gh-137200: support frame lineno setter with BRANCH_LEFT and BRANCH_RIGHT events (GH-137229)

xuantengh · web-flow · commit d18f73ae1349 · 2025-07-31T14:22:22.000+01:00
diff --git a/Lib/test/test_monitoring.py b/Lib/test/test_monitoring.py
@@ -3,6 +3,7 @@
 import collections
 import dis
 import functools
+import inspect
 import math
 import operator
 import sys
@@ -1709,6 +1710,27 @@ def func(v=1):
             ('branch right', 'func', 6, 8),
             ('branch right', 'func', 2, 10)])
 
+    def test_callback_set_frame_lineno(self):
+        def func(s: str) -> int:
+            if s.startswith("t"):
+                return 1
+            else:
+                return 0
+
+        def callback(code, from_, to):
+            # try set frame.f_lineno
+            frame = inspect.currentframe()
+            while frame and frame.f_code is not code:
+                frame = frame.f_back
+
+            self.assertIsNotNone(frame)
+            frame.f_lineno = frame.f_lineno + 1 # run next instruction
+
+        sys.monitoring.set_local_events(TEST_TOOL, func.__code__, E.BRANCH_LEFT)
+        sys.monitoring.register_callback(TEST_TOOL, E.BRANCH_LEFT, callback)
+
+        self.assertEqual(func("true"), 1)
+
 
 class TestBranchConsistency(MonitoringTestBase, unittest.TestCase):
 
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
@@ -1685,6 +1685,8 @@ frame_lineno_set_impl(PyFrameObject *self, PyObject *value)
         case PY_MONITORING_EVENT_PY_RESUME:
         case PY_MONITORING_EVENT_JUMP:
         case PY_MONITORING_EVENT_BRANCH:
+        case PY_MONITORING_EVENT_BRANCH_LEFT:
+        case PY_MONITORING_EVENT_BRANCH_RIGHT:
         case PY_MONITORING_EVENT_LINE:
         case PY_MONITORING_EVENT_PY_YIELD:
             /* Setting f_lineno is allowed for the above events */
