A more ergonomic way for adding context that needs formatting about anyhow HOT 1 CLOSED

use anyhow::{anyhow, Error, Result};
use std::fmt;

trait LazyContext<T, E> {
    fn context(self, args: fmt::Arguments) -> Result<T, Error>;
}

impl<T, E> LazyContext<T, E> for Result<T, E>
where
    Self: anyhow::Context<T, E>,
{
    fn context(self, args: fmt::Arguments) -> Result<T, Error> {
        match self {
            Ok(ok) => Ok(ok),
            Err(_) => anyhow::Context::context(self, args.to_string()),
        }
    }
}

fn main() -> Result<()> {
    fn f(_: usize) -> Result<()> { Err(anyhow!("something wrong")) }

    let id = 0;
    f(id).context(format_args!("failed to fetch id {}", id))?;
    Ok(())
}