gh-95882: fix regression in the traceback of exceptions propagated from inside a contextlib context manager (#95883)

1 files changed, 57 insertions, 0 deletions

diff --git a/Lib/test/test_contextlib_async.py b/Lib/test/test_contextlib_async.py
index b64673d..3d43ed0 100644
--- a/Lib/test/test_contextlib_async.py
+++ b/Lib/test/test_contextlib_async.py
@@ -5,6 +5,7 @@ from contextlib import (
 import functools
 from test import support
 import unittest
+import traceback
 
 from test.test_contextlib import TestBaseExitStack
 
@@ -126,6 +127,62 @@ class AsyncContextManagerTestCase(unittest.TestCase):
         self.assertEqual(state, [1, 42, 999])
 
     @_async_test
+    async def test_contextmanager_traceback(self):
+        @asynccontextmanager
+        async def f():
+            yield
+
+        try:
+            async with f():
+                1/0
+        except ZeroDivisionError as e:
+            frames = traceback.extract_tb(e.__traceback__)
+
+        self.assertEqual(len(frames), 1)
+        self.assertEqual(frames[0].name, 'test_contextmanager_traceback')
+        self.assertEqual(frames[0].line, '1/0')
+
+        # Repeat with RuntimeError (which goes through a different code path)
+        class RuntimeErrorSubclass(RuntimeError):
+            pass
+
+        try:
+            async with f():
+                raise RuntimeErrorSubclass(42)
+        except RuntimeErrorSubclass as e:
+            frames = traceback.extract_tb(e.__traceback__)
+
+        self.assertEqual(len(frames), 1)
+        self.assertEqual(frames[0].name, 'test_contextmanager_traceback')
+        self.assertEqual(frames[0].line, 'raise RuntimeErrorSubclass(42)')
+
+        class StopIterationSubclass(StopIteration):
+            pass
+
+        class StopAsyncIterationSubclass(StopAsyncIteration):
+            pass
+
+        for stop_exc in (
+            StopIteration('spam'),
+            StopAsyncIteration('ham'),
+            StopIterationSubclass('spam'),
+            StopAsyncIterationSubclass('spam')
+        ):
+            with self.subTest(type=type(stop_exc)):
+                try:
+                    async with f():
+                        raise stop_exc
+                except type(stop_exc) as e:
+                    self.assertIs(e, stop_exc)
+                    frames = traceback.extract_tb(e.__traceback__)
+                else:
+                    self.fail(f'{stop_exc} was suppressed')
+
+                self.assertEqual(len(frames), 1)
+                self.assertEqual(frames[0].name, 'test_contextmanager_traceback')
+                self.assertEqual(frames[0].line, 'raise stop_exc')
+
+    @_async_test
     async def test_contextmanager_no_reraise(self):
         @asynccontextmanager
         async def whee():