Rust

Error Handling

• Library code: Use thiserror for defining error types with meaningful variants. Each variant should carry enough context to diagnose the issue.
• Application code: Use anyhow for ad-hoc error propagation with context via .context().
• Avoid .unwrap() in library code — use ? operator or explicit error handling. .unwrap() is acceptable in tests and quick prototypes.
• Avoid .expect() with vague messages — if you must panic, the message should explain why the invariant should hold.

Result and Option Chaining

Prefer chaining combinators over nested match statements when the logic is linear:

// ✅ Clear chain
let name = config.get("user")
    .and_then(|u| u.get("name"))
    .map(|n| n.to_uppercase())
    .unwrap_or_default();

// ❌ Deeply nested matches for the same logic