Issue #21714: Disallow the construction of invalid paths using Path.with_name(). Original patch by Antony Lee.

1 files changed, 4 insertions, 0 deletions

diff --git a/Lib/pathlib.py b/Lib/pathlib.py
index d3d1af8dec..c1ec07af8e 100644
--- a/Lib/pathlib.py
+++ b/Lib/pathlib.py
@@ -749,6 +749,10 @@ class PurePath(object):
         """Return a new path with the file name changed."""
         if not self.name:
             raise ValueError("%r has an empty name" % (self,))
+        drv, root, parts = self._flavour.parse_parts((name,))
+        if (not name or name[-1] in [self._flavour.sep, self._flavour.altsep]
+            or drv or root or len(parts) != 1):
+            raise ValueError("Invalid name %r" % (name))
         return self._from_parsed_parts(self._drv, self._root,
                                        self._parts[:-1] + [name])