gh-38464: Make tkinter nametowidget() work with cloned menus

Map the auto-generated name of a cloned menu (a menu used as a menubar
or a cascade) back to the original widget instead of raising KeyError.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: serhiy-storchaka

Lib/test/test_tkinter/test_misc.py

@@ -390,6 +390,32 @@ def test_nametowidget(self):
         self.assertIs(self.root.nametowidget(str(b)), b)
         self.assertRaises(KeyError, self.root.nametowidget, '.nonexistent')
 
+    def test_nametowidget_menu_clone(self):
+        # A menu used as a menubar or cascade is cloned by Tk under an
+        # auto-generated name (each path component is the original name
+        # prefixed with one or more '#' clone markers).  nametowidget()
+        # maps such a name back to the original widget (gh-38464).
+        menubar = tkinter.Menu(self.root)
+        filemenu = tkinter.Menu(menubar, tearoff=0)
+        menubar.add_cascade(label='File', menu=filemenu)
+        submenu = tkinter.Menu(filemenu, tearoff=0)
+        filemenu.add_cascade(label='More', menu=submenu)
+        self.root['menu'] = menubar
+        self.root.update_idletasks()
+
+        originals = {menubar, filemenu, submenu}
+        clones = []
+        def collect(parent):
+            for name in self.root.tk.splitlist(
+                    self.root.tk.call('winfo', 'children', parent)):
+                clones.append(name)
+                collect(name)
+        collect('.')
+        # Every menu (originals and clones) resolves to an original widget.
+        self.assertTrue(any('#' in name for name in clones))
+        for name in clones:
+            self.assertIn(self.root.nametowidget(name), originals)
+
     def test_focus_methods(self):
         f = tkinter.Frame(self.root, width=150, height=100)
         f.pack()

Lib/tkinter/__init__.py

@@ -1788,7 +1788,16 @@ def nametowidget(self, name):
         for n in name:
             if not n:
                 break
-            w = w.children[n]
+            try:
+                w = w.children[n]
+            except KeyError:
+                # Menu clones (a menu used as a menubar or a cascade) get
+                # auto-generated names where each path component is the
+                # original name prefixed with one or more '#' clone markers.
+                # Map such a name back to the original widget.
+                if not n.startswith('#'):
+                    raise
+                w = w.children[n.rsplit('#', 1)[-1]]
 
         return w
 

Misc/NEWS.d/next/Library/2026-06-26-15-00-00.gh-issue-38464.yDPjKH.rst

@@ -0,0 +1,3 @@
+:meth:`!tkinter.Misc.nametowidget` now resolves the auto-generated names of
+cloned menus (a menu used as a menubar or a cascade) back to the original
+widget.