bpo-29707: Document that os.path.ismount() is not able to reliable detect bind mounts. (GH-11238)
(cherry picked from commit 32ebd8508d4807a7c85d2ed8e9c3b44ecd6de591)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Doc/library/os.path.rst b/Doc/library/os.path.rst
index f6ff010..d78ab06 100644
--- a/Doc/library/os.path.rst
+++ b/Doc/library/os.path.rst
@@ -277,10 +277,11 @@
Return ``True`` if pathname *path* is a :dfn:`mount point`: a point in a
file system where a different file system has been mounted. On POSIX, the
- function checks whether *path*'s parent, :file:`path/..`, is on a different
- device than *path*, or whether :file:`path/..` and *path* point to the same
+ function checks whether *path*'s parent, :file:`{path}/..`, is on a different
+ device than *path*, or whether :file:`{path}/..` and *path* point to the same
i-node on the same device --- this should detect mount points for all Unix
- and POSIX variants. On Windows, a drive letter root and a share UNC are
+ and POSIX variants. It is not able to reliably detect bind mounts on the
+ same filesystem. On Windows, a drive letter root and a share UNC are
always mount points, and for any other path ``GetVolumePathName`` is called
to see if it is different from the input path.