force_require for bundler

force_require.rb

# force_require.rb
#
# == Usage
#
#   require 'bundler/setup'
#   require './force_require'
#   
#   force_require 'g'
#   g 'foo'
#   
#   require 'g' # => LoadError
#
module Kernel
  def new_require(name)
    begin
      org_require name
    rescue LoadError
      if Thread.current[:force_require_mode]
        force_require name
      else
        raise
      end
    end
  end
  alias_method :org_require, :require
  alias_method :require, :new_require

  def force_require(name)
    Thread.current[:force_require_mode] = true
    Gem.all_load_paths.each do |dir|
      Dir[File.join(dir, "#{name}#{Gem.suffix_pattern}")].each do |file|
        require file
        return true
      end
    end
    raise LoadError, "no such file to load -- #{name}"
  ensure
    Thread.current[:force_require_mode] = false
  end
  alias_method :require!, :force_require
end

It seems that TLS = Thread Local Storage.

BTW, I wonder if recursive call should be considered too. doesn't it?

ex)

begin
  orig, Thread.current[:__force_require] = Thread.current[:__force_require], true
  ...
ensure
  Thread.current[:__force_require] = orig
end

I get it!