errcheck VS reason

In our codebase I noticed a few cases where people ignored errors returned from functions by assigning them to _, ie result, _ := foo(). The errcheck linter doesn't seem to catch this, does anyone know of a linter that does?

And we also expect that the caller will check the error and handle it. There is a popular linter that checks it for us: errcheck.

You should be using golangci-lint, because all serious Go programmers should. golangci-lint contains errcheck, which will detect if you overwrite an error without having done something with it in the meantime. I consider this one of the most important linters (this doesn't just detect things that may sorta kinda someday turn into bugs, this quite likely is a bug RIGHT NOW), and it helps you have the confidence you can overwrite errors as you go and don't need to keep allocating new ones.

Run golangci-lint over your code if you haven't already and pay special attention to errcheck's output.

errcheck has a flag for that ;)

https://github.com/kisielk/errcheck, which is in most of the combined linter packages by default.

We'll agree to disagree about unused imports; imports have can side-effects.

I prefer functions returning errors over throwing exceptions. Whether it's Go's errors or ML-style options/results, they're both better than exceptions. I cannot remember the last time I had a bug from not checking an error in Go. There's also errcheck which I use as part of my linting that will catch unchecked errors, such that I cannot even commit the code.

> Go compiler raise an error if a variable (error) goes unused

It doesn't though. It's perfectly valid to not use the return value of a function that only returns an error, for instance.

There are static error checking tools you can use like https://github.com/kisielk/errcheck to work around this, but most people don't use them.

I've run into a lack of Go error checking many times. Many times it's just the trivial case, where the compiler doesn't warn about not checking the result of an error-returning function.

But often it'll be subtler, and the result of Go's API design. One example is its file writing API, which requires you to close the file and check its error to be correct. Many times people will just `defer file.Close()`, but that isn't good enough - you're ignoring the error there.

Worse still is e.g: writing to a file through a bufio.Writer. To be correct, you need to remember to flush the writer, check that error, then close the file and check that error. There's no type-level support to make sure you do that.

I'd be really happy with that! Building the functionality of errcheck[1] and ineffassign[2] into the compiler — or at the very least, into govet — would go a long way to allay my worries with Go.

I think the reason they don't do this is that it's a slight (albeit a very tiny one) against Go's philosophy of errors being values, just like any other. While the `error` type is standard and used throughout Go source code, it still just has a simple three-line definition[3] and is not treated as a special case anywhere else; there is nothing stopping you from returning your own error type if you wish. A third-party linter could simply check for the `error` type specifically, but the first-party tools should not, and there's nothing like Rust's `#[must_use]` attribute that could be used instead. I respect Go's philosophy, but I feel like pragmatism must win in this case.

[1]: https://github.com/kisielk/errcheck

Hey HN, at Ahrefs we have been working on an online book that hopefully helps React developers get up and running with Melange, an OCaml to JavaScript compiler. You can read more about Melange here: https://melange.re/.

There are still a few chapters that we'd like to add before considering it "complete", but it might be already helpful for some folks out there, that's why we decided to publish it early.

The book uses Reason syntax to implement React components using ReasonReact components. You can read more about both in:

https://reasonml.github.io/

ReScript is "Fast, Simple, Fully Typed JavaScript from the Future". What that means is that ReScript has a lightning fast compiler, an easy to learn JS like syntax, strong static types, with amazing features like pattern matching and variant types. Until 2020 it was called "BuckleScript" and is closely related to ReasonML.

This tracks with how I've seen "normal" languages converge on similar, flawed imitations of better type systems through tools and repurposed syntax. Thank you for confirming.

Do you have any recommendations or warnings regarding general languages which reach in the opposite direction? Reason[1] and F#[2] are both examples: they attach pre-existing ecosystems and compile-for-$PLATFORM tools to OCaml-like typing.

OCaml itself is also intriguing for personal projects. However, I'm worried the "GPL" in its standard library's LGPL license might scare people despite both the linking exception and Jane Street's MIT alternative.

1. https://reasonml.github.io/

ReasonML purely as a syntax layer on top of OCaml is still being updated and released[1]. Incidentally, I'm one of the maintainers of that project too :-)

With this Melange release, we're hoping to somewhat revive ReasonML and channel some folks back to the community from the perspective of a vertically integrated platform that has seen major investment in the past few years.

[1]: https://github.com/reasonml/reason

Why not use https://reasonml.github.io/ instead? Or just use Typescript?

Quieted down, but I depend on projects with worst graphs:

https://github.com/reasonml/reason/graphs/contributors

There is also reasonml for Web development.