Print missing options for ActiveRecord associations

print-ar-missing-options.rb

require_relative "config/environment"

Rails.application.eager_load!
Rails.root.glob("app/models/**/*.rb").each { |f| require_relative f }

has_xxx_required_options    = %i[dependent inverse_of].freeze
belongs_to_required_options = %i[inverse_of].freeze
needs                       = Hash.new { |h, k| h[k] = Set.new }

ActiveRecord::Base.descendants.each do |klass|
  klass.reflections.each_value do |reflection|
    case reflection
    when ActiveRecord::Reflection::HasOneReflection, ActiveRecord::Reflection::HasManyReflection
      has_xxx_required_options.each { |key| needs[key] << reflection unless reflection.options[key] }
    when ActiveRecord::Reflection::BelongsToReflection
      belongs_to_required_options.each { |key| needs[key] << reflection unless reflection.options[key] }
    when ActiveRecord::Reflection::ThroughReflection
      # do nothing
    else
      raise "dunno about #{reflection.inspect}"
    end
  end
end

needs.each do |option, reflections|
  puts "\n\n= MISSING `:#{option}`\n\n"

  reflections.group_by { |it| it.active_record.name }.sort_by(&:first).each do |model, arr|
    arr.each do |reflection|
      puts "* #{model}.#{reflection.macro}(:#{reflection.name})"
    end
  end
end