[3.13] gh-135878: Fix crash in types.SimpleNamespace.__repr__ (GH-135889) (#135895)

miss-islington · sobolevn · ZeroIntensity · web-flow · commit 469f69d4e2ce · 2025-06-24T16:59:29.000Z
gh-135878: Fix crash in `types.SimpleNamespace.__repr__` (GH-135889) (cherry picked from commit b3ab94a) Co-authored-by: sobolevn <mail@sobolevn.me> Co-authored-by: Peter Bierma <zintensitydev@gmail.com>
diff --git a/Misc/NEWS.d/next/Library/2025-06-24-14-43-24.gh-issue-135878.Db4roX.rst b/Misc/NEWS.d/next/Library/2025-06-24-14-43-24.gh-issue-135878.Db4roX.rst
@@ -0,0 +1,3 @@
+Fixes a crash of :class:`types.SimpleNamespace` on :term:`free threading` builds,
+when several threads were calling its :meth:`~object.__repr__` method at the
+same time.
diff --git a/Objects/namespaceobject.c b/Objects/namespaceobject.c
@@ -120,9 +120,10 @@ namespace_repr(PyObject *ns)
         if (PyUnicode_Check(key) && PyUnicode_GET_LENGTH(key) > 0) {
             PyObject *value, *item;
 
-            value = PyDict_GetItemWithError(d, key);
-            if (value != NULL) {
+            int has_key = PyDict_GetItemRef(d, key, &value);
+            if (has_key == 1) {
                 item = PyUnicode_FromFormat("%U=%R", key, value);
+                Py_DECREF(value);
                 if (item == NULL) {
                     loop_error = 1;
                 }
@@ -131,7 +132,7 @@ namespace_repr(PyObject *ns)
                     Py_DECREF(item);
                 }
             }
-            else if (PyErr_Occurred()) {
+            else if (has_key < 0) {
                 loop_error = 1;
             }
         }

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+Fixes a crash of :class:`types.SimpleNamespace` on :term:`free threading` builds,
	`2`	+when several threads were calling its :meth:`~object.__repr__` method at the
	`3`	`+same time.`
Original file line number	Diff line number	Diff line change
`@@ -120,9 +120,10 @@ namespace_repr(PyObject *ns)`
`120`	`120`	`if (PyUnicode_Check(key) && PyUnicode_GET_LENGTH(key) > 0) {`
`121`	`121`	`PyObject value, item;`
`122`	`122`
`123`		`- value = PyDict_GetItemWithError(d, key);`
`124`		`- if (value != NULL) {`
	`123`	`+ int has_key = PyDict_GetItemRef(d, key, &value);`
	`124`	`+ if (has_key == 1) {`
`125`	`125`	`item = PyUnicode_FromFormat("%U=%R", key, value);`
	`126`	`+ Py_DECREF(value);`
`126`	`127`	`if (item == NULL) {`
`127`	`128`	`loop_error = 1;`
`128`	`129`	`}`
`@@ -131,7 +132,7 @@ namespace_repr(PyObject *ns)`
`131`	`132`	`Py_DECREF(item);`
`132`	`133`	`}`
`133`	`134`	`}`
`134`		`- else if (PyErr_Occurred()) {`
	`135`	`+ else if (has_key < 0) {`
`135`	`136`	`loop_error = 1;`
`136`	`137`	`}`
`137`	`138`	`}`