Gem::PackageTask#define

# File tmp/rubies/ruby-4.1.0-preview1/lib/rubygems/package_task.rb, line 98
def define
  Gem::ContentAddress.eligible!(gem_spec) if content_addressable

  super

  gem_file = File.basename gem_spec.cache_file
  gem_path = File.join package_dir, gem_file
  gem_dir = package_dir_path

  if content_addressable
    build_target = stamp_file
    gem_description = "content-addressable gem #{gem_spec.name}-#{gem_spec.version} " \
      "(Platform: #{gem_spec.platform}, Ruby ABI: #{content_addressable_ruby_abi})"

    discard_stale_stamp_file
  else
    build_target = gem_path
    gem_description = "gem file #{gem_file}"
  end

  task package: [:gem]

  directory package_dir
  directory gem_dir

  desc "Build the #{gem_description}"
  task gem: [build_target]

  trace = Rake.application.options.trace
  Gem.configuration.verbose = trace

  file build_target => [package_dir, gem_dir] + @gem_spec.files do
    previous_gem = recorded_gem_path if content_addressable
    built_gem_path = nil

    chdir(gem_dir) do
      when_writing "Creating #{gem_description}" do
        built_gem_file = Gem::Package.build gem_spec, content_addressable: content_addressable

        verbose trace do
          mv built_gem_file, ".."
        end

        if content_addressable
          built_gem_path = File.join(package_dir, built_gem_file)
          File.write File.join("..", File.basename(stamp_file)), built_gem_path
        end
      end
    end

    if previous_gem && built_gem_path && previous_gem != built_gem_path
      verbose trace do
        rm_f previous_gem
      end
    end
  end
end