Porcelain.spawn does not return status nor writes to stderr

[Yuri Khomyakov]

Hey,
I just started using elixir and I love it.
I encountered a problem where I do not have the exit code when executing a shell.
If, for example, I run ipconfig everything works. If I send a bad command I get an error immediately which is great, but the problem is when I need to get stderr + status code, for exmaple, running ipconfig /notexists porcelain writes everything to stdout and I do not get the exit code anywhere at all.
Thanks!

 def run_cmd(command, args \\ [], opts \\ []) do
    combined_opts = [
      dir: File.cwd!,
      out: :stream,
      result: :discard,
      err: :stream,
    ] ++ opts
    # spawn process that returns a stream, 
    # enum each on stream and send it to server for use, send ok after finish
    Porcelain.spawn(command, args, combined_opts)
    |> case do
      {:error, err} -> {:error, err}
      %Porcelain.Process{:out => out} -> 
        Enum.each(out, &stream_to_server/1)
        {:ok, ""}
    end`

run_cmd("ipconfig", ["/all"]) # works normal
run_cmd("notexists") # works normal
run_cmd("ipconfig", ["notexists"]) # returns std out instead of stderr + status code