New bigint(20) cannot be FK reference to int(11)

test_new_fk_to_old_table.rb

# frozen_string_literal: true
# https://gist.github.com/rab/9b63001d5f926468afdfa00248cf648e

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"

  git_source(:github) { |repo| "https://github.com/#{repo}.git" }

  # Activate the gem you are reporting the issue against.
  gem "activerecord", "5.1.3"
  # gem "sqlite3"
  gem "mysql2"
end

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

# Ensure backward compatibility with Minitest 4
Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")
# uh, ok, but what about a database-DEPENDENT bug report?
# ActiveRecord::Base.establish_connection(adapter: "mysql2", database: "???", 
#   username: "?", password: "?", 
#   host: "localhost",
#   socket: "/tmp/mysql.sock",
#   reconnect: false,
#   pool: 5,
#   encoding: "utf8"
# )

ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
end

class CreateMember < ActiveRecord::Migration[5.0] # or any version that creates int(11) primary keys
  def change
    create_table :members do |t|
      t.string :name
    end
  end
end

class CreateRole < ActiveRecord::Migration[5.1]
  def change
    create_table :roles do |t|
      t.string :name, index: true, unique: true
      t.string :description
    end
  end
end

class CreateHat < ActiveRecord::Migration[5.1]
  def change
    create_table :hats do |t|
      t.references :member, foreign_key: true    # probably just need THIS one and not roles at all
      t.references :role, foreign_key: true
    end
  end
end

# class Member < ActiveRecord::Base
# end

# class Role < ActiveRecord::Base
# end

class Hat < ActiveRecord::Base
end

class BugTest < Minitest::Test
  def test_normal_tables
    CreateMember.migrate(:up)
    CreateRole.migrate(:up)
    CreateHat.migrate(:up)
  rescue => oops
    fail "Oops!"
  else
    Hat.reset_column_information
    # For sqlite3, this would actually be "integer" and not be a problem
    assert_equal "int(11)", Hat.columns.detect {|col| col.name == 'member_id'}.sql_type
  end
end