dangerous-methods.rb

# frozen_string_literal: true
require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'activerecord'
  gem 'benchmark-ips'
end

require 'benchmark/ips'
require 'active_record'

module ActiveRecord
  class Base
    def self.new_dangerous_attribute_method?(name)
      if self == Base
        @dangerous_attribute_methods ||= (
          instance_methods +
          private_instance_methods -
          superclass.instance_methods -
          superclass.private_instance_methods
        ).map { |m| -m.to_s }.to_set.freeze
        @dangerous_attribute_methods.include?(name.to_s)
      else
        Base.new_dangerous_attribute_method?(name)
      end
    end
  end
end

class Model < ActiveRecord::Base
end

Benchmark.ips do |x|
  x.report('original#hit') { Model.dangerous_attribute_method?('save') }
  x.report('original#miss') { Model.dangerous_attribute_method?('name') }

  x.report('new#hit') { Model.new_dangerous_attribute_method?('save') }
  x.report('new#miss') { Model.new_dangerous_attribute_method?('name') }

  x.compare!
end  

results.txt

Warming up --------------------------------------
        original#hit   116.563k i/100ms
       original#miss   138.858k i/100ms
             new#hit   228.266k i/100ms
            new#miss   228.769k i/100ms
Calculating -------------------------------------
        original#hit      1.571M (± 1.1%) i/s -      7.926M in   5.045043s
       original#miss      1.953M (± 1.2%) i/s -      9.859M in   5.048572s
             new#hit      4.211M (± 1.4%) i/s -     21.229M in   5.041961s
            new#miss      4.256M (± 1.4%) i/s -     21.504M in   5.053145s

Comparison:
            new#miss:  4256484.2 i/s
             new#hit:  4211316.6 i/s - same-ish: difference falls within error
       original#miss:  1953077.8 i/s - 2.18x  slower
        original#hit:  1571290.1 i/s - 2.71x  slower