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Small pattern that made my code much cleaner (lemmy.ca)

submitted 11 months ago by kia@lemmy.ca to c/rust@programming.dev

9 comments fedilink hide all child comments

This is a really simple silly thing I just realized, but I noticed I have a lot code that looks something like this:

fn foo() -> Result&lt;(), Error> {
    // do something
}

fn bar() -> Option&lt;()> {
    let Ok(f) = foo() else {
        return None;
    };
}

I hated that if-statement. I realized today that I could simplify to:

fn bar() -> Option&lt;()> {
    let f = foo().ok()?;
}

And that cleaned up my code a lot. It's a tiny thing, but when it's okay to discard the error from the result, makes such a big difference when you have a lot of them!

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[–] Turun@feddit.de 5 points 11 months ago (1 children)

You're not wrong, but there are some situations in rust that are just so full of errors. Not because the situation will regularly fail in a variety of ways, but because rust can't prove that there never will be errors. And depending on how important the application is (vs the required boilerplate) just ignoring errors can be a reasonable choice

File system handling has been named. Creating a tokio runtime is also just .unwrap() whenever I have seen it. Creating a python module with pyo3 contains a big chunk of m.add_function(...?)?; which may just as well be unwrap()s.

[–] nous@programming.dev 6 points 11 months ago (1 children)

Unwaps or panicing or returning the error to the caller are all forms of handling the error - crash the program with a message that can tell you what went wrong and where in the code it happened. These give you a path to see what went wrong

But silently ignoring an error is rarely the right move. It stops you from seeing what the cause of the problem is and often leads to some weird non sensical failure somewhere else. Which I have seen time and time again lead to hours down a rabbit hole trying to understand why things are not working because you are missing the root cause of the problem.

There are times when you really don't care about a failure at all, but those times are rare and should be carefully considered first, crashing the program is generally the first thing you should do if you are unsure.

[–] Turun@feddit.de 3 points 11 months ago

Fair enough. I didn't consider "just crash lol" as handling the error, but your distinction is a good one.