gh-79932: do not allow to clear a suspended frame

Lib/test/test_frame.py

@@ -2,6 +2,7 @@
 import re
 import sys
 import textwrap
+import traceback
 import types
 import unittest
 import weakref
@@ -111,6 +112,25 @@ def g():
         f.clear()
         self.assertTrue(endly)
 
+    def test_clear_suspended_generator(self):
+        # Attempting to clear a suspended generator frame is forbidden.
+        def g():
+            for i in range(5):
+                try:
+                    1/0
+                except ZeroDivisionError as e:
+                    yield (e, i)
+
+        gen = g()
+        res = []
+        for e, i in gen:
+            res.append(i)
+            with self.assertRaises(RuntimeError):
+                f = e.__traceback__.tb_frame
+                self.assertIsNotNone(f)
+                f.clear()
+        self.assertEqual(res, list(range(5)))
+
     def test_lineno_with_tracing(self):
         def record_line():
             f = sys._getframe(1)

Objects/frameobject.c

@@ -949,7 +949,8 @@ frame_clear(PyFrameObject *f, PyObject *Py_UNUSED(ignored))
 {
     if (f->f_frame->owner == FRAME_OWNED_BY_GENERATOR) {
         PyGenObject *gen = _PyFrame_GetGenerator(f->f_frame);
-        if (gen->gi_frame_state == FRAME_EXECUTING) {
+        if (gen->gi_frame_state == FRAME_EXECUTING ||
+            gen->gi_frame_state == FRAME_SUSPENDED) {
             goto running;
         }
         _PyGen_Finalize((PyObject *)gen);