Crate expect_exit

Display an error message and exit without a panic.

The expect-exit library defines the Expected, ExpectedWithError, and ExpectedResult traits and implements them for the standard Result and Option types as appropriate. This allows a program to display an error message and exit with a non-zero exit code without invoking a Rust panic, yet optionally unwinding the stack so that various objects may perform some clean-up actions.

The methods with an _e suffix append an appropriate error message to the supplied one. The methods with an _f suffix allow the caller to only build the error message if an error is to be reported, similar to the Option.or_else method.

use expect_exit::{Expected, ExpectedResult};

{
    env::var(name).or_exit_f(|| format!("{} not specified in the environment", name))

    fs::read_to_string(path).or_exit_e_f(|| format!("Could not read {:?}", path))

    tx.send(result).await.or_exit_e("Could not tell the main thread");

    let config = parse().expect_result("Could not parse the config")?;
    Ok(config.value + 1)
}

The traits are currently implemented for the standard Option and Result types as appropriate.

Structs

ExpectationFailed

The error object returned by the ExpectedResult methods.

Traits

Expected	Unwrap or exit with the specified message.
ExpectedResult	Test the value and return a result object containing either the inner value or an error object that, when displayed, will provide the specified error message.
ExpectedWithError	Unwrap or exit with an appropriate error message.

Functions

die	Display the specified message, then exit without unwinding the stack.
die_perror	Display the specified message and append an appropriate description of the error, then exit without unwinding the stack.
exit	Display the specified message, then unwind the stack and exit.
exit_perror	Display the specified message and append an appropriate description of the error, then unwind the stack and exit.
exit_unwind	Unwind the stack and end the process with the specified exit code.