Unwrap means it forces to evaluate the result as an ”ok value”. If it’s an ”error value”, it will crash. It’s a bad practice to rely on it, as it’s one of the most common ways a Rust programs can crash.
Rust offers many options to handle errors that don’t risk crashing. For example, unwrap_or_default, which means ”if it’s an error value, use the default value for this type, such as 0 for integers”
Unwrap means it forces to evaluate the result as an ”ok value”. If it’s an ”error value”, it will crash. It’s a bad practice to rely on it, as it’s one of the most common ways a Rust programs can crash.
Rust offers many options to handle errors that don’t risk crashing. For example, unwrap_or_default, which means ”if it’s an error value, use the default value for this type, such as 0 for integers”
I mean using unwrap is not bad practice if the value is guaranteed to not be none, which can happen frequently in some applications.
If it’s guaranteed to not be
None, why is it anOption?Oh, it can happen when you do calculations with compile-time constants…
But the GP’s claim that it’s a “frequent” thing is suspect.
(Crashing is also useful when you are writing and-user applications, but you’ll probably want .expect like in the meme.)
Here’s a bad example but hopefully captures the why. https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=43d055381e7bb52569c339d4526818f4
We have a condition we know must be satisfied (the option will always be Some), but cant prove in code.
A good example would be regex. After validating it when writing the program it should always compile, although this could also be solved with a proc macro that validates the regex at compile time.
Unwrap is good for prototyping and trying out stuff fast, but it generally shouldn’t make it past a code review onto main, unless you’re very sure
Thanks.