The actual implementation calls os.path.normcase from tempfile._get_default_tempdir. In this scenario here, that resolves to the ntpath module & triggers a lowercase conversion.

On the other hand, the posixpath module is simply an identity function.

Now, it *is* possible to force a Windows file system to run in a case-sensitive configuration. Since ntpath.py forces lower case, this could actually cause breakage in that situation, however rare.

In my opinion, changing the ntpath.normcase function to retain case probably yields more correct behavior.