From 145291db28ab5ea94808a3703a31575abb179dee Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 1 Jul 2025 16:19:53 +0200
Subject: [PATCH 01/10] gh-135075: Make PyObject_SetAttr() fail with NULL value
 and exception

Make PyObject_SetAttr() and PyObject_SetAttrString() fail if called
with NULL value and an exception set.
---
 Doc/c-api/object.rst                          |  4 ++
 Lib/test/test_capi/test_object.py             | 15 ++++++++
 ...-07-01-16-22-39.gh-issue-135075.angu3J.rst |  2 +
 Modules/_testcapi/object.c                    | 37 ++++++++++++++++++
 Objects/object.c                              | 38 ++++++++++++++-----
 5 files changed, 87 insertions(+), 9 deletions(-)
 create mode 100644 Misc/NEWS.d/next/C_API/2025-07-01-16-22-39.gh-issue-135075.angu3J.rst

diff --git a/Doc/c-api/object.rst b/Doc/c-api/object.rst
index 0fd159f1eb87f8..a1de82e2df2837 100644
--- a/Doc/c-api/object.rst
+++ b/Doc/c-api/object.rst
@@ -197,6 +197,8 @@ Object Protocol
    in favour of using :c:func:`PyObject_DelAttr`, but there are currently no
    plans to remove it.
 
+   The function must not be called with ``NULL`` *v* and an an exception set.
+
 
 .. c:function:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
 
@@ -207,6 +209,8 @@ Object Protocol
    If *v* is ``NULL``, the attribute is deleted, but this feature is
    deprecated in favour of using :c:func:`PyObject_DelAttrString`.
 
+   The function must not be called with ``NULL`` *v* and an an exception set.
+
    The number of different attribute names passed to this function
    should be kept small, usually by using a statically allocated string
    as *attr_name*.
diff --git a/Lib/test/test_capi/test_object.py b/Lib/test/test_capi/test_object.py
index d4056727d07fbf..276bbbb54dfc1d 100644
--- a/Lib/test/test_capi/test_object.py
+++ b/Lib/test/test_capi/test_object.py
@@ -247,5 +247,20 @@ def func(x):
 
         func(object())
 
+    def test_object_setattr_null_exc(self):
+        class Obj:
+            pass
+        obj = Obj()
+
+        obj.attr = 123
+        with self.assertRaises(SystemError):
+            _testcapi.object_setattr_null_exc(obj, 'attr')
+        self.assertTrue(hasattr(obj, 'attr'))
+
+        with self.assertRaises(SystemError):
+            _testcapi.object_setattrstring_null_exc(obj, 'attr')
+        self.assertTrue(hasattr(obj, 'attr'))
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/Misc/NEWS.d/next/C_API/2025-07-01-16-22-39.gh-issue-135075.angu3J.rst b/Misc/NEWS.d/next/C_API/2025-07-01-16-22-39.gh-issue-135075.angu3J.rst
new file mode 100644
index 00000000000000..88e0fa65f45dd0
--- /dev/null
+++ b/Misc/NEWS.d/next/C_API/2025-07-01-16-22-39.gh-issue-135075.angu3J.rst
@@ -0,0 +1,2 @@
+Make :c:func:`PyObject_SetAttr` and :c:func:`PyObject_SetAttrString` fail if
+called with ``NULL`` value and an exception set. Patch by Victor Stinner.
diff --git a/Modules/_testcapi/object.c b/Modules/_testcapi/object.c
index 798ef97c495aeb..be30c17e522052 100644
--- a/Modules/_testcapi/object.c
+++ b/Modules/_testcapi/object.c
@@ -485,6 +485,41 @@ is_uniquely_referenced(PyObject *self, PyObject *op)
 }
 
 
+static PyObject *
+object_setattr_null_exc(PyObject *self, PyObject *args)
+{
+    PyObject *obj, *name;
+    if (!PyArg_ParseTuple(args, "OO", &obj, &name)) {
+        return NULL;
+    }
+
+    PyErr_SetString(PyExc_ValueError, "error");
+    if (PyObject_SetAttr(obj, name, NULL) < 0) {
+        return NULL;
+    }
+    assert(PyErr_Occurred());
+    return NULL;
+}
+
+
+static PyObject *
+object_setattrstring_null_exc(PyObject *self, PyObject *args)
+{
+    PyObject *obj;
+    const char *name;
+    if (!PyArg_ParseTuple(args, "Os", &obj, &name)) {
+        return NULL;
+    }
+
+    PyErr_SetString(PyExc_ValueError, "error");
+    if (PyObject_SetAttrString(obj, name, NULL) < 0) {
+        return NULL;
+    }
+    assert(PyErr_Occurred());
+    return NULL;
+}
+
+
 static PyMethodDef test_methods[] = {
     {"call_pyobject_print", call_pyobject_print, METH_VARARGS},
     {"pyobject_print_null", pyobject_print_null, METH_VARARGS},
@@ -511,6 +546,8 @@ static PyMethodDef test_methods[] = {
     {"test_py_is_funcs", test_py_is_funcs, METH_NOARGS},
     {"clear_managed_dict", clear_managed_dict, METH_O, NULL},
     {"is_uniquely_referenced", is_uniquely_referenced, METH_O},
+    {"object_setattr_null_exc", object_setattr_null_exc, METH_VARARGS},
+    {"object_setattrstring_null_exc", object_setattrstring_null_exc, METH_VARARGS},
     {NULL},
 };
 
diff --git a/Objects/object.c b/Objects/object.c
index 1223983753ac46..516732d8b98f6c 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -1213,16 +1213,27 @@ PyObject_HasAttrString(PyObject *obj, const char *name)
 int
 PyObject_SetAttrString(PyObject *v, const char *name, PyObject *w)
 {
-    PyObject *s;
-    int res;
+    if (Py_TYPE(v)->tp_setattr != NULL) {
+        PyThreadState *tstate = _PyThreadState_GET();
+        if (w == NULL && _PyErr_Occurred(tstate)) {
+            PyObject *exc = _PyErr_GetRaisedException(tstate);
+            _PyErr_SetString(tstate, PyExc_SystemError,
+                "PyObject_SetAttrString() must not be called with NULL value "
+                "and an exception set");
+            _PyErr_ChainExceptions1Tstate(tstate, exc);
+            return -1;
+        }
 
-    if (Py_TYPE(v)->tp_setattr != NULL)
         return (*Py_TYPE(v)->tp_setattr)(v, (char*)name, w);
-    s = PyUnicode_InternFromString(name);
-    if (s == NULL)
+    }
+
+    PyObject *s = PyUnicode_InternFromString(name);
+    if (s == NULL) {
         return -1;
-    res = PyObject_SetAttr(v, s, w);
-    Py_XDECREF(s);
+    }
+
+    int res = PyObject_SetAttr(v, s, w);
+    Py_DECREF(s);
     return res;
 }
 
@@ -1440,6 +1451,16 @@ PyObject_HasAttr(PyObject *obj, PyObject *name)
 int
 PyObject_SetAttr(PyObject *v, PyObject *name, PyObject *value)
 {
+    PyThreadState *tstate = _PyThreadState_GET();
+    if (value == NULL && _PyErr_Occurred(tstate)) {
+        PyObject *exc = _PyErr_GetRaisedException(tstate);
+        _PyErr_SetString(tstate, PyExc_SystemError,
+            "PyObject_SetAttr() must not be called with NULL value "
+            "and an exception set");
+        _PyErr_ChainExceptions1Tstate(tstate, exc);
+        return -1;
+    }
+
     PyTypeObject *tp = Py_TYPE(v);
     int err;
 
@@ -1451,8 +1472,7 @@ PyObject_SetAttr(PyObject *v, PyObject *name, PyObject *value)
     }
     Py_INCREF(name);
 
-    PyInterpreterState *interp = _PyInterpreterState_GET();
-    _PyUnicode_InternMortal(interp, &name);
+    _PyUnicode_InternMortal(tstate->interp, &name);
     if (tp->tp_setattro != NULL) {
         err = (*tp->tp_setattro)(v, name, value);
         Py_DECREF(name);

From 3b78e5b3e3a3b16a240409b542b121e29102b22f Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 1 Jul 2025 16:38:46 +0200
Subject: [PATCH 02/10] Complete the doc

---
 Doc/c-api/object.rst | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Doc/c-api/object.rst b/Doc/c-api/object.rst
index a1de82e2df2837..e61da97132159e 100644
--- a/Doc/c-api/object.rst
+++ b/Doc/c-api/object.rst
@@ -198,6 +198,8 @@ Object Protocol
    plans to remove it.
 
    The function must not be called with ``NULL`` *v* and an an exception set.
+   This case can arise from forgetting ``NULL`` checks and would delete the
+   attribute.
 
 
 .. c:function:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
@@ -210,6 +212,8 @@ Object Protocol
    deprecated in favour of using :c:func:`PyObject_DelAttrString`.
 
    The function must not be called with ``NULL`` *v* and an an exception set.
+   This case can arise from forgetting ``NULL`` checks and would delete the
+   attribute.
 
    The number of different attribute names passed to this function
    should be kept small, usually by using a statically allocated string

From bb6777bcb093b5ba1607256592cad400bcb25da8 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Tue, 1 Jul 2025 17:22:37 +0200
Subject: [PATCH 03/10] Move the check

---
 Objects/object.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/Objects/object.c b/Objects/object.c
index 516732d8b98f6c..3ed7d55593dffa 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -1213,17 +1213,17 @@ PyObject_HasAttrString(PyObject *obj, const char *name)
 int
 PyObject_SetAttrString(PyObject *v, const char *name, PyObject *w)
 {
-    if (Py_TYPE(v)->tp_setattr != NULL) {
-        PyThreadState *tstate = _PyThreadState_GET();
-        if (w == NULL && _PyErr_Occurred(tstate)) {
-            PyObject *exc = _PyErr_GetRaisedException(tstate);
-            _PyErr_SetString(tstate, PyExc_SystemError,
-                "PyObject_SetAttrString() must not be called with NULL value "
-                "and an exception set");
-            _PyErr_ChainExceptions1Tstate(tstate, exc);
-            return -1;
-        }
+    PyThreadState *tstate = _PyThreadState_GET();
+    if (w == NULL && _PyErr_Occurred(tstate)) {
+        PyObject *exc = _PyErr_GetRaisedException(tstate);
+        _PyErr_SetString(tstate, PyExc_SystemError,
+            "PyObject_SetAttrString() must not be called with NULL value "
+            "and an exception set");
+        _PyErr_ChainExceptions1Tstate(tstate, exc);
+        return -1;
+    }
 
+    if (Py_TYPE(v)->tp_setattr != NULL) {
         return (*Py_TYPE(v)->tp_setattr)(v, (char*)name, w);
     }
 

From 402967d3a521107cdd96556bbd2a5e8b1a9f5645 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 14:43:40 +0200
Subject: [PATCH 04/10] Move tests to _testcapi/abstract.c

---
 Modules/_testcapi/abstract.c | 37 ++++++++++++++++++++++++++++++++++++
 Modules/_testcapi/object.c   | 37 ------------------------------------
 2 files changed, 37 insertions(+), 37 deletions(-)

diff --git a/Modules/_testcapi/abstract.c b/Modules/_testcapi/abstract.c
index d4045afd515909..3c7fe1af40a940 100644
--- a/Modules/_testcapi/abstract.c
+++ b/Modules/_testcapi/abstract.c
@@ -178,6 +178,41 @@ sequence_fast_get_item(PyObject *self, PyObject *args)
 }
 
 
+static PyObject *
+object_setattr_null_exc(PyObject *self, PyObject *args)
+{
+    PyObject *obj, *name;
+    if (!PyArg_ParseTuple(args, "OO", &obj, &name)) {
+        return NULL;
+    }
+
+    PyErr_SetString(PyExc_ValueError, "error");
+    if (PyObject_SetAttr(obj, name, NULL) < 0) {
+        return NULL;
+    }
+    assert(PyErr_Occurred());
+    return NULL;
+}
+
+
+static PyObject *
+object_setattrstring_null_exc(PyObject *self, PyObject *args)
+{
+    PyObject *obj;
+    const char *name;
+    if (!PyArg_ParseTuple(args, "Os", &obj, &name)) {
+        return NULL;
+    }
+
+    PyErr_SetString(PyExc_ValueError, "error");
+    if (PyObject_SetAttrString(obj, name, NULL) < 0) {
+        return NULL;
+    }
+    assert(PyErr_Occurred());
+    return NULL;
+}
+
+
 static PyMethodDef test_methods[] = {
     {"object_getoptionalattr", object_getoptionalattr, METH_VARARGS},
     {"object_getoptionalattrstring", object_getoptionalattrstring, METH_VARARGS},
@@ -191,6 +226,8 @@ static PyMethodDef test_methods[] = {
 
     {"sequence_fast_get_size", sequence_fast_get_size, METH_O},
     {"sequence_fast_get_item", sequence_fast_get_item, METH_VARARGS},
+    {"object_setattr_null_exc", object_setattr_null_exc, METH_VARARGS},
+    {"object_setattrstring_null_exc", object_setattrstring_null_exc, METH_VARARGS},
     {NULL},
 };
 
diff --git a/Modules/_testcapi/object.c b/Modules/_testcapi/object.c
index be30c17e522052..798ef97c495aeb 100644
--- a/Modules/_testcapi/object.c
+++ b/Modules/_testcapi/object.c
@@ -485,41 +485,6 @@ is_uniquely_referenced(PyObject *self, PyObject *op)
 }
 
 
-static PyObject *
-object_setattr_null_exc(PyObject *self, PyObject *args)
-{
-    PyObject *obj, *name;
-    if (!PyArg_ParseTuple(args, "OO", &obj, &name)) {
-        return NULL;
-    }
-
-    PyErr_SetString(PyExc_ValueError, "error");
-    if (PyObject_SetAttr(obj, name, NULL) < 0) {
-        return NULL;
-    }
-    assert(PyErr_Occurred());
-    return NULL;
-}
-
-
-static PyObject *
-object_setattrstring_null_exc(PyObject *self, PyObject *args)
-{
-    PyObject *obj;
-    const char *name;
-    if (!PyArg_ParseTuple(args, "Os", &obj, &name)) {
-        return NULL;
-    }
-
-    PyErr_SetString(PyExc_ValueError, "error");
-    if (PyObject_SetAttrString(obj, name, NULL) < 0) {
-        return NULL;
-    }
-    assert(PyErr_Occurred());
-    return NULL;
-}
-
-
 static PyMethodDef test_methods[] = {
     {"call_pyobject_print", call_pyobject_print, METH_VARARGS},
     {"pyobject_print_null", pyobject_print_null, METH_VARARGS},
@@ -546,8 +511,6 @@ static PyMethodDef test_methods[] = {
     {"test_py_is_funcs", test_py_is_funcs, METH_NOARGS},
     {"clear_managed_dict", clear_managed_dict, METH_O, NULL},
     {"is_uniquely_referenced", is_uniquely_referenced, METH_O},
-    {"object_setattr_null_exc", object_setattr_null_exc, METH_VARARGS},
-    {"object_setattrstring_null_exc", object_setattrstring_null_exc, METH_VARARGS},
     {NULL},
 };
 

From a8d21f6108d7e68539f4554053b12aec9f7a87d7 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 14:50:48 +0200
Subject: [PATCH 05/10] Enhance tests

---
 Lib/test/test_capi/test_object.py | 19 ++++++++++++-------
 Modules/_testcapi/abstract.c      | 12 ++++++------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/Lib/test/test_capi/test_object.py b/Lib/test/test_capi/test_object.py
index 276bbbb54dfc1d..028b176b58b066 100644
--- a/Lib/test/test_capi/test_object.py
+++ b/Lib/test/test_capi/test_object.py
@@ -251,15 +251,20 @@ def test_object_setattr_null_exc(self):
         class Obj:
             pass
         obj = Obj()
-
         obj.attr = 123
-        with self.assertRaises(SystemError):
-            _testcapi.object_setattr_null_exc(obj, 'attr')
-        self.assertTrue(hasattr(obj, 'attr'))
 
-        with self.assertRaises(SystemError):
-            _testcapi.object_setattrstring_null_exc(obj, 'attr')
-        self.assertTrue(hasattr(obj, 'attr'))
+        exc = ValueError("error")
+        with self.assertRaises(SystemError) as cm:
+            _testcapi.object_setattr_null_exc(obj, 'attr', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
+
+        with self.assertRaises(SystemError) as cm:
+            _testcapi.object_setattrstring_null_exc(obj, 'attr', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
 
 
 if __name__ == "__main__":
diff --git a/Modules/_testcapi/abstract.c b/Modules/_testcapi/abstract.c
index 3c7fe1af40a940..6a3901b283f149 100644
--- a/Modules/_testcapi/abstract.c
+++ b/Modules/_testcapi/abstract.c
@@ -181,12 +181,12 @@ sequence_fast_get_item(PyObject *self, PyObject *args)
 static PyObject *
 object_setattr_null_exc(PyObject *self, PyObject *args)
 {
-    PyObject *obj, *name;
-    if (!PyArg_ParseTuple(args, "OO", &obj, &name)) {
+    PyObject *obj, *name, *exc;
+    if (!PyArg_ParseTuple(args, "OOO", &obj, &name, &exc)) {
         return NULL;
     }
 
-    PyErr_SetString(PyExc_ValueError, "error");
+    PyErr_SetObject((PyObject*)Py_TYPE(exc), exc);
     if (PyObject_SetAttr(obj, name, NULL) < 0) {
         return NULL;
     }
@@ -198,13 +198,13 @@ object_setattr_null_exc(PyObject *self, PyObject *args)
 static PyObject *
 object_setattrstring_null_exc(PyObject *self, PyObject *args)
 {
-    PyObject *obj;
+    PyObject *obj, *exc;
     const char *name;
-    if (!PyArg_ParseTuple(args, "Os", &obj, &name)) {
+    if (!PyArg_ParseTuple(args, "OsO", &obj, &name, &exc)) {
         return NULL;
     }
 
-    PyErr_SetString(PyExc_ValueError, "error");
+    PyErr_SetObject((PyObject*)Py_TYPE(exc), exc);
     if (PyObject_SetAttrString(obj, name, NULL) < 0) {
         return NULL;
     }

From 7cc691dfafebaba58659ce606d5d7b0f65630144 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 14:52:22 +0200
Subject: [PATCH 06/10] Add versionchanged

---
 Doc/c-api/object.rst | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Doc/c-api/object.rst b/Doc/c-api/object.rst
index e61da97132159e..4a185751cf3658 100644
--- a/Doc/c-api/object.rst
+++ b/Doc/c-api/object.rst
@@ -201,6 +201,9 @@ Object Protocol
    This case can arise from forgetting ``NULL`` checks and would delete the
    attribute.
 
+   .. versionchanged:: next
+      Raise an exception if called with ``NULL`` *v* and an an exception set.
+
 
 .. c:function:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
 
@@ -223,6 +226,9 @@ Object Protocol
    For more details, see :c:func:`PyUnicode_InternFromString`, which may be
    used internally to create a key object.
 
+   .. versionchanged:: next
+      Raise an exception if called with ``NULL`` *v* and an an exception set.
+
 .. c:function:: int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)
 
    Generic attribute setter and deleter function that is meant

From 3cb999df99bda06cdb2ff66514fc15dbe15454b5 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 14:58:15 +0200
Subject: [PATCH 07/10] Test undecodable name

---
 Lib/test/test_capi/test_object.py | 7 +++++++
 Modules/_testcapi/abstract.c      | 3 ++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_capi/test_object.py b/Lib/test/test_capi/test_object.py
index 028b176b58b066..9e61d0fa91ec43 100644
--- a/Lib/test/test_capi/test_object.py
+++ b/Lib/test/test_capi/test_object.py
@@ -266,6 +266,13 @@ class Obj:
         self.assertIsNone(cm.exception.__cause__)
         self.assertHasAttr(obj, 'attr')
 
+        with self.assertRaises(SystemError) as cm:
+            # undecodable name
+            _testcapi.object_setattrstring_null_exc(obj, b'\xff', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Modules/_testcapi/abstract.c b/Modules/_testcapi/abstract.c
index 6a3901b283f149..c1f769456accef 100644
--- a/Modules/_testcapi/abstract.c
+++ b/Modules/_testcapi/abstract.c
@@ -200,7 +200,8 @@ object_setattrstring_null_exc(PyObject *self, PyObject *args)
 {
     PyObject *obj, *exc;
     const char *name;
-    if (!PyArg_ParseTuple(args, "OsO", &obj, &name, &exc)) {
+    Py_ssize_t size;
+    if (!PyArg_ParseTuple(args, "Oz#O", &obj, &name, &size, &exc)) {
         return NULL;
     }
 

From d8ac1ac2313396331f6ff4299bda634c199dac07 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 16:37:58 +0200
Subject: [PATCH 08/10] Move tests to test_capi/test_abstract.py

---
 Lib/test/test_capi/test_abstract.py | 26 ++++++++++++++++++++++++++
 Lib/test/test_capi/test_object.py   | 26 --------------------------
 2 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/Lib/test/test_capi/test_abstract.py b/Lib/test/test_capi/test_abstract.py
index 7d548ae87c0fa6..21cacb201b02b9 100644
--- a/Lib/test/test_capi/test_abstract.py
+++ b/Lib/test/test_capi/test_abstract.py
@@ -1077,6 +1077,32 @@ def test_iter_nextitem(self):
         with self.assertRaisesRegex(TypeError, regex):
             PyIter_NextItem(10)
 
+    def test_object_setattr_null_exc(self):
+        class Obj:
+            pass
+        obj = Obj()
+        obj.attr = 123
+
+        exc = ValueError("error")
+        with self.assertRaises(SystemError) as cm:
+            _testcapi.object_setattr_null_exc(obj, 'attr', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
+
+        with self.assertRaises(SystemError) as cm:
+            _testcapi.object_setattrstring_null_exc(obj, 'attr', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
+
+        with self.assertRaises(SystemError) as cm:
+            # undecodable name
+            _testcapi.object_setattrstring_null_exc(obj, b'\xff', exc)
+        self.assertIs(cm.exception.__context__, exc)
+        self.assertIsNone(cm.exception.__cause__)
+        self.assertHasAttr(obj, 'attr')
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Lib/test/test_capi/test_object.py b/Lib/test/test_capi/test_object.py
index 9e61d0fa91ec43..1be5c08bdda3d5 100644
--- a/Lib/test/test_capi/test_object.py
+++ b/Lib/test/test_capi/test_object.py
@@ -247,32 +247,6 @@ def func(x):
 
         func(object())
 
-    def test_object_setattr_null_exc(self):
-        class Obj:
-            pass
-        obj = Obj()
-        obj.attr = 123
-
-        exc = ValueError("error")
-        with self.assertRaises(SystemError) as cm:
-            _testcapi.object_setattr_null_exc(obj, 'attr', exc)
-        self.assertIs(cm.exception.__context__, exc)
-        self.assertIsNone(cm.exception.__cause__)
-        self.assertHasAttr(obj, 'attr')
-
-        with self.assertRaises(SystemError) as cm:
-            _testcapi.object_setattrstring_null_exc(obj, 'attr', exc)
-        self.assertIs(cm.exception.__context__, exc)
-        self.assertIsNone(cm.exception.__cause__)
-        self.assertHasAttr(obj, 'attr')
-
-        with self.assertRaises(SystemError) as cm:
-            # undecodable name
-            _testcapi.object_setattrstring_null_exc(obj, b'\xff', exc)
-        self.assertIs(cm.exception.__context__, exc)
-        self.assertIsNone(cm.exception.__cause__)
-        self.assertHasAttr(obj, 'attr')
-
 
 if __name__ == "__main__":
     unittest.main()

From 4267f325efd80d646e2057765ad36199409dda1f Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 16:39:08 +0200
Subject: [PATCH 09/10] Remove useless test

---
 Lib/test/test_capi/test_abstract.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Lib/test/test_capi/test_abstract.py b/Lib/test/test_capi/test_abstract.py
index 21cacb201b02b9..3a2ed9f5db82f0 100644
--- a/Lib/test/test_capi/test_abstract.py
+++ b/Lib/test/test_capi/test_abstract.py
@@ -1101,7 +1101,6 @@ class Obj:
             _testcapi.object_setattrstring_null_exc(obj, b'\xff', exc)
         self.assertIs(cm.exception.__context__, exc)
         self.assertIsNone(cm.exception.__cause__)
-        self.assertHasAttr(obj, 'attr')
 
 
 if __name__ == "__main__":

From a11c2ee703afaa8427ddf370ff4b429bdf7b2529 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 2 Jul 2025 16:40:52 +0200
Subject: [PATCH 10/10] Rephrase versionchanged

---
 Doc/c-api/object.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Doc/c-api/object.rst b/Doc/c-api/object.rst
index 4a185751cf3658..21fa1491b33d86 100644
--- a/Doc/c-api/object.rst
+++ b/Doc/c-api/object.rst
@@ -202,7 +202,7 @@ Object Protocol
    attribute.
 
    .. versionchanged:: next
-      Raise an exception if called with ``NULL`` *v* and an an exception set.
+      Must not be called with NULL value if an exception is set.
 
 
 .. c:function:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v)
@@ -227,7 +227,8 @@ Object Protocol
    used internally to create a key object.
 
    .. versionchanged:: next
-      Raise an exception if called with ``NULL`` *v* and an an exception set.
+      Must not be called with NULL value if an exception is set.
+
 
 .. c:function:: int PyObject_GenericSetAttr(PyObject *o, PyObject *name, PyObject *value)