From: Oskar Roesler <o.roesler@oscloud.info>
Date: Wed, 9 Jul 2025 15:54:58 +0000 (+0200)
Subject: gh-81520: Document unexpected `os.path.ismount` behaviour with btrfs subvolumes ... 
X-Git-Tag: v3.15.0a1~1038
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=591abcc01fcf1c65c7fdfaca7274f5d3f9f022da;p=thirdparty%2FPython%2Fcpython.git

gh-81520: Document unexpected `os.path.ismount` behaviour with btrfs subvolumes (GH-136058)
---

diff --git a/Doc/library/os.path.rst b/Doc/library/os.path.rst
index f72aee19d8f3..1c1cf07a655a 100644
--- a/Doc/library/os.path.rst
+++ b/Doc/library/os.path.rst
@@ -298,9 +298,10 @@ the :mod:`glob` module.)
    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.  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.
+   same filesystem. On Linux systems, it will always return ``True`` for btrfs
+   subvolumes, even if they aren't mount points. 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.
 
    .. versionchanged:: 3.4
       Added support for detecting non-root mount points on Windows.