gh-152691: Document Windows reserved names in tarfile guidance

zainnadeem786 · zainnadeem786 · commit 8a7e4e7014b2 · 2026-06-30T20:30:05.000+05:00
diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
@@ -1195,6 +1195,10 @@ Here is an incomplete list of things to consider:
 * Check filenames against an allow-list of characters
   (to filter out control characters, confusables, foreign path separators,
   and so on).
+* Check for platform-specific filename semantics. For example, on Windows
+  some names can refer to NTFS alternate data streams rather than ordinary
+  files, or have other reserved meanings. Use :func:`os.path.isreserved`
+  where appropriate to detect reserved pathnames.
 * Check that filenames have expected extensions (discouraging files that
   execute when you “click on them”, or extension-less files like Windows
   special device names).
