Struct Report 

pub struct Report<E>(/* private fields */);

Opinionated solution to format an error in a user-friendly way. Useful as the return type from main and test functions.

Most users will use the snafu::report procedural macro instead of directly using this type. To use it directly, change the return type of the function to Report and wrap the body of your function with Report::capture.

Nightly Rust

Enabling the unstable-try-trait feature flag will allow you to use the ? operator directly:

use snafu::{prelude::*, Report};

fn main() -> Report<PlaceholderError> {
    let _v = may_fail_with_placeholder_error()?;

    Report::ok()
}

Interaction with the Provider API

If you return a Report from your function and enable the unstable-provider-api feature flag, additional capabilities will be added:

1. If provided, a Location will be appended to each error message.
2. If provided, a Backtrace will be included in the output.
3. If provided, a ExitCode will be used as the return value.

Stability of the output

The exact content and format of a displayed Report are not stable, but this type strives to print the error and as much user-relevant information in an easily-consumable manner

Implementations

impl<E> Report<E>

pub fn from_error(error: E) -> Self

Convert an error into a Report.

use snafu::{prelude::*, Report};

#[derive(Debug, Snafu)]
struct PlaceholderError;

fn main() -> Result<(), Report<PlaceholderError>> {
    let _v = may_fail_with_placeholder_error().map_err(Report::from_error)?;
    Ok(())
}

fn may_fail_with_placeholder_error() -> Result<u8, PlaceholderError> {
    Ok(42)
}

pub fn capture(body: impl FnOnce() -> Result<(), E>) -> Self

Executes a closure that returns a Result, converting any error to a Report.

use snafu::{prelude::*, Report};

#[derive(Debug, Snafu)]
struct PlaceholderError;

fn main() -> Report<PlaceholderError> {
    Report::capture(|| {
        let _v = may_fail_with_placeholder_error()?;

        Ok(())
    })
}

fn may_fail_with_placeholder_error() -> Result<u8, PlaceholderError> {
    Ok(42)
}

pub const fn ok() -> Self

A Report that indicates no error occurred.

Trait Implementations

impl<E> Debug for Report<E>

where E: Error,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<E> Display for Report<E>

where E: Error,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<E> From<Result<(), E>> for Report<E>

fn from(other: Result<(), E>) -> Self

Converts to this type from the input type.

impl<E> Termination for Report<E>

where E: Error,

Available on crate feature std only.

fn report(self) -> ExitCode

Is called to get the representation of the value as status code. This status code is returned to the operating system.