Why Go Can't Try

56 points by nexneo 80 days ago | 72 comments

chis 79 days ago |

These AI written articles carry all the features and appearance of a well reasoned, logical article. But if you actually pause to think through what they're saying the conclusions make no sense.

In this case no, it's not the case that go can't add a "try" keyword because its errors are unstructured and contain arbitrary strings. That's how Python works already. Go hasn't added try because they want to force errors to be handled explicitly and locally.

win311fwg 79 days ago | |

It is simpler than that. Go hasn't added "try" because, much like generics for a long time, nobody has figured out how to do it sensibly yet. Every proposal, of which there have been many, have all had gaping holes. Some of the proposals have gotten as far as being implemented in a trying-it-out capacity, but even they fell down to scrutiny once people started trying to use it in the real world.

Once someone figures it out, they will come. The Go team has expressed wanting it.

WalterGR 79 days ago | | |

> nobody has figured out how to do it sensibly yet.

In general or specifically in Go?

qezz 79 days ago | |

The mentioned in the article `try` syntax doesn't actually make things less explicit in terms of error handling. Zig has `try` and the error handling is still very much explicit. Rust has `?`, same story.

jcmfernandes 79 days ago | |

I just read the article and I didn't get away with that rationale. Now, this isn't to say that I agree with the author. I don't see why go would *have* to add typed error sets to have a try keyword.

Yes, mimicking Zig's error handling mechanics in go is very much impossible at this point, but I don't see why we can't have a flavor of said mechanics.

LovelyButterfly 79 days ago | |

What led you to believe this is an AI written article?

seethishat 79 days ago |

The programmer is explicitly throwing away the error returned by ReadFile (using the underscore) in the criticism of Go.

    data, _ := os.ReadFile(path)

Saying that is not explicit is just wrong.

n_u 79 days ago | |

I think the argument is that the compiler does not enforce that the error must be checked. It's just a convention. Because you know Go, you know it's convention for the second return value to be an error. But if you don't know Go, it's just an underscore.

In a language like Rust, if the return type is `Result<MyDataType, MyErrorType>`, the caller cannot access the `MyDataType` without using some code that acknowledges there might be an error (match, if let, unwrap etc.). It literally won't compile.

sethops1 79 days ago | | |

When you see .unwrap in Rust code, you know it smells bad. When you see x, _ := in Go code, you know it smells bad.

> But if you don't know Go, it's just an underscore.

And if you don't know rust, .unwrap is just a getter method.

AnimalMuppet 79 days ago | | |

Go has tools for checking things like this. It's just not in the compiler. If you don't want to enforce that all errors are checked, go doesn't force you to. If you do, it requires you to run an extra tool in your build process.

(Or in your commit hook. If you want to develop without worrying about such things, and then clean it up before checkin, that's a development approach that go is perfectly fine with.)

maccard 79 days ago | | |

> if the return type is `Result<MyDataType, MyErrorType>`, the caller cannot access the `MyDataType` without using some code that acknowledges there might be an error (match, if let, unwrap etc.)

I think you can make the same argument here - rust provides unwrap and if you don’t know go, that’s just how you get the value out of the Result Type.

gopher_space 79 days ago | |

Criticisms of Go seem like they pivot on the author's understanding of what's being done with `_` and sometimes `nil`. It's a strongly-typed language with a lot of flexibility around type, and that's nice to have when working on edge systems like a data ingester.

jiehong 79 days ago | |

How about:

    file.Close()

Did you see the non handled error here? The compiler doesn’t care.

cryptos 79 days ago |

My takeaway is that Go almost always prefers simplicity and not so much good software engineering. `nil` without compiler checks is another example, or designing a new language without generics. However the overall simplicity has its own value.

sheept 79 days ago | |

I agree, its strength (beyond goroutines) is that anyone who knows one of the popular languages (Python, Java, etc) can easily translate their idioms and data structures to Go, and the code would remain easy to read even without much Go experience. That's probably one reason why the TypeScript compiler team chose Go.

But this makes the language feel like Python, in some ways. Besides nil, the lack of expressivity in its expressions makes it more idiomatic to write things imperatively with for loops and appending to slices instead of mapping over the slice. Its structurally typed interfaces feel more like an explicit form of duck typing.

Also, Go has generics now, finally.

saynay 79 days ago | | |

> But this makes the language feel like Python

From what I remember of a presentation they had on how and why the made Go, this is no coincidence. They had a lot of Python glue code at Google, but had issues running it in production due to mismatched library dependencies, typing bugs, etc. So they made Go to be easy to adopt their Python code to (and especially get the people writing that code to switch), while addressing the specific production issues they faced.

andriy_koval 79 days ago | | |

> he popular languages (Python, Java, etc) can easily translate their idioms and data structures to Go, and the code would remain easy to read even without much Go experience

disagree, they made many decisions which are different from mainstream: OOP, syntax as examples.

marcosdumay 79 days ago | |

It's a very improved 1960s language.

For some uses, that's all you need, and having more features often detract from your experience. But I'm doubtful on how often exactly, I have been able to carve out a simple sub-language that is easier to use than go from every stack that I've tried.

antonvs 79 days ago | |

I think of it as a bit like Python with stronger types.

I'm not convinced that you couldn't have good software engineering support and simplicity in the same language. But for a variety of mostly non-technical reasons, no mainstream language provides that combination, forcing developers to make the tradeoff that they perceive as suiting them best.

advisedwang 79 days ago |

The Go team has discussed syntactic sugar for error handling many times. They're not against it, they're just holding out for a proposal that checks a lot of boxes and makes everyone happy, which hasn't happened yet.

thayne 79 days ago | |

> and makes everyone happy

But that's never going to happen because there is a very vocal subpopulation (I think it is a minority, but don't know for sure, and it is hard to measure that kind of thing) that is opposed to any "syntactic sugar" and wants it to stay the way it is.

f33d5173 79 days ago | |

I they wanted error handling they would have thought for a bit then picked a good enough solution. "We only want 'X but perfect'" is the same as "we don't want X".

release-object 79 days ago | |

Example: https://go.dev/blog/error-syntax

verdverm 79 days ago | |

It's a settled matter at this point for the foreseeable future

https://go.dev/blog/error-syntax

tl;dr - proposals are no longer being considered

kbolino 79 days ago |

The author doesn't touch on it, but the bigger problem with things like Foo|Bar as an actual type (rather than as a type constraint) is that every type must have a default/zero value in Go. This has proven to be a difficult problem for all of the proposals around adding sum types, whether they're used as errors or otherwise. For example, to support interface{Foo|Bar} as a reified type, you'd have to tolerate the nil case, which means you either couldn't call any methods even if they're common to Foo and Bar, or else the compiler would have to synthesize some implementation for the nil case, which would probably have to just panic anyway. And an exhaustive type-switch would always have to have "case nil:" (or "default:") and so on.

candiddevmike 79 days ago | |

> every type must have a default/zero value in Go

Hot take, maybe, but this is one of the few "mistakes" I see with Go. It makes adding QoL things like you mentioned difficult, requires shoehorning pointers to allow for an unset condition, some types don't have a safe default/zero value like maps, and makes comparisons (especially generic) overly complex.

verdverm 79 days ago | | |

Go specifically does not want to add QoL things because it means the compiler team has to spend time implementing that extra syntax and semantics versus making a minimal set of features better.

xigoi 79 days ago | |

Why not just define default(Foo|Bar) as default(Foo)?

kbolino 79 days ago | | |

There are cases where privileging the first alternative makes sense (like Maybe[T] = None|T with None = struct{} e.g.), and there are cases where it doesn't (like Either[L,R] = L|R). There has been an extensive amount of discussion about a number of different proposals, e.g. https://github.com/golang/go/issues/54685, https://github.com/golang/go/issues/57644, etc., but so far, much like "better" error handling, no workable consensus has yet emerged.

qezz 79 days ago |

In Zig you need an allocator to allocate anything, so whenever you need to add some extra information to an error, you pass a diagnostics object as an output argument to a potentially failing function. In this case it becomes a bit harder to compare it to Go's errors, each with pros and cons. I think comparing Go errors to Rust errors would be more fair.

There are some articles about the diagnostic pattern in Zig, e.g. [1], [2]

[1] https://github.com/ziglang/zig/issues/2647#issuecomment-5898...

[2] https://mikemikeb.com/blog/zig_error_payloads/

tialaramex 79 days ago | |

How so? In Rust you also need an allocator to allocate anything. Zig's diagnostics idiom is just that, an idiom. It would be very weird to do this in Rust, but then it's a pretty weird choice in Zig, they've just decided to do it anyway.

qezz 79 days ago | | |

What I meant by "you need an allocator" is "you need to explicitly pass the allocator of your choice to the function" [if you want to attach some data to the error]. In rust you can simply return anything as error, not only an enum variant.

a-poor 79 days ago |

What is broken about the go error type? If anything the fact that it is a simple interface makes the `try` syntax sugar more doable – right?

Let's say you have this:

``` part, err := doSomething() if err != nil { return nil, err }

data, err := somethingElse(part) if err != nil { return nil, err }

return data, nil ```

Then as long as your function followed the contract 0+ returns and then 1 `error` return, that could absolutely be turned into just the 0+ returns and auto-return error.

The fact that the `Error` interface is easy to match and extend, plus the common pattern of adding an error as the last return makes this possible.

What am I missing here?

qezz 79 days ago | |

> What is broken about the go error type?

There's not much broken with the error type itself, but the "real" problem is that the Go team decided not to change the way errors are handled, so it becomes a question of error handling ergonomics.

The article doesn't have a clear focus unfortunately, and I think it's written by an LLM. So I think it's more useful to read the struggles on the Go team's article

https://go.dev/blog/error-syntax

barelysapient 79 days ago |

Go got a ton right. Especially for being almost 20 years old. But errors is one thing that needs a v2. I love Zig's enumerable errors and deferErr function.

guilhas 79 days ago |

Coming from Java/C# with exceptions Go felt like an improvement

Most languages eventually end up confusing 'try-catch', errors, exceptions, handle?, re-throw?... Together with most programmers mixing internal erros, business errors, transient... Creating complex error types with error factories, if and elses... Everything returning the same simple error is simply genious

Also a lot of zig posts are tone def like this. "Oh look something so simple and we're the first to think about it. We must be really good"

fweimer 79 days ago |

It's more complicated. There is no single correct way to check for errors. Some standard library functions can return data and an error: https://pkg.go.dev/io#Reader

kbolino 79 days ago | |

This is true, but it feels like a mistake. It's too late to change now, of course, but I feel like (0, nil) and (!=0, !=nil) should both have been forbidden. The former is "discouraged" now, at least. It does simplify implementations to allow these cases, but it complicates consumers of the interface, and there are far more of the latter than the former.

OpenWaygate 79 days ago |

One reason I don't like JS or others is that they have too many ways to do the same thing, then you'll be challenged which is better and why on interview. Go offers fewer, more explicit options, not only on error handling.

littlestymaar 78 days ago |

This argument is a bit nonsensical given that Rust has a try operator (`?`) while having errors that are much more similar to Go's than they are to Zig's.

RadiozRadioz 79 days ago |

I keep feeling this feeling and it depresses me. I start reading an article and then gradually realise it's a load of AI slop, but by the time I get that realisation I've already wasted several minutes of my life. It's a sinking feeling like I've been duped, but not for anybody's gain - the "author" isn't earning anything from my view, they've just wasted my time for no reason. Even my misfortune is valueless. It happens again and again and again, it's wearing me down.

What are we doing here?

renehsz 79 days ago |

In my experience, writing a few lines to handle errors is really not as big of a deal as a lot of people make it out to be. However, I've seen numerous times how error handling can become burdensome in poorly structured codebases that make failure states hard to manage.

Many developers, especially those in a rush, or juniors, or those coming from exception-based languages, tend to want to bubble errors up the call stack without much thought. But I think that's rarely the best approach. Errors should be handled deliberately, and those handlers should be tested. When a function has many ways in which it can fail, I take it as a sign to rethink the design. In almost every case, it's possible to simplify the logic to reduce potential failure modes, minimizing the burden of writing and testing error handling code and thus making the program more robust.

To summarize, in my experience, well-written code handles errors thoughtfully in a few distinct places. Explicit error handling does not have to be a burden. Special language features are not strictly necessary. But of course, it takes a lot of experience to know how to structure code in a way that makes error handling easy.

pie_flavor 79 days ago |

Everyone compares Go to Rust. This AI-generated slop mentions Rust at the top, then launches into an explanation of how Go is not like Zig, where Rust is also not like Zig, but instead is extremely like Go. This answers no questions at all about the argument people actually participate in.

pinkmuffinere 79 days ago |

Is it because “do or do not, there is no try”?

deathanatos 79 days ago |

The plot seems to get real lost in the article.

Sure … it is true that Go errors can carry data, and Zig ones perhaps do not, but I don't see how that is what disqualifies a `try` from being possible. Rust's errors are rich, and Rust had `try!` (which is now just `?`).

The article's reasoning around rich errors seems equally muddled.

> In Zig, there's no equivalent. If both calls fail with error.FileNotFound, the error value alone can't tell you which file was missing.

Which is why I'm not a huge fan of Zig's error type … an int cannot convey the necessary context! (Sometime I'd've thought C had so thoroughly demonstrated as bad with, e.g., `mkdir` telling people "No such file or directory." — yeah, no such directory, that's why I'm calling `mkdir` — that all new designs would not be limited to using integer error codes.)

But then we go for …

> Zig's answer is the Error Return Trace: instead of enriching the error value, the compiler tracks the error's path automatically.

But the error's "path" cannot tell you what file was missing, either…

> It tells you where the error traveled, not what it means. Rather than enriching the error value, Zig enriches the tooling.

Sure … like, again, a true-ish statement (or opinion), but one that just doesn't contribute to the point, I guess? A backtrace is also useful, but having the exact filename is useful, too. It depends on the exact bug that I'm tracking: sometimes the backtrace is what I need, sometimes the name of the missing file is what I need. Having both would be handy, depending on circumstance, and the call stack alone does not tell you the name of the missing file.

… how does either prevent a `try` statement?

We try to argue that somehow the stdlib would need to change, but I do not see how that can be. It seems like Go could add try, as syntactic sugar for the pattern at the top of the article. (& if the resulting types would have type errored before, they could after sugaring, etc.)

tehnub 79 days ago |

Why Article By AI?

scuff3d 79 days ago |

"Here's the uncomfortable truth: a try keyword in Go without fixing the error type is just syntax sugar. You'd get slightly less typing but none of the real benefits - no exhaustiveness checking, no compiler-inferred error sets, no guarantee that you've actually handled every case."

... So what? From what I can tell that's all anyone has asked for in the context of something to just return nil/error up the call stack.

BadBadJellyBean 79 days ago | |

Exactly. I don't like that many people say "It's not perfect so it's useless.". I don't want to write or read the `if err != nil` statement over and over again. It is messy. It is tiresome. It could be solved by syntactic sugar.

scuff3d 79 days ago | | |

I actually think it defeats the Go teams stated purpose. It may technically be "more explicit" but it causes too problems. First someone is far more likely to just use the old value, _ trick bedside the current usage is just so annoying. Secondly, it conditions a lot of devs to just skim over the if check, because half the damn time it's just bs.

A little syntax sugar that won't break backwards compatibly and makes the intent of the code clearer is a win-win. I've never seen a really reasonable response from the Go team on why they don't want to do it.

peterldowns 79 days ago | |

llm garbage

zoilism 79 days ago | | |

agreed, the author should be upfront that it was written by an LLM

edunteman 79 days ago | | |

The llm detector in my brain went off too

skywhopper 79 days ago |

How utterly arrogant to insist that “every Go developer” wishes the language abandoned its principles in order to add some syntactic sugar to save a few lines of code. No, we don’t all feel a pang of envy at magic keywords that only work in certain function call configurations. Sheesh.

impure 79 days ago |

I really hate it when people try to justify Go’s design decisions. Try would be very useful. The real reason why is because the Go team refuses to take any lesson from any other programming language except for C. That’s why there are so many questionable decision. Also I was a little disappointed there was no mention of panics which are one such questionable decision. Also the author stopped trying to cover up their AI written tracks at the conclusion because you already read it so who cares.

AnimalMuppet 79 days ago | |

> the Go team refuses to take any lesson from any other programming language except for C.

Go acknowledges taking the design of the object file format from, IIRC, Modula-2. You are very wrong.