What causes "Cannot specify `--path` option without a value" in ruby/ruby?

Pass a real relative path inside the gem: `bundle open rack --path lib/rack`

ruby/ruby · error · InvalidOption

Cannot specify `--path` option without a value

Error message

Cannot specify `--path` option without a value

What it means

CLI::Open (lib/bundler/cli/open.rb:13) implements `bundle open GEM --path <relative-path>` to open a subdirectory of the gem in your editor. The constructor keeps options[:path] when non-nil, and run raises Bundler::InvalidOption if that value is present but empty — an empty string would produce a meaningless File.join and an editor launched at an invalid path.

Source

Thrown at lib/bundler/cli/open.rb:13

# frozen_string_literal: true

module Bundler
  class CLI::Open
    attr_reader :options, :name, :path
    def initialize(options, name)
      @options = options
      @name = name
      @path = options[:path] unless options[:path].nil?
    end

    def run
      raise InvalidOption, "Cannot specify `--path` option without a value" if !@path.nil? && @path.empty?
      editor = [ENV["BUNDLER_EDITOR"], ENV["VISUAL"], ENV["EDITOR"]].find {|e| !e.nil? && !e.empty? }
      return Bundler.ui.info("To open a bundled gem, set $EDITOR or $BUNDLER_EDITOR") unless editor
      return unless spec = Bundler::CLI::Common.select_spec(name, :regex_match)
      if spec.default_gem?
        Bundler.ui.info "Unable to open #{name} because it's a default gem, so the directory it would normally be installed to does not exist."
      else
        root_path = spec.full_gem_path
        command = editor_command(editor) << File.join([root_path, path].compact)
        Bundler.with_original_env do
          system(*command, { chdir: root_path })
        end || Bundler.ui.info("Could not run '#{command.join(" ")}'")
      end
    end

    def editor_command(editor)
      # On Windows an editor is often configured with a full path such as
      # C:\Program Files\Microsoft VS Code\Code.exe, which shell splitting
      # would corrupt. Take a value that names an existing file as a

View on GitHub (pinned to 0e5b888e1c)

Solutions

Pass a real relative path inside the gem: `bundle open rack --path lib/rack`
If the value is optional in your script, omit the --path flag entirely when it is empty
Default the variable: `--path "${SUBDIR:-lib}"`

Example fix

# before
$ bundle open nokogiri --path ""
# => Cannot specify `--path` option without a value

# after
$ bundle open nokogiri --path ext/nokogiri

Defensive patterns

Strategy: validation

Validate before calling

subpath = ENV['GEM_SUBPATH']
args = %w[bundle open mygem]
args += ['--path', subpath] if subpath && !subpath.strip.empty?
system(*args)

Type guard

def usable_open_path?(value)
  !value.nil? && !value.empty?
end

Try / catch

begin
  Bundler::CLI::Open.new(options, name).run
rescue Bundler::InvalidOption => e
  warn e.message
  exit 1
end

Prevention

Only pass --path when the variable is non-empty
Default subpaths in wrappers: ${SUBPATH:-lib}

When it happens

Trigger: `bundle open rack --path ''` or `--path ""`, typically when the value comes from a shell variable that is set but empty (e.g. $MY_GEM_SUBDIR unset with set -u style quoting producing "").

Common situations: Scripts parameterizing the subpath with a variable that is occasionally empty; CI env vars defined as blank strings; a trailing `--path` with an accidentally empty quoted argument.

Related errors

AI-assisted analysis of ruby/ruby@0e5b888e1c (2026-08-21). Data as JSON: /api/errors/b3c755ad72091a02. Report an issue: GitHub.