Sorbet: Support `:require: false` gems in Gemfile

[elliottt]

Problem

Some dependencies listed in a project's Gemfile do not need to have rbis generated for them. For example, rubocop can be run during development, and not relied on as a library from within a project.

Proposed solution

Make sorbet sensitive to a :sorbet_ignore Gemfile group. This would allow users to control which gems are provided to sorbet.

source 'https://rubygems.org'
gem 'cantor'
gem 'sorbet', :group => :development
gem 'sorbet-runtime'

group :sorbet_ignore do
  gem 'rubocop'
end

Additional info

Through some experimentation, modifying the sites where we call Bundler.load to first run:

Bundler.settings.set_command_option :without, [:sorbet_ignore]

causes gems in the :sorbet_ignore section to no longer show up in the spec set.

[jeffcarbs]

Would this be something that can be specified in the sorbet folder somehow, either passed as a command line option or specified in the sorbet/config? I don't love the idea of modifying my Gemfile to simply support the srb init which will really only be run once or very infrequently.

[rafaelfranca]

Usually rubocop is on the gemfile entry as gem 'rubocop', require: false since you don't need, and usually don't want to load rubocop in your application. How about sorbet respecting the :require option?

[ptarjan]

+1 to using require: false for this

[elliottt]

require: false sounds good to me.

[andi-dev]

I am not 100% sure if I followed the expectations in this issue correctly, but it seems that sorbet is already respecting require: false since this commit was merged: https://github.com/sorbet/sorbet/commit/6dccbfa886b3031b6df618335da6be8f62b09c02#diff-fc7ece157e1d959d151e970fb52e9747R557