gh-96192: fix os.ismount() to use a path that is str or bytes (#96194)

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>
Co-authored-by: Eryk Sun <eryksun@gmail.com>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Lib/posixpath.py

@@ -195,6 +195,7 @@ def ismount(path):
         if stat.S_ISLNK(s1.st_mode):
             return False
 
+    path = os.fspath(path)
     if isinstance(path, bytes):
         parent = join(path, b'..')
     else:

Lib/test/test_posixpath.py

@@ -178,6 +178,8 @@ def test_islink(self):
     def test_ismount(self):
         self.assertIs(posixpath.ismount("/"), True)
         self.assertIs(posixpath.ismount(b"/"), True)
+        self.assertIs(posixpath.ismount(FakePath("/")), True)
+        self.assertIs(posixpath.ismount(FakePath(b"/")), True)
 
     def test_ismount_non_existent(self):
         # Non-existent mountpoint.

Misc/NEWS.d/next/Library/2022-08-23-03-13-18.gh-issue-96192.TJywOF.rst

+Fix handling of ``bytes`` :term:`path-like objects <path-like object>` in :func:`os.ismount()`.