Prints hierarchical view of Rails models

base_model_walker.rb

# active_record model descendant walker

def model
  (ARGV.first || 'ApplicationRecord').classify.safe_constantize.tap do |model|
    raise "Provide valid model name.  Argv: #{ARGV.first}" unless model
    raise "Model must be a sub-class of ActiveRecord::Base  Argv: #{ARGV.first}" unless model < ActiveRecord::Base || model == ActiveRecord::Base
  end
end

def base_model(model)
  if model.superclass == ApplicationRecord || model == ApplicationRecord || model == ActiveRecord::Base
    return model
  end
  return base_model(model.superclass)
end

def print_subclasses(model, prefix = "")
  puts "#{prefix}#{model.name}"
  model.descendants.sort_by(&:name).each { |m| print_subclasses(m, "#{prefix}  ") if m.superclass == model }
end

silence_warnings { print_subclasses(base_model(model)) }

model_walker.rb

# model descendant walker

def print_subclasses(model, prefix = "")
  puts "#{prefix}#{model.name}"
  model.descendants.sort_by(&:name).each { |m| print_subclasses(m, "#{prefix}  ") if m.superclass == model }
end

silence_warnings { print_subclasses(ARGV.first.classify.safe_constantize) }