gh-151815: Fix segfault in template_iter on allocation failure

timurmamedov1 · timurmamedov1 · commit aa005aa3d560 · 2026-06-21T14:28:57.000-04:00
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-06-20-14-00-00.gh-issue-151815.TmplIt.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-06-20-14-00-00.gh-issue-151815.TmplIt.rst
@@ -0,0 +1,2 @@
+Fix segfault in t-string iterator deallocation when :c:func:`PyObject_GetIter`
+fails during construction, caused by ``Py_CLEAR`` on uninitialized pointers.
diff --git a/Objects/templateobject.c b/Objects/templateobject.c
@@ -226,6 +226,8 @@ template_iter(PyObject *op)
     if (iter == NULL) {
         return NULL;
     }
+    iter->stringsiter = NULL;
+    iter->interpolationsiter = NULL;
 
     PyObject *stringsiter = PyObject_GetIter(self->strings);
     if (stringsiter == NULL) {

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Fix segfault in t-string iterator deallocation when :c:func:`PyObject_GetIter`
	`2`	+fails during construction, caused by ``Py_CLEAR`` on uninitialized pointers.
Original file line number	Diff line number	Diff line change
`@@ -226,6 +226,8 @@ template_iter(PyObject *op)`
`226`	`226`	`if (iter == NULL) {`
`227`	`227`	`return NULL;`
`228`	`228`	`}`
	`229`	`+ iter->stringsiter = NULL;`
	`230`	`+ iter->interpolationsiter = NULL;`
`229`	`231`
`230`	`232`	`PyObject *stringsiter = PyObject_GetIter(self->strings);`
`231`	`233`	`if (stringsiter == NULL) {`