Crate backtrace_error

This is a tiny crate that provides a tiny error-wrapper struct BacktraceError with only two features:

• Captures a backtrace on From-conversion from its wrapped type (if RUST_BACKTRACE is on etc.)
• Pretty-prints that backtrace in its Display implementation.

It also includes an extension trait ResultExt that you can use to give you .unwrap_or_backtrace and .expect_or_backtrace methods on any Result<T, BacktraceError<E>>. These methods do do the same as unwrap or expect on Result except they pretty-print the backtrace on Err, before panicking.

Example

Usage is straightforward: put some existing error type in it. No macros!

use backtrace_error::{BacktraceError,ResultExt};
use std::{io,fs};
 
type IOError = BacktraceError<io::Error>;
 
fn open_file() -> Result<fs::File, IOError> {
   Ok(fs::File::open("/does-not-exist.nope")?)
}

fn do_stuff() -> Result<fs::File, IOError>
{
    open_file()
}
 
fn main()
{
    // This will panic but first print a backtrace of
    // the error site, then a backtrace of the panic site.
    let file = do_stuff().unwrap_or_backtrace();
}

I am very sorry for having written Yet Another Rust Error Crate but strangely everything I looked at either doesn’t capture backtraces, doesn’t print them, only debug-prints them on a failed unwrap (which is illegible), provides a pile of features I don’t want through expensive macros, or some combination thereof. I don’t need any of that, I just want to capture backtraces for errors when they occur, and print them out sometime later.

I figured maybe someone out there has the same need, so am publishing it.

Structs

BacktraceError

Traits

ResultExt