RunError is not a proper Error

[vorner]

When working with current_thread::Runtime::run, I've noticed the returned RunError does not implement Error (so it is uncomfortable to handle as an error). It also doesn't seem to have any documentation (it is not a link), no idea why, so it is not clear under which circumstances it can happen.

[carllerche]

👍 would appreciate a PR.

[kpp]

@vorner would you please provide a MRE to test against?

[vorner]

I'll probably provide even the PR later this weekend, but here goes the MRE (if MRE is Minimum Reproducer or something like that).

extern crate failure;
extern crate tokio;

use failure::Error;
use tokio::prelude::future;
use tokio::runtime::current_thread::Runtime;

fn main() -> Result<(), Error> {
    let mut runtime = Runtime::new()?;
    // Well, this one would actually spawn some things…
    runtime.block_on(future::ok::<_, Error>(()))?;
    // This should wait for the rest of the spawned things… but it doesn't work, because RunError
    // doesn't implement the Error trait
    runtime.run()?;
    Ok(())
}

I went this way in actual real code, because current_thread::run doesn't allow the initialization future to error out and abort on startup.

Both tokio and failure are on their newest versions.

[carllerche]

The PR has been merged 👍 Thanks again.