Error handling best practices in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main difference between panic! and Result in Rust error handling?

panic! stops the program immediately when an unrecoverable error occurs, while Result allows the program to handle recoverable errors gracefully without stopping.

intermediate

Why should you prefer returning Result over using panic! in library code?

Returning Result lets the user of the library decide how to handle errors, making the code more flexible and robust. panic! forces the program to stop, which is usually not desired in libraries.

beginner

What does the ? operator do in Rust error handling?

The ? operator simplifies error propagation by returning the error immediately if it occurs, or unwrapping the successful value to continue execution.

intermediate

What is the benefit of defining custom error types in Rust?

Custom error types help provide clear, specific error information and make it easier to handle different error cases distinctly in your code.

beginner

When should you use unwrap() or expect() in Rust?

Use unwrap() or expect() only when you are sure an error cannot happen or when a failure means the program cannot continue safely. Otherwise, prefer proper error handling with Result.

What does the Result type represent in Rust?

A A macro for printing errors

B A function that always panics

C A type for asynchronous operations

D A value that can be either success or error

Result is an enum that holds either Ok for success or Err for error.

Which Rust feature helps propagate errors without writing explicit match statements?

A The <code>panic!</code> macro

B The <code>unwrap()</code> method

C The <code>? operator</code>

D The <code>loop</code> keyword

The ? operator returns the error early if it occurs, simplifying error handling.

What is a good practice when writing Rust libraries regarding error handling?

A Return <code>Result</code> types to let users handle errors

B Always use <code>panic!</code> for errors

C Ignore errors silently

D Use <code>unwrap()</code> everywhere

Returning Result gives control to the library user to decide how to handle errors.

When is it appropriate to use unwrap() in Rust?

A When you are certain the value is not an error

B Never use <code>unwrap()</code>

C When you want to propagate errors

D When you want to handle errors gracefully

unwrap() should be used only when you are sure the value is valid, otherwise it will panic.

Why define custom error types in Rust?

A To make error messages shorter

B To provide specific error information and better handling

C To avoid using <code>Result</code>

D To make the code run faster

Custom error types help distinguish error cases and improve clarity in error handling.

Explain the difference between panic! and returning a Result in Rust error handling.

Think about when you want the program to stop versus when you want to handle errors.

Describe how the ? operator helps simplify error handling in Rust.

It helps avoid writing many match statements.