Trait ErrorTrace 

pub trait ErrorTrace: Error {
    // Required methods
    fn freeze(&self) -> FrozenTrace;
    fn trace(&self) -> ErrorTraceFormatter<'_, '_, '_>;
    fn trace_colored(&self) -> ErrorTraceColorFormatter<'_, '_, '_>;
}

Allows one to write an error and all of its dependencies.

Example

use std::error::Error;
use std::fmt::{Display, Formatter, Result as FResult};

use error_trace::ErrorTrace as _;

#[derive(Debug)]
struct SomeError {
    msg: String,
}
impl Display for SomeError {
    fn fmt(&self, f: &mut Formatter<'_>) -> FResult { write!(f, "{}", self.msg) }
}
impl Error for SomeError {}

#[derive(Debug)]
struct HigherError {
    msg:   String,
    child: SomeError,
}
impl Display for HigherError {
    fn fmt(&self, f: &mut Formatter<'_>) -> FResult { write!(f, "{}", self.msg) }
}
impl Error for HigherError {
    fn source(&self) -> Option<&(dyn 'static + Error)> { Some(&self.child) }
}



let err = HigherError {
    msg:   "Oh no, something went wrong!".into(),
    child: SomeError { msg: "A specific reason".into() },
};
assert_eq!(
    err.trace().to_string(),
    r#"Oh no, something went wrong!

Caused by:
 o A specific reason

"#
);

Required Methods

fn freeze(&self) -> FrozenTrace

“Freezes” the trace of this error.

This is useful in case you’re dealing with errors where you don’t want to propagate the type (e.g., due to lifetimes) but do want to propagate the trace.

Returns

A FrozenTrace that returns the same trace when formatter, except all errors are serialized to Strings.

Example

use error_trace::ErrorTrace as _;

let err = HigherError {
    msg:   "Oh no, something went wrong!".into(),
    child: SomeError { msg: "A specific reason".into() },
};
assert_eq!(
    err.freeze().trace().to_string(),
    r#"Oh no, something went wrong!

Caused by:
 o A specific reason

"#
);

fn trace(&self) -> ErrorTraceFormatter<'_, '_, '_>

Returns a formatter for showing this Error and all its sources.

This function can be used similarly to Path::display(), since its result implements Display.

Returns

A new ErrorTraceFormatter that implements Display.

Example

use error_trace::ErrorTrace as _;

let err = HigherError { msg: "Oh no, something went wrong!".into(), child: SomeError { msg: "A specific reason".into() } };
assert_eq!(err.trace().to_string(), r#"Oh no, something went wrong!

Caused by:
 o A specific reason

"#);

fn trace_colored(&self) -> ErrorTraceColorFormatter<'_, '_, '_>

Available on crate feature colors only.

Returns a formatter for showing this Error and all its sources with nice colors.

This function can be used similarly to Path::display(), since its result implements Display.

Returns

A new ErrorTraceColorFormatter that implements Display.

Example

use error_trace::ErrorTrace as _;

let err = HigherError { msg: "Oh no, something went wrong!".into(), child: SomeError { msg: "A specific reason".into() } };
assert_eq!(err.trace_colored().to_string(), r#"Oh no, something went wrong!

Caused by:
 o A specific reason

"#);

Implementors

impl<T: ?Sized + Error> ErrorTrace for T