gh-116735: Use MISSING for CALL event if argument is absent (GH-116737)

gaogaotiantian · web-flow · commit 59e30f41ed6f · 2024-03-15T14:46:18.000Z
diff --git a/Lib/test/test_monitoring.py b/Lib/test/test_monitoring.py
@@ -1808,9 +1808,10 @@ def test_gh108976(self):
         sys.monitoring.set_events(0, 0)
 
     def test_call_function_ex(self):
-        def f(a, b):
+        def f(a=1, b=2):
             return a + b
         args = (1, 2)
+        empty_args = []
 
         call_data = []
         sys.monitoring.use_tool_id(0, "test")
@@ -1819,8 +1820,10 @@ def f(a, b):
         sys.monitoring.register_callback(0, E.CALL, lambda code, offset, callable, arg0: call_data.append((callable, arg0)))
         sys.monitoring.set_events(0, E.CALL)
         f(*args)
+        f(*empty_args)
         sys.monitoring.set_events(0, 0)
         self.assertEqual(call_data[0], (f, 1))
+        self.assertEqual(call_data[1], (f, sys.monitoring.MISSING))
 
 
 class TestOptimizer(MonitoringTestBase, unittest.TestCase):
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-03-13-16-55-25.gh-issue-116735.o3w6y8.rst b/Misc/NEWS.d/next/Core and Builtins/2024-03-13-16-55-25.gh-issue-116735.o3w6y8.rst
@@ -0,0 +1 @@
+For ``INSTRUMENTED_CALL_FUNCTION_EX``, set ``arg0`` to ``sys.monitoring.MISSING`` instead of ``None`` for :monitoring-event:`CALL` event.
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
@@ -3774,7 +3774,7 @@ dummy_func(
             EVAL_CALL_STAT_INC_IF_FUNCTION(EVAL_CALL_FUNCTION_EX, func);
             if (opcode == INSTRUMENTED_CALL_FUNCTION_EX) {
                 PyObject *arg = PyTuple_GET_SIZE(callargs) > 0 ?
-                    PyTuple_GET_ITEM(callargs, 0) : Py_None;
+                    PyTuple_GET_ITEM(callargs, 0) : &_PyInstrumentation_MISSING;
                 int err = _Py_call_instrumentation_2args(
                     tstate, PY_MONITORING_EVENT_CALL,
                     frame, this_instr, func, arg);
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+For ``INSTRUMENTED_CALL_FUNCTION_EX``, set ``arg0`` to ``sys.monitoring.MISSING`` instead of ``None`` for :monitoring-event:`CALL` event.