Trait error_stack::Context

pub trait Context: Display + Debug + Send + Sync + 'static { }

Defines the current context of a Report.

When in a std environment or on a nightly toolchain, every Error is a valid Context. This trait is not limited to Errors and can also be manually implemented on a type.

Example

Used for creating a Report or for switching the Report’s context:

use std::{fmt, fs, io};

use error_stack::{Context, Result, ResultExt, Report};

#[derive(Debug)]
pub enum ConfigError {
    ParseError,
}

impl fmt::Display for ConfigError {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        ...
    }
}

// In this scenario, `Error` is not implemented for `ConfigError` for some reason, so implement
// `Context` manually.
impl Context for ConfigError {}

pub fn read_file(path: &str) -> Result<String, io::Error> {
    // Creates a `Report` from `io::Error`, the current context is `io::Error`
    fs::read_to_string(path).map_err(Report::from)
}

pub fn parse_config(path: &str) -> Result<Config, ConfigError> {
    // The return type of `parse_config` requires another context. By calling `change_context`
    // the context may be changed.
    read_file(path).change_context(ConfigError::ParseError)?;

    ...
}

Implementors

impl<C: Error + Send + Sync + 'static> Context for C