Ransack issue #628 - two associations where the second one is part of the default scope generates invalid SQL.

two_associations_one_with_default_scope.rb

# two_associations_one_with_default_scope.rb

# Run it in your console with: `ruby two_associations_one_with_default_scope.rb`

# If you change the gem dependencies, run it with:
# `rm gemfile* && ruby two_associations_one_with_default_scope.rb`

unless File.exist?('Gemfile')
  File.write('Gemfile', <<-GEMFILE)
    source 'https://rubygems.org'
    # Rails master
    gem 'rails', github: 'rails/rails'
    # Rails release
    # gem 'rails', '5.0.0'
    gem 'sqlite3'
    gem 'ransack', github: 'activerecord-hackery/ransack'
    gem 'polyamorous', github: 'activerecord-hackery/polyamorous'
  GEMFILE

  system 'bundle install'
end

require 'bundler'
Bundler.setup(:default)

require 'active_record'
require 'minitest/autorun'
require 'logger'
require 'ransack'

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

# Display versions.
message = "Running test case with Ruby #{RUBY_VERSION}, Active Record #{
  ::ActiveRecord::VERSION::STRING}, Arel #{Arel::VERSION} and #{
  ::ActiveRecord::Base.connection.adapter_name}"
line = '=' * message.length
puts line, message, line

ActiveRecord::Schema.define do
  create_table "documents", force: true do |t|
    t.string   "code"
    t.string   "title"
  end
  create_table "revisions", force: true do |t|
    t.integer  "document_id"
    t.string   "code"
    t.string   "title"
  end
  create_table "file_assets", force: true do |t|
    t.string   "file_name"
    t.integer  "revision_id"
  end
end

class Document < ActiveRecord::Base
  has_many :revisions, inverse_of: :document
end
class FileAsset < ActiveRecord::Base
  belongs_to :revision, inverse_of: :file_assets
end
class Revision < ActiveRecord::Base
  belongs_to :document, inverse_of: :revisions
  has_many :file_assets, inverse_of: :revision
  default_scope { joins(:document) }
end

class BugTest < Minitest::Test

  def setup
    @query = <<-SQL
      SELECT \"revisions\".* FROM \"revisions\"
      INNER JOIN \"documents\"
        ON \"documents\".\"id\" = \"revisions\".\"document_id\"
      LEFT OUTER JOIN \"file_assets\"
        ON \"file_assets\".\"revision_id\" = \"revisions\".\"id\"
      WHERE ((\"file_assets\".\"file_name\" = 'AAA'
        AND \"documents\".\"code\" = 'BBB'))
    SQL
    .squish!
  end

  def test_query
    document = Document.create!(code: 'BBB', title: 'Second')
    revision = document.revisions.create!(code: 'CCC', title: 'Third')
    revision.file_assets.create!(file_name: 'AAA')

    result = Revision.find_by_sql(@query)
    assert_equal revision.id, result.first.id
  end

  def test_default_scope
    #  p Revision
    #    .joins(:document)
    #    .left_outer_join(:file_assets)
    #    .where(file_assets: { file_name: 'AAA' }, document: { code: 'BBB' })
    #    .to_sql

    sql = Revision
          .ransack({file_assets_file_name_eq: "AAA", document_code_eq: "BBB"})
          .result
          .to_sql
    assert_equal(@query, sql)
  end
end