Q: warning: unable to rmdir 'submodule': Directory not empty

Hi!

I wonder whether you'd think this is a bug:
When a branch uses a submodule (named "submodule" here), and when you checkout another branch that does not (yet) have that submodule, I get an error message saying:
warning: unable to rmdir 'submodule': Directory not empty

Well obviously the directory is not empty. The point is: Is the user expected to remove submodule directories manually before switching branches?

When I tried "git checkout master --recurse-submodules" instead, the submodule directory was "mostly deleted", only leaving two object files that weren't ".gitignore"d.
(But the error message was the same)

Wouldn't a message like "... submodule directory contains untracked files; won't delete those..." be better?

Regards,
Ulrich