I'd encourage the author to spend more time learning Go. They've come to incorrect conclusions -- especially regarding errors. Read more of the stdlib to see how powerful they can be, e.g. net.OpError: https://cs.opensource.google/go/go/+/refs/tags/go1.25.5:src/...
> The user now has an interface value error that the only thing
> they can do is access the string representation of ... The only
> resort the consumer of this library has is to parse the string
> value of this error for useful information.
This shows a lack of understanding about the `error` interface, `errors.Is`, `errors.As`, error wrapping etc.
Personally, I think Go errors are fantastic, just the right sprinkling of structure on top of values. And panic/recover for truly exceptional circumstances.
Yeah, I'm brand new to learning Go, but that was the first thing I thought when I got to his section on errors. You're supposed to return a generalized error and then use errors.is or errors.as to figure out what specific type of error it is so that you can access the specific data on it. And the reason you do it that way instead of just returning a concrete error type is because one function might want to return different error types depending on what specific thing happened. Just like you can throw different exception types in other languages. And obviously if that's happening, the reason you can't just directly access stuff without doing errors.is or as is because you don't know which it is until you do that.
I think it's a shame that Go doesn't have sum types, exhaustiveness checking, and pattern matching, because it would make its error model more enforceable and concise (see Gleam!) but given that it doesn't for whatever reason, I think the solution it's gone with is genuinely the best possible second option that gives you 90% of the benefits of result and option (out of band errors, structured error data, errors as values so you can directly and in line decide what to do with them without special control flow, no invisible or non-local control flow, it's immediately obvious when anything can return an error, etc).
And I say this as someone who started out hating go.
I think Go's concept of error wrapping is probably unusual to newcomers to the language who might be used to, say, pulling in a dependency for error handling (logrus or whatever) when it's all there in the stdlib in what Go has decided to be the idiomatic way to do errors and logging.
It's nice when you understand how to do it well and move on from, say, printing errors directly where they happen rather than creating, essentially, a stack of wrapped errors that gets dumped at an interface boundary, giving you much more context.
I think it's probably confusing until you understand interfaces, which coming from other languages you might not be familiar with (my guess for what happened in this blog post). If you don't know what an interface is then maybe you assume err.Error() is some kind of string, without realizing Error() is just a required function but the err could be whatever type.
My understanding is that using `error` as a return type performs type erasure and that the only information given to the caller is the value of the `e.Error()` function. I now understand that this isn't the case.
You're right, but I still think they have a point. What I miss from `error.Is/As` is exhaustive matching. I'd love a way to statically guarantee I haven't missed an important error type. It really comes back to the absence of sum types.
Yeah, the lack of sum types of any kind in Go is the only thing that I really miss when coming back from Rust. It's, I think, a big part of the reason that Gleam has seen a lot of growth. It has many of the syntactic benefits of Go with the compiler guarantees of Rust (though it's weird in some other ways, like dramatically favoring continuation-passing-style in programmer facing syntax).
> I'd love a way to statically guarantee I haven't missed an important error type.
It wouldn't be hard — rather easy, even — to write a static analyzer for that if you constrained your expectations to cases where sum types could practically be used. No reason to not do it right now!
But sum types don't really solve for a lot of cases. Even in Go you can add additional constraints to errors to get something approaching sum types. You don't have to use a naked `error`. But you are bound to start feeling pain down the road if you try. There is good reason why even the languages that support defined error sets have trended back to using open-ended constructs.
It does sound great in theory, no doubt, but reality is not so kind.
> There is good reason why even the languages that support defined error sets have trended back to using open-ended constructs.
Rust does it that way & has never trended in any other direction. The generally-accepted wisdom is "thiserror¹ for libraries, anyhow² for applications"—i.e., any error that's liable to be handled by a machine should be an enum of exhaustively-matchable error kinds, whereas anything that's just being propagated to the user should be stringified & decorated with context as it bubbles up.
Certainly, unified error types which wrap and erase more specific errors are sometimes desirable, but equally they often are not. Languages which support exhaustive matching support both, permitting us to choose based on context.
I have my own complain against Rust's error handlings, but I can't bring myself to praise what Go has been doing.
One problem with the error interface is that you can't know exactly which error type will be returned, and the Go authors may add new error types form time to time. `net.OpError` itself is a great example for that, which is a newer type than net.Error.
This style of error signalling is best used when the error handling is binary, either "No error, continue" or "Errored out, abort", but not branched out path like "If encountered error A, do this. If encountered error B, do that. Otherwise, abort".
Rust's error handling encourages such branched out handlings by default, but if you want to so the same in Go, there will be a nightmarish manual type discovery and tracking operation waiting for you.
So for me, I rather use a dedicated signal code to tell which error branch I should do next rather than relying on the error, i.e:
if next, err := func(); err != nil { // If errored, abort it
return err
} else if next == condition1 {
return op1()
} else if next == condition2 {
return op2()
} else {
panic("unsupported condition")
}
The author is clearly aware of `error.Is` as they use it in the snippet they complain about. The problem is Go's errors are not exhaustive, the equivalent to ENOTDIR does not exist. So you can't `errors.Is` it. And while Stat does tell you what specific error type it'll be in the documentation, that error type also doesn't have the error code. Just more strings!
Is this a problem with Go the language or Go the standard library or Go the community as a whole? Hard to say. But if the standard library uses errors badly, it does provide rather compelling evidence that the language design around it wasn't that great.
I use Go as my preferred language and I think the author is mostly right.
There’s no way for me to know or even check what are the possible errors this function can return? Sure, sometimes a comment in the library might be illuminating, but sometimes not.
I agree that errors as values that I can handle at the call site rarely feel useful.
Some of the Is, As ergonomics have improved, but damn if coding agents don’t love to just fmt.error any code it writes. Thus hiding the useful information about the error in a string.
Technically, if you use `fmt.Errorf`, then the caller can't get anything useful out of your errors.
Types are promises. All the `error` interface promises is a string representation. I acknowledge that most of the time there is more information available. However, from the function signature _alone_, you wouldn't know. I understand that this is more of a theoretical problem then a practical problem but it still holds (in my opinion).
The subtlety missed in these conversations is that almost all the information there is for typical error handling --- that is, all the information that would be present in a typical Rust error handling scenario as well --- is encoded in the type tree of the errors.
(Rust then improves drastically on the situation with pattern matching, which would simply improve Go with no tradeoffs I can really discern, just so we're clear that I'm not saying Go's error story is at parity with Go. But I'd also point out that Rust error handling at a type level is kind of a painful mess as well.)
It's not super ergonomic, but the information is there, in about the same density as it would be in a Rust app, supporting the same error handling strategies (ie, discriminating between transient and durable errors, &c).
In fairness, the idea that you needed to scrape error strings to handle errors was a very popular complaint about Go that was valid 10 years ago, including in the standard library.
They are an improvement over most languages, but the are _not_ better than sum types for the reasons listed above. Way less flexible and forces a lot more verbosity when compared to more functional languages.
Hes definitely wrong on how the error types can help account for that but it would be best in class if we could properly chain them AND use all the greatness from interfaces.
The author is wrong, there exist mechanisms to cast errors. But they all suck! It's all just guessing and grepping for -hopefully- unique error messages.
One of the things I wish more people talked about isn't just the language or the syntax, but the ecosystem. Programming isn't just typing, it's dealing with dependencies and trying to wire everything up so you can have tests, benchmarks, code-generation and build scripts all working together well.
When I use modern languages like Go or Rust I don't have to deal with all the stuff added to other languages over the past 20 years like unicode, unit testing, linting, or concurrency.
I use Go where the team knows Java, Ruby or TypeScript but needs performance with low memory overhead. All the normal stuff is right there in the stdlib like JSON parsing, ECC / RSA encryption, or Image generation. You can write a working REST API with zero dependencies. Not to mention so far all Go programs I've ever seen still compile fine unlike those Python or Ruby projects where everything is broken because it's been 8mo.
However, I'd pick Rust when the team isn't scared of learning to program for real.
I don't like that for fairly basic things one has to quickly reach for crates. I suppose it allows the best implementation to emerge and not be concerned with a breaking change to the language itself.
I also don't like how difficult it is to cross-compile from Linux to macOS. zig cc exists, but quickly runs into a situation where a linker flag is unsupported. The rust-lang/libc also (apparently?) insists on adding a flag related to iconv for macOS even though it's apparently not even used?
But writing Rust is fun. You kind of don't need to worry so much about trivialities because the compiler is so strict and can focus on the interesting stuff.
Yeah, I've never seen an all-in-one language like Go before. Not just a huge stdlib where you don't have to vet the authors on github to see if you'll be okay using their package, but also a huge amount of utility built in like benchmarking, testing, multiple platforms, profiling, formatting, and race-detection to name a few. I'm sad they still allow null, but they got a lot right when it comes to the tools.
Everything is literally built-in. It's the perfect scripting language replacement with the fast compile time and tiny language spec (Java 900 pages vs Go 130 pages) making it easy to fully train C-family devs into it within a couple weeks.
Oh Go with Rust's result/none setup and maybe better consts like in the article would be great.
Too ba null/nil is to stay since no Go 2.
Or maybe they would? Iirc 1.21 had technically a breaking change related to for loops. If it was just possible to have migration tooling. I guess too large of a change.
Technically, with generics, you could get a Result that is almost as good as Rust, but it is unidiomatic and awkward to write:
type Result[T, E any] struct {
Val T
Err E
IsErr bool
}
type Payload string
type ProgError struct {
Prog string
Code int
Reason string
}
func DoStuff(x int) Result[Payload, ProgError] {
if x > 8 {
return Result[Payload, ProgError]{Err: ProgError{Prog: "ls", code: 1, "no directory"}}
}
return Result[Payload, ProgError]{Val: "hello"}
}
This was not the case for a long time. Actually it seems like it's fairly recently you get native AOT and trimming to actually reduce build sizes and build time. Otherwise all the binaries come with a giant library
Even back in .NET Core 3.1 days C# had more than competitive performance profile with Go, and _much_ better multi-core scaling at allocation-heavy workloads.
It is disingenuous to say that whatever it ships with is huge also.
The common misconception by the industry that AOT is optimal and desired in server workloads is unfortunate. The deployment model (single slim binary vs many files vs host-dependent) is completely unrelated to whether the application utilizes JIT or AOT. Even with carefully gathered profile, Go produces much worse compiler output for something as trivial as hashmap lookup in comparison to .NET (or JVM for that matter).
There’s cross-rs which simplifies things. But the main problem is less linker flags being unsupported and more cross compiling C dependencies somewhere in the dependency chain and that’s always a nightmare, not really anything to do with Rust (Go should have similar difficulties with cross compilation).
Buuut with Go one in general tends to reach less for dependencies so less likely to run into this and cgo is not go ;) https://go-proverbs.github.io
but for cross-compiling actually ended up filtering out the liconv flag with a bash wrapper and compiled a custom zig cc version with the support for exported_symbols_list patched in, things appear to work.
Should look into cross-rs I suppose. Hope it's not one of those "download macos sdk from this unofficial source" setups that people seem to do. Apparently not allowed by Apple.
Cross compiling to Apple products from non Apple products is going to run into the same hurdle around SDK setup as any other. There exists documentation but it’s probably not the easiest task. This limitation though applies equally to any library that depends on system C headers and/or system libraries.
The crates.io ecosystem for Rust... is like the amazing girlfriend that you go head over heels for, make her your wife, and then you meet the in-laws ... but it's too late now.
Unlimited access to a bunch of third party code is great as you're getting started.
Until it isn't and you're swimming in a fishing net full of code you didn't write and dependencies you do not want. Everything you touch eventually brings all of tokio along with it. And 3 or 4 different versions of random number generators or base64 utilities, etc. etc.
I can't speak for other Rust programmers but I can speak for myself.
I obviously enjoy programming Rust and I like many of the choices it made, but I am well aware of the tradeoffs Rust has made and I understand why other languages chose not to make them. Nor do I think Rust functions equally as well in every single use case.
I imagine most Rust users think like this, but unfortunately there seems to be a vocal minority who hold very dogmatic views of programming who have shaped how most people view the Rust community.
Go is a pleasure to use. The stdlib is one of the most complete, while keeping the keyword count low. LLMs understand it very well, project size stays low, line count stays low (if err nil included), doesn't need a bunch of scaffolded boilerplate in the project directory, and it compiles very quickly for a ton of OS and architectures. Very seldom do I ever need to go outside of the stdlib.
Is it perfect for everything? no. Is it the fastest compiled language out there? no. But, it'll do most things very well, and for me that's good enough. I choose go because when I need to make something, it steps aside and lets me build, and for that I have great respect and appreciation for it.
I will be defering all detractors and negative comments ;)
I admit that it's nice to have a very simple, straightforward, and minimal build process. No dealing with VMs, no setting up environments, just install Go and then compile your program. Reminds me of C back in the late 90s.
what does this mean? Go lib seems tiny compared to JDK. anytime i review some Go code from adjacent team i'm turned off by weird stuff like append and slices everywhere, as well as a bunch of strange string packages
When I think of a massive stdlib I think of a language like groovy
The api surface is relatively small, but the capabilities you get from it (http serving, json parsing, crypto, in addition to table stakes like io, args, flags etc) are very high. Having a small api surface is why you need to use primatives so often, but the upside benefit to that is there is less domain specific knowledge, since you end up using familiar types and libraries in more of your code.
When I use Go, I find I can get more real work done with only the standard library than with any other language I've used (including Java, although that was quite a while ago now). It may not have the most stuff, it is more focused - but I'm okay with esoteric stuff not being in there since the tradeoff seems to be that there are high-quality implementations of e.g. an HTTP client and server, crypto functions, a unit testing library, JSON en/decoding etc, which I can definitely use in production. Conversely in Java the answer seems to be to use BouncyCastle / Tomcat / Jackson / etc, so while there may be a big stdlib, it ends up being less useful.
In my experience, people building APIs w/ python are almost always using frameworks, while people building APIs w/ golang are almost always using stdlib
Literally the simplest way to deal with errors (cognitively and character wise). Since AI autocomplete entered the scene, typing this repetitive (for a reason) pattern became not a problem at all (I'm not even talking about post Claude Code era)
> The only resort the consumer of this library has is to parse the string value of this error for useful information.
> typing this repetitive (for a reason) pattern became not a problem at all
Code is read 10x more than it is written. The noise this pattern introduces inhibits reading and rapid comprehension.
Things are getting marginally better now that go has errors.Is and errors.As, and also now that go is starting to get some functional iterators. But go is one of the least quickly-understandable of the modern languages currently in use.
Here is the thing... it's NOT a 'noise'. Untill you see handling 'error path' as noise, you will be trapped in searching magic bullet language solution to hide it. We've all been there.
Your last sentence makes sense only if you consider “happy path” to be what you call “understanding how function works”. A lot of programmers are annoyed that Go forces them to think about “error path” as equally important. Later many say that Go forces you to be the better programmer. But it takes time. In any case, saying “language has a problem” is a wrong frame for thinking about this design choice.
This is something gophers constantly repeat, but it is entirely a self-inflicted issue that other languages more modern than C don’t actually struggle with.
When in Rust, it is explicitly clear when and where errors can come up, and what types of errors I have to deal with. It is far less clear in golang, since there is no help from the type system when I’m using errors.Is and errors.As. Not being verbose doesn’t make error handling any less explicit.
Nobody is upset about having to pay attention to the unhappy path. This is entirely a straw man that gophers fall back to in order to feel like they’re somehow enlightened, shut down conversation, and to avoid having to consider what other people are saying. We are desperately hoping to help you realize that there are other, better ways that don’t come at the ridiculous readability costs inflicted by the anemic golang approach.
It really is okay to stop making excuses and accept that your preferred language has warts. I promise. Nobody will think less of you.
That's not a straw man, it's a valid reply to your first argument about "error handling code being an obstacle to understanding how function works". Why it makes you angry and makes you resort to ad hominem, I don't know, but that's clearly the end of the discussion.
No, it is a knee-jerk response that invariably assumes that a belief that golang’s specific approach is bad is equivalent to believing that errors are of secondary importance, and assumes that anyone who disagrees with the golang approach just doesn’t get how important it is to deal with errors.
You would rather dismiss other perspectives out of hand than actually reflect on how your chosen language might evolve.
In my perspective, this has been the entire historical progression of golang. Everyone vehemently denies that there’s a problem, eventually the language authors address it, and then everyone insists that it’s always been known that they needed to deal with the issue.
I don’t know why this seems to be so endemic to the golang community. Other languages’ adherents seem more than willing to accept the shortcomings of their preferred tools. But gophers continually insist that all the problems are actually strengths right up until it’s fixed and then they retcon their previous beliefs. It’s extremely off-putting.
>> difficulty of writing if err != nil
>Literally the simplest way to deal with errors (cognitively and character wise). Since AI autocomplete entered the scene, typing this repetitive (for a reason) pattern became not a problem at all (I'm not even talking about post Claude Code era)
I agree with you. I don't have problems with the `if err!=nil` syntax.
From my post:
> It’s become something of a meme to bemoan the supposed difficulty of writing if err != nil. I actually won’t make that point because I think it is a very surface level point that has been talked about to death and *I don’t think the ‘verbosity’ of this code snippet is such an issue.*
I apologize if my language was ambiguous on whether or whether not I had a problem with that syntax.
>In his example author could easily use his `progError` type instead.
I agree, but it was my impression that type erasure was more idiomatic. I should have made it clear that I was criticizing that idiom, not the language.
You are right. I should have done my research on that before writing that point. I still think that downcasting isn't the most elegant solution because it defeats the point of using the opaque return type but I agree that it is nowhere near as much of a problem as I thought it was.
The simplest thing is not to do anything but defer to caller to handle it, in languages like Python, Java, JavaScript. Often that is also the only realistic way to an error, especially for library code.
To be fair, the author says it's the "_supposed_ difficulty of writing err != nil" and says that the verbosity isn't an issue here. But he also earlier says that he "[hates] having to write pub all the time in Rust" to denote public visibilities. So typing seven extra characters in one place = tolerable, but four extra characters elsewhere = detestable
Writing `pub` is personally more annoying to me than writing `if err != nil`. I understand that most people don't like how capitalization determines visibility, but I think it actually makes sense when you think about it.
I commend Go for popularizing the channel-based concurrency, since I do think that that is a very elegant way of structuring stuff (especially compared to mutexes), but I have to admit that I don’t have a lot of fun writing Go.
I agree with a lot of the sentiment of this post; the weirdness with “tuples”, the weirdness of the error types, and etc. It’s not a “bad” language, just one that I don’t enjoy using.
Historically to get something similar to Go-style concurrency I would use Clojure with core.async, but more recently I have started using Rust and Tokio.
IMO, this is because Go succeeded at its intended to goal: to create a language that people with very little Computer Science (but some C/C++ programming) experience can be productive in. It eschews basically all abstractions that take more than 30s to explain to someone, which leaves a lot of really useful ones on the cutting room floor.
I agree with your point in general, but I would challenge the idea that tuples aren't something that is intuitive to explain (even in less than 30 seconds). Perhaps it's difficult to explain why tuples and not lists, but that's also relatively simple (homogeneous vs heterogeneous)
That’s fair. I came into Go relatively late and from a more Functional Programming background, so the language ends up being kind of annoying to me but that is probably not the case for others.
Don't get me wrong, I don't think it was a good goal. But that goal is the original sin of Go as a language, and most of the bad decisions that have been made in Go's design are in pursuit of it.
What are they top 3 languages that you have used that can be used as Go alternatives ranked by fun in your opinion (I am guessing Clojure and Rust are two of them)?
You’re right! I think overall I have most fun with Clojure.
I also really like Julia; it has a channel mechanism and it has a very nice macro syntax. It also is obscenely fast at number crunching tasks and I find the language pretty pleasant to use with a nice syntax. I use Julia whenever I need to do anything involving CPU bound number crunching stuff (which admittedly isn’t too often).
All that said, I have been mostly favoring Rust because the memory footprint is so much smaller and I still have a fair amount of fun with it :).
Also, depending on the task, I also get a fair bit of mileage out of ZeroMQ, which can bolt on channel-like semantics in a pinch. It’s not as nice as having it build directly into the language but it does support more flexible patterns. Whenever I have to use Java I almost always end up importing JeroMQ the moment that that built in BlockingQueues stop being sufficient.
The error story is not ideal but less bad than that most of the time, as you can downcast to access extra error data. Still, harder than it needs to be.
Overall, I've grown to like using the language even despite its warts.
What is with people and their need for enums? Functionally using go const with iota gives you the same damn thing and people use enums that way 99% of the time. I find Rusts reliance on enums annoying as hell. At this point I consider Rust a bandwagon language. The syntax is abysmal and we have had memory safe languages far before Rust. That I wont get into because as a Vulnerability Researcher I find the Rust push super misguided and it sets me off.
To be more clear, I want sum types with exhaustive matching - which Go does not support.
I get by without it Go enums are an inferior representation of the same logical concepts. Sure, I can have (kind, value) and cast things for a hacky sum type for some kind enum. But Go lacks closed enums/exhaustive matching.
You can at least validate the match arms with things like type switches and marker interfaces, but they're still not exhaustive and they're terribly verbose.
And, again, I can get by without them! But I miss them because Rust-style enum representation comes up _so often_, even if you don't like the rest of Rust.
I mean, you have atomic and compound data types. Atomic ones represent single values, like "a string" or "an integer", and compound ones represent multiple atomic types combined in some way, like a struct or an enum. Enums are useful for the same reason structs are useful, they do the same core thing, just model it in a different way. It's the difference between "and" and "or", which are both useful tools.
When people say they want sum types, they generally mean they want both sum types and exhaustive pattern matching. Either of these features on isolation are nice to have, but both together are incredibly powerful to the point where having just one is almost not worth it.
Is this what people mean by Enums? I must not have used languages where Enums have those powers. I have often been very confused by statements people make about Enums so that would make some sense.
How do sum types address the problem that the underlying type (int or string or whatever) is totally capable of describing values other than those your code was compiled with? I'm mostly thinking of version skew with something like a dynamic library or plugin, although casting would probably also have the same effect.
Yes, this is generally what people mean when they talk about enums in modern languages.
The in memory and ABI representation of enums/sum types is language dependent.
In Rust, an enum is equivalent to a C union where there's a discriminant value which is an integer of sufficient size to cover all variants (u8 is sufficient for 255 different variants), followed by as many bytes as the largest variant (a tagged union). Mucking around with the underlying bytes to change the discriminant and cause type confusion is UB. All the same strategies you'd take in C for versioning and ensure binary backwards compatibility would apply. When exposing these you would likely want a higher level abstraction/self-describing wire format, if you don't have control over both sides of the ABI boundary.
Other higher level languages do this for you already. I believe Swift is one of those, where it has a COM-like ABI layer that the compiler makes injects transparently to correctly interact with a dynamic library, handling versioning for you.
I am of the opinion that we need a new attempt at a multi-platform, language-agnostic, self-describing ABI, "COM for the modern world". I think some people have talked about using WASM for this.
Keep in mind that the concept (pattern matching, sum types) is not tied to how they are represented (Scala has both, but they are represented different to what I described earlier; IIRC it uses inheritance to represent the variants).
The problem is that this makes enums non-enumerable. They need to be represented as a range or union type to do that. I am pretty sure I know why/how Go ended up like this because it’s inherited behavior from proto, wrote a large comment later down the thread explaining why.
As someone who's been back into Go a couple of times (oscillating between Python, "C-ish" languages and the like), the ONE thing I hate about Go is error handling. The rest I can live with just fine.
Error handling in Go is actually very nice. You do not have unhandled errors, not possible unless you really want to not handle the error. Now I even use it similar in Python, amazing how many errors I did not handle at all. But what got me into using Go is that there is no libc dependency, just system calls, static binary, that is just amazing. I can compile Go compiler in like few minutes. Rust I cannot even compile after 24h, I use rust-bin in Gentoo,luckily that exists.
Could I ask what hardware this is on? Even when building LLVM from scratch too as part of building the toolchain (which hasn't been the default for a while now, but could see Gentoo doing so), it never took that long on any hardware I own. (Granted, I never tried on the EEE PC I've got on some drawer, and its 2G of RAM would likely kill the whole thing before it got started.)
$ time ./x.py build
... snip ...
Build completed successfully in 0:21:24
real 21m24.736s
user 67m48.195s
sys 1m54.906s
Subsequent builds during development are faster (as 1. it doesn't build the same compiler multiple times, you can use the stage 1 build as normal, stage 2 is not strictly necessary and 2. if you modify one of the constituent crates of the compiler, the ones that are lower in the dep tree don't get recompiled). I've used this laptop on and off for rustc development for the last 10 years. Nowadays I spent more time using a cloud desktop that has much faster IO, but still use it during travels sometimes.
From the sound of it, I suspect that your issue might be that you don't have enough RAM and your build is swapping a lot.
This is an older thinkpad I am using, 4 cores, 16G of ram. LLVM is now dependency you cannot get rid of. That is painfull, but in the morning, after several hours it is usually done. Rust is LLVM plus I am not sure what, really painfull. And Gentoo also forces many different arches and flags for some reason, use flags are masked, you cannot easily disable them.
That sounds similar to the hardware on my T460 (2 cores, 4 threads, 16G). Would you consider cloning the repo and building it with the same command as my other comment? I'm really intrigued if the issue is the hardware/platform or "just" the Gentoo configuration or something else that doesn't affect the default build process.
Are you joking? It's trivially easy to drop the err or just not handle it accidentally in ways that are essentially impossible in rust. Especially when people re-use the `err` variable.
I've only written a handful of production projects in Go so my experience isn't very deep, but I find the syntax to be the ugliest of any PL. The mixed capitalizing based on function privacy, to me, is awful (among other things, i.e. personally I loathe curly brace initialization/definition). I'm sure you get used to it? It doesn't help that it just feels very hacked together, from the wonky generics, the lack of useful types like tuples and enums, the bolted on module system, to the annoying error handling, to say the least.
That said, compile times are great, the concurrency is dead simple, it's performant, and it's still easy to be really productive in it so it's not like I'd never consider it. Many other languages have many of the same issues, anyway.
> The mixed capitalizing based on function privacy, to me, is awful
Awful compared to ... what? `private` and `public` keywords? Ugly hacks like pythons `_` and `__`?
> it just feels very hacked together
> the wonky generics
What exactly about the generics is "wonky"? "Wonky" is not a term defined in any programming textbook I ever read. And languages are not designed on feelings, especially when the design goal is to be as pragmatic as possible, as is the case in Go.
And btw. 99% of the time tuples are used, it's as a stand-in for multiple-returns. E.g. Python does that. Go simply has...multiple returns.
> and enums,
Outside of language-enthusiasm with matching and whatnot (which more often than not is used because it looks cool rather than being useful), the most common (and again, 99%) use of enums, is to give names to magic values. Go has that covered:
type Color string
const (
RED Color = iota
GREEN
BLUE
)
> the bolted on module system
Pray tell what exactly is "bolted on" about modules? They are simply an extension of the import system, nothing more, nothing less.
> the annoying error handling
The "annoying" thing about it is that it's explicit and forced. Both of which are positives as far as I'm concerned, because I AM FREKKIN DONE with shitty 10-mile stacktraces because some joksters library threw an "exception" 400 layers down in some sub-sub-sub-sub transient dependency lib.
I want to clarify that I think very highly of Go as a language. I think it gets most things right. It's hard to introduce an abstraction into a language while still making sure that it's not abused. Rust's trait and type system, while powerful have been abused to create some absolutely incomprehensible and long types. Go, on the other hand, doesn't suffer from this issue. If I was too harsh against Go, that was certainly a mistake.
I think that the criticisms of my section on error handling are, for the most part, spot on. My impression was that type erasure for errors was the idiomatic solution, which is patently untrue. When writing the blog post, I was unaware of the functions in the `errors` module as well as the syntactic sugar and general acceptance of downcasting errors. While I would still maintain that Rust errors are more convenient to work with, I must admit that there really isn't any good excuse for my ignorance on this.
When it comes to enums, I stand by my statements on them.
I still believe that it is useful to restrict the values a type might have. And no, I am not using the term enum to mean a rust-style "enum" (tagged union). I am talking about classical enums, more or less as they appear in C.
As an aside, I am not terribly surprised that my website doesn't work well on some browsers. I hacked together the website including the HTML and CSS a couple of years ago and some of the hacks I used I ought to be ashamed of.
Not shilling for Go here but there are a few misconceptions in this blog post. In addition to the others mentioned:
> All of these examples involve assigning to a constant a value known at compile time but none of them will work
Maps are not known at compile time. Hash functions are randomized based on a seed only known at execution time. The hashed value of "HELLO" is actually different each time the program runs. Even if the hash function weren't random, the runtime has to allocate buckets for map values on the heap, which involves calling the OS to get memory addresses for those buckets, etc.
In Go, `const` means "the compiler can completely evaluate this expression and store the final bytes in the executable," which has the effect of making them non-reassignable, but protection from reassignment is not an actual feature of the language the way it is in Java and C++ (goes back to the maintainers wanting to keep it simple).
Doesn't protection from reassignment not exist in most languages anyways? In C++ you should be able to cast away the const. Realistically you probably can achieve this in any language with reflection.
Unless a const is literally a compile time constant inserted through the program, it's likely able to be changed somehow in most languages.
You can definitely protect from reassignment in those languages (e.g. `final` in Java) but they don't completely prevent you from changing the underlying data. Rust would be one that comes to mind that has true immutability. I guess the Go maintainers just didn't want to go down that road, which I get.
Author is still early in their exploration and has some definite mistakes in here. Probably the biggest one is around the error handling, thinking that the only way to interact with an error is through the error interface itself. That is intended as a baseline interaction, a fallback for when nothing else is appropriate, such as just slamming an error into a log. If you want to interact with specific errors, you should use the various functions in the errors package [1] to check for specific types, and then use those specific types in whatever they support. Go error support is quite good; you can return an error object that says "The user was not found, the file the user was supposed to be found in was not found, and while trying to log this the log failed to accept the write" as various error types composed together, and any consumer of the error using the errors package can pick out the various bits of the error they understand using those tools without having to understand the error binding them together or the components it doesn't care about . You should never use string manipulation to check errors unless you have no choice, and whatever library left you with no choice should have an issue filed against it. It doesn't come up often, but it does sometimes come up; most recently I had the AWS SDK emitting an error I could only use string functions on, but I think they've since fixed it.
I don't like the term "enums" because of the overloading between simple integers that indicate something (the older, more traditional meaning) and using them to mean "sum types" when we have the perfectly sensible term "sum type" already, that doesn't conflict with the older meaning. If you want sum types, a better approach is to combine the sort of code structure defined here: https://appliedgo.net/spotlight/sum-types-in-go/ with a linter to enforce it https://github.com/alecthomas/go-check-sumtype , which is even better used as a component of golangci-lint: https://golangci-lint.run/
I'd also add my own warnings about reaching for sum types when they aren't necessary, in a language where they are not first class citizens: https://jerf.org/iri/post/2960/ but at the same time I'd also underline that I do use them when appropriate in my Go code, so it's not a warning to never use them. It's more a warning that sum types are not somehow Platonically ideal. They're tools, subject to cost/benefit analysis just like anything else.
> If you want sum types, a better approach is to combine the sort of code [...]
I'm currently of the opinion that where you truly need this type of thing, write tests that use the ast package to validate that your expectations hold. That way you don't need to do anything strange with the code, and logic failure will show up alongside all of your other logic failures.
While it does venture into implementation details that shouldn't be tested, Go offers a discriminator between your actual tests and throwaway tests (i.e. `package foo_test` v.s. `package foo`), so as long as you've clearly mark the intent I find this to be an acceptable tradeoff. As implementation changes, and you no longer need that validation, others will know that your throwaway tests are intended as such.
> I don't like the term "enums" because of the overloading between simple integers that indicate something (the older, more traditional meaning)
I disagree with this. I'm old as hell, and I learned programming in a context where enums were always ints, but I remember being introduced to int enums as "we're going to use ints to represent the values of our enum," not "enums are when you use ints to represent a set of values." From the very beginning of my acquaintance with enums, long before I encountered a language that offered any other implementation of them, it was clear that enums were a concept independent of ints, and ints just happened to be an efficient way of representing them.
"Enum" is literally defined as a numbering mechanism. While integers are the most natural type used to store numbers, you could represent those numbers as strings if you really wanted. The key takeaway is that a enum is a value, not a type.
The type the link was struggling to speak of seems to be a tagged union. Often tagged union implementations use enums to generate the tag value, which seems to be the source of confusion. But even in tagged unions, the enum portion is not a type. It remains just an integer value (probably; using a string would be strange, but not impossible I guess).
Disagree. Enums are named for being enumerable which is not the same thing as simply having an equivalent number.
It’s incredibly useful to be able to easily iterate over all possible values of a type at runtime or otherwise handle enum types as if they are their enum value and not just a leaky wrapper around an int.
If you let an enum be any old number or make the user implement that themselves, they also have to implement the enumeration of those numbers and any optimizations that you can unlock by explicitly knowing ahead of time what all possible values of a type are and how to quickly enumerate them.
What’s a better representation: letting an enum with two values be “1245927” or “0” or maybe even a float or a string whatever the programmer wants? Or, should they be 0 and 1 or directly compiled into the program on a way that allows the programmer to only ever need to think about the enum values and not the implementation?
IMO the first approach completely defeats the purpose of an enum. It’s supposed to be a union type, not a static set of values of any type. If I want the enum to be tagged or serializable to a string that should be implemented on top of the actual enumerable type.
They’re not mutually exclusive at all, it’s just that making enums “just tags” forces you to think about their internals even if you don’t need to serialize them and doesn’t give you enumerability, so why would I even use those enums at all when a string does the same thing with less jank?
> Enums are named for being enumerable which is not the same thing as simply having an equivalent number.
Exactly. Like before, in the context of compilers, it refers to certain 'built-in' values that are generated by the compiler; which is done using an enumerable. Hence the name. It is an implementation detail around value creation and has nothing to do with types. Types exist in a very different dimension.
> It’s supposed to be a union type
It is not supposed to be anything, only referring to what it is — a feature implemented with an enumerable. Which, again, produces a value. Nothing to do with types.
I know, language evolves and whatnot. We can start to use it to be mean the same thing as tagged unions if we really want, but if we're going to rebrand "enums", what do we call what was formally known as enums? Are we going to call that "tagged unions" since that term now serves no purpose, confusing everyone?
That's the problem here. If we already had a generally accepted term to use to refer to what was historically known as enums, then at least we could use that in place of "enums" and move on with life. But with "enums" trying to take on two completely different, albeit somewhat adjacent due to how things are sometimes implemented, meanings, nobody has any clue as to what anyone is talking about and there is no clear path forward on how to rectify that.
Perhaps Go even chose the "itoa" keyword in place of "enum" in order to try and introduce that new term into the lexicon. But I think we can agree that it never caught on. If I, speaking to people who have never used Go before, started talking about iotas, would they know what I was talking about? I expect the answer is a hard "no".
Granted, more likely it was done because naming a keyword that activates a feature after how the feature is implemented under the hood is pretty strange when you think about it. I'm not sure "an extremely small amount" improves upon the understanding of what it is, but at least tries to separate what it is from how it works inside of the black box.
It feels obvious that that's where the term originated, but I've never seen it used as a definition. In a mathematical context, something is enumerable if it can be put into 1:1 correspondence with the integers, but it doesn't need to be defined by a canonical correspondence. This suggests that being a finite (in a programming context where the set of ints is finite) set of discrete values is the defining feature, not the representation.
Sum types can be put into 1:1 correspondence with the integers, barring the inclusion of a non-enumerable type in a language's specification that can be used in sum types. However I would observe that this is generally a parlor trick and it's fairly uncommon to simply iterate through a sum type. As is so often the case, the exceptions will leap to mind and some people are already rushing to contradict me in the replies... but they are coming to mind precisely because they are the exceptions. Yes, you can sensibly iterate on "type Color = Red | Green | Blue", I've written code to do the equivalent in various languages many times and most complicated enumerations (in the old sense) I do come equipped with some array that has all the legal values so people can iterate over them (if they are not contiguous for some reason), so I know it can be done and can be useful. But the instant you have a general number type, or goodness help you, a generalized String type, as part of your sum type, you aren't going to be iterating on all possible values. And the way in which you can put the sum types into a 1:1 correspondence won't match your intuition either, since you'll need to diagonalize on the type, otherwise any unbounded array/string will get you "stuck" on the mapping and you'll never get past it.
So while you can theoretically argue it makes sense to call them an "enum" I don't like it precisely because "enumerating" the "enum" types (being sum types here), in general, is not a sensible operation. It is sensible in specific, but that's not really all that special. We don't generally name types by what a small percentage of the instances can do or are, we name them by what all instances can do or are. A degenerate sum type "type Value = Value" is still a sum, albeit a degenerate one of "1", but nobody ever enumerates all values of "type Email = Email { username :: String, domain :: String }". (Or whatever more precise type you'd like to use there. Just the first example that came to mind.) There are also cases where you actively don't want users enumerating your sum type, e.g., some sort of token that indicates secure access to some resource that you shouldn't be able to get, even in principle, by simple enumerating across your enum.
If it's called an "enum" I want to be able to "enum"erate it.
> In most applications of int enums, the particular integers can be chosen at random
I’m not sure the definition of "enum" enforces how things are identified. Random choice would be as good as any other, theoretically. In practice, as it relates to programming, random choice is harder to implement due to collision possibilities. Much simpler is to simply increment an integer, which is how every language I've ever used does it; even Rust, whose implementation is very similar to Go's implementation.
But it remains that the key takeaway is that the enum is a value. The whole reason for using an enum is for the sake of runtime comparison. It wouldn't even make sense to be a type as it is often used. It is bizarre that it keeps getting called one.
Another comment already mentioned that the OP don't understand how to work with errors in Go.
As with any language, Go has its own philosophy and you have to first understand why it was created and what it brings to the table. To summarize it in one phrase "Less is more"
I think this post should be a mandatory reading for everybody learning Go. If this resonates with you it's possible you're gonna like the language:
The way I do this is decide which language I like (just by gut feel) and then come up with reasons why it is good / better than others. I think almost everyone does the same thing, really.
But you can learn about yourself and others by writing down specifically the things you like and don’t like, and reading other people doing the same. With the possibility of liking different things for different reasons in the future. Or just better understanding how to best use the tools you like.
I'm curious what the alternative would be? Python's threads/sub-processing almost requires IO queues to function well, and are nearly the same semantically as channels...
I'm not saying these are "good", just wondering what alternatives look like?
One alternative is STM, software transactional memory which is modular and composable. I think Haskell was first to implement it but its also in Clojure and some Scala libs.
This is what ZIO's type safe version looks like https://zio.dev/reference/stm/ Scala's for-comprehension is syntactic sugar for calls to flatMap, map, and withFilter, similar to Haskell's do-notation.
Correct me if I'm wrong, but the Error interface means you can display the error as a string, but you don't have to? Like the err.Error() is idiomatic if you just want to display something, but you could also use the error itself
Also "In Go, errors are values. They just aren’t particularly useful values"
...sometimes user mistakes are due to the language being too complicated, maybe for no benefit, but I don't think that's the case here. It's a very good thing that you can just slap .Error() on any error to print it quickly, and not too crazy complex to say an error can be any normal type that you can use, as long as it also can print Error()
My guess is that the author hasn’t fully frocked how go interfaces work yet. Go errors implement the error interface, but that just makes them interoperable, it doesn’t mean that’s all they are.
Correct me if I am wrong, but does it not mean that they are type-erased though? The whole point of returning an interface is to perform type-erasure.
If I have
struct S { X int }
func (s *S) Error() string { ... }
but I return it as an error:
func DoStuff() error
Then all the caller gets is an error interface. Without downcasting (`.(T)`/`errors.As`), you can only compare it to other instances (if the library author provided them) or see the string representation.
Yes, that's correct. The interface limits what guarantees the caller has about the type without runtime introspection. I don't think that really makes it any harder to handle expected error conditions though, since type assertions return a boolean. eg:
if myErr, ok := err.(MyError); ok {
// handle MyError case
}
...
But you should always expect that there could be errors you don't expect to exhaustively handle with special logic.
They don't seem to understand Go much at all. Comparisons to Rust are somewhat misplaced but that's a different topic... Back to errors. Errors are interface values. They are simple yet powerful. You can create sentinel errors that can be wrapped or just passed to be checked then discarded. Go has all the functionality it needs to provide what ever it is Rust cult members believe makes Rust error handling so great. You can use the primitive constructs Go provides to do nearly the same damn things Rust can do and it won't look like a pile of hieroglyphs your local crackhead would draw. Best of all... Its simple and the syntax of Go (veering off topic) doesn't make me want to jump off a bridge. Stop gaslighting yourselves into thinking Rust syntax is reasonable and that its some perfectly proven language with all edge cases put to rest..
I'm using the Firefox Developer version on Windows and everything renders correctly for me. I tested Firefox on Android and everything is present there as well.
No issues here on Firefox 146 Fedora/GNOME. Also imagine it's not uncommon for a personal site to not test for Safari if they're not in the Apple ecosystem.
I think I know why Go ended up without good enum support.
(Disclaimer, formerly worked at Google and used proto/grpc/go there and now in my own startup in github.com/accretional/collector which tries to address this problem with a type registry and fully reflective API. Not privy to the full history, just reasoning.)
Proto is designed so that messages can be deserialized into older/previous proto definitions by clients even if the server is responding with messages of a more recent version. Field numbers Re what let you to start serializing new fields (add a new field with an unused/the next number) or safely stop setting fields in proto responses (reserve a field) without risking older clients misinterpreting the data as belonging to some existing field they know about. This requires you to encode the field numbers alongside the field data in the proto wire format.
Two major problems: nothing in proto itself enforces that field numbers are assigned sequentially, because there is no single source of truth for the proto schema (you can still have one of your own, but it’s not a “thing” in proto). Also, the whole point of field numbers is that they can be selectively missing/reserved/ignored and allow you to deserialize messages without special handling for version changes in your code at runtime.
So, field numbers aren’t a dense, easily enumerable range of numbers, they’re basically tags that can be any number between 1 and 536,870,911 except for the reserved 19,000-19,999. This smells like serious tech debt/ a design flaw that completely closes the door for even fixing this at Google or anywhere else, because it’s arbitrarily in the middle of the range of field numbers and a leaked implementation detail from the internals. You couldn’t build your own dense field number management/sequential enforcement system on top of proto without ripping that part out, but your existing proto usage relies on that part and changing it would break existing clients because you’re removing field numbers, which is the whole fucking point of proto, and makes it difficult to roll out even if you did fix it yourself.
So, representing union/enumerable types in proto is impossible. For proto enums to have forward compatibility, they have to handle adding new enum values over time, or need to remove and reserve old ones. So, proto enums end up being basically just field numbers. That’s exactly what you see in Golang enums and I don’t think it’s a coincidence: Google has no good way to serialize/deserialize/operate on enumerable enums or union types anywhere they use proto/grpc. Golang inherits this “enums” implementation from protobuf because it’s the context in which it was created.
Wha do you mean by “fixing this” or it being a design flaw?
I agree with the point about sequential allocation, but that can also be solved by something like a linter. How do you achieve compatibility with old clients without allowing something similar to reserved field numbers to deal with version skew ambiguity?
I view an enum more as an abstraction to create subtypes, especially named ones. “Enumerability” is not necessarily required and in some cases is detrimental (if you design software in the way proto wants you to). Whether an enum is “open” or “closed” is a similar decision to something like required vs optional fields enforced by the proto itself (“hard” required being something that was later deprecated).
One option would be to have enums be “closed” and call it a day - but then that means you can never add new values to a public enum without breaking all downstream software. Sometimes this may be justified, but other times it’s not something that is strictly required (basically it comes down to whether an API of static enumerability for the enum is required or not).
IMO the Go way is the most flexible and sane default. Putting aside dedicated keywords etc, the “open by default” design means you can add enum values when necessary. You can still do dynamic closed enums with extra code. Static ones are still not possible though without codegen. However if the default was closed enums, you wouldn’t be able to use it when you wanted an open one, and would have it set it up the way it does now anyway.
No its because 99% of the time people use enums to give names to magic constants... That is it. Go went for simplicity and const+iota achieves it just fine. People act like enums make or break software itself or something.
Yea but with a tiny bit more effort they could have ensured that an invalid value is never assigned to an enum, iterate over the values, ensure switch statements handle every case, etc.
That seems unlikely to me to be the actual explanation. It could very well be what you prefer or how you would do it, but I can definitely assure you that the Go/other infrastructure teams think about these problems and hear plenty of complaints about lack of union type support.
I'm not sure I understand your argument. You're saying that you can't really use enums for field numbers. And let's say that you're absolutely correct about that.
It still seems to me that you're addressing a completely separate issue from having a specific field that is an enum - not an enum of a field number, but an enum of something else, like encryption algorithm or SHA type or something.
I’m pointing out that proto’s enums are wrappers around proto field numbers, which are numerical ids for proto message fields that enable forward/backward compatibility across proto message version changes. These field numbers are necessarily sparse but don’t even need to be assigned sequentially, and in fact, because of the leaked implementation details from the internal field number range you have to assume they are non-sequential. So field numbers are sparse, which makes them non-enumerable even though they’re represented with numeric tags.
Hence, proto enums are essentially non-enumerable wrappers around numeric values. And this is (almost certainly) why Golang’s enums are structured the same way, as transparent wrappers around values that are not necessarily sequential or enumerable.
C++ does sparse enums just fine. Are you saying that those are not "real" enums because their sparse? Or that C++ doesn't have "real" enums because it allows that? Or what?
10 years ago we started out with Python. We switched to Go probably 8 years back. I think my little startup would have utterly failed without Go. Thx google :)
But yes Enums are so much nicer in Kotlin vs Go. That's true, it doesn't impact productivity much, but he has a point.
I think some pythonistas maybe got their feeling hurt by your comment causing it to grey out.
Over the last 25 years in the SaaS world, I have never seen python evolve into a system that is easy to reason about and debug. It lets you do too many things. In over 30 cases, I have seen teams deliver better software faster in Go after replacing their Python.
Man this post is a rollercoaster. First half of the post I was absolutely starstruck by how amazing go is(I haven't had time to play with it myself yet), and was making mental note after mental note to try it out asap!
Then I got to the second half of the post, with the things he didn't like about go.
No enums? Wtf? Not having sum types is a lesser evil imo, it places you in the mediocre, but mediocre is mostly ok so that's kinda fine. But no enums? We're stuck with magic numbers? Hell naw, we banished that demon in the nineties, I ain't signing up to bring it back!
In go you don't strictly need magic numbers because you can define constants:
type Status int
const (
IoProblem Status = iota // we start at zero and go down from there
JsonParse
...
)
The problem is that there is no exhaustiveness with these constant groups. The type Number is not a closed set of just IoProblem and JsonParse like an enum in C. It is just an int.
I don't buy that example about errors at the end at all. The problem the author is trying to solve is to write code that calls a foreign/fixed-API function that is known to return a particular subtype of Error, and wants to extract structured information from it. But you can't, because the type returned is just the outer Error type that only has a string.
Obviously, though, the only way this happens is if you know a priori what actually failed, because otherwise it might be some other error type. And you don't, obviously, because it's an error! If your behavior is deterministic then just return whatever you want in your own API. If it's not, you need to parse/extract/inspect the error.
Basically it's entirely contrived. This never happens, and to the extent it does it's a terrible bug where you have code making assumptions about runtime error state without fully inspecting that state.
The second failure is that Go does in fact have runtime type inspection facilities ("type assertions" is the particular jargon) and if you want you can absolutely "cast" that error into a derived type to get the data out. So it's not even a problem in the language as it exists.
but how would you do that otherwise? Genuinely curious cause I looked up both the go docs and source (disclaimer: not a go dev), and there doesn't seem a way to handle that specific kind of error through stuff like `errors.Is`, at least from what I can tell, at least in the os and fs packages
Another languages that just “gets” concurrent right (imo) is erlang/elixir. I’ve done elixir for the last 3 years off and on.
Can someone with experience in both Go and Elixir compare the two? I’m sure I can have GPT whip up a comparison and see the syntax diffeeences, but I’m curious what the real experience “in the trench” is like.
I've used both professionally. I think elixir has some amazing ideas. I love pattern matching. However! Just like all other interpreted languages, in elixir, I have to go to the call sites of the function that I am editing to understand what it is that is actually available and to understand what I can edit. I don't know what has been passed into my function. The lack of types is not fixed by having a type spec and dialyzer. Pattern matching helps. I wish Go had it. But when it comes to a growing organization, more and more of the codebase cannot fit in your head, and I find that teams and organizations are indeed faster in Go.
I recall hearing that Jose was making progress on types. Not sure where that landed.
One of the few languages I've known that didn't provide any standard features for libraries (until the sixth major revision), Scheme, has been the worse for it.
I'd encourage the author to spend more time learning Go. They've come to incorrect conclusions -- especially regarding errors. Read more of the stdlib to see how powerful they can be, e.g. net.OpError: https://cs.opensource.google/go/go/+/refs/tags/go1.25.5:src/...
This shows a lack of understanding about the `error` interface, `errors.Is`, `errors.As`, error wrapping etc.Personally, I think Go errors are fantastic, just the right sprinkling of structure on top of values. And panic/recover for truly exceptional circumstances.
Yeah, I'm brand new to learning Go, but that was the first thing I thought when I got to his section on errors. You're supposed to return a generalized error and then use errors.is or errors.as to figure out what specific type of error it is so that you can access the specific data on it. And the reason you do it that way instead of just returning a concrete error type is because one function might want to return different error types depending on what specific thing happened. Just like you can throw different exception types in other languages. And obviously if that's happening, the reason you can't just directly access stuff without doing errors.is or as is because you don't know which it is until you do that.
I think it's a shame that Go doesn't have sum types, exhaustiveness checking, and pattern matching, because it would make its error model more enforceable and concise (see Gleam!) but given that it doesn't for whatever reason, I think the solution it's gone with is genuinely the best possible second option that gives you 90% of the benefits of result and option (out of band errors, structured error data, errors as values so you can directly and in line decide what to do with them without special control flow, no invisible or non-local control flow, it's immediately obvious when anything can return an error, etc).
And I say this as someone who started out hating go.
I think Go's concept of error wrapping is probably unusual to newcomers to the language who might be used to, say, pulling in a dependency for error handling (logrus or whatever) when it's all there in the stdlib in what Go has decided to be the idiomatic way to do errors and logging.
It's nice when you understand how to do it well and move on from, say, printing errors directly where they happen rather than creating, essentially, a stack of wrapped errors that gets dumped at an interface boundary, giving you much more context.
I think it's probably confusing until you understand interfaces, which coming from other languages you might not be familiar with (my guess for what happened in this blog post). If you don't know what an interface is then maybe you assume err.Error() is some kind of string, without realizing Error() is just a required function but the err could be whatever type.
My understanding is that using `error` as a return type performs type erasure and that the only information given to the caller is the value of the `e.Error()` function. I now understand that this isn't the case.
You're right, but I still think they have a point. What I miss from `error.Is/As` is exhaustive matching. I'd love a way to statically guarantee I haven't missed an important error type. It really comes back to the absence of sum types.
Yeah, the lack of sum types of any kind in Go is the only thing that I really miss when coming back from Rust. It's, I think, a big part of the reason that Gleam has seen a lot of growth. It has many of the syntactic benefits of Go with the compiler guarantees of Rust (though it's weird in some other ways, like dramatically favoring continuation-passing-style in programmer facing syntax).
> I'd love a way to statically guarantee I haven't missed an important error type.
It wouldn't be hard — rather easy, even — to write a static analyzer for that if you constrained your expectations to cases where sum types could practically be used. No reason to not do it right now!
But sum types don't really solve for a lot of cases. Even in Go you can add additional constraints to errors to get something approaching sum types. You don't have to use a naked `error`. But you are bound to start feeling pain down the road if you try. There is good reason why even the languages that support defined error sets have trended back to using open-ended constructs.
It does sound great in theory, no doubt, but reality is not so kind.
> There is good reason why even the languages that support defined error sets have trended back to using open-ended constructs.
Rust does it that way & has never trended in any other direction. The generally-accepted wisdom is "thiserror¹ for libraries, anyhow² for applications"—i.e., any error that's liable to be handled by a machine should be an enum of exhaustively-matchable error kinds, whereas anything that's just being propagated to the user should be stringified & decorated with context as it bubbles up.
Certainly, unified error types which wrap and erase more specific errors are sometimes desirable, but equally they often are not. Languages which support exhaustive matching support both, permitting us to choose based on context.
[1]: https://docs.rs/thiserror/latest/thiserror/
[2]: https://docs.rs/anyhow/latest/anyhow/
> e.g. net.OpError
I have my own complain against Rust's error handlings, but I can't bring myself to praise what Go has been doing.
One problem with the error interface is that you can't know exactly which error type will be returned, and the Go authors may add new error types form time to time. `net.OpError` itself is a great example for that, which is a newer type than net.Error.
This style of error signalling is best used when the error handling is binary, either "No error, continue" or "Errored out, abort", but not branched out path like "If encountered error A, do this. If encountered error B, do that. Otherwise, abort".
Rust's error handling encourages such branched out handlings by default, but if you want to so the same in Go, there will be a nightmarish manual type discovery and tracking operation waiting for you.
So for me, I rather use a dedicated signal code to tell which error branch I should do next rather than relying on the error, i.e:
The author is clearly aware of `error.Is` as they use it in the snippet they complain about. The problem is Go's errors are not exhaustive, the equivalent to ENOTDIR does not exist. So you can't `errors.Is` it. And while Stat does tell you what specific error type it'll be in the documentation, that error type also doesn't have the error code. Just more strings!
Is this a problem with Go the language or Go the standard library or Go the community as a whole? Hard to say. But if the standard library uses errors badly, it does provide rather compelling evidence that the language design around it wasn't that great.
I use Go as my preferred language and I think the author is mostly right.
There’s no way for me to know or even check what are the possible errors this function can return? Sure, sometimes a comment in the library might be illuminating, but sometimes not.
I agree that errors as values that I can handle at the call site rarely feel useful.
Some of the Is, As ergonomics have improved, but damn if coding agents don’t love to just fmt.error any code it writes. Thus hiding the useful information about the error in a string.
The article claims:
"The user now has an interface value error that the only thing they can do is access the string representation of."
This is false. Didn't used to be, but that was many years ago.
>this is false.
It's mostly false.
Technically, if you use `fmt.Errorf`, then the caller can't get anything useful out of your errors.
Types are promises. All the `error` interface promises is a string representation. I acknowledge that most of the time there is more information available. However, from the function signature _alone_, you wouldn't know. I understand that this is more of a theoretical problem then a practical problem but it still holds (in my opinion).
The subtlety missed in these conversations is that almost all the information there is for typical error handling --- that is, all the information that would be present in a typical Rust error handling scenario as well --- is encoded in the type tree of the errors.
(Rust then improves drastically on the situation with pattern matching, which would simply improve Go with no tradeoffs I can really discern, just so we're clear that I'm not saying Go's error story is at parity with Go. But I'd also point out that Rust error handling at a type level is kind of a painful mess as well.)
>that is, all the information that would be present in a typical Rust error handling scenario as well --- is encoded in the type tree of the errors.
it's only present when you downcast though?
It's not super ergonomic, but the information is there, in about the same density as it would be in a Rust app, supporting the same error handling strategies (ie, discriminating between transient and durable errors, &c).
I feel that in general, in the past 20+ odd years there has been an over emphasis on complex control flow with errors.
Lots of different fine grained error types with complex logic spread out over several call layers.
ime it’s better to aim for simpler handling, which seems to match go
In fairness, the idea that you needed to scrape error strings to handle errors was a very popular complaint about Go that was valid 10 years ago, including in the standard library.
They are an improvement over most languages, but the are _not_ better than sum types for the reasons listed above. Way less flexible and forces a lot more verbosity when compared to more functional languages.
Hes definitely wrong on how the error types can help account for that but it would be best in class if we could properly chain them AND use all the greatness from interfaces.
The author is wrong, there exist mechanisms to cast errors. But they all suck! It's all just guessing and grepping for -hopefully- unique error messages.
One of the things I wish more people talked about isn't just the language or the syntax, but the ecosystem. Programming isn't just typing, it's dealing with dependencies and trying to wire everything up so you can have tests, benchmarks, code-generation and build scripts all working together well.
When I use modern languages like Go or Rust I don't have to deal with all the stuff added to other languages over the past 20 years like unicode, unit testing, linting, or concurrency.
I use Go where the team knows Java, Ruby or TypeScript but needs performance with low memory overhead. All the normal stuff is right there in the stdlib like JSON parsing, ECC / RSA encryption, or Image generation. You can write a working REST API with zero dependencies. Not to mention so far all Go programs I've ever seen still compile fine unlike those Python or Ruby projects where everything is broken because it's been 8mo.
However, I'd pick Rust when the team isn't scared of learning to program for real.
I like Rust.
I don't like that for fairly basic things one has to quickly reach for crates. I suppose it allows the best implementation to emerge and not be concerned with a breaking change to the language itself.
I also don't like how difficult it is to cross-compile from Linux to macOS. zig cc exists, but quickly runs into a situation where a linker flag is unsupported. The rust-lang/libc also (apparently?) insists on adding a flag related to iconv for macOS even though it's apparently not even used?
But writing Rust is fun. You kind of don't need to worry so much about trivialities because the compiler is so strict and can focus on the interesting stuff.
Yeah, I've never seen an all-in-one language like Go before. Not just a huge stdlib where you don't have to vet the authors on github to see if you'll be okay using their package, but also a huge amount of utility built in like benchmarking, testing, multiple platforms, profiling, formatting, and race-detection to name a few. I'm sad they still allow null, but they got a lot right when it comes to the tools.
Everything is literally built-in. It's the perfect scripting language replacement with the fast compile time and tiny language spec (Java 900 pages vs Go 130 pages) making it easy to fully train C-family devs into it within a couple weeks.
Oh Go with Rust's result/none setup and maybe better consts like in the article would be great.
Too ba null/nil is to stay since no Go 2.
Or maybe they would? Iirc 1.21 had technically a breaking change related to for loops. If it was just possible to have migration tooling. I guess too large of a change.
Technically, with generics, you could get a Result that is almost as good as Rust, but it is unidiomatic and awkward to write:
C# is pretty close.
This was not the case for a long time. Actually it seems like it's fairly recently you get native AOT and trimming to actually reduce build sizes and build time. Otherwise all the binaries come with a giant library
Even back in .NET Core 3.1 days C# had more than competitive performance profile with Go, and _much_ better multi-core scaling at allocation-heavy workloads.
It is disingenuous to say that whatever it ships with is huge also.
The common misconception by the industry that AOT is optimal and desired in server workloads is unfortunate. The deployment model (single slim binary vs many files vs host-dependent) is completely unrelated to whether the application utilizes JIT or AOT. Even with carefully gathered profile, Go produces much worse compiler output for something as trivial as hashmap lookup in comparison to .NET (or JVM for that matter).
There’s cross-rs which simplifies things. But the main problem is less linker flags being unsupported and more cross compiling C dependencies somewhere in the dependency chain and that’s always a nightmare, not really anything to do with Rust (Go should have similar difficulties with cross compilation).
Fair take for nontrivial projects.
Buuut with Go one in general tends to reach less for dependencies so less likely to run into this and cgo is not go ;) https://go-proverbs.github.io
but for cross-compiling actually ended up filtering out the liconv flag with a bash wrapper and compiled a custom zig cc version with the support for exported_symbols_list patched in, things appear to work.
Should look into cross-rs I suppose. Hope it's not one of those "download macos sdk from this unofficial source" setups that people seem to do. Apparently not allowed by Apple.
Cross compiling to Apple products from non Apple products is going to run into the same hurdle around SDK setup as any other. There exists documentation but it’s probably not the easiest task. This limitation though applies equally to any library that depends on system C headers and/or system libraries.
I feel like we're talking in loops.
Go is generally fine for crosscompiling.
edit: what gave me pain with Rust for a cli was clap (with derive, the default). Go just worked.
The crates.io ecosystem for Rust... is like the amazing girlfriend that you go head over heels for, make her your wife, and then you meet the in-laws ... but it's too late now.
Unlimited access to a bunch of third party code is great as you're getting started.
Until it isn't and you're swimming in a fishing net full of code you didn't write and dependencies you do not want. Everything you touch eventually brings all of tokio along with it. And 3 or 4 different versions of random number generators or base64 utilities, etc. etc.
> However, I'd pick Rust when the team isn't scared of learning to program for real.
I've been learning Rust. It's elegant, and I am enjoying it.
The Rust people however are absolutely annoying though. Never have I seen such a worse group of language zealots.
I can't speak for other Rust programmers but I can speak for myself.
I obviously enjoy programming Rust and I like many of the choices it made, but I am well aware of the tradeoffs Rust has made and I understand why other languages chose not to make them. Nor do I think Rust functions equally as well in every single use case.
I imagine most Rust users think like this, but unfortunately there seems to be a vocal minority who hold very dogmatic views of programming who have shaped how most people view the Rust community.
Guess I am scared to program for real since I don't use a "real" language like Rust. What a wild statement to make.
Go is a pleasure to use. The stdlib is one of the most complete, while keeping the keyword count low. LLMs understand it very well, project size stays low, line count stays low (if err nil included), doesn't need a bunch of scaffolded boilerplate in the project directory, and it compiles very quickly for a ton of OS and architectures. Very seldom do I ever need to go outside of the stdlib.
Is it perfect for everything? no. Is it the fastest compiled language out there? no. But, it'll do most things very well, and for me that's good enough. I choose go because when I need to make something, it steps aside and lets me build, and for that I have great respect and appreciation for it.
I will be defering all detractors and negative comments ;)
You defer at the beginning, not at the end in Go. /jk
Hey you caught that! I was hoping someone would notice the joke :)
I admit that it's nice to have a very simple, straightforward, and minimal build process. No dealing with VMs, no setting up environments, just install Go and then compile your program. Reminds me of C back in the late 90s.
> The stdlib is one of the most complete
what does this mean? Go lib seems tiny compared to JDK. anytime i review some Go code from adjacent team i'm turned off by weird stuff like append and slices everywhere, as well as a bunch of strange string packages
When I think of a massive stdlib I think of a language like groovy
The api surface is relatively small, but the capabilities you get from it (http serving, json parsing, crypto, in addition to table stakes like io, args, flags etc) are very high. Having a small api surface is why you need to use primatives so often, but the upside benefit to that is there is less domain specific knowledge, since you end up using familiar types and libraries in more of your code.
When I use Go, I find I can get more real work done with only the standard library than with any other language I've used (including Java, although that was quite a while ago now). It may not have the most stuff, it is more focused - but I'm okay with esoteric stuff not being in there since the tradeoff seems to be that there are high-quality implementations of e.g. an HTTP client and server, crypto functions, a unit testing library, JSON en/decoding etc, which I can definitely use in production. Conversely in Java the answer seems to be to use BouncyCastle / Tomcat / Jackson / etc, so while there may be a big stdlib, it ends up being less useful.
Python's standard library seems comparable IME
I would not agree with that assertion. Just off the top of my head, being familiar with both:
- context
- net/http as a full server framework, not just a request library
- net/http/pprof
- runtime/pprof
- runtime/trace
- embed
- testing as the canonical, required test framework
- net/rpc
- net/http/cgi
- net/http/fcgi
- net/http/httptest
- os/signal with integrated channel-based delivery
- sync/atomic with language-aligned memory model semantics
- runtime as a documented and supported API surface
In my experience, people building APIs w/ python are almost always using frameworks, while people building APIs w/ golang are almost always using stdlib
Then ask a JS web developer what "big standard library" would mean, and Go probably would fit somehow with that definition :)
It seems to be very relative depending on where you come from.
> difficulty of writing if err != nil
Literally the simplest way to deal with errors (cognitively and character wise). Since AI autocomplete entered the scene, typing this repetitive (for a reason) pattern became not a problem at all (I'm not even talking about post Claude Code era)
> The only resort the consumer of this library has is to parse the string value of this error for useful information.
Well, no. See for wrap/unwrap functionality https://go.dev/blog/go1.13-errors
> In Go, errors are values. They just aren’t particularly useful values.
In his example author could easily use his `progError` type instead.
Gosh, why it's so tempting to write a post about bad language instead of just reading docs or article about idiomatic usage?
> typing this repetitive (for a reason) pattern became not a problem at all
Code is read 10x more than it is written. The noise this pattern introduces inhibits reading and rapid comprehension.
Things are getting marginally better now that go has errors.Is and errors.As, and also now that go is starting to get some functional iterators. But go is one of the least quickly-understandable of the modern languages currently in use.
> The noise this pattern introduces
Here is the thing... it's NOT a 'noise'. Untill you see handling 'error path' as noise, you will be trapped in searching magic bullet language solution to hide it. We've all been there.
Handling errors doesn’t have to be noisy. Handling errors the way golang requires is.
When it takes five times as long to figure out how a function actually works (not only due to error handling, to be fair), the language has a problem.
Your last sentence makes sense only if you consider “happy path” to be what you call “understanding how function works”. A lot of programmers are annoyed that Go forces them to think about “error path” as equally important. Later many say that Go forces you to be the better programmer. But it takes time. In any case, saying “language has a problem” is a wrong frame for thinking about this design choice.
This is something gophers constantly repeat, but it is entirely a self-inflicted issue that other languages more modern than C don’t actually struggle with.
When in Rust, it is explicitly clear when and where errors can come up, and what types of errors I have to deal with. It is far less clear in golang, since there is no help from the type system when I’m using errors.Is and errors.As. Not being verbose doesn’t make error handling any less explicit.
Nobody is upset about having to pay attention to the unhappy path. This is entirely a straw man that gophers fall back to in order to feel like they’re somehow enlightened, shut down conversation, and to avoid having to consider what other people are saying. We are desperately hoping to help you realize that there are other, better ways that don’t come at the ridiculous readability costs inflicted by the anemic golang approach.
It really is okay to stop making excuses and accept that your preferred language has warts. I promise. Nobody will think less of you.
That's not a straw man, it's a valid reply to your first argument about "error handling code being an obstacle to understanding how function works". Why it makes you angry and makes you resort to ad hominem, I don't know, but that's clearly the end of the discussion.
No, it is a knee-jerk response that invariably assumes that a belief that golang’s specific approach is bad is equivalent to believing that errors are of secondary importance, and assumes that anyone who disagrees with the golang approach just doesn’t get how important it is to deal with errors.
You would rather dismiss other perspectives out of hand than actually reflect on how your chosen language might evolve.
In my perspective, this has been the entire historical progression of golang. Everyone vehemently denies that there’s a problem, eventually the language authors address it, and then everyone insists that it’s always been known that they needed to deal with the issue.
I don’t know why this seems to be so endemic to the golang community. Other languages’ adherents seem more than willing to accept the shortcomings of their preferred tools. But gophers continually insist that all the problems are actually strengths right up until it’s fixed and then they retcon their previous beliefs. It’s extremely off-putting.
>> difficulty of writing if err != nil >Literally the simplest way to deal with errors (cognitively and character wise). Since AI autocomplete entered the scene, typing this repetitive (for a reason) pattern became not a problem at all (I'm not even talking about post Claude Code era)
I agree with you. I don't have problems with the `if err!=nil` syntax.
From my post: > It’s become something of a meme to bemoan the supposed difficulty of writing if err != nil. I actually won’t make that point because I think it is a very surface level point that has been talked about to death and *I don’t think the ‘verbosity’ of this code snippet is such an issue.*
I apologize if my language was ambiguous on whether or whether not I had a problem with that syntax.
>In his example author could easily use his `progError` type instead.
I agree, but it was my impression that type erasure was more idiomatic. I should have made it clear that I was criticizing that idiom, not the language.
>Well, no. See for wrap/unwrap functionality https://go.dev/blog/go1.13-errors
You are right. I should have done my research on that before writing that point. I still think that downcasting isn't the most elegant solution because it defeats the point of using the opaque return type but I agree that it is nowhere near as much of a problem as I thought it was.
It’s still an issue because the type system doesn’t actually help you out when you want to handle all the possible types of error.
The simplest thing is not to do anything but defer to caller to handle it, in languages like Python, Java, JavaScript. Often that is also the only realistic way to an error, especially for library code.
To be fair, the author says it's the "_supposed_ difficulty of writing err != nil" and says that the verbosity isn't an issue here. But he also earlier says that he "[hates] having to write pub all the time in Rust" to denote public visibilities. So typing seven extra characters in one place = tolerable, but four extra characters elsewhere = detestable
Its not really a matter of logic, I guess.
Writing `pub` is personally more annoying to me than writing `if err != nil`. I understand that most people don't like how capitalization determines visibility, but I think it actually makes sense when you think about it.
the problem with the err != nil spam is that manual unwinding destroys useful information: the stack
that and the fact you can accidently silently ignore it without it being a compiler error
I commend Go for popularizing the channel-based concurrency, since I do think that that is a very elegant way of structuring stuff (especially compared to mutexes), but I have to admit that I don’t have a lot of fun writing Go.
I agree with a lot of the sentiment of this post; the weirdness with “tuples”, the weirdness of the error types, and etc. It’s not a “bad” language, just one that I don’t enjoy using.
Historically to get something similar to Go-style concurrency I would use Clojure with core.async, but more recently I have started using Rust and Tokio.
IMO, this is because Go succeeded at its intended to goal: to create a language that people with very little Computer Science (but some C/C++ programming) experience can be productive in. It eschews basically all abstractions that take more than 30s to explain to someone, which leaves a lot of really useful ones on the cutting room floor.
I agree with your point in general, but I would challenge the idea that tuples aren't something that is intuitive to explain (even in less than 30 seconds). Perhaps it's difficult to explain why tuples and not lists, but that's also relatively simple (homogeneous vs heterogeneous)
That’s fair. I came into Go relatively late and from a more Functional Programming background, so the language ends up being kind of annoying to me but that is probably not the case for others.
Don't get me wrong, I don't think it was a good goal. But that goal is the original sin of Go as a language, and most of the bad decisions that have been made in Go's design are in pursuit of it.
What are they top 3 languages that you have used that can be used as Go alternatives ranked by fun in your opinion (I am guessing Clojure and Rust are two of them)?
You’re right! I think overall I have most fun with Clojure.
I also really like Julia; it has a channel mechanism and it has a very nice macro syntax. It also is obscenely fast at number crunching tasks and I find the language pretty pleasant to use with a nice syntax. I use Julia whenever I need to do anything involving CPU bound number crunching stuff (which admittedly isn’t too often).
All that said, I have been mostly favoring Rust because the memory footprint is so much smaller and I still have a fair amount of fun with it :).
Also, depending on the task, I also get a fair bit of mileage out of ZeroMQ, which can bolt on channel-like semantics in a pinch. It’s not as nice as having it build directly into the language but it does support more flexible patterns. Whenever I have to use Java I almost always end up importing JeroMQ the moment that that built in BlockingQueues stop being sufficient.
Lack of enums are the main point for me.
The error story is not ideal but less bad than that most of the time, as you can downcast to access extra error data. Still, harder than it needs to be.
Overall, I've grown to like using the language even despite its warts.
What is with people and their need for enums? Functionally using go const with iota gives you the same damn thing and people use enums that way 99% of the time. I find Rusts reliance on enums annoying as hell. At this point I consider Rust a bandwagon language. The syntax is abysmal and we have had memory safe languages far before Rust. That I wont get into because as a Vulnerability Researcher I find the Rust push super misguided and it sets me off.
To be more clear, I want sum types with exhaustive matching - which Go does not support.
I get by without it Go enums are an inferior representation of the same logical concepts. Sure, I can have (kind, value) and cast things for a hacky sum type for some kind enum. But Go lacks closed enums/exhaustive matching.
You can at least validate the match arms with things like type switches and marker interfaces, but they're still not exhaustive and they're terribly verbose.
And, again, I can get by without them! But I miss them because Rust-style enum representation comes up _so often_, even if you don't like the rest of Rust.
> What is with people and their need for enums?
I mean, you have atomic and compound data types. Atomic ones represent single values, like "a string" or "an integer", and compound ones represent multiple atomic types combined in some way, like a struct or an enum. Enums are useful for the same reason structs are useful, they do the same core thing, just model it in a different way. It's the difference between "and" and "or", which are both useful tools.
It doesn’t have the enum keyword, but there is an idiomatic way to make enums in the language. They just end up being typed constants.
When people say they want sum types, they generally mean they want both sum types and exhaustive pattern matching. Either of these features on isolation are nice to have, but both together are incredibly powerful to the point where having just one is almost not worth it.
Is this what people mean by Enums? I must not have used languages where Enums have those powers. I have often been very confused by statements people make about Enums so that would make some sense.
How do sum types address the problem that the underlying type (int or string or whatever) is totally capable of describing values other than those your code was compiled with? I'm mostly thinking of version skew with something like a dynamic library or plugin, although casting would probably also have the same effect.
Yes, this is generally what people mean when they talk about enums in modern languages.
The in memory and ABI representation of enums/sum types is language dependent.
In Rust, an enum is equivalent to a C union where there's a discriminant value which is an integer of sufficient size to cover all variants (u8 is sufficient for 255 different variants), followed by as many bytes as the largest variant (a tagged union). Mucking around with the underlying bytes to change the discriminant and cause type confusion is UB. All the same strategies you'd take in C for versioning and ensure binary backwards compatibility would apply. When exposing these you would likely want a higher level abstraction/self-describing wire format, if you don't have control over both sides of the ABI boundary.
Other higher level languages do this for you already. I believe Swift is one of those, where it has a COM-like ABI layer that the compiler makes injects transparently to correctly interact with a dynamic library, handling versioning for you.
I am of the opinion that we need a new attempt at a multi-platform, language-agnostic, self-describing ABI, "COM for the modern world". I think some people have talked about using WASM for this.
Keep in mind that the concept (pattern matching, sum types) is not tied to how they are represented (Scala has both, but they are represented different to what I described earlier; IIRC it uses inheritance to represent the variants).
The problem is that this makes enums non-enumerable. They need to be represented as a range or union type to do that. I am pretty sure I know why/how Go ended up like this because it’s inherited behavior from proto, wrote a large comment later down the thread explaining why.
As someone who's been back into Go a couple of times (oscillating between Python, "C-ish" languages and the like), the ONE thing I hate about Go is error handling. The rest I can live with just fine.
Error handling in Go is actually very nice. You do not have unhandled errors, not possible unless you really want to not handle the error. Now I even use it similar in Python, amazing how many errors I did not handle at all. But what got me into using Go is that there is no libc dependency, just system calls, static binary, that is just amazing. I can compile Go compiler in like few minutes. Rust I cannot even compile after 24h, I use rust-bin in Gentoo,luckily that exists.
> Rust I cannot even compile after 24h
Could I ask what hardware this is on? Even when building LLVM from scratch too as part of building the toolchain (which hasn't been the default for a while now, but could see Gentoo doing so), it never took that long on any hardware I own. (Granted, I never tried on the EEE PC I've got on some drawer, and its 2G of RAM would likely kill the whole thing before it got started.)
On a Lenovo T460 (mid-range laptop from 2016), with a fresh clone of https://github.com/rust-lang/rust/ and the default config:
Subsequent builds during development are faster (as 1. it doesn't build the same compiler multiple times, you can use the stage 1 build as normal, stage 2 is not strictly necessary and 2. if you modify one of the constituent crates of the compiler, the ones that are lower in the dep tree don't get recompiled). I've used this laptop on and off for rustc development for the last 10 years. Nowadays I spent more time using a cloud desktop that has much faster IO, but still use it during travels sometimes.From the sound of it, I suspect that your issue might be that you don't have enough RAM and your build is swapping a lot.
This is an older thinkpad I am using, 4 cores, 16G of ram. LLVM is now dependency you cannot get rid of. That is painfull, but in the morning, after several hours it is usually done. Rust is LLVM plus I am not sure what, really painfull. And Gentoo also forces many different arches and flags for some reason, use flags are masked, you cannot easily disable them.
That sounds similar to the hardware on my T460 (2 cores, 4 threads, 16G). Would you consider cloning the repo and building it with the same command as my other comment? I'm really intrigued if the issue is the hardware/platform or "just" the Gentoo configuration or something else that doesn't affect the default build process.
> You do not have unhandled errors
Are you joking? It's trivially easy to drop the err or just not handle it accidentally in ways that are essentially impossible in rust. Especially when people re-use the `err` variable.
I've only written a handful of production projects in Go so my experience isn't very deep, but I find the syntax to be the ugliest of any PL. The mixed capitalizing based on function privacy, to me, is awful (among other things, i.e. personally I loathe curly brace initialization/definition). I'm sure you get used to it? It doesn't help that it just feels very hacked together, from the wonky generics, the lack of useful types like tuples and enums, the bolted on module system, to the annoying error handling, to say the least.
That said, compile times are great, the concurrency is dead simple, it's performant, and it's still easy to be really productive in it so it's not like I'd never consider it. Many other languages have many of the same issues, anyway.
> The mixed capitalizing based on function privacy, to me, is awful
Awful compared to ... what? `private` and `public` keywords? Ugly hacks like pythons `_` and `__`?
> it just feels very hacked together
> the wonky generics
What exactly about the generics is "wonky"? "Wonky" is not a term defined in any programming textbook I ever read. And languages are not designed on feelings, especially when the design goal is to be as pragmatic as possible, as is the case in Go.
> the lack of useful types like tuples and enums,
Need a tuple? Use an array and don't change it.
And btw. 99% of the time tuples are used, it's as a stand-in for multiple-returns. E.g. Python does that. Go simply has...multiple returns.> and enums,
Outside of language-enthusiasm with matching and whatnot (which more often than not is used because it looks cool rather than being useful), the most common (and again, 99%) use of enums, is to give names to magic values. Go has that covered:
> the bolted on module systemPray tell what exactly is "bolted on" about modules? They are simply an extension of the import system, nothing more, nothing less.
> the annoying error handling
The "annoying" thing about it is that it's explicit and forced. Both of which are positives as far as I'm concerned, because I AM FREKKIN DONE with shitty 10-mile stacktraces because some joksters library threw an "exception" 400 layers down in some sub-sub-sub-sub transient dependency lib.
I definitely prefer public private over case defined visibility.
You can't use an array for different types.
Matching _is_ useful, no one uses matching just because it looks "cool".
You can have explicit forced AND exhaustive error handling without exceptions. Go actually lacks this.
> I definitely prefer public private over case defined visibility.
And I think `public` and `private` keywords are a verbose mess that adds nothing to a language.
> You can't use an array for different types.
Yes I can. I even provided an example for exactly that: `[4]any` can hold references to any type.
> Matching _is_ useful
A lot of things are useful, doesn't mean they are used for that useful case most of the time.
> You can have explicit forced AND exhaustive error handling without exceptions
Go has wrapped and typed errors, covering exactly that.
Thanks for all of the comments!
I want to clarify that I think very highly of Go as a language. I think it gets most things right. It's hard to introduce an abstraction into a language while still making sure that it's not abused. Rust's trait and type system, while powerful have been abused to create some absolutely incomprehensible and long types. Go, on the other hand, doesn't suffer from this issue. If I was too harsh against Go, that was certainly a mistake.
I think that the criticisms of my section on error handling are, for the most part, spot on. My impression was that type erasure for errors was the idiomatic solution, which is patently untrue. When writing the blog post, I was unaware of the functions in the `errors` module as well as the syntactic sugar and general acceptance of downcasting errors. While I would still maintain that Rust errors are more convenient to work with, I must admit that there really isn't any good excuse for my ignorance on this.
When it comes to enums, I stand by my statements on them.
I still believe that it is useful to restrict the values a type might have. And no, I am not using the term enum to mean a rust-style "enum" (tagged union). I am talking about classical enums, more or less as they appear in C.
As an aside, I am not terribly surprised that my website doesn't work well on some browsers. I hacked together the website including the HTML and CSS a couple of years ago and some of the hacks I used I ought to be ashamed of.
Cracked at "I need to contribute my own beating so this horse is really dead"
Not shilling for Go here but there are a few misconceptions in this blog post. In addition to the others mentioned:
> All of these examples involve assigning to a constant a value known at compile time but none of them will work
Maps are not known at compile time. Hash functions are randomized based on a seed only known at execution time. The hashed value of "HELLO" is actually different each time the program runs. Even if the hash function weren't random, the runtime has to allocate buckets for map values on the heap, which involves calling the OS to get memory addresses for those buckets, etc.
In Go, `const` means "the compiler can completely evaluate this expression and store the final bytes in the executable," which has the effect of making them non-reassignable, but protection from reassignment is not an actual feature of the language the way it is in Java and C++ (goes back to the maintainers wanting to keep it simple).
Doesn't protection from reassignment not exist in most languages anyways? In C++ you should be able to cast away the const. Realistically you probably can achieve this in any language with reflection.
Unless a const is literally a compile time constant inserted through the program, it's likely able to be changed somehow in most languages.
You can definitely protect from reassignment in those languages (e.g. `final` in Java) but they don't completely prevent you from changing the underlying data. Rust would be one that comes to mind that has true immutability. I guess the Go maintainers just didn't want to go down that road, which I get.
Author is still early in their exploration and has some definite mistakes in here. Probably the biggest one is around the error handling, thinking that the only way to interact with an error is through the error interface itself. That is intended as a baseline interaction, a fallback for when nothing else is appropriate, such as just slamming an error into a log. If you want to interact with specific errors, you should use the various functions in the errors package [1] to check for specific types, and then use those specific types in whatever they support. Go error support is quite good; you can return an error object that says "The user was not found, the file the user was supposed to be found in was not found, and while trying to log this the log failed to accept the write" as various error types composed together, and any consumer of the error using the errors package can pick out the various bits of the error they understand using those tools without having to understand the error binding them together or the components it doesn't care about . You should never use string manipulation to check errors unless you have no choice, and whatever library left you with no choice should have an issue filed against it. It doesn't come up often, but it does sometimes come up; most recently I had the AWS SDK emitting an error I could only use string functions on, but I think they've since fixed it.
I don't like the term "enums" because of the overloading between simple integers that indicate something (the older, more traditional meaning) and using them to mean "sum types" when we have the perfectly sensible term "sum type" already, that doesn't conflict with the older meaning. If you want sum types, a better approach is to combine the sort of code structure defined here: https://appliedgo.net/spotlight/sum-types-in-go/ with a linter to enforce it https://github.com/alecthomas/go-check-sumtype , which is even better used as a component of golangci-lint: https://golangci-lint.run/
I'd also add my own warnings about reaching for sum types when they aren't necessary, in a language where they are not first class citizens: https://jerf.org/iri/post/2960/ but at the same time I'd also underline that I do use them when appropriate in my Go code, so it's not a warning to never use them. It's more a warning that sum types are not somehow Platonically ideal. They're tools, subject to cost/benefit analysis just like anything else.
[1]: https://pkg.go.dev/errors
> If you want sum types, a better approach is to combine the sort of code [...]
I'm currently of the opinion that where you truly need this type of thing, write tests that use the ast package to validate that your expectations hold. That way you don't need to do anything strange with the code, and logic failure will show up alongside all of your other logic failures.
While it does venture into implementation details that shouldn't be tested, Go offers a discriminator between your actual tests and throwaway tests (i.e. `package foo_test` v.s. `package foo`), so as long as you've clearly mark the intent I find this to be an acceptable tradeoff. As implementation changes, and you no longer need that validation, others will know that your throwaway tests are intended as such.
> I don't like the term "enums" because of the overloading between simple integers that indicate something (the older, more traditional meaning)
I disagree with this. I'm old as hell, and I learned programming in a context where enums were always ints, but I remember being introduced to int enums as "we're going to use ints to represent the values of our enum," not "enums are when you use ints to represent a set of values." From the very beginning of my acquaintance with enums, long before I encountered a language that offered any other implementation of them, it was clear that enums were a concept independent of ints, and ints just happened to be an efficient way of representing them.
"Enum" is literally defined as a numbering mechanism. While integers are the most natural type used to store numbers, you could represent those numbers as strings if you really wanted. The key takeaway is that a enum is a value, not a type.
The type the link was struggling to speak of seems to be a tagged union. Often tagged union implementations use enums to generate the tag value, which seems to be the source of confusion. But even in tagged unions, the enum portion is not a type. It remains just an integer value (probably; using a string would be strange, but not impossible I guess).
Disagree. Enums are named for being enumerable which is not the same thing as simply having an equivalent number.
It’s incredibly useful to be able to easily iterate over all possible values of a type at runtime or otherwise handle enum types as if they are their enum value and not just a leaky wrapper around an int.
If you let an enum be any old number or make the user implement that themselves, they also have to implement the enumeration of those numbers and any optimizations that you can unlock by explicitly knowing ahead of time what all possible values of a type are and how to quickly enumerate them.
What’s a better representation: letting an enum with two values be “1245927” or “0” or maybe even a float or a string whatever the programmer wants? Or, should they be 0 and 1 or directly compiled into the program on a way that allows the programmer to only ever need to think about the enum values and not the implementation?
IMO the first approach completely defeats the purpose of an enum. It’s supposed to be a union type, not a static set of values of any type. If I want the enum to be tagged or serializable to a string that should be implemented on top of the actual enumerable type.
They’re not mutually exclusive at all, it’s just that making enums “just tags” forces you to think about their internals even if you don’t need to serialize them and doesn’t give you enumerability, so why would I even use those enums at all when a string does the same thing with less jank?
> Enums are named for being enumerable which is not the same thing as simply having an equivalent number.
Exactly. Like before, in the context of compilers, it refers to certain 'built-in' values that are generated by the compiler; which is done using an enumerable. Hence the name. It is an implementation detail around value creation and has nothing to do with types. Types exist in a very different dimension.
> It’s supposed to be a union type
It is not supposed to be anything, only referring to what it is — a feature implemented with an enumerable. Which, again, produces a value. Nothing to do with types.
I know, language evolves and whatnot. We can start to use it to be mean the same thing as tagged unions if we really want, but if we're going to rebrand "enums", what do we call what was formally known as enums? Are we going to call that "tagged unions" since that term now serves no purpose, confusing everyone?
That's the problem here. If we already had a generally accepted term to use to refer to what was historically known as enums, then at least we could use that in place of "enums" and move on with life. But with "enums" trying to take on two completely different, albeit somewhat adjacent due to how things are sometimes implemented, meanings, nobody has any clue as to what anyone is talking about and there is no clear path forward on how to rectify that.
Perhaps Go even chose the "itoa" keyword in place of "enum" in order to try and introduce that new term into the lexicon. But I think we can agree that it never caught on. If I, speaking to people who have never used Go before, started talking about iotas, would they know what I was talking about? I expect the answer is a hard "no".
Granted, more likely it was done because naming a keyword that activates a feature after how the feature is implemented under the hood is pretty strange when you think about it. I'm not sure "an extremely small amount" improves upon the understanding of what it is, but at least tries to separate what it is from how it works inside of the black box.
It feels obvious that that's where the term originated, but I've never seen it used as a definition. In a mathematical context, something is enumerable if it can be put into 1:1 correspondence with the integers, but it doesn't need to be defined by a canonical correspondence. This suggests that being a finite (in a programming context where the set of ints is finite) set of discrete values is the defining feature, not the representation.
Sum types can be put into 1:1 correspondence with the integers, barring the inclusion of a non-enumerable type in a language's specification that can be used in sum types. However I would observe that this is generally a parlor trick and it's fairly uncommon to simply iterate through a sum type. As is so often the case, the exceptions will leap to mind and some people are already rushing to contradict me in the replies... but they are coming to mind precisely because they are the exceptions. Yes, you can sensibly iterate on "type Color = Red | Green | Blue", I've written code to do the equivalent in various languages many times and most complicated enumerations (in the old sense) I do come equipped with some array that has all the legal values so people can iterate over them (if they are not contiguous for some reason), so I know it can be done and can be useful. But the instant you have a general number type, or goodness help you, a generalized String type, as part of your sum type, you aren't going to be iterating on all possible values. And the way in which you can put the sum types into a 1:1 correspondence won't match your intuition either, since you'll need to diagonalize on the type, otherwise any unbounded array/string will get you "stuck" on the mapping and you'll never get past it.
So while you can theoretically argue it makes sense to call them an "enum" I don't like it precisely because "enumerating" the "enum" types (being sum types here), in general, is not a sensible operation. It is sensible in specific, but that's not really all that special. We don't generally name types by what a small percentage of the instances can do or are, we name them by what all instances can do or are. A degenerate sum type "type Value = Value" is still a sum, albeit a degenerate one of "1", but nobody ever enumerates all values of "type Email = Email { username :: String, domain :: String }". (Or whatever more precise type you'd like to use there. Just the first example that came to mind.) There are also cases where you actively don't want users enumerating your sum type, e.g., some sort of token that indicates secure access to some resource that you shouldn't be able to get, even in principle, by simple enumerating across your enum.
If it's called an "enum" I want to be able to "enum"erate it.
> In most applications of int enums, the particular integers can be chosen at random
I’m not sure the definition of "enum" enforces how things are identified. Random choice would be as good as any other, theoretically. In practice, as it relates to programming, random choice is harder to implement due to collision possibilities. Much simpler is to simply increment an integer, which is how every language I've ever used does it; even Rust, whose implementation is very similar to Go's implementation.
But it remains that the key takeaway is that the enum is a value. The whole reason for using an enum is for the sake of runtime comparison. It wouldn't even make sense to be a type as it is often used. It is bizarre that it keeps getting called one.
Another comment already mentioned that the OP don't understand how to work with errors in Go.
As with any language, Go has its own philosophy and you have to first understand why it was created and what it brings to the table. To summarize it in one phrase "Less is more"
I think this post should be a mandatory reading for everybody learning Go. If this resonates with you it's possible you're gonna like the language:
https://commandcenter.blogspot.com/2012/06/less-is-exponenti...
I believe I read this when it was first published but it still holds up very well today.
The way I do this is decide which language I like (just by gut feel) and then come up with reasons why it is good / better than others. I think almost everyone does the same thing, really.
But you can learn about yourself and others by writing down specifically the things you like and don’t like, and reading other people doing the same. With the possibility of liking different things for different reasons in the future. Or just better understanding how to best use the tools you like.
fyi your about page doesn't work: https://benraz.dev/about.html
I always felt like go channels were more of a clever solution than a good one. Goroutines are a pleasure to work with though.
I'm curious what the alternative would be? Python's threads/sub-processing almost requires IO queues to function well, and are nearly the same semantically as channels...
I'm not saying these are "good", just wondering what alternatives look like?
One alternative is STM, software transactional memory which is modular and composable. I think Haskell was first to implement it but its also in Clojure and some Scala libs.
This is what ZIO's type safe version looks like https://zio.dev/reference/stm/ Scala's for-comprehension is syntactic sugar for calls to flatMap, map, and withFilter, similar to Haskell's do-notation.
too young too simple, sometimes naive.
Correct me if I'm wrong, but the Error interface means you can display the error as a string, but you don't have to? Like the err.Error() is idiomatic if you just want to display something, but you could also use the error itself
https://pkg.go.dev/errors#As
here's an example that uses a field from your blog example error type: https://go.dev/play/p/SoVrnfXfzZy
Also "In Go, errors are values. They just aren’t particularly useful values"
...sometimes user mistakes are due to the language being too complicated, maybe for no benefit, but I don't think that's the case here. It's a very good thing that you can just slap .Error() on any error to print it quickly, and not too crazy complex to say an error can be any normal type that you can use, as long as it also can print Error()
My guess is that the author hasn’t fully frocked how go interfaces work yet. Go errors implement the error interface, but that just makes them interoperable, it doesn’t mean that’s all they are.
Correct me if I am wrong, but does it not mean that they are type-erased though? The whole point of returning an interface is to perform type-erasure.
If I have
but I return it as an error: Then all the caller gets is an error interface. Without downcasting (`.(T)`/`errors.As`), you can only compare it to other instances (if the library author provided them) or see the string representation.Yes, that's correct. The interface limits what guarantees the caller has about the type without runtime introspection. I don't think that really makes it any harder to handle expected error conditions though, since type assertions return a boolean. eg:
But you should always expect that there could be errors you don't expect to exhaustively handle with special logic.They don't seem to understand Go much at all. Comparisons to Rust are somewhat misplaced but that's a different topic... Back to errors. Errors are interface values. They are simple yet powerful. You can create sentinel errors that can be wrapped or just passed to be checked then discarded. Go has all the functionality it needs to provide what ever it is Rust cult members believe makes Rust error handling so great. You can use the primitive constructs Go provides to do nearly the same damn things Rust can do and it won't look like a pile of hieroglyphs your local crackhead would draw. Best of all... Its simple and the syntax of Go (veering off topic) doesn't make me want to jump off a bridge. Stop gaslighting yourselves into thinking Rust syntax is reasonable and that its some perfectly proven language with all edge cases put to rest..
Safari doesn't show the t's. Why?? Chrome does.
exactly wtf is up with this website, firefox doesn't show t's, random f's, d's - it's a complete mess.
No issues here on Firefox 146 Fedora/GNOME. Also imagine it's not uncommon for a personal site to not test for Safari if they're not in the Apple ecosystem.
As a fellow Fedora/GNOME user, fun fact: GNOME Web uses the same web engine as Safari! They both use Webkit, so it's not out of reach.
My best guess is that the font I am using (WOFF2 variable font) might be tripping up the browser.
That's probably it. I am getting these problems with Safari 17.6, with a newer one, Safari 26.0.1, there is no problem.
FF working as expected for me on Ubuntu
I think I know why Go ended up without good enum support.
(Disclaimer, formerly worked at Google and used proto/grpc/go there and now in my own startup in github.com/accretional/collector which tries to address this problem with a type registry and fully reflective API. Not privy to the full history, just reasoning.)
Proto is designed so that messages can be deserialized into older/previous proto definitions by clients even if the server is responding with messages of a more recent version. Field numbers Re what let you to start serializing new fields (add a new field with an unused/the next number) or safely stop setting fields in proto responses (reserve a field) without risking older clients misinterpreting the data as belonging to some existing field they know about. This requires you to encode the field numbers alongside the field data in the proto wire format.
Two major problems: nothing in proto itself enforces that field numbers are assigned sequentially, because there is no single source of truth for the proto schema (you can still have one of your own, but it’s not a “thing” in proto). Also, the whole point of field numbers is that they can be selectively missing/reserved/ignored and allow you to deserialize messages without special handling for version changes in your code at runtime.
So, field numbers aren’t a dense, easily enumerable range of numbers, they’re basically tags that can be any number between 1 and 536,870,911 except for the reserved 19,000-19,999. This smells like serious tech debt/ a design flaw that completely closes the door for even fixing this at Google or anywhere else, because it’s arbitrarily in the middle of the range of field numbers and a leaked implementation detail from the internals. You couldn’t build your own dense field number management/sequential enforcement system on top of proto without ripping that part out, but your existing proto usage relies on that part and changing it would break existing clients because you’re removing field numbers, which is the whole fucking point of proto, and makes it difficult to roll out even if you did fix it yourself.
So, representing union/enumerable types in proto is impossible. For proto enums to have forward compatibility, they have to handle adding new enum values over time, or need to remove and reserve old ones. So, proto enums end up being basically just field numbers. That’s exactly what you see in Golang enums and I don’t think it’s a coincidence: Google has no good way to serialize/deserialize/operate on enumerable enums or union types anywhere they use proto/grpc. Golang inherits this “enums” implementation from protobuf because it’s the context in which it was created.
Wha do you mean by “fixing this” or it being a design flaw?
I agree with the point about sequential allocation, but that can also be solved by something like a linter. How do you achieve compatibility with old clients without allowing something similar to reserved field numbers to deal with version skew ambiguity?
I view an enum more as an abstraction to create subtypes, especially named ones. “Enumerability” is not necessarily required and in some cases is detrimental (if you design software in the way proto wants you to). Whether an enum is “open” or “closed” is a similar decision to something like required vs optional fields enforced by the proto itself (“hard” required being something that was later deprecated).
One option would be to have enums be “closed” and call it a day - but then that means you can never add new values to a public enum without breaking all downstream software. Sometimes this may be justified, but other times it’s not something that is strictly required (basically it comes down to whether an API of static enumerability for the enum is required or not).
IMO the Go way is the most flexible and sane default. Putting aside dedicated keywords etc, the “open by default” design means you can add enum values when necessary. You can still do dynamic closed enums with extra code. Static ones are still not possible though without codegen. However if the default was closed enums, you wouldn’t be able to use it when you wanted an open one, and would have it set it up the way it does now anyway.
No its because 99% of the time people use enums to give names to magic constants... That is it. Go went for simplicity and const+iota achieves it just fine. People act like enums make or break software itself or something.
Yea but with a tiny bit more effort they could have ensured that an invalid value is never assigned to an enum, iterate over the values, ensure switch statements handle every case, etc.
That seems unlikely to me to be the actual explanation. It could very well be what you prefer or how you would do it, but I can definitely assure you that the Go/other infrastructure teams think about these problems and hear plenty of complaints about lack of union type support.
I'm not sure I understand your argument. You're saying that you can't really use enums for field numbers. And let's say that you're absolutely correct about that.
It still seems to me that you're addressing a completely separate issue from having a specific field that is an enum - not an enum of a field number, but an enum of something else, like encryption algorithm or SHA type or something.
Am I missing your point?
I’m pointing out that proto’s enums are wrappers around proto field numbers, which are numerical ids for proto message fields that enable forward/backward compatibility across proto message version changes. These field numbers are necessarily sparse but don’t even need to be assigned sequentially, and in fact, because of the leaked implementation details from the internal field number range you have to assume they are non-sequential. So field numbers are sparse, which makes them non-enumerable even though they’re represented with numeric tags.
Hence, proto enums are essentially non-enumerable wrappers around numeric values. And this is (almost certainly) why Golang’s enums are structured the same way, as transparent wrappers around values that are not necessarily sequential or enumerable.
But why is sequential a requirement? That is, in C++ I can have an enum like
C++ does sparse enums just fine. Are you saying that those are not "real" enums because their sparse? Or that C++ doesn't have "real" enums because it allows that? Or what?10 years ago we started out with Python. We switched to Go probably 8 years back. I think my little startup would have utterly failed without Go. Thx google :)
But yes Enums are so much nicer in Kotlin vs Go. That's true, it doesn't impact productivity much, but he has a point.
I think some pythonistas maybe got their feeling hurt by your comment causing it to grey out.
Over the last 25 years in the SaaS world, I have never seen python evolve into a system that is easy to reason about and debug. It lets you do too many things. In over 30 cases, I have seen teams deliver better software faster in Go after replacing their Python.
Man this post is a rollercoaster. First half of the post I was absolutely starstruck by how amazing go is(I haven't had time to play with it myself yet), and was making mental note after mental note to try it out asap!
Then I got to the second half of the post, with the things he didn't like about go.
No enums? Wtf? Not having sum types is a lesser evil imo, it places you in the mediocre, but mediocre is mostly ok so that's kinda fine. But no enums? We're stuck with magic numbers? Hell naw, we banished that demon in the nineties, I ain't signing up to bring it back!
>No enums? [...] We're stuck with magic numbers?
In go you don't strictly need magic numbers because you can define constants:
The problem is that there is no exhaustiveness with these constant groups. The type Number is not a closed set of just IoProblem and JsonParse like an enum in C. It is just an int.I don't buy that example about errors at the end at all. The problem the author is trying to solve is to write code that calls a foreign/fixed-API function that is known to return a particular subtype of Error, and wants to extract structured information from it. But you can't, because the type returned is just the outer Error type that only has a string.
Obviously, though, the only way this happens is if you know a priori what actually failed, because otherwise it might be some other error type. And you don't, obviously, because it's an error! If your behavior is deterministic then just return whatever you want in your own API. If it's not, you need to parse/extract/inspect the error.
Basically it's entirely contrived. This never happens, and to the extent it does it's a terrible bug where you have code making assumptions about runtime error state without fully inspecting that state.
The second failure is that Go does in fact have runtime type inspection facilities ("type assertions" is the particular jargon) and if you want you can absolutely "cast" that error into a derived type to get the data out. So it's not even a problem in the language as it exists.
His example criticizing errors in `rootInfo` func is silly. There is utterly no need to do a `strings.HasSuffix(err.Error(), "not a directory")`.
but how would you do that otherwise? Genuinely curious cause I looked up both the go docs and source (disclaimer: not a go dev), and there doesn't seem a way to handle that specific kind of error through stuff like `errors.Is`, at least from what I can tell, at least in the os and fs packages
He can do a test using `errors.Is(err, syscall.ENOTDIR)`
From what the comments are saying I think you downcast with `errors.As` and then work on the underlying error type. But I don't know for sure.
Another languages that just “gets” concurrent right (imo) is erlang/elixir. I’ve done elixir for the last 3 years off and on.
Can someone with experience in both Go and Elixir compare the two? I’m sure I can have GPT whip up a comparison and see the syntax diffeeences, but I’m curious what the real experience “in the trench” is like.
I've used both professionally. I think elixir has some amazing ideas. I love pattern matching. However! Just like all other interpreted languages, in elixir, I have to go to the call sites of the function that I am editing to understand what it is that is actually available and to understand what I can edit. I don't know what has been passed into my function. The lack of types is not fixed by having a type spec and dialyzer. Pattern matching helps. I wish Go had it. But when it comes to a growing organization, more and more of the codebase cannot fit in your head, and I find that teams and organizations are indeed faster in Go.
I recall hearing that Jose was making progress on types. Not sure where that landed.
I was curious in particular about the concurrency story between the two, but thanks for the higher level feedback.
One of the few languages I've known that didn't provide any standard features for libraries (until the sixth major revision), Scheme, has been the worse for it.
Another tired error-handling take. It ain't pretty but it works.
It is pretty and it can do pretty much exactly what Rust enums do if they learned basic idiomatic Go.. Rust is a cult at this point honestly.