#5471: fix expanduser() for $HOME set to "/".
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index 6eb45fd..0ec430d 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -262,7 +262,7 @@
         except KeyError:
             return path
         userhome = pwent.pw_dir
-    userhome = userhome.rstrip('/')
+    userhome = userhome.rstrip('/') or userhome
     return userhome + path[i:]