create_or_find_by sequence exhaustion

test.rb

# 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"
  gem "pg"
end

require "active_record"
require "minitest/autorun"
require "logger"

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "postgresql", database: "rails")
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts, force: true do |t|
  end
end

class Post < ActiveRecord::Base
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_primary_key_growth
    post = Post.create!
    2_500_000_000.times { Post.create_or_find_by(id: post.id) }

    # This fails
    # Failure:
    #   BugTest#test_primary_key_growth [create_or_find_by.rb:56]:
    #   Expected: 2
    #     Actual: #<Comment id: 3, post_id: 2>
  end
end