find_in_source_paths

# File lib/bundler/vendor/thor/lib/thor/actions.rb, line 132
    def find_in_source_paths(file)
      possible_files = [file, file + TEMPLATE_EXTNAME]
      relative_root = relative_to_original_destination_root(destination_root, false)

      source_paths.each do |source|
        possible_files.each do |f|
          source_file = File.expand_path(f, File.join(source, relative_root))
          return source_file if File.exist?(source_file)
        end
      end

      message = "Could not find #{file.inspect} in any of your source paths. ".dup

      unless self.class.source_root
        message << "Please invoke #{self.class.name}.source_root(PATH) with the PATH containing your templates. "
      end

      message << if source_paths.empty?
                   "Currently you have no source paths."
                 else
                   "Your current source paths are: \n#{source_paths.join("\n")}"
                 end

      raise Error, message
    end