Gem::Commands::GenerateIndexCommand#execute

# File tmp/rubies/ruby-3.2.0/lib/rubygems/commands/generate_index_command.rb, line 67
def execute
  # This is always true because it's the only way now.
  options[:build_modern] = true

  if !File.exist?(options[:directory]) ||
     !File.directory?(options[:directory])
    alert_error "unknown directory name #{options[:directory]}."
    terminate_interaction 1
  else
    indexer = Gem::Indexer.new options.delete(:directory), options

    if options[:update]
      indexer.update_index
    else
      indexer.generate_index
    end
  end
end