[3.14] gh-133932: Tagged ints are heap-safe (free threading) (gh-142431)

colesbury · web-flow · commit 378b24b54e2d · 2025-12-08T18:16:28.000-05:00
The previous fix (gh-134494) didn't fix the free threading build.
diff --git a/Include/internal/pycore_stackref.h b/Include/internal/pycore_stackref.h
@@ -323,7 +323,7 @@ _PyStackRef_FromPyObjectSteal(PyObject *obj)
 static inline bool
 PyStackRef_IsHeapSafe(_PyStackRef stackref)
 {
-    if (PyStackRef_IsDeferred(stackref)) {
+    if (PyStackRef_IsDeferred(stackref) && !PyStackRef_IsTaggedInt(stackref)) {
         PyObject *obj = PyStackRef_AsPyObjectBorrow(stackref);
         return obj == NULL || _Py_IsImmortal(obj) || _PyObject_HasDeferredRefcount(obj);
     }
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-12-08-15-46-06.gh-issue-133932.HAxa4p.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-12-08-15-46-06.gh-issue-133932.HAxa4p.rst
@@ -0,0 +1,2 @@
+Fix crash in the free threading build when clearing frames that hold tagged
+integers.

Original file line number	Diff line number	Diff line change
`@@ -323,7 +323,7 @@ _PyStackRef_FromPyObjectSteal(PyObject *obj)`
`323`	`323`	`static inline bool`
`324`	`324`	`PyStackRef_IsHeapSafe(_PyStackRef stackref)`
`325`	`325`	`{`
`326`		`- if (PyStackRef_IsDeferred(stackref)) {`
	`326`	`+ if (PyStackRef_IsDeferred(stackref) && !PyStackRef_IsTaggedInt(stackref)) {`
`327`	`327`	`PyObject *obj = PyStackRef_AsPyObjectBorrow(stackref);`
`328`	`328`	`return obj == NULL \|\| _Py_IsImmortal(obj) \|\| _PyObject_HasDeferredRefcount(obj);`
`329`	`329`	`}`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+Fix crash in the free threading build when clearing frames that hold tagged`
	`2`	`+integers.`