ruby/rubygems · error · Gem::Exception

malformed spec name: #{spec_file_name.inspect}

Error message

malformed spec name: #{spec_file_name.inspect}

What it means

Error "malformed spec name: #{spec_file_name.inspect}" thrown in ruby/rubygems.

Source

Thrown at lib/rubygems/source.rb:116

        File.stat(Gem.user_home).uid == Process.uid
      rescue Errno::ENOENT
        false
      end
  end

  ##
  # Fetches a specification for the given Gem::NameTuple.

  def fetch_spec(name_tuple)
    fetcher = Gem::RemoteFetcher.fetcher

    spec_file_name = name_tuple.spec_name

    # The name tuple comes from a remote index and is not otherwise
    # validated, so refuse anything that would escape the spec cache
    # directory when used as a path component.
    if File.basename(spec_file_name) != spec_file_name
      raise Gem::Exception, "malformed spec name: #{spec_file_name.inspect}"
    end

    source_uri = enforce_trailing_slash(uri) + "#{Gem::MARSHAL_SPEC_DIR}#{spec_file_name}"

    cache_dir = cache_dir source_uri

    local_spec = File.join cache_dir, spec_file_name

    if File.exist? local_spec
      spec = Gem.read_binary local_spec
      Gem.load_safe_marshal
      spec = begin
               Gem::SafeMarshal.safe_load(spec)
             rescue StandardError
               nil
             end
      return spec if spec
    end

View on GitHub (pinned to 86cbb817a3)

Solutions

1. Rename the spec file to the '<name>-<version>.gemspec' format so it can be parsed

When it happens

Trigger: Thrown at lib/rubygems/source.rb:116 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of ruby/rubygems@86cbb817a3 (2026-08-23). Data as JSON: /api/errors/d74ac9006d0bf102. Report an issue: GitHub.