rust-error-handling

Result and Option are Rust's core error-handling types. Result wraps success or failure values; Option wraps presence or absence. Use the ? operator to propagate errors cleanly through functions, or match to handle both cases explicitly at decision points.

Use thiserror to define structured, domain-specific error types with clear variants—ideal for libraries and applications that need type safety. Use anyhow for rapid error handling and error chains without defining custom types, better for applications where error details matter less than the chain.

Define an enum or struct implementing the std::error::Error trait, or use the thiserror crate to derive Error with #[derive(Error)] and annotate variants with #[error(...)] messages. This gives you typed errors that integrate with Result propagation.

Yes. File I/O and parsing operations return Result by default—std::fs functions and parsing methods wrap errors automatically. Chain them with ? to propagate failures, or map and unwrap_or to provide fallbacks and satisfy type requirements.

Return Result types from functions at service boundaries, use ? to chain operations cleanly, and convert internal errors to public error types before crossing boundaries. thiserror and anyhow both support error conversion via From trait implementations.

Yes. Use Result for operations that can fail with error detail, and Option for values that may or may not exist. Both work together—convert between them as needed using ok(), err(), and match patterns to fit your error-handling strategy.