Remove @deleter from setters which only reject the deletion

They raised TypeError for deletion, and the generated code now raises AttributeError.
serhiy-storchaka · Sep 19, 2026 · Aug 19, 2026 · Aug 19, 2026 · Aug 20, 2026 · Aug 20, 2026
commit 5b9d005d240a133495d9be5664b4ad61499bc8ed
diff --git a/Lib/test/test_ctypes/test_delattr.py b/Lib/test/test_ctypes/test_delattr.py
@@ -8,12 +8,12 @@ class X(Structure):
 
 class TestCase(unittest.TestCase):
     def test_simple(self):
-        with self.assertRaises(TypeError):
+        with self.assertRaises(AttributeError):
             del c_int(42).value
 
     def test_chararray(self):
         chararray = (c_char * 5)()
-        with self.assertRaises(TypeError):
+        with self.assertRaises(AttributeError):
             del chararray.value
 
     def test_struct(self):

@@ -683,17 +683,17 @@ def test_invalid_setattr(self):
         self.assertRaisesRegex(TE, msg, setattr, exc, '__context__', 1)
 
     def test_invalid_delattr(self):
-        TE = TypeError
+        AE = AttributeError
         try:
             raise IndexError(4)
         except Exception as e:
             exc = e
 
-        msg = "may not be deleted"
-        self.assertRaisesRegex(TE, msg, delattr, exc, 'args')
-        self.assertRaisesRegex(TE, msg, delattr, exc, '__traceback__')
-        self.assertRaisesRegex(TE, msg, delattr, exc, '__cause__')
-        self.assertRaisesRegex(TE, msg, delattr, exc, '__context__')
+        msg = "cannot be deleted"
+        self.assertRaisesRegex(AE, msg, delattr, exc, 'args')
+        self.assertRaisesRegex(AE, msg, delattr, exc, '__traceback__')
+        self.assertRaisesRegex(AE, msg, delattr, exc, '__cause__')
+        self.assertRaisesRegex(AE, msg, delattr, exc, '__context__')
 
     def testNoneClearsTracebackAttr(self):
         try:

diff --git a/Lib/test/test_funcattrs.py b/Lib/test/test_funcattrs.py
@@ -229,7 +229,7 @@ def not_generic(): pass
         for func in (not_generic, lambda_):
             with self.subTest(func=func):
                 self.assertEqual(func.__type_params__, ())
-                with self.assertRaises(TypeError):
+                with self.assertRaises(AttributeError):
                     del func.__type_params__
                 with self.assertRaises(TypeError):
                     func.__type_params__ = 42

diff --git a/Lib/test/test_raise.py b/Lib/test/test_raise.py
@@ -257,7 +257,7 @@ def test_attrs(self):
         self.assertIs(tb.tb_next.tb_next, None)
 
         # Invalid assignments
-        with self.assertRaises(TypeError):
+        with self.assertRaises(AttributeError):
             del tb.tb_next
 
         with self.assertRaises(TypeError):

diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
@@ -1533,22 +1533,15 @@ _ctypes_PyCArrayType_Type_value_get_impl(CDataObject *self)
 /*[clinic input]
 @critical_section
 @setter
-@deleter
 _ctypes.PyCArrayType_Type.value
-    value: object(subclass_of='&PyBytes_Type', type='PyBytesObject *') = NULL
+    value: object(subclass_of='&PyBytes_Type', type='PyBytesObject *')
 [clinic start generated code]*/
 
 static int
 _ctypes_PyCArrayType_Type_value_set_impl(CDataObject *self,
                                          PyBytesObject *value)
-/*[clinic end generated code: output=21cbd436230dc33e input=d35228bbfb2f5228]*/
+/*[clinic end generated code: output=21cbd436230dc33e input=47d40501c4ecae23]*/
 {
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError,
-                        "can't delete attribute");
-        return -1;
-    }
-
     Py_ssize_t size = PyBytes_GET_SIZE(value);
     if (size > self->b_size) {
         PyErr_SetString(PyExc_ValueError,
@@ -5388,22 +5381,15 @@ class _ctypes.Simple "CDataObject *" "clinic_state()->Simple_Type"
 /*[clinic input]
 @critical_section
 @setter
-@deleter
 _ctypes.Simple.value
 [clinic start generated code]*/
 
 static int
 _ctypes_Simple_value_set_impl(CDataObject *self, PyObject *value)
-/*[clinic end generated code: output=f267186118939863 input=4e6c1143d17c2c3f]*/
+/*[clinic end generated code: output=f267186118939863 input=977af9dc9e71e857]*/
 {
     PyObject *result;
 
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError,
-                        "can't delete attribute");
-        return -1;
-    }
-
     ctypes_state *st = get_module_state_by_def(Py_TYPE(Py_TYPE(self)));
     StgInfo *info;
     if (PyStgInfo_FromObject(st, (PyObject *)self, &info) < 0) {

diff --git a/Modules/_ctypes/clinic/_ctypes.c.h b/Modules/_ctypes/clinic/_ctypes.c.h
diff --git a/Objects/clinic/exceptions.c.h b/Objects/clinic/exceptions.c.h
diff --git a/Objects/clinic/funcobject.c.h b/Objects/clinic/funcobject.c.h
@@ -346,19 +346,14 @@ BaseException_args_get_impl(PyBaseExceptionObject *self)
 /*[clinic input]
 @critical_section
 @setter
-@deleter
 BaseException.args
 [clinic start generated code]*/
 
 static int
 BaseException_args_set_impl(PyBaseExceptionObject *self, PyObject *value)
-/*[clinic end generated code: output=331137e11d8f9e80 input=177ad350c8b45219]*/
+/*[clinic end generated code: output=331137e11d8f9e80 input=2400047ea5970a84]*/
 {
     PyObject *seq;
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError, "args may not be deleted");
-        return -1;
-    }
     seq = PySequence_Tuple(value);
     if (!seq)
         return -1;
@@ -386,19 +381,14 @@ BaseException___traceback___get_impl(PyBaseExceptionObject *self)
 /*[clinic input]
 @critical_section
 @setter
-@deleter
 BaseException.__traceback__
 [clinic start generated code]*/
 
 static int
 BaseException___traceback___set_impl(PyBaseExceptionObject *self,
                                      PyObject *value)
-/*[clinic end generated code: output=a82c86d9f29f48f0 input=53a1df586023d786]*/
+/*[clinic end generated code: output=a82c86d9f29f48f0 input=12676035676badad]*/
 {
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError, "__traceback__ may not be deleted");
-        return -1;
-    }
     if (PyTraceBack_Check(value)) {
         Py_XSETREF(self->traceback, Py_NewRef(value));
     }
@@ -432,19 +422,15 @@ BaseException___context___get_impl(PyBaseExceptionObject *self)
 /*[clinic input]
 @critical_section
 @setter
-@deleter
 BaseException.__context__
 [clinic start generated code]*/
 
 static int
 BaseException___context___set_impl(PyBaseExceptionObject *self,
                                    PyObject *value)
-/*[clinic end generated code: output=b4cb52dcca1da3bd input=fe79e7c0a0854004]*/
+/*[clinic end generated code: output=b4cb52dcca1da3bd input=c0971adf47fa1858]*/
 {
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError, "__context__ may not be deleted");
-        return -1;
-    } else if (value == Py_None) {
+    if (value == Py_None) {
         value = NULL;
     } else if (!PyExceptionInstance_Check(value)) {
         PyErr_SetString(PyExc_TypeError, "exception context must be None "
@@ -476,19 +462,15 @@ BaseException___cause___get_impl(PyBaseExceptionObject *self)
 /*[clinic input]
 @critical_section
 @setter
-@deleter
 BaseException.__cause__
 [clinic start generated code]*/
 
 static int
 BaseException___cause___set_impl(PyBaseExceptionObject *self,
                                  PyObject *value)
-/*[clinic end generated code: output=6161315398aaf541 input=3fdd9a0d1674abc9]*/
+/*[clinic end generated code: output=6161315398aaf541 input=e1b403c0bde3f62a]*/
 {
-    if (value == NULL) {
-        PyErr_SetString(PyExc_TypeError, "__cause__ may not be deleted");
-        return -1;
-    } else if (value == Py_None) {
+    if (value == Py_None) {
         value = NULL;
     } else if (!PyExceptionInstance_Check(value)) {
         PyErr_SetString(PyExc_TypeError, "exception cause must be None "