Gem::Commands::ContentsCommand#files_in_gem

# File tmp/rubies/ruby-4.1.0-preview1/lib/rubygems/commands/contents_command.rb, line 93
def files_in_gem(spec)
  gem_path = spec.full_gem_path

  if options[:lib_only]
    # raw_require_paths rather than require_paths, since the latter prepends
    # the absolute extension_dir, which would escape the glob base
    require_paths = spec.raw_require_paths
    return [] if require_paths.empty?

    glob = "{#{require_paths.join ","}}/**/*"
  else
    glob = "**/*"
  end

  Dir.glob(glob, base: gem_path).map do |file|
    [gem_path, file]
  end
end