address feedback

Author: picnixz

Lib/test/test_tcl.py

@@ -544,13 +544,19 @@ def test_set_object_concurrent_mutation_in_sequence_conversion(self):
         # Prevent SIGSEV when the object to convert is concurrently mutated.
         # See: https://github.com/python/cpython/issues/143310.
 
+        string = "value"
+
         class Value:
             def __str__(self):
                 values.clear()
-                return "value"
+                return string
+
+        class List(list):
+            pass
 
-        self.passValue(values := [Value(), "pad"])
-        self.passValue(values := collections.UserList([Value(), "pad"]))
+        expect = (string, "pad") if self.wantobjects else f"{string} pad"
+        self.assertEqual(self.passValue(values := [Value(), "pad"]), expect)
+        self.assertEqual(self.passValue(values := List([Value(), "pad"])), expect)
 
     def test_user_command(self):
         result = None

Misc/NEWS.d/next/Library/2026-01-01-11-21-57.gh-issue-143310.8rxtH3.rst

@@ -1,3 +1,3 @@
-:mod:`tkinter`: fix a crash when a Python object is mutated during the
-conversion to a Tcl object (e.g., when setting a Tcl variable). Patch by
-Bénédikt Tran.
+:mod:`tkinter`: fix a crash when a Python :class:`list` is mutated during
+the conversion to a Tcl object (e.g., when setting a Tcl variable).
+Patch by Bénédikt Tran.

Modules/_tkinter.c

@@ -1032,7 +1032,7 @@ AsObj(PyObject *value)
     }
 
     if (PyList_Check(value)) {
-        PyObject *value_as_tuple = PySequence_Tuple(value);
+        PyObject *value_as_tuple = PyList_AsTuple(value);
         if (value_as_tuple == NULL) {
             return NULL;
         }