ruby/rubygems · error · Gem::Package::FormatError

#{e.message}

Error message

#{e.message}

What it means

Error "#{e.message}" thrown in ruby/rubygems.

Source

Thrown at lib/rubygems/package.rb:637

    @gem.with_read_io do |io|
      Gem::Package::TarReader.new io do |reader|
        read_checksums reader

        verify_files reader
      end
    end

    verify_checksums @digests, @checksums

    @security_policy&.verify_signatures @spec, @digests, @signatures

    true
  rescue Gem::Security::Exception
    @spec = nil
    @files = []
    raise
  rescue Errno::ENOENT => e
    raise Gem::Package::FormatError.new e.message
  rescue Zlib::GzipFile::Error, EOFError, Gem::Package::TarInvalidError => e
    raise Gem::Package::FormatError.new e.message, @gem
  end

  private

  ##
  # Returns the full path for installing +filename+ into +destination_dir+,
  # which must already be resolved with File.realpath by the caller.
  #
  # If +filename+ is not inside +destination_dir+ an exception is raised.

  def install_location(filename, destination_dir) # :nodoc:
    raise Gem::Package::PathError.new(filename, destination_dir) if
      filename.start_with? "/"

    destination = File.expand_path(filename, destination_dir)

View on GitHub (pinned to 86cbb817a3)

Solutions

1. Re-download the gem file; it could not be read
2. If you built the gem, rebuild it with `gem build foo.gemspec`

When it happens

Trigger: Thrown at lib/rubygems/package.rb:637 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ruby/rubygems@86cbb817a3 (2026-08-23). Data as JSON: /api/errors/7d68f9c1b50a4ead. Report an issue: GitHub.