jedisct1/rust-xfailure

Helper macros for using failure in a more traditional way

xfailure

The bail! macro from the failure crate doesn't behave in an intuitive way, and returns a string instead of the actual error.

This situation may change in the future. Meanwhile, this trivial crate provides an xbail! macro that acts like error_chain's bail! macro.

xfailure is also available on crates.io.

rust-xfailure's Issues

Type of xbail!(...) is not `!`

Using xbail does not correctly mark subsequent code as unreachable, the way return (or any other "abrupt" expression like panic or break) would.

use failure::Error;
use xfailure::xbail;

pub fn f(cond: bool) -> Result<(), Error> {
    let x;
    if cond {
        x = 1;
    } else {
        xbail!(std::io::Error::from_raw_os_error(22));
    }
    println!("{}", x);
    Ok(())
}

error[E0381]: borrow of possibly-uninitialized variable: `x`
  --> src/main.rs:12:20
   |
12 |     println!("{}", x);
   |                    ^ use of possibly-uninitialized `x`

Using return instead of xbail in the repro makes it compile correctly.

- xbail!(std::io::Error::from_raw_os_error(22));
+ return Err(Error::from(std::io::Error::from_raw_os_error(22)));

I think xbail should expand to a return expression, not ?.