# File lib/rubygems/source_index.rb, line 73
    def load_specification(file_name)
      begin
        spec_code = File.read(file_name).untaint
        gemspec = eval spec_code, binding, file_name
        if gemspec.is_a?(Gem::Specification)
          gemspec.loaded_from = file_name
          return gemspec
        end
        alert_warning "File '#{file_name}' does not evaluate to a gem specification"
      rescue SyntaxError => e
        alert_warning e
        alert_warning spec_code
      rescue Exception => e
        alert_warning(e.inspect.to_s + "\n" + spec_code)
        alert_warning "Invalid .gemspec format in '#{file_name}'"
      end
      return nil
    end