But you breezily claiming they made the same blunder as Java omits the fact that they didn't make the same blunder as Rust and Swift and end up with nightmarish compile times because of their type system.

Almost every language feature has difficult trade-offs. They considered iteration time a priority one feature and designed the language as such. It's very easy for someone looking at a language on paper to undervalue that feature but when you sit down and talk to users or watch them work, you realize that a fast feedback loop makes them more productive than almost any brilliant type system feature you can imagine.

To be fair, they were working on parametric polymorphism since the beginning. There are countless public proposals, and many more that never made it beyond the walls of Google.

Problem was that they struggled to find a design that didn't make the same blunder as Java. I'm sure it would have been easy to add Java-style generics early on, but... yikes. Even the Java team themselves warned the Go team to not make that mistake.

[1] Okay fine, you can fake it with enough SRTPs, but Don Syme will come and burn your house down.

Am I missing something? Is this really a good idea for a language that can't express monads naturally?

Source: I'm one of the people who designed it.

That said as mentioned in a lot of places, changing errors to be sum types is not the approach they're looking for, since it would create a split between APIs across the ecosystem.

What do you mean? Much of the discussion around errors from above link is clearly based on the ideas of Haskell/monads. Did you foolishly search for "monad" and call it a day without actually reading it in full to reach this conclusion?

In fact, I would even suggest that the general consensus found there is that a monadic-like solution is the way forward, but it remains unclear how to make that make sense in Go without changing just about everything else about the language to go along with it. Thus the standstill we're at now.

Reading this article? in fact yes(?):

> After so many years of trying, with three full-fledged proposals by the Go team and literally hundreds (!) of community proposals, most of them variations on a theme, all of which failed to attract sufficient (let alone overwhelming) support, the question we now face is: how to proceed? Should we proceed at all?

> We think not.

This is a problem of the go designers, in the sense that are not capable to accept the solutions that are viable because none are total to their ideals.

And never will find one.

____

I have use more than 20 langs and even try to build one and is correct that this is a real unsolved problem, where your best option is to pick one way and accept that it will optimize for some cases at huge cost when you divert.

But is know that the current way of Go (that is a insignificant improvement over the C way) sucks and ANY of the other ways are truly better (to the point that I think go is the only lunatic in town that take this path!), but none will be perfect for all the scenarios.

It’s okay for Go to be different than other languages. For folks who can’t stand it, there are lots of other options. As it is, Go is massively successful and most active Go programmers don’t mind the error handling situation. The complaints are mostly from folks who didn’t choose it themselves or don’t even actually use it.

The fact that this is the biggest complaint about Go proves to me the language is pretty darn incredible.

1. Minimalism.

Go has always had an ethos of extreme minimalism and have deliberately cultivated an ecosystem and userbase that also places a premium on that. Whereas, say, the Perl ecosystem would be delighted to have the language add one or seven knew ways of solving the same problem, the Go userbase doesn't want that. They want one way to do things and highly value consistency, idiomatic code, and not having to make unnecessary implementation choices when programming.

In every programming language, there is a cost to adding features, but that cost is relatively higher in Go.

2. Concurrency.

Concurrency, channels, and goroutines are central to the design of the language. While I'm sure you can combine exception handling with CSP-based concurrency, I wouldn't guarantee that the resulting language is easy to use correctly. What happens when an uncaught exception unwinds the entire stack of a goroutine? How does that affect other goroutines that it spawned or that spawned it? What does it do to goroutines that are waiting on channels that expect to hear from it?

There may be a good design there, but it may also be that it's just really really hard to reason about programs that heavily use CSP-style concurrency and exceptions for error handling.

The Go designers cared more about concurrency than error handling, so they chose a simpler error handling model that doesn't interfere with goroutines as much. (I understand that panics complicate this story. I'm not a Go expert. This is just what I've inferred from the outside.)

I understand many of Go's design choices, I find them intellectually pleasing, but I tend to dislike them in practice.

That being said, my complaints about Go's error-handling are not the `if err != nil`. It's verbose but readable. My complaints are:

1. Returning bogus values alongside errors.

2. Designing the error mechanism based on the assumptions that errors are primarily meant to be logged and that you have to get out of your way to develop errors that can actually be handled.

Assuming that all complainants are just idiots is purely misinformed and quite frankly a bit of gaslighting.

Also I don't understand how to implement transparent proxies in Go for reactive UI programming.

Of all the languages in common use, golang is the one that makes the least sense holistically. Return values are tuples, but there's nothing that lets you operate on them. Enums aren't actually limited to the values you define, so there's no way to ensure your switch cases are exhaustive when one is added in the future. Requiring meaningful zero values means that your error cases return valid, meaningful values that can accidentally be used when they return with an error.

It’s usually pretty obvious why: eg

    if err == nil { 
         // we can exit early because we don’t need to keep retrying

  if !(err != nil) {

would be clearer, I think. Seems like it's the same but would color differently in my editor.

Yes, exactly. The unusual thing _should_ look unusual.

Note that ignoring errors doesn't necessarily lead ti a crash; there are plenty of functions where an error won't ever happen in practice, either because preconditions are checked by the program before the function call or because the function's implementation has changed and the error return is vestigal.

No it won't. It could lead to a crash or some other nasty bug, but this is absolutely not a fact you can design around, because it's not always true.

Whereas in Go, the error is visible everywhere. As a developer I see its path more easily since it's always there, and so I have a better mind to handle it right there.

Additionally, it's less easy to group errors together. A try/catch with multiple throwable functions catches an error...which function threw it though? If you want to actually handle an error, I'd prefer handling it from a particular function and not guessing which it came from.

Java with type-checked exceptions is nice. I wish Swift did that a bit better.

What I have learned in this time is: Go is a very good, very high quality, very well designed language. PHP is a terrible, terrible, terrible language -- at least if your mission is creating highly reliable software. If your goal is rapid prototyping of the visual appearance of a webpage, PHP is good for that -- that's what it was originally invented for, back in the 1990s, and it's still the best language for that specific use case.

In PHP, if you are looking at a line of code, it's impossible to tell what happens if an error occurs. There's an error_reporting level that can be changed anywhere else in the codebase at any time. So an error might be thrown in the user's face, or not -- depending on the error_reporting level and what the error is. This can also interact with output buffering. (I guess if the "@" sign is present, at least then you know output of an error message is suppressed.) There's a error_handler function that could be set. Oh but it gets worse! Even if you have the entire codebase and can scour every line of code, and trace every possible execution path, you still can't tell what will happen if an error occurs at the line of code you are looking at -- because there are php.ini settings that come into play!

This is without even mentioning the try/catch exception handling system, which PHP also has, and that you think is such a good thing. So if an error happens on the line you are looking at, execution may switch to somewhere above you in the call stack. But (at least in theory) if you have the complete source code, you can figure out all the places where that might be.

This is an absolute nightmare if you care about reliability. The worst thing you could possibly have in a programming language if you care about reliability is to be unable to tell what happens when an error occurs and reason about the program's behavior.

Contrast this with Go. In Go, I can know what happens if an error occurs because it's right there. There's an "if err != nil {..." block that tells me exactly what happens.

By porting code to Go, I've been able to increase the reliability tremendously. The thing about go, is that using Go doesn't automatically give you reliability -- you have to learn the techniques and tools in Go that give you reliability. But once you do that, the quality of software you can produce is vastly higher.

I've spent the last decade or so learning this. Learning how to structure the code to make maximum use of the compiler's static type checking to catch errors. Making use of the static analysis tools that catch errors. Using a combination of errcheck and staticcheck (mentioned elsewhere in this discussion), you can guarantee every err return value is actually checked and handled. So the oft-cited language flaw of Go allowing you to forget to handle errors becomes a non-issue. Go has built-in support for unit tests and the excellent polymorphism system makes tests easier to make than in PHP. And, getting back to the topic at hand, in Go, I created my own system for handling the err values that get returned so junk errors created by hackers trying to find security vulnerabilities on our server get filtered out, while actual errors that I need to fix get logged and brought swiftly to my attention. Can you do something similar in PHP? In theory, perhaps, but we are to afraid of breaking things to try to massively refactor our ~2 million lines of PHP code in order to do that. So we have various log files and database entries that get clogged with errors, and sometimes we notice errors that we need to fix, but usually we don't. Usually we don't know anything is wrong until we get customer complaints on the Help Desk.

Anyway, I'm glad the Go team rejected the idea of changing Go's error handling. Is Go's error handling verbose, tedious, and repetitive? Yes. But it's also unambiguous and gives you total control over how your program responds when an error occurs, which is exactly what you want if you want to write software with the maximum reliability.

Don't just take my word for it. Notice how lots of "cloud infrastructure" is written in Go. Kubernetes is written in Go, Docker is written in Go, Terraform is written in Go, etc.

Yes, I know some people, like Facebook, have managed to write decently reliable code in PHP. But I suspect Facebook has thrown massive amounts of dollars and people at the problem. Various other PHP projects, like certain website creation systems that shall not be named, have a reputation for being buggy.

Sorry, I couldn't let you say PHP has better error handling without a response. It may be "better" for having more compact, prettier looking code. But it's not better for writing actually reliable software. If you want to write actually reliable software, Go is way better.

https://github.com/dave/courtney

Do I need clear and useful things? Maybe not. Would I like to have them anyway? Yes.

Years ago, I configured a Java project's logging framework to automatically exclude all the "uninteresting" frames in stack traces. It was beautiful. Every stack trace showed just the path taken through our application. And we could see the stack of "caused-by" exceptions, and common frames (across exceptions) were automatically cut out, too.

Granted, I'm pretty sure logback's complexity is anathema to Go. But my goodness, it had some nice features...

And then you just throw the stack trace in IntelliJ's "analyze stacktrace" box and you get clickable links to each line in every relevant file... I can dream.

> the wrapping is very greppable when done well

Yeah, that's my other problem with it. _When done well._ Every time I write an `if err != nil {}` block, I need to decide whether to return the error as is (`return err`) or decorate it with further context (`return fmt.Errorf("stuff broke: %w", err)`). (Or use `%v` if I don't want to wrap. Yet another little nuance I find myself needing to explain to junior devs over and over. And don't get me started about putting that in the `fmt` package.)

So anyway, I've seen monstrosities of errors where there were 6+ "statement: statement: statement: statement: statement: final error" that felt like a dark comedy. I've also seen very high-level errors where I dearly wished for some intermediate context, but instead just had "failed to do a thing: EOF".

That all being said, stack traces are really expensive. So, you end up with some "fun" optimizations: https://stackoverflow.com/questions/58696093/when-does-jvm-s...

The argument for explicit error values is often something like "it encourages people to actually handle their errors, rather than ignoring them". And on the face of it, this has some merit: we've all seen code that assumes an HTTP request can't fail, and now a small timeout crashes the entire backup procedure or whatever.

But if "handle the error" simply means "decorate it with a trace and return it", then exceptions already do this, then you're really admitting that there is no fundamental difference from a exception, because this is exactly what exceptions do, all on their own. Sure, they produce less useful traces, but that's usually a tiny difference. After all, the argument wasn't "you'll get better stack traces than exceptions give you", it was "people will be more careful to handle errors".

This is also relevant, because if the goal is to get better error traces, that can also be done with exceptions, with just some small improvements to syntax and semantics (e.g. add syntax for decorating a call site with user supplied context that will get included in any exception bubbled from it; add support in an exception to only print non-library stack frames, add support in the language to declare certain variables as "important" and have them auto-included in stack traces - many ideas).

My guess is they will still write Go even if error handling stays the same forever.

Common Lisp actually does cool things (if a bit niche) things with MRVs, they're side-channels through which you can obtain additional information if you need it e.g. every common lisp rounding functions returns rounded value... and the remainder as an extra value.

So if you call

  (let ((v (round 5 2)))
    (format t "~D" v))

  (multiple-value-bind (q r) (round 5 2)
    (format t "~D ~D" q r))

You can pass multiple return values of a function as parameters to another function if they fit the signature.

for example:

  func process[T any](value T, err error) {
    if err != nil {
      // handle error
    }
    // handle value
  }

  for {
    process(fetchFoo(ctx))
    process(fetchBar(ctx))
  }

Perhaps what you are really trying to say is that multiple function arguments is insane full stop. You can pass in an array/tuple to the single input just the same. But pretty much every language has settled on them these days – so it would be utterly bizarre to not support them both in and out. We may not have known any better in the C days, but multiple input arguments with only one output argument is plain crazy in a modern language. You can't even write an identity function.