shutil.rmtree breaks on recursive calls with PurePath

[zolstein]

Running 19.3.0 on macOS Mojave 10.14.6

The following script works when run with python3 (3.7.6) but breaks with graalpython with the following error:

import os
import pathlib
import shutil

a = pathlib.PurePath('a')
ab = a / 'b'
os.makedirs(ab)
shutil.rmtree(a)

Error:

Traceback (most recent call last):
  File "/Users/zach/work/pytz/shutil_test.py", line 8, in <module 'shutil_test.py'>
    shutil.rmtree(a)
  File "/Library/Java/JavaVirtualMachines/graalvm-ce-java8-19.3.0/Contents/Home/jre/languages/python/lib-python/3/shutil.py", line 516, in rmtree
    return _rmtree_unsafe(path, onerror)
  File "/Library/Java/JavaVirtualMachines/graalvm-ce-java8-19.3.0/Contents/Home/jre/languages/python/lib-python/3/shutil.py", line 395, in _rmtree_unsafe
    _rmtree_unsafe(fullname, onerror)
  File "/Library/Java/JavaVirtualMachines/graalvm-ce-java8-19.3.0/Contents/Home/jre/languages/python/lib-python/3/shutil.py", line 374, in _rmtree_unsafe
    with os.scandir(path) as scandir_it:
TypeError: path should be string, bytes or os.PathLike, not str

This happens only when trying to remove a directory that has another directory inside it; i.e. shutil.rmtree(ab) works fine. It also works when passing in paths as strings.

[timfel]

Thanks for the report. This is a case where the wrong specialization is picked in our CastToPathNode.