Example of backtrace usage in thiserror

thiserror_backtrace.rs

#![feature(backtrace)]

extern crate thiserror;

use thiserror::Error;
use std::backtrace::Backtrace;

#[derive(Error, Debug)]
pub enum DataStoreError {
    //#[error("data store disconnected")]
    //Disconnect(#[from] io::Error),
    #[error("the data for key `{0}` is not available")]
    Redaction(String),
    #[error("invalid header (expected {expected:?}, found {found:?})")]
    InvalidHeader {
        expected: String,
        found: String,
        backtrace: Backtrace,
    },
    #[error("unknown data store error")]
    Unknown,
}

pub fn explode() -> Result<(),DataStoreError> {
    Err(DataStoreError::InvalidHeader { expected: "A".to_owned(), found: "B".to_owned(), backtrace: Backtrace::force_capture() })
}

fn main() {
    use std::error::Error;
    let e = explode().err().unwrap();
    let b = e.backtrace();
    println!("e = {}", e);
    println!("b = {:?}", b);
}

this code does not seem valid anymore in current rust (1.69) since about 1.65 where std::backtrace::Backtrace was stabilized but now does not have any method named .backtrace() anymore, also requires to use #![feature(error_generic_member_access)] and #![feature(provide_any)] the updated part would look something like:

// instead of e.backtrace();
let b = std::any::request_ref::<std::backtrace::Backtrace>(&e);
// but request_ref now returns a Option instead of always a Backtrace