ar_sti_assoc_create_type_check.rb

raise "remove me: this bug has been fixed in rails 6" if RAILS6

module PatchPolymorphicCheck
  ON_BAD_CREATE = :log
  POOP = "💩".freeze

  def _handle_create_type(inst, meth, &block)
    klass  = inst.class
    actual = klass.name
    expect = inst[klass.inheritance_column]

    if expect && actual != expect
      msg = "Bad %s called through STI relation. Expected %s, but got %s." \
        % [meth, expect, actual]

      case ON_BAD_CREATE
      when :log
        Rails.logger.debug msg
      when :deprecate
        ActiveSupport::Deprecation.warn msg
      when :raise
        raise ArgumentError, msg
      else
        raise ArgumentError, "Bad value: #{ON_BAD_CREATE}"
      end

      $stderr.print POOP
      inst = block[inst]
    end

    inst
  end

  def new(attributes = {}, &block)
    _handle_create_type(super, :new) do |inst|
      inst.becomes inst[inst.class.inheritance_column].constantize
    end
  end

  def create(attributes = {}, &block)
    _handle_create_type(super, :create) { |inst| inst.class.find inst.id }
  end

  def create!(attributes = {}, &block)
    _handle_create_type(super, :create!) { |inst| inst.class.find inst.id }
  end
end

ActiveRecord::AssociationRelation.prepend PatchPolymorphicCheck