A name with all whitespace is not "".  But I am not stopping anyone from uploading "     .zip" as their buildpack name.  Although I question if there is much of a difference between the line I added and the uploaded_file.to_s 2 lines later.  Seems the only difference is that I look at the filename only rather than include the path.

I can easily add a strip, but I was just treating flowing through whatever is provided via the form upload.