class ActionView::Digestor

def digest(name:, format: nil, finder:, dependencies: nil)
  if dependencies.nil? || dependencies.empty?
    cache_key = "#{name}.#{format}"
  else
    dependencies_suffix = dependencies.flatten.tap(&:compact!).join(".")
    cache_key = "#{name}.#{format}.#{dependencies_suffix}"
  end
  # this is a correctly done double-checked locking idiom
  # (Concurrent::Map's lookups have volatile semantics)
  finder.digest_cache[cache_key] || @@digest_mutex.synchronize do
    finder.digest_cache.fetch(cache_key) do # re-check under lock
      path = TemplatePath.parse(name)
      root = tree(path.to_s, finder, path.partial?)
      dependencies.each do |injected_dep|
        root.children << Injected.new(injected_dep, nil, nil)
      end if dependencies
      finder.digest_cache[cache_key] = root.digest(finder)
    end
  end
end