* Not predictable equal? behaviour *.md

Not predictable equal? behaviour

• Try to guess what is the return value of question.equal?("hurting yourself") in test_1.rb.

• true? Are you sure?

• Run test_1.rb

ruby test_1.rb

• Remove # frozen_string_literal: true from test_2.rb

• Rerun test_1.rb

ruby test_1.rb

• Are you surprised?

• Now imagine this code somewhere in production?

• Still not hurting?

• What if test_1.rb and test_2.rb has 1000+ of lines with huge amount of useless indirections?

• OK, have a nice day debugging... 👍

test_1.rb

# frozen_string_literal: true

require_relative "test_2"

require "byebug"

question = QUESTION

p question.equal?("hurting yourself")

p question.object_id

p "hurting yourself".object_id

byebug
byebug

test_2.rb

# frozen_string_literal: true

QUESTION = "hurting yourself"