scope_leak.rb

# Activate the gem you are reporting the issue against.
require 'active_record'
require 'minitest/autorun'
require 'logger'

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  create_table :posts do |t|
    t.string :title
  end
end

class Post < ActiveRecord::Base
  def self.total_post_count
    Post.count
  end
end

class BugTest < Minitest::Test
  def test_scope_leak
    Post.create! title: "one"
    Post.create! title: "two"
    Post.create! title: "three"

    assert_equal 3, Post.total_post_count
    assert_equal 3, Post.where(title: "one").total_post_count
  end
end