From 2e774c234531d1f7776f86ef93c967e2d2782d01 Mon Sep 17 00:00:00 2001
From: Irit Katriel <iritkatriel@yahoo.com>
Date: Fri, 17 May 2024 16:51:32 -0400
Subject: [PATCH] gh-118692: Avoid creating unnecessary StopIteration instances
 for monitoring

---
 Include/internal/pycore_opcode_metadata.h |  4 ++--
 Python/bytecodes.c                        |  8 ++------
 Python/ceval.c                            | 14 +++++++++++---
 Python/generated_cases.c.h                |  8 ++------
 4 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/Include/internal/pycore_opcode_metadata.h b/Include/internal/pycore_opcode_metadata.h
index 2a237bc6dd8ee5..665b8627dfcc52 100644
--- a/Include/internal/pycore_opcode_metadata.h
+++ b/Include/internal/pycore_opcode_metadata.h
@@ -1060,8 +1060,8 @@ const struct opcode_metadata _PyOpcode_opcode_metadata[268] = {
     [INSTRUMENTED_CALL] = { true, INSTR_FMT_IBC00, HAS_ARG_FLAG | HAS_ERROR_FLAG | HAS_ESCAPES_FLAG },
     [INSTRUMENTED_CALL_FUNCTION_EX] = { true, INSTR_FMT_IX, 0 },
     [INSTRUMENTED_CALL_KW] = { true, INSTR_FMT_IB, HAS_ARG_FLAG | HAS_ERROR_FLAG | HAS_ESCAPES_FLAG },
-    [INSTRUMENTED_END_FOR] = { true, INSTR_FMT_IX, HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG | HAS_ESCAPES_FLAG },
-    [INSTRUMENTED_END_SEND] = { true, INSTR_FMT_IX, HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG | HAS_ESCAPES_FLAG },
+    [INSTRUMENTED_END_FOR] = { true, INSTR_FMT_IX, HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG },
+    [INSTRUMENTED_END_SEND] = { true, INSTR_FMT_IX, HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG },
     [INSTRUMENTED_FOR_ITER] = { true, INSTR_FMT_IBC, HAS_ARG_FLAG | HAS_ERROR_FLAG | HAS_ERROR_NO_POP_FLAG | HAS_ESCAPES_FLAG },
     [INSTRUMENTED_INSTRUCTION] = { true, INSTR_FMT_IX, HAS_ERROR_FLAG | HAS_ESCAPES_FLAG },
     [INSTRUMENTED_JUMP_BACKWARD] = { true, INSTR_FMT_IBC, HAS_ARG_FLAG | HAS_EVAL_BREAK_FLAG },
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 55eda9711dea1f..434eb804213810 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -292,11 +292,9 @@ dummy_func(
             /* Need to create a fake StopIteration error here,
              * to conform to PEP 380 */
             if (PyGen_Check(receiver)) {
-                PyErr_SetObject(PyExc_StopIteration, value);
-                if (monitor_stop_iteration(tstate, frame, this_instr)) {
+                if (monitor_stop_iteration(tstate, frame, this_instr, value)) {
                     ERROR_NO_POP();
                 }
-                PyErr_SetRaisedException(NULL);
             }
             DECREF_INPUTS();
         }
@@ -307,11 +305,9 @@ dummy_func(
 
         tier1 inst(INSTRUMENTED_END_SEND, (receiver, value -- value)) {
             if (PyGen_Check(receiver) || PyCoro_CheckExact(receiver)) {
-                PyErr_SetObject(PyExc_StopIteration, value);
-                if (monitor_stop_iteration(tstate, frame, this_instr)) {
+                if (monitor_stop_iteration(tstate, frame, this_instr, value)) {
                     ERROR_NO_POP();
                 }
-                PyErr_SetRaisedException(NULL);
             }
             Py_DECREF(receiver);
         }
diff --git a/Python/ceval.c b/Python/ceval.c
index 128e0417a9fd63..324d062fe9bb43 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -231,7 +231,8 @@ static void monitor_reraise(PyThreadState *tstate,
                  _Py_CODEUNIT *instr);
 static int monitor_stop_iteration(PyThreadState *tstate,
                  _PyInterpreterFrame *frame,
-                 _Py_CODEUNIT *instr);
+                 _Py_CODEUNIT *instr,
+                 PyObject *value);
 static void monitor_unwind(PyThreadState *tstate,
                  _PyInterpreterFrame *frame,
                  _Py_CODEUNIT *instr);
@@ -2215,12 +2216,19 @@ monitor_reraise(PyThreadState *tstate, _PyInterpreterFrame *frame,
 
 static int
 monitor_stop_iteration(PyThreadState *tstate, _PyInterpreterFrame *frame,
-                       _Py_CODEUNIT *instr)
+                       _Py_CODEUNIT *instr, PyObject *value)
 {
     if (no_tools_for_local_event(tstate, frame, PY_MONITORING_EVENT_STOP_ITERATION)) {
         return 0;
     }
-    return do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_STOP_ITERATION);
+    assert(!PyErr_Occurred());
+    PyErr_SetObject(PyExc_StopIteration, value);
+    int res = do_monitor_exc(tstate, frame, instr, PY_MONITORING_EVENT_STOP_ITERATION);
+    if (res < 0) {
+        return res;
+    }
+    PyErr_SetRaisedException(NULL);
+    return 0;
 }
 
 static void
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 8b8112209cc78a..96161c5a6586fd 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -3260,11 +3260,9 @@
             /* Need to create a fake StopIteration error here,
              * to conform to PEP 380 */
             if (PyGen_Check(receiver)) {
-                PyErr_SetObject(PyExc_StopIteration, value);
-                if (monitor_stop_iteration(tstate, frame, this_instr)) {
+                if (monitor_stop_iteration(tstate, frame, this_instr, value)) {
                     goto error;
                 }
-                PyErr_SetRaisedException(NULL);
             }
             Py_DECREF(value);
             stack_pointer += -1;
@@ -3281,11 +3279,9 @@
             value = stack_pointer[-1];
             receiver = stack_pointer[-2];
             if (PyGen_Check(receiver) || PyCoro_CheckExact(receiver)) {
-                PyErr_SetObject(PyExc_StopIteration, value);
-                if (monitor_stop_iteration(tstate, frame, this_instr)) {
+                if (monitor_stop_iteration(tstate, frame, this_instr, value)) {
                     goto error;
                 }
-                PyErr_SetRaisedException(NULL);
             }
             Py_DECREF(receiver);
             stack_pointer[-2] = value;