rbs_parser VS tapioca

We discovered a bug in `srb init` for Ruby 3.1 recently that a teammate of mine is working on fixing at the moment. It's likely that if you tried again in a few days it'll have been fixed. Sorry about that, totally agree that the out-of-box experience should just work.

I wrote up an FAQ about the state of Ruby 3 and RBS here:

https://sorbet.org/docs/faq#when-ruby-3-gets-types-what-will...

The tl;dr is that RBI files (not RBS files) will probably always be the preferred way to declare types for third party code (because it will always support exactly the same set of features that Sorbet does). We have some people in the community look into teaching Sorbet to read the RBS format, but the existing parsers for RBS files are written in Ruby and are very slow, and there are some ambiguities in the spec that make writing a third party parser that compiles to native code tricky. You can see an attempt to write a fast RBS parser in C++ here[1], but again given that RBI files do everything we need them to right now and we have other features people are asking us for, we haven't prioritized RBS support incredibly highly.

Sorbet works completely fine without RBS files!

[1] https://github.com/Shopify/rbs_parser

This article might help clear some things up:

https://sorbet.org/blog/2020/07/30/ruby-3-rbs-sorbet

tl;dr:

- RBS files are what Ruby 3 uses to describe types in separate files

- RBI files are what Sorbet uses to describe types in separate files

- Sorbet invented its RBI file syntax before RBS files existed. RBI files use the same syntax for types and signatures as in type annotations that live inside `*.rb` source code with Sorbet.

- We've been meaning to add support to Sorbet to consume both RBI files and RBS files, but we haven't had a chance to get around to it.

If someone beat us to it and implemented support for RBS files in Sorbet that would be amazing! Shopify took an early stab at implementing an RBS parser in C++ for performance[1], but I'm not sure what the status of it is today.

[1] https://github.com/Shopify/rbs_parser

(disclaimer: I work on the Sorbet team)

I think I understand GP's motivation: RBI files and RBS files are two different formats, and as a user of the language, people tend to want to use the officially blessed solution the language provides.

In case you weren't aware, parlour[1] is a popular open source project for working with RBI files. I believe it supports transparently converting between RBI files (Sorbet) and RBS files (Ruby 3).

There is also rbs_parser[2], a C++ parser for RBS files to convert them to RBI files, written by Shopify, a major user of Sorbet.

Stepping back: I haven't personally read many complaints from Sorbet users describing how the current state of RBI/RBS interop gets in the way of what they can actually do with Sorbet. Almost all the feature requests we get about Sorbet (both inside Stripe and outside) are for fixing bugs or implementing new language-level features. RBI files as implemented seem to work.

Sorbet already has an extensive set of RBI files covering the Ruby standard library (at least as good or better to my knowledge than any existing repository of types for RBS files), and there are plentiful tools for working with RBI files, listed here.[3]

If lack of first-party RBS support in Sorbet is holding you back from trying Sorbet, I'd strongly encourage you to give Sorbet a try anyways! Many people have shared great experiences adopting Sorbet in their Ruby codebases.

[1] https://github.com/AaronC81/parlour

[2] https://github.com/Shopify/rbs_parser

[3] https://sorbet.org/en/community

First let's introduce the tool: Sorbet is a gem developed by Stripe that aims to bring type notation syntax and type checking support for the Ruby ecosystem by utilizing the "Gradual typing" philosophy, it also provide type generation from YARD comments via the tapioca gem, allowing to grow alongside the already built Ruby codebase.

Have you tried https://github.com/Shopify/tapioca with Sorbet? Typing in general has ways to go sure, but I find this combination quite usable in my day to day.

Sorbet can do this, as long as you have type signatures for your code. Given Ruby's highly dynamic nature that's where tools like Tapioca come in to generate these, for example for Active Record models where instance methods are generated based on the database schema. But the moment when something returns T.untyped you're back where you were before - it helps but isn't perfect.

Regarding Sorbet and Rails, I recommend Tapioca [1].

The Rails app that I worked on had a few edge cases Tapioca didn't cover so I wrote a simple script to load the Rails app and generate RBI files (e.g. generate RBI definitions for fixture methods in ApplicationTestCase). The Tapioca codebase helped provide a path for that [2]. Tapioca also continues to add to their DSL compilers. The work to integrate Sorbet paid off very quickly.

Also, T::Enum and T::Struct are handy in any Ruby codebase.

[1] https://github.com/Shopify/tapioca

I'm pretty sure sorbet-rails is just a rails-wrapper gem for the sorbet gem :-) (HAML does exactly same thing) and tapioca seems to be some convenience library to generate RBI (https://github.com/Shopify/tapioca)