Error

Q: How deeply does Rust in Action: Systems programming concepts and techniques cover Error?

Builds a custom error enum through Debug, Display, Error, map_err(), and From, but does not detail custom source-error methods.

As explained in Rust in Action: Systems programming concepts and techniques

std::error::Error is Rust's standard trait for representing errors that can provide descriptions and optional source errors.

std::error::Error is Rust’s standard trait for errors that provide descriptions and can optionally expose source errors. It gives different error types a common interface, which is useful when one function must handle failures from several dependencies. section 8.5.2

A practical pattern is to define an enum containing each upstream error, derive Debug, implement Display, and then implement Error. The wrapper preserves the original error variants instead of erasing them behind Box<dyn Error>. section 8.5.2

Combining file and address-parsing errors

A function can return Result<(), UpstreamError> while opening a file and parsing "::1". With map_err(), each failure becomes IO or Parsing; with From implementations, both operations can use ?. A missing file then reports the preserved IO variant.

How Rust in Action: Systems programming concepts and techniques covers it

Cover of Rust in Action: Systems programming concepts and techniques

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Also explained in

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Rust Servers, Services, and AppsThe Error trait is a Rust standard-library trait for types that represent and describe errors.
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Learn Rust in a Month of LunchesError is the Rust standard trait that classifies error types and supports human-readable descriptions and error-source relationships.

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Related concepts

error typeimplemented by · An error type is a data type whose values represent failure conditions and may carry information or behavior for reporting and handling those failures.
thiserrorimplemented by · thiserror is a Rust library crate providing derive macros that generate standard error-trait implementations for custom error types.
traitkind of · A trait is a type-level construct that defines reusable behavior or members that types can implement or compose.
trait objectused by · A Rust trait object is a value accessed through a trait interface with its concrete implementing type hidden and methods dispatched dynamically.
anyhowused by · anyhow is a Rust library that provides flexible application error handling with dynamically composed errors and propagated context.
Actix Errorimplements · Actix Error is Actix Web's general-purpose error type for representing handler and application failures.

This explainer was generated by Manning's knowledge graph from the text of Rust in Action: Systems programming concepts and techniques. The section links point to the parts of the book it draws on.