[3.13] pythongh-144169: Fix three crashes in AST objects with non-str kwargs (pythonGH-144178) (python#144260)

(cherry picked from commit 639c1ad)

Co-authored-by: Jelle Zijlstra <[email protected]>
Co-authored-by: Victor Stinner <[email protected]>

Author: JelleZijlstra

Lib/test/test_ast/test_ast.py

@@ -3141,6 +3141,27 @@ class _AllFieldTypes(ast.AST):
         self.assertIs(obj.a, None)
         self.assertEqual(obj.b, [])
 
+    def test_non_str_kwarg(self):
+        warn_msg = "got an unexpected keyword argument <object object"
+        with (
+            self.assertRaises(TypeError),
+            self.assertWarnsRegex(DeprecationWarning, warn_msg),
+        ):
+            ast.Name(**{object(): 'y'})
+
+        class FakeStr:
+            def __init__(self, value):
+                self.value = value
+
+            def __hash__(self):
+                return hash(self.value)
+
+            def __eq__(self, other):
+                return isinstance(other, str) and self.value == other
+
+        with self.assertRaisesRegex(TypeError, "got multiple values for argument"):
+            ast.Name("x", **{FakeStr('id'): 'y'})
+
 
 @support.cpython_only
 class ModuleStateTests(unittest.TestCase):

Misc/NEWS.d/next/Library/2026-01-23-06-43-21.gh-issue-144169.LFy9yi.rst

@@ -0,0 +1,2 @@
+Fix three crashes when non-string keyword arguments are supplied to objects
+in the :mod:`ast` module.

Parser/asdl_c.py

@@ -939,7 +939,7 @@ def visitModule(self, mod):
                 }
                 if (p == 0) {
                     PyErr_Format(PyExc_TypeError,
-                        "%.400s got multiple values for argument '%U'",
+                        "%.400s got multiple values for argument %R",
                         Py_TYPE(self)->tp_name, key);
                     res = -1;
                     goto cleanup;
@@ -962,7 +962,7 @@ def visitModule(self, mod):
                 else if (contains == 0) {
                     if (PyErr_WarnFormat(
                         PyExc_DeprecationWarning, 1,
-                        "%.400s.__init__ got an unexpected keyword argument '%U'. "
+                        "%.400s.__init__ got an unexpected keyword argument %R. "
                         "Support for arbitrary keyword arguments is deprecated "
                         "and will be removed in Python 3.15.",
                         Py_TYPE(self)->tp_name, key