Rust Error Handling Interview Q&A
Practical error handling guide for Result design and propagation with runnable examples and review-ready checklists.
Topic: Error Handling
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Rust Error Handling Interview Q&A
Problem
Teams often struggle with Result design and propagation when code grows quickly and review cycles shorten. This guide turns that into a repeatable process.
Diagnostic checklist
- Define one concrete failure mode before changing code.
- Reduce to a minimal example first.
- Validate assumptions around ownership, mutability, and API boundaries.
- Keep fix scope small and testable.
Runnable example
fn main() {
let data = vec![1, 2, 3, 4];
let sum: i32 = data.iter().sum();
println!("sum={}", sum);
}Counterexample
fn main() {
let s = String::from("hello");
let moved = s;
println!("{}", s); // moved value
}How to decide in production
1. Start with correctness and explicit ownership.
2. Add instrumentation before optimizing.
3. Keep interfaces small and typed.
4. Record tradeoffs directly in code and PR description.