Unreachable log info of frame_try_runtime::TryRuntime

[Chralt98]

Discussed in #361

^{Originally posted by Chralt98 May 23, 2022}
This will never get printed, if it relies on frame-executive. Because the first unwrap in try_runtime_upgrade() would lead to a panic, therefore the code stops executing and wouldn't reach the log::info from the call stack.

#![allow(unused)]
fn main() {
  try_runtime_upgrade().map_err(|err| {
      println!("Additional information");
      err
  }).unwrap();
}

fn try_runtime_upgrade() -> Result<(), &'static str> {
    let x: Result<(), &'static str> = Err("fatal error").unwrap();
    Ok(())
}

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: "fatal error"', src/main.rs:7:58

"Additional information" never mentioned.

[shawntabrizi]

You shouldn't be using unwrap, you should be handling the result with something like ? or similar.

Of course if you unwrap and cause a panic, you will not trigger proper Rust error handling.

[Chralt98]

My question: Isn't this code unreachable?

[weichweich]

Yes that code is unreachable. I think at time of writing I didn't expect that Executive::try_runtime_upgrade() panics if the try runtime encountered an error.