repro case for issue with join tables in non-default db

secondary_db_join_table_test.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  $stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true) do
  source 'https://rubygems.org'

  # repros in 4.x and on master
  gem 'activerecord', '4.2.3'

  #gem 'rails', github: 'rails/rails'
  #gem 'arel', github: 'rails/arel'
  
  gem 'sqlite3'
end

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

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: 'primary.sqlite3')
ActiveRecord::Base.logger = Logger.new(STDOUT)

# Abstract base class for models in the default database
class Primary < ActiveRecord::Base
  self.abstract_class = true
end

# Abstract base class for models in the secondary database
class Secondary < ActiveRecord::Base
  establish_connection(adapter: 'sqlite3', database: 'secondary.sqlite3')
  self.abstract_class = true
end

ActiveRecord::Schema.define do
  create_table :primary_models, force: true
  create_table :primary_associateds, force: true
  create_join_table :primary_associateds, :primary_models, force: true
end

# quick and dirty schema definition for the secondary db
sql = <<-EOSQL 
    DROP TABLE IF EXISTS "secondary_models"
    DROP TABLE IF EXISTS "secondary_associateds"
    DROP TABLE IF EXISTS "secondary_associateds_models"
    CREATE TABLE "secondary_models" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL)
    CREATE TABLE "secondary_associateds" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL)
    CREATE TABLE "secondary_associateds_models" ("secondary_model_id" INTEGER NOT NULL, "secondary_associated_id" INTEGER NOT NULL)
EOSQL
sql.split("\n").each{|line| Secondary.connection.execute line }


# A pair of HABTM-associated models in each db
class PrimaryModel < Primary
  has_and_belongs_to_many :primary_associateds
end
class PrimaryAssociated < Primary; end

class SecondaryModel < Secondary
  has_and_belongs_to_many :secondary_associateds
end
class SecondaryAssociated < Secondary; end

class JoinTableTest < Minitest::Test
  def test_associations_primary
    model = PrimaryModel.create!
    associated = PrimaryAssociated.create!
    assert_equal 0, model.primary_associateds.count
    model.primary_associateds << associated
    assert_equal 1, model.primary_associateds.reload.count
  end

  def test_associations_secondary
    model = SecondaryModel.create!
    associated = SecondaryAssociated.create!

    # normal SELECT works
    assert_equal 0, model.secondary_associateds.count

    # adding to the association proxy raises: ActiveRecord::StatementInvalid: Could not find table 'secondary_associateds_models'
    model.secondary_associateds << associated
    assert_equal 1, model.secondary_associateds.reload.count
  end
end