gh-135878: Fix crash in types.SimpleNamespace.__repr__ (#135889)

sobolevn · ZeroIntensity · web-flow · commit b3ab94acd308 · 2025-06-24T19:33:25.000+03:00
Co-authored-by: Peter Bierma &lt;zintensitydev@gmail.com&gt;
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
@@ -124,9 +124,10 @@ 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;
                 }
@@ -135,7 +136,7 @@ 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
`@@ -124,9 +124,10 @@ namespace_repr(PyObject *ns)`
`124`	`124`	`if (PyUnicode_Check(key) && PyUnicode_GET_LENGTH(key) > 0) {`
`125`	`125`	`PyObject value, item;`
`126`	`126`
`127`		`- value = PyDict_GetItemWithError(d, key);`
`128`		`- if (value != NULL) {`
	`127`	`+ int has_key = PyDict_GetItemRef(d, key, &value);`
	`128`	`+ if (has_key == 1) {`
`129`	`129`	`item = PyUnicode_FromFormat("%U=%R", key, value);`
	`130`	`+ Py_DECREF(value);`
`130`	`131`	`if (item == NULL) {`
`131`	`132`	`loop_error = 1;`
`132`	`133`	`}`
`@@ -135,7 +136,7 @@ namespace_repr(PyObject *ns)`
`135`	`136`	`Py_DECREF(item);`
`136`	`137`	`}`
`137`	`138`	`}`
`138`		`- else if (PyErr_Occurred()) {`
	`139`	`+ else if (has_key < 0) {`
`139`	`140`	`loop_error = 1;`
`140`	`141`	`}`
`141`	`142`	`}`