gh-160676: Cover tier-2 monitoring callback errors

Author: vankudothuadhinaik

Lib/test/test_monitoring.py

@@ -2677,6 +2677,37 @@ def test_func(x):
 
 class TestTier2Optimizer(CheckEvents):
 
+    @requires_specialization
+    def test_raise_callback_stop_iteration_in_for_tier2(self):
+        _testinternalcapi = import_helper.import_module("_testinternalcapi")
+        _opcode = import_helper.import_module("_opcode")
+        threshold = _testinternalcapi.SPECIALIZATION_THRESHOLD
+        callback_executor = None
+
+        def run():
+            for i in range(threshold + 1):
+                sys.monitoring.set_events(
+                    TEST_TOOL,
+                    E.RAISE if i == threshold else 0,
+                )
+
+        def on_raise(code, offset, exc):
+            nonlocal callback_executor
+            if code is run.__code__ and isinstance(exc, StopIteration):
+                callback_executor = _opcode.get_executor(code, offset)
+                raise RuntimeError("monitor callback failed")
+
+        try:
+            sys.monitoring.register_callback(TEST_TOOL, E.RAISE, on_raise)
+            with self.assertRaisesRegex(RuntimeError, "monitor callback failed"):
+                run()
+            self.assertIsNotNone(callback_executor)
+            uops = [op[0] for op in callback_executor]
+            self.assertIn("_ITER_NEXT_INLINE", uops)
+        finally:
+            sys.monitoring.set_events(TEST_TOOL, 0)
+            sys.monitoring.register_callback(TEST_TOOL, E.RAISE, None)
+
     def test_monitoring_already_opimized_loop(self):
         _testinternalcapi = import_helper.import_module("_testinternalcapi")
 

Python/bytecodes.c

@@ -3818,7 +3818,8 @@ dummy_func(
             if (item == NULL) {
                 if (_PyErr_Occurred(tstate)) {
                     if (_PyErr_ExceptionMatches(tstate, PyExc_StopIteration)) {
-                        if (_PyEval_MonitorRaise(tstate, frame, frame->instr_ptr) < 0) {
+                        int err = _PyEval_MonitorRaise(tstate, frame, frame->instr_ptr);
+                        if (err < 0) {
                             ERROR_NO_POP();
                         }
                         _PyErr_Clear(tstate);

Python/ceval.c

@@ -3834,7 +3834,8 @@ _PyStackRef _PyForIter_VirtualIteratorNext(PyThreadState* tstate, _PyInterpreter
     if (next == NULL) {
         if (_PyErr_Occurred(tstate)) {
             if (_PyErr_ExceptionMatches(tstate, PyExc_StopIteration)) {
-                if (_PyEval_MonitorRaise(tstate, frame, frame->instr_ptr) < 0) {
+                int err = _PyEval_MonitorRaise(tstate, frame, frame->instr_ptr);
+                if (err < 0) {
                     return PyStackRef_ERROR;
                 }
                 _PyErr_Clear(tstate);