The ability to quickly parse, understand and reason about code is not superficial, it is essential to the job. And that is essentially what those verbose blocks of text get in the way of.
Golang code has a rhythm: you do the thing, you check the error, you do the thing, you check the error. After a while it becomes automatic and easy to read, like any other syntax/formatting. You notice if the error isn't checked.
Yes, at first it's jarring. But to be honest, the jarring thing is because Go code checks the error every time it does something, not because of the actual "if err != nil" syntax.
I've gotten used to Javas getter/setter spam, does that make it a good idea?
Moreover, don't you think that something like Rusts ? operator wouldn't be a perfect solution for handling the MOST common type of error handling, aka not handling it, just returning it up the stack?
val, err := doAThing()
if err != nil {
return nil, err
}
val := doAThing()?I'd be very surprised if, in Rust codebases, there's not an implicit bias against wrapping and towards using `?`, just to help keep things "clean"; which has implications not only for debugging, but also for situations where doing something more is required for correctness.
I see two issues with the `?` operator:
1. Most Go code doesn't actually do
return nil, err
return nil, fmt.Errorf("opening file %s as user %s: %w", file, user, err)
What takes less effort to type, `?` or the annotated line above?
This could probably be solved by enforcing that a `?` be followed by an annotation:
val := doAThing()?("opening file %s as user %s: %w", file, user, err)
2. A question mark is a single character and therefore can be easy to miss whereas a three line if statement can't.
Moreover, because in practice Go code has enforced formatting, you can reliably find every return path from a function by visually scanning the beginning of each line for the return statement. A `?` may very well be hiding 70 columns to the right.
1. Most often found in library code, the error types have the metadata embedded in them so they can nicely be bubbled up the stack. That's where you'll find `do_a_thing().map_err(|e| Error::FileOpenError { file, user, e })?`, or perhaps a whole `match` block.
2. In application code, where matching the actual error is not paramount, but getting good messages to an user is; solutions like anyhow are widely used, and allow to trivially add context to a result: `do_a_thing().context("opening file")?`. Or for formatted contexts (sadly too verbose for my taste): `do_a_thing().with_context(|| format!("opening file {file} as user {user}"))?`. This will automatically carry the whole context stack and print it when the error is stringified.
Overall, what I like about this approach is the common case is terse and short and does not hinder readability, and easily gives the option for more details.
As for the second point, what I like about _not_ easily seeing all return paths (which are a /\? away in vim anyways), is that special handling stands out way more when reading the file. When all of the sudden you have a match block on a result, you know it's important.
I'm a huge fan of keeping things simple; my experience has shown me that complex things have lots of obscure failure points, while simple things are generally more robust.
> More terse is not the same as more readable (in fact, I find the reverse).
I generally agree, but I also find that "all explicit" also hinders readability because it tends to drown the nitty-gritty details. As always it's a matter of balance :) And I think that neither go nor rust are great in this matter as one is verbose and the other falls in the "keyword soup" with the chain call, the closure, and the format macro. I'm pretty sure something in between could be found.
Rust's error handling is clearly better than Go's, but Go's is better than exceptions and the complaints about verbosity are largely complaints about having to actually consider errors.
I'm honestly asking as someone neutral in this, what is the difference? What is the difference between building out a stack trace yourself by handling errors manually, and just using exceptions?
I have not seen anyone provide a practical reason that you get any more information from Golangs error handling than you do from an exception. It seems like exceptions provide the best of both worlds, where you can be as specific or as general as you want, whereas Golang forces you to be specific every time.
I don't see the point of being forced to deal with an "invalid sql" error. I want the route to error out in that case because it shouldn't even make it to prod. Then I fix the SQL and will never have that error in that route again.
With exception style code the overwhelming temptation will be to call `string_to_int()` and forget that it might throw an exception.
Cut to your app crashing when someone types an invalid number.
Now, you can handle errors like this properly with exceptions, and checked exceptions are used sometimes. But generally it's extremely tedious and verbose (even more than in Go!) and people don't bother.
There's also the fact that stack traces are not proper error messages. Ordinary users don't understand them. I don't want to have to debug your code when something goes wrong. People generally disabled them entirely on web services (Go's main target) due to security fears.
Is it? In my experience it's very short, especially considering you can catch multiple errors. Do my users really need a different error message for "invalid sql" vs "sql connection timeout?" They don't need to know any of that.
> There's also the fact that stack traces are not proper error messages
I would say there's not a proper error message to derive from explicitly handling sql errors. Certainly not a different message per error. I would rather capture all of it and say something like "Something went wrong while accessing the database. Contact an admin." Then log the stack trace for devs
Yes! A connection timeout means it might work if they try again later. Invalid SQL means it's not going to fix itself.
But in any case, the error messages are probably the minor part. The bigger issue is about properly handling errors and not just crashing the whole program / endpoint handler when something goes wrong.
> I would say there's not a proper error message to derive from explicitly handling sql errors. Certainly not a different message per error. I would rather capture all of it and say something like "Something went wrong while accessing the database. Contact an admin." Then log the stack trace for devs
Ugh these are the worst errors. Think about the best possible action that the user could take for different failure modes.
"Contact an admin" is pretty much always bottom of the list because it rarely works. More likely options are "try again later", "try different inputs", "clear caches and cookies", "Google a more specific error".
Giving up on making an error message because you only have a stack trace and don't want to show it means users can't pick between those actions.
If you have written a "something went wrong" error I literally hate you.
You're totally misunderstanding what I'm saying. If I have an error the user can act on, I'll make that error message for them. If they can't act on it, I will make a generic catcher and ask them to contact an admin because that's the only thing they can do. It is not my experience that any of these things you've written (try again later, try a different input) are applicable when an error comes up in my apps. It's always an unexpected bug a developer needs to fix, because we've already handled the other error paths. And the bug is not from "not explicitly handling the error."
> Think about the best possible action that the user could take for different failure modes.
What if contacting an admin IS the best possible action? Which is what I'm referring to.
In the case of invalid sql, your route should crash because it's broken. Or catch it and stop it. It's functionally the same thing.
You seem to be under the impression that having exceptions mean people can't handle errors explicitly? It just prevents the plumbing of manually bubbling up the error. It means you can do so MORE granularly. Also, there are some errors that are functionally the same whether you handle them explicitly or not. There are unexpected errors, and even Golang won't save you from that. Golang doesn't even care if you handle an error. It will compile fine. Even PHP will tell you if you haven't handled an exception.
> If you have written a "something went wrong" error I literally hate you.
Lol.
Not at all! It's possible, but it's very tedious, and the lazy "catch it in main" option is so easy that in practice when you look at code that uses exceptions people actually don't handle errors explicitly.
> It means you can do so MORE granularly.
Again, it doesn't just mean that you can; it means that you will. And for proper production software that's not a good thing.
> There are unexpected errors
Only in languages with exceptions. In a language like Rust there are no unexpected errors; you have to handle errors or the compiler will shout at you.
But again, handling an error doesn't necessarily prevent bugs. Just because you handled an error doesn't mean the error won't happen in Prod. It just means when it does, you wrote a message for it or custom behavior. Which could be good, or it might be functionally as effective as returning a stack traces message. It depends on the situation.
For what it's worth, I've never seen people not handle errors that the user could do anything with. If it's relevant to the user, we handle it.
It absolutely does. Checked exceptions sort of half get there too but they are quite rarely used (I think they are used in Android quite well). They were actually removed from C++ because literally nobody used them.
> handling an error doesn't necessarily prevent bugs.
I never made that claim.
> I've never seen people not handle errors that the user could do anything with.
We already talked about "something went wrong" messages. Surely you have seen one of those?
My point is that "something went wrong" messages are for errors the user CANT and SHOULDNT do anything with.
What? Of course there is. Rust added panic! exactly because unexpected errors are quite possible.
Unexpected errors, or exceptions as they are conventionally known, are a condition that arises when the programmer made a mistake. Rust does not have a complete type system. Mistakes that only show up at runtime absolutely can be made.
You cannot force your dependencies to hand you a stack trace with every error. But in languages that use exceptions a stack trace can be provided for "free" -- not free in runtime cost, but certainly free in development cost.