#resource and #resources fail quietly and succeed quietly when invalid arguments are passed to :only and :except options respectively

[joshuay03]

This came up when pairing with a dev who is newish to Rails. They assumed that passing a custom action argument to :only when using #resources would auto-magically define a route for it with some defaults. Reading the examples in the documentation for these methods, it's not clear (especially to beginners) what all the accepted arguments for these options are, there are only examples using default actions.

I think it would be beneficial if an error was raised if invalid arguments are passed in.

Steps to reproduce

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  gem "rails", github: "rails/rails", branch: "main"
end

require "action_controller/railtie"

class TestApp < Rails::Application
  config.root = __dir__
  config.hosts << "example.org"
  config.secret_key_base = "secret_key_base"

  config.logger = Logger.new($stdout)
  Rails.logger  = config.logger
end

require "minitest/autorun"
require "rack/test"

class BugTest < Minitest::Test
  include Rack::Test::Methods

  def test_invalid_resources_only_option
    assert_raises(ArgumentError) do # ❌ fails quietly, no routes generated
      app.routes.draw do
        resources :posts, only: :foo
      end

      # => routes: []
      Rails.logger.info("routes: #{app.routes.routes.map { |r| r.defaults[:action] }}")
    end
  end

  def test_invalid_resources_except_option
    assert_raises(ArgumentError) do # ❌ succeeds quietly, all default routes generated
      app.routes.draw do
        resources :posts, except: :foo
      end

      # => routes: ["index", "create", "new", "edit", "show", "update", "update", "destroy"]
      Rails.logger.info("routes: #{app.routes.routes.map { |r| r.defaults[:action] }}")
    end
  end

  private
    def app
      Rails.application
    end
end

Expected behavior

Passing invalid options to :only or :except should raise an error with an informative message.

Actual behavior

Passing invalid options to :only fails quietly and no routes are generated.
Passing invalid arguments to :except succeeds quietly and all default routes are generated (index, create, new, show, update, and destroy).

System configuration

Rails version: Edge

Ruby version: 3.3.0

[joshuay03]

#51464