Struct Error 

pub struct Error { /* private fields */ }

An error type that wraps an inner type-erased boxed std::error::Error or an Exn frame.

In that, it’s similar to anyhow, but with support for tracking the call site and trees of errors.

Warning: source() information is stringified and type-erased

All source() values when created with Error::from_error() are turned into frames, but lose their type information completely. An existing Error is retained as a nested error instead. This is because they are only seen as reference and thus can’t be stored.

The auto-chain-error feature

If it’s enabled, this type is merely a wrapper around ChainedError. This happens automatically so applications that require this don’t have to go through an extra conversion.

When both the tree-error and auto-chain-error features are enabled, the tree-error behavior takes precedence and this type uses the tree-based representation.

Implementations

impl Error

Utilities

pub fn error(&self) -> &(dyn Error + 'static)

Return the error stored at this error boundary.

This is the first error yielded by Self::iter_errors() and is distinct from Self::probable_cause().

pub fn probable_cause(&self) -> &(dyn Error + 'static)

Return the error that is most likely the root cause, based on heuristics. Note that if there is nothing but this error, i.e. no source or children, this error is returned.

pub fn iter_errors(&self) -> impl Iterator<Item = &(dyn Error + 'static)> + '_

Return the stored error and all frame errors and native sources reachable from it, recursively expanding nested Error values.

The first item is the error stored inside this Error, not this Error wrapper. Remaining errors are ordered logically breadth-first; a frame’s direct native source precedes its explicitly raised child frames. These are references to the underlying errors, so their concrete types remain available for downcasting and their own Display implementations can be used. Use Self::iter_errors_with_locations() to access caller locations.

pub fn iter_errors_with_locations( &self, ) -> impl Iterator<Item = DisplaySource<'_>> + '_

Return the same errors as Self::iter_errors(), paired with their captured caller locations where available and in the same order.

pub fn can_retry(&self) -> bool

Return true if any stored error, or an error in its source() chain, is:

• explicitly marked with RetryableError, or
• an std::io::Error with kind Interrupted, UnexpectedEof, OutOfMemory, TimedOut, BrokenPipe, AddrInUse, ConnectionAborted, ConnectionReset, or ConnectionRefused.

Nested Error values are inspected recursively. false only means that no known retryable error was found; it does not guarantee that retrying cannot succeed.

pub fn is_corrupted(&self) -> bool

Return true if malformed or internally inconsistent data caused the failure.

pub fn is_not_found(&self) -> bool

Return true if a requested resource was not found.

pub fn is_validation(&self) -> bool

Return true if invalid input caused the failure.

impl Error

pub fn from_error(error: impl Error + Send + Sync + 'static) -> Self

Create a new instance representing the given error.

pub fn from_boxed(error: Box<dyn Error + Send + Sync + 'static>) -> Self

Create a new instance representing an already boxed error.

impl Error

pub fn downcast_any_ref<T: Error + 'static>(&self) -> Option<&T>

Find the first stored error or native source that downcasts to T in logical breadth-first order.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

fn source(&self) -> Option<&(dyn Error + 'static)>

Return the first source of an Exn error, or the source of a boxed error.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl<E> From<Exn<E>> for Error

where E: Error + Send + Sync + 'static,

fn from(err: Exn<E>) -> Self

Converts to this type from the input type.