[throwaway894345]

I really like Rust, but in my mind it's still relegated to the periphery of tasks that must be super fast (like C/C++, to your point) and/or low-level. Rust has made impressive strides at reducing the toil involved in compile-time memory management, but there is still a big productivity gap between the borrow checker and GC.

Frankly, people are making boatloads of money off of software written in Python and JS--languages which are both far less safe than Go and far slower and yet Go is on par with those languages with respect to productivity (I argue it's more productive due to its static typing features, but others argue it's less productive presumably because of the learning curve). Most software doesn't need to be so fast or correct.

Also, I work in distributed systems and SaaS (software as a service). In this world, most errors are silly type errors ("undefined is not a function", forgetting to `await` some async function, etc) that would be caught with a flat-footed type system like Go's. Beyond that, the next largest bucket are issues that even a sophisticated type system like Rust's wouldn't help with, such as infrastructure issues (missing/misconfiguration of some cloud permission, networking rule, etc), misconfiguration of the service, race condition with many processes accessing the same networked resource, deployment error, etc. This means that Rust's stated advantages aren't really as nice as they initially sound.

As a programmer, I can appreciate a super fast language with a strict type system; however, as an engineer or a technologist, Rust is rarely a good fit for me. Go seems to be a lot closer to the sweet spot, which makes sense because it was developed expressly with distributed systems in mind.

[josephg]

> In this world, most errors are silly type errors

I can’t speak to python, but typescript has basically fixed this problem overnight in the javascript ecosystem. The typescript compiler finds almost all small bugs like this while I’m coding. And as an added bonus, type hints allow the IDE to be much more helpful - adding to jump to function support, autocomplete, method parameter suggestions (or documentation on hover). And typescript is easier to read than javascript because you don’t have to guess what data type some variable is.

I love javascript’s quick and dirty nature, but I still use typescript instead of javascript now for any code I write that I expect to survive the week. (And as a bonus: you still get IDE type hints when calling typescript functions from raw javascript!)

Typescript’s type system is also more powerful than Go’s. It supports enums, genetics and type unions (eg x: string | number).

Go sits in the awkward place of having a worse type system and no significant advantages over typescript for me. It’s awkward to use go on the web. Go is faster than javascript on the server but that usually doesn’t matter. And when it does I can reach for C or Rust. Both of which work really well with native code, or with JS through wasm.

Rust is much harder to learn than Go - but personally I’ve climbed that hill already. Once you’re over that hill, Rust is much more expressive. On purpose both ways - go isn’t trying to be expressive, and rust is. I love rust’s parametric enums and output types in traits. Which I now sorely miss in other languages.

I can imagine Go shining a lot more brightly when working with a team which has mixed skill levels. Most of my work lately has been solo, so I don’t need gofmt to enforce a consistent code style, or anything like that. I do miss Go’s green threads. Rust’s afterthought scattergun approach with threads and futures feels like a mess. But I can’t see myself ever really using Go. It’s weak in areas I want it to be strong (eg the type system). And strong in areas I just don’t care much about. (Eg consistency).

[tptacek]

Rust is very expressive, but it also makes some tasks that are relatively simple in other languages much harder (anything involving tree structures, for instance), and some of what it gives you expressive control over is stuff you usually don't need to think about at all in other languages.

Rust can do some things Go simply isn't suited for right now; for instance, there is no way we're getting kernel Go in the foreseeable future. You couldn't reasonably build a browser, or browser components, in Go.

Both languages have their place. There is a lot of overlap, and the original comment about how one might prefer Rust if what they miss most in Go is generics makes sense. But the idea that the only thing you'd gain by choosing Go over Rust is easier development on big teams is just false. One language is GC'd, the other is borrow-checked. GC makes a lot of things faster to build. This debate ended in the mid-1990s.

[zozbot234]

> Rust is very expressive, but it also makes some tasks that are relatively simple in other languages much harder (anything involving tree structures, for instance)

Much harder, not really. Rust lets you add mutability, reference counting and thread safety to your data structures, you just need to know when to use these features. Yes, Go has fully general GC but very few problem domains have a real need for general GC.

[throwaway894345]

> Yes, Go has fully general GC but very few problem domains have a real need for general GC.

No, no one needs a GC, but many problem domains need productivity, and GC is the most productive way to manage memory to date. As previously mentioned, Rust has made truly impressive strides in improving productivity of borrow-checking, but it still remains quite far behind GC.

[josephg]

Yes, having written a b-tree in rust recently I can confirm this. My child node pointers look like this:

    enum Node<E: EntryTraits, I: TreeIndex<E>> {
        Internal(Pin<Box<NodeInternal<E, I>>>),
        Leaf(Pin<Box<NodeLeaf<E, I>>>),
    }

Yikes. I could probably clean this up a little, but not a lot.

I've been working on this code for months and I still have no idea if my internal b-tree functions should be taking a &mut self, self: Pin<&mut Self> or a NonNull<...> or something else. The compiled code is blazing fast, and being able to control behaviour so clearly with a few parametric type parameters is amazing.

But the process of figuring out the best way to code it up is awful, and it requires all of my attention and capacity. I doubt Rust will ever gain the sort of mainstream usage that javascript & Go have because of how complicated otherwise simple problems can become. Its a great language for the linux kernel and web browsers. But I can't imagine many normal programmers will want to build regular websites and apps in rust.

GC languages are slower, but credit where its due - they make it so much easier to just dive in and spend all your braincells thinking about your problem domain.

[pjmlp]

I have been in plenty of hills since I wrote those first BASIC lines on a Timex 2068.

Just like consumers don't care if their favourite music application is written in Electron, as long it plays their favourite album on their newly acquired speakers, they also don't care what type system was used to deliver such experience.

With Go finally getting generics, it will be pretty alright, 99% of distributed computing applications need not care about zero GC code, only proper use of value types.

[zzt123]

Your point about Go shining a lot more brightly when working with a team which has mixed skill levels was one of the design goals of Go, so it seems they’ve succeeded on that front if you’ve come to that conclusion independently!

[silisili]

IMO, Go is the easiest language to read by far. Python can be, but lets one use a lot of hard to figure out magic. Go is very much WYSIWYG, and to me that's its greatest strength. It's easy for anyone to jump in about anywhere. And that lends itself well to teamwork.

[josephg]

I find that's only true so long as the problem you're solving fits well into Go's view of the world.

If you want to make a data structure holding the equivalent of a parametric enum (or tagged union from C), go is very awkward to use compared with richer languages like Swift or Rust. Go is also awkward if you want to implement custom generic data structures.

Eg, this[1] code I wrote a couple years ago for doing text based operational transform became about 1.5x longer in Go compared to rust or typescript because its so awkward to express a parametric enum in go. And it was much harder to read & more buggy as a result. Sadly I lost the go version of the code. I'd be curious if someone with more go experience could do a better job, but I'm skeptical.

Hopefully the situation improves somewhat when generics land.

[1] https://github.com/josephg/textot.rs/blob/03c84b7c35a375ba7d...

[throwaway894345]

I agree that enums are the thing that Go is lacking. I would really like first-class enums perhaps even more than generics. Hopefully we get them.

[readlikeasloth]

> I can imagine Go shining a lot more brightly when working with a team which has mixed skill levels.

Thank you for expressing that thought. However: I came quite to the opposite conclusion. I´m currently working in a small team with members that are not so versatile in coding, coming from a JavaScript background. It has been surprisingly easy to teach them Spring Boot. You follow a typical layout and everything falls into its place. I have my reservation that the same holds true for Go. It feels like there is much more room for confusion. Do I use global functions or receivers? How do I inject my dependencies and where do manage them? How do I build constructors and do I really need them? I found surprisingly little advice on those topics.

[tialaramex]

> but there is still a big productivity gap between the borrow checker and GC.

The borrow checker and GC aren't really doing the same thing though. One very important distinction in some fields (but unimportant in others) is that GC only really cares about memory resources. So you are (or should be) doing explicit manual cleanup for all non-memory resources in a GC language. Rust isn't, in Rust we don't write explicit resource cleanup for a programmable interrupt controller, or a file, or a database connection -- the resource knows how to manage itself, and Rust promises to tell it immediately when it falls out of use, whereas a GC can't promise to ever clean up which is why Go doesn't even bother providing a means to do this automatically for your non-memory resources when they're garbage collected (Java does, but again, no promises it ever fires, so, don't rely on this).

[throwaway34241]

> Go doesn't even bother providing a means to do this automatically for your non-memory resources when they're garbage collected (Java does, but again, no promises it ever fires, so, don't rely on this).

It sounds like you are talking about finalizers? If so, they exist in Go in a similar way to the Java feature [1].

[1] https://pkg.go.dev/runtime#SetFinalizer

[throwaway894345]

Finalizers aren’t quite the same. They run when memory pressure exceeds some threshold, but the GC analog for borrow-checking is something that will clean up a resource when the pressure on the resource in question exceeds some threshold (e.g., file handles). And even then I’m not sure if that ticks all requirements for resource management.

[throwaway34241]

I meant to respond only to the quoted section comparing Java and Go, which states that Go doesn't have a way to do cleanup on GC (finalizers). I agree with you (and the two other replies and the quoted section itself) that finalizers are not a replacement for RAII etc.

I don't use them for resource cleanup, but I think they probably make sense for library authors as a back-up mechanism (for example, the standard library has a finalizer to close file handles, and the current runtime does GC every two minutes in the absence of memory pressure). You can also explicitly run the GC in Go, and while generally there's a lot of problems with that idea I could maybe imagine it being viable for certain unusual workloads.

[beltsazar]

You usually want to release non-memory resources deterministically, but finalizers in C#/Java/Go are not deterministic. That's why finalizers usually are not used for resource management. Instead, C# has using statements, Java try-with-resources, Go defer statements.

[sagichmal]

Finalizers are not guaranteed to run. They're not ersatz destructors.

[throwaway34241]

Yes, if you look at the quote I was responding to, it appears they are saying Go doesn't have finalizers, which is incorrect.

[xpressvideoz]

Huh, I also thought Go had no concept of finalizers. That is a bit... awkward way to set a finalizer. But thinking it again, it may just be due to my unfamiliarity.

[pjmlp]

That is a misconception, RAII like code can be achieved in two ways:

- defer (possibly add a go vet check for when missing it)

- when Go 1.18 brings generics, the withFunc pattern from FP where lambdas get given a resource released on function exist, thus having regions/arena like resource management

[tialaramex]

The description for go vet says, "it should be used as guidance only". Go vet is in fact a linter (go lint is also a linter, but one focused on style).

So what you're doing there is adding a control to try to mitigate the consequences of a language failing. Go doesn't actually prevent you from getting this wrong, but a linter such as go vet can flag cases where it suspects you screwed up, and maybe you'll catch the worst mistakes most of the time this way and by having usage conventions.

We shouldn't mistake this for equivalent capability. The complicated cases that tempt people to ignore or switch off such linting are exactly the cases most likely to have an undetected problem.

So this is "RAII like" only in the sense that "Just remember to do it properly" is RAII like, and we could make exactly the same claim for C.

[pjmlp]

Just like you need to use clang tidy to fix all the issues with writing proper C++ code.

[tialaramex]

Fair. However, there continues to be an unresolved tension in the C++ community about whether they want C++ to focus on its considerable legacy by ensuring enduring compatibility ("No ABI breaks, ever!") or to continue growing and changing even if that means not everybody can follow ("Performance trumps compatibility, ship it!"). Although we can anticipate some sort of compromise, it just isn't possible to have a C++ 2x that delivers everything the modernizers want yet still runs people's technically conforming C++ 11 code unchanged with that binary DLL they've got no source code for. Some people will be unhappy, maybe everybody in the C++ community will end up unhappy.

In the "no breaking changes" case I agree that C++ objects that live in the free store are in the same place as Go, the programmer has a responsible which they may not fulfil, to manage this resource and a linter can only help mitigate this problem.

But plenty of people including Stroustrup want to do lifetime management, despite potential breaking changes from that, and under lifetime management the compiler has visibility into your object lifetimes and can reject programs which inadvertently leak.

Now, that doesn't (can't) make leaks impossible, but it means any leak is now in some sense "on purpose" and would happen for GC'd resources too, it isn't just an accident. For example Rust's mem::forget will prevent the drop happening for the object you're forgetting, but it's not as though you type mem::forget() by mistake. You clearly wanted to achieve that (e.g. you stole the underlying Unix file descriptor from a File and sent it over a socket to a separate process, so now cleaning up that descriptor is the Wrong Thing™) and incorrect usage is not the same category of error as forgetting a with clause in Python.

[deathanatos]

defer (/using/with) all require the programmer to remember, and write, O(use site) times, the code to release the resource.

RAII destructors, on the other hand, do not permit the coder (at the use site of the type) to forget, as the destructor is invoked automatically when the variable goes out of scope.

In my time reviewing Python (also GC, "with" provides a similar functionality), this is a very common error.

[pjmlp]

Apparently you missed my go vet reference on purpose, just make all of us aware of it not being the same.

Same applies to using on .NET, where forgetting to call using on an IDisposable type can trigger a compiler error, via Roslyn plugins.

Also seem to be unaware how closure based RAII works on FP languages.

RAII isn't triggered on heap allocated objects unless smart pointers are used everywhere.

Python doesn't have a static analysis tool for with, nor does it support value types with stack allocation. Not all GC languages were born equal.

[nemetroid]

> RAII isn't triggered on heap allocated objects unless smart pointers are used everywhere.

It's triggered unless you have memory leaks.

[pjmlp]

So it isn't.

[throwaway894345]

Agreed, but per my original post, the additional safety that Rust affords protects against a very small share of bugs in SaaS applications. The value proposition isn’t good because you trade so much productivity for a small improvement in quality, and productivity is at a premium and quality (sadly) can be mitigated in other, less costly ways (e.g., progressively rolling out new changes, continuous deployment i.e., bugs can be patched in hours rather than months, etc).

[Zababa]

I have the opposite view on the type systems: Rust's type system is really great for business logic because it's really expressive (based on algebraic data types), but the language being made for low level stuff makes some things a pain. If you do something like DDD, ADTs really shine, especially when combined with pattern matching. I do agree that when you can afford a GC, Rust can be annoying.

[Blikkentrekker]

> I really like Rust, but in my mind it's still relegated to the periphery of tasks that must be super fast (like C/C++, to your point) and/or low-level. Rust has made impressive strides at reducing the toil involved in compile-time memory management, but there is still a big productivity gap between the borrow checker and GC.

Even if it weren't for the performance I would use Rust over Go due to the lack of generics alone, as well as the associated general philosophy of Go that boilerplate is good and one should repeat oneself as much as possible.

[throwaway894345]

I really, really like type systems, but I’ve built enough software to know that the returns for most applications diminish after a Go-like type system is in place, and there are many other factors that are more important than type systems (and Rust gets a lot of these right too!) such as performance, productivity, tooling breadth and quality (especially build tooling and package management), ecosystem, deployment/distribution story, learning curve, readability, etc. Ultimately I’m of the opinion that as cool as type systems are, for most software they need to exist in service of productivity which means you need a basic type system that helps you but gets out of your way. Type systems can’t catch many classes of bugs that are increasingly prevalent in a world where our services are getting increasingly smaller (or rather, where more infrastructure and networking are being put in between the logical components of our application) and we’re often able to detect bug fixes before they impact a significant number of users (progressive deployments, automated rollbacks, continuous deployment, etc) but the discourse around type systems hasn’t caught up yet.

[Blikkentrekker]

It has nothing to do with catching bugs.

It has to do with that one sometimes has to write 80 lines of code in Go to to the same as 3 lines of Rust code due to having to repeat oneself all the time.

[throwaway894345]

That’s an even more superficial concern. No one is bottlenecked on the rate at which they can type.

[Blikkentrekker]

One especially is in the case where it's boilerplate code that does not rely on any real deep thought but writes itself, and with the possibility of bugs in it, most of all. Anyone can make a simple typo or forget something in the endless boilerplate.

It also gets in the way of reading code.

[erik_seaberg]

Maintainers are bottlenecked by the rate we can (re)read. Boilerplate is the problem that makes us want powerful languages; if it didn’t matter we could have stayed with assembly.