove the backtrace.
                let _ = backtrace.take();
            }
        }
    }

	// Return the program result, not printing the backtrace.
    return result;

but handler.backtrace_mut() isn't a thing.