gistfile1.rb

# Activate the gem you are reporting the issue against.
gem 'activerecord', '4.1.0'
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:')
ActiveRecord::Base.logger = Logger.new(STDOUT)

ActiveRecord::Schema.define do
  ActiveRecord::Base.connection.execute("create table if not exists Templatemids (name varchar(30),TemplateID serial primary key, PluginFile text);")
end

class MidTemplate < ActiveRecord::Base
  self.table_name = "templatemids"  
  self.primary_key = :templateid
  
  validates_presence_of :name
end

class BugTest < Minitest::Test
  def test_stack_overflow_error
    mid_template_params = {name: ""}
    mid_template = MidTemplate.new(mid_template_params)
    mid_template.save
  end
end