error-handling-basics

name	error-handling-basics
description	Essential Rust error handling rules for anyhow and thiserror users

Error Handling Basics

Display must not include the source

Error reporters walk .source() separately. Including it in Display causes double-printing:

// Wrong
#[error("operation failed: {0}")]
MyError(#[source] io::Error)

// Right
#[error("operation failed")]
MyError(#[source] io::Error)

Context describes what was attempted, not what failed

// Wrong: repeats what the source error already says
.context("file not found")

// Right: says what you were trying to do
.context("failed to load user config")

Production backtrace config

Set RUST_BACKTRACE=1 RUST_LIB_BACKTRACE=0. This gives panic backtraces without the performance cost of capturing one on every anyhow::Error.

More guidance

For comprehensive patterns (opaque library errors, internal error composition, structured logging, custom application error types), install the error battery pack:

cargo install cargo-bp
cargo bp add error