Rust Error Excellence

Rust treats errors as values, not exceptions. This skill ensures your errors provide maximum context for developers and users.

The Result<T, E> Pattern

Always return Result for functions that can fail. Use the ? operator to propagate errors up the stack.

Crate Selection

• anyhow: Best for applications. It provides a flexible, easy-to-use error type for top-level handling.
• thiserror: Best for libraries. It allows you to define custom, derive-based error enums that users can match against.

Best Practices

• Context: Use .with_context(|| ...) in Anyhow to add human-readable breadcrumbs to errors.
• Avoid Panics: Use unwrap() and expect() ONLY in tests or when you can prove an invariant is impossible to break.
• Custom Errors: Define domain-specific error enums for complex logic.