I encountered this issue again today in issue46118.

I started looking into creating the patchcheck, but I realize it may be a little tricky to detect the introduction of a new folder, because `git diff` doesn't actually report new folders, and my initial research indicates it's [far from straightforward](https://stackoverflow.com/a/36293191/70170).

I thought maybe git diff --dirstat might help, but it doesn't. It reports 100% different for a new file in a new folder and same for a new file in an existing folder.