[Python-checkins] [3.10] gh-92118: Add test for traceback when exception is modified by (Async)ExitStack.__exit__ (GH-92339) (GH-92343)

[iritkatriel]

https://github.com/python/cpython/commit/9b47252d5433894c26fc07aa87b1bd6bb4238e5e
commit: 9b47252d5433894c26fc07aa87b1bd6bb4238e5e
branch: 3.10
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: iritkatriel <1055913+iritkatriel at users.noreply.github.com>
date: 2022-05-05T18:47:59+01:00
summary:

[3.10] gh-92118: Add test for traceback when exception is modified by (Async)ExitStack.__exit__ (GH-92339) (GH-92343)

files:
M Lib/test/test_contextlib.py
M Lib/test/test_contextlib_async.py

diff --git a/Lib/test/test_contextlib.py b/Lib/test/test_contextlib.py
index fbaae2dd09fd9..68bd45d97232c 100644
--- a/Lib/test/test_contextlib.py
+++ b/Lib/test/test_contextlib.py
@@ -4,6 +4,7 @@
 import sys
 import tempfile
 import threading
+import traceback
 import unittest
 from contextlib import *  # Tests __all__
 from test import support
@@ -701,6 +702,38 @@ def test_exit_suppress(self):
             stack.push(lambda *exc: True)
             1/0
 
+    def test_exit_exception_traceback(self):
+        # This test captures the current behavior of ExitStack so that we know
+        # if we ever unintendedly change it. It is not a statement of what the
+        # desired behavior is (for instance, we may want to remove some of the
+        # internal contextlib frames).
+
+        def raise_exc(exc):
+            raise exc
+
+        try:
+            with self.exit_stack() as stack:
+                stack.callback(raise_exc, ValueError)
+                1/0
+        except ValueError as e:
+            exc = e
+
+        self.assertIsInstance(exc, ValueError)
+        ve_frames = traceback.extract_tb(exc.__traceback__)
+        expected = \
+            [('test_exit_exception_traceback', 'with self.exit_stack() as stack:')] + \
+            self.callback_error_internal_frames + \
+            [('_exit_wrapper', 'callback(*args, **kwds)'),
+             ('raise_exc', 'raise exc')]
+
+        self.assertEqual(
+            [(f.name, f.line) for f in ve_frames], expected)
+
+        self.assertIsInstance(exc.__context__, ZeroDivisionError)
+        zde_frames = traceback.extract_tb(exc.__context__.__traceback__)
+        self.assertEqual([(f.name, f.line) for f in zde_frames],
+                         [('test_exit_exception_traceback', '1/0')])
+
     def test_exit_exception_chaining_reference(self):
         # Sanity check to make sure that ExitStack chaining matches
         # actual nested with statements
@@ -968,6 +1001,10 @@ def first():
 
 class TestExitStack(TestBaseExitStack, unittest.TestCase):
     exit_stack = ExitStack
+    callback_error_internal_frames = [
+        ('__exit__', 'raise exc_details[1]'),
+        ('__exit__', 'if cb(*exc_details):'),
+    ]
 
 
 class TestRedirectStream:
diff --git a/Lib/test/test_contextlib_async.py b/Lib/test/test_contextlib_async.py
index 127d7500656a5..d6a34e22ac424 100644
--- a/Lib/test/test_contextlib_async.py
+++ b/Lib/test/test_contextlib_async.py
@@ -412,6 +412,13 @@ def __exit__(self, *exc_details):
             return self.run_coroutine(self.__aexit__(*exc_details))
 
     exit_stack = SyncAsyncExitStack
+    callback_error_internal_frames = [
+        ('__exit__', 'return self.run_coroutine(self.__aexit__(*exc_details))'),
+        ('run_coroutine', 'raise exc'),
+        ('run_coroutine', 'raise exc'),
+        ('__aexit__', 'raise exc_details[1]'),
+        ('__aexit__', 'cb_suppress = cb(*exc_details)'),
+    ]
 
     def setUp(self):
         self.loop = asyncio.new_event_loop()