bpo-45160: Ttk optionmenu only set variable once (GH-28291) (GH-29131)
(cherry picked from commit add46f84769a7e6fafa50954f79b7c248231fa4e)
Co-authored-by: E-Paine <63801254+E-Paine@users.noreply.github.com>
diff --git a/Lib/tkinter/test/test_ttk/test_extensions.py b/Lib/tkinter/test/test_ttk/test_extensions.py
index 438d21d..cddd1f2 100644
--- a/Lib/tkinter/test/test_ttk/test_extensions.py
+++ b/Lib/tkinter/test/test_ttk/test_extensions.py
@@ -301,6 +301,19 @@ def test_unique_radiobuttons(self):
optmenu.destroy()
optmenu2.destroy()
+ def test_trace_variable(self):
+ # prior to bpo45160, tracing a variable would cause the callback to be made twice
+ success = []
+ items = ('a', 'b', 'c')
+ textvar = tkinter.StringVar(self.root)
+ def cb_test(*args):
+ self.assertEqual(textvar.get(), items[1])
+ success.append(True)
+ optmenu = ttk.OptionMenu(self.root, textvar, "a", *items)
+ textvar.trace("w", cb_test)
+ optmenu['menu'].invoke(1)
+ self.assertEqual(success, [True])
+
class DefaultRootTest(AbstractDefaultRootTest, unittest.TestCase):
diff --git a/Lib/tkinter/ttk.py b/Lib/tkinter/ttk.py
index b854235..acdd565 100644
--- a/Lib/tkinter/ttk.py
+++ b/Lib/tkinter/ttk.py
@@ -1643,7 +1643,10 @@ def set_menu(self, default=None, *values):
menu.delete(0, 'end')
for val in values:
menu.add_radiobutton(label=val,
- command=tkinter._setit(self._variable, val, self._callback),
+ command=(
+ None if self._callback is None
+ else lambda val=val: self._callback(val)
+ ),
variable=self._variable)
if default: