Needed to work around Ruby File.join returning ASCII-8BIT result. Dunno if aligning argument encodings was strictly necessary for my usecase, but I left it in, even though I noticed that UTF-16 and -32 won't work in any case (ArgumentError: string contains null byte). This workaround blows in your face if there is an argument that can't be encod…

file_join_encoding_workaround.rb

# Work around https://bugs.ruby-lang.org/issues/6104
if RUBY_VERSION =~ /^1\.9/ && RUBY_REVISION < 34865
  class File
    class << self
      def join_with_encoding_fix(*args)
        target_encoding = args.first.to_s.encoding
        aligned_args = args.map { |arg| arg.to_s.dup.encode!(target_encoding) }
        join_without_encoding_fix(*aligned_args).force_encoding(target_encoding)
      end
      alias_method :join_without_encoding_fix, :join
      alias_method :join, :join_with_encoding_fix
    end
  end
end