Tapioca is a library used to generate RBI (Ruby interface) files for use with Sorbet. RBI files provide the structure (classes, modules, methods, parameters) of the gem/library to Sorbet to assist with typechecking.
As yet, no gem exports type information in a consumable format and it would be a huge effort to manually maintain such an interface file for all the gems that your codebase depends on. Thus, there is a need for an automated way to generate the appropriate RBI file for a given gem. The
tapioca gem, developed at Shopify, is able to do exactly that to almost 99% accuracy. It can generate the definitions for all statically defined types and most of the runtime defined types exported from Ruby gems (non-Ruby gems are not handled yet).
When you run
tapioca sync in a project,
tapioca loads all the gems that are in your dependency list from the Gemfile into memory. It then performs runtime introspection on the loaded types to understand their structure and generates an appropriate RBI file for each gem with a versioned filename.
For gems that have a normal default
require and load all of their constants through such a require, everything works seamlessly. However, for gems that are marked as
require: false in the Gemfile, or for gems that export optionally loaded types via different requires, where a single require does not load the whole gem code into memory,
tapioca will not be able to load some of the types into memory and, thus, won't be able to generate complete RBIs for them. For this reason, we need to keep a small external file named
sorbet/tapioca/require.rb that is executed after all the gems in the Gemfile have been required and before generation of gem RBIs have started. This file is responsible for adding the requires for additional files from gems, which are not covered by the default require.
For example, suppose you are using the class
BetterHtml::Parser exported from the
better_html gem. Just doing a
require "better_html" (which is the default require) does not load that type:
$ bundle exec pry  pry(main)> require 'better_html' => true  pry(main)> BetterHtml => BetterHtml  pry(main)> BetterHtml::Parser NameError: uninitialized constant BetterHtml::Parser from (pry):3:in `__pry__`  pry(main)> require 'better_html/parser' => true  pry(main)> BetterHtml::Parser => BetterHtml::Parser
In order to make sure that
tapioca can reflect on that type, we need to add the line
require "better_html/parser" to the
sorbet/tapioca/require.rb file. This will make sure
BetterHtml::Parser is loaded into memory and a type annotation is generated for it in the
better_html.rbi file. If this extra
require line is not added to
sorbet/tapioca/require.rb file, then the definition for that type will be missing from the RBI file.
If you ever run into a case, where you add a gem or update the version of a gem and run
tapioca sync but don't have some types you expect in the generated gem RBI files, you will need to make sure you have added the necessary requires to the
Add this line to your application's
group :development do gem 'tapioca', require: false end
and do not forget to execute
$ bundle exec tapioca Commands: tapioca generate [gem...] # generate RBIs from gems tapioca help [COMMAND] # Describe available commands or one specific command tapioca init # initializes folder structure tapioca sync # sync RBIs to Gemfile Options: --pre, -b, [--prerequire=file] # A file to be required before Bundler.require is called --post, -a, [--postrequire=file] # A file to be required after Bundler.require is called --out, -o, [--outdir=directory] # The output directory for generated RBI files # Default: sorbet/rbi/gems --cmd, -c, [--generate-command=command] # The command to run to regenerate RBI files --typed, -t, [--typed-overrides=gem:level] # Overrides for typed sigils for generated gem RBIs
Initialize folder structure
This will create the
sorbet/tapioca/require.rb files for you, if they don't exist. If any of the files already exist, they will not be changed.
Generate for gems
tapioca generate [gems...]
This will generate RBIs for the specified gems and place them in the RBI directory.
Generate for all gems in Gemfile
This will sync the RBIs with the gems in the Gemfile and will add, update, and remove RBIs as necessary.
--prerequire [file]: A file to be required before
--postrequire [file]: A file to be required after
--out [directory]: The output directory for generated RBI files, default to
--generate-command [command]: The command to run to regenerate RBI files (used in header comment of the RBI files), defaults to the current command.
--typed-overrides [gem:level]: Overrides typed sigils for generated gem RBIs for gem
levelcan be one of
strong, see the Sorbet docs for more details).
Bug reports and pull requests are welcome on GitHub at https://github.com/Shopify/tapioca. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
The gem is available as open source under the terms of the MIT License.