document library accepts files that dont exist.
steps to reproduce
1) add page
2) add document library portlet
3) add folder
4) add document in the created folder
5) choose classic uploader
6) i used this filepath, even though i didnt have an L:
you can choose any file path as long as it ends with a .txt
7)fill in and save( title - Test1 Document1, description This is test1 document1.)
8) save and you'll see your request processed successfully.
9) you are also able to download the empty file too.