Re: shutil.rmtree() fails when used in Fedora (rpm) "mock" environment

What is the probability of replacing os.lstat, os.close or os.rmdir from
another thread at just the right time?

If the thead does "import os", and its start is logically connected to
calling _rmtree_safe_fd(), I'd say it's a very good chance! That is,
again, granted that the reference to os.lstat *can* be modified in
this way.

But, before we keep guessing any further, it'd be best if OP could get
us the info on what's stored in "func" and "os.lstat" at the time the
assertion fails.