load_specification (Gem::SourceIndex)

    # File lib/rubygems/source_index.rb, line 83
          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