[Python-checkins] bpo-46672: fix `NameError` in `asyncio.gather` if type check fails (GH-31187) (GH-31440)

[asvetlov]

https://github.com/python/cpython/commit/f1916cde24053f4c8b6799730666d19474f8dd09
commit: f1916cde24053f4c8b6799730666d19474f8dd09
branch: 3.10
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: asvetlov <andrew.svetlov at gmail.com>
date: 2022-02-20T17:28:42+02:00
summary:

bpo-46672: fix `NameError` in `asyncio.gather` if type check fails (GH-31187) (GH-31440)

Co-authored-by: Alex Waygood <Alex.Waygood at Gmail.com>
(cherry picked from commit 4ab8167b9c60d1a04b2e3116d0c52db254b68cda)

Co-authored-by: Nikita Sobolev <mail at sobolevn.me>

Co-authored-by: Nikita Sobolev <mail at sobolevn.me>

files:
A Misc/NEWS.d/next/Library/2022-02-07-13-15-16.bpo-46672.4swIjx.rst
M Lib/asyncio/tasks.py
M Lib/test/test_asyncio/test_tasks.py

diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 2bee5c050ded7..c4bedb5c72b0e 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -721,7 +721,7 @@ def _done_callback(fut):
         nonlocal nfinished
         nfinished += 1
 
-        if outer.done():
+        if outer is None or outer.done():
             if not fut.cancelled():
                 # Mark exception retrieved.
                 fut.exception()
@@ -777,6 +777,7 @@ def _done_callback(fut):
     nfuts = 0
     nfinished = 0
     loop = None
+    outer = None  # bpo-46672
     for arg in coros_or_futures:
         if arg not in arg_to_fut:
             fut = _ensure_future(arg, loop=loop)
diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 4782c92a7c155..398b143d2d0c6 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -3593,6 +3593,20 @@ async def outer():
         test_utils.run_briefly(self.one_loop)
         self.assertIsInstance(f.exception(), RuntimeError)
 
+    def test_issue46672(self):
+        with mock.patch(
+            'asyncio.base_events.BaseEventLoop.call_exception_handler',
+        ):
+            async def coro(s):
+                return s
+            c = coro('abc')
+
+            with self.assertRaises(TypeError):
+                self._gather(c, {})
+            self._run_loop(self.one_loop)
+            # NameError should not happen:
+            self.one_loop.call_exception_handler.assert_not_called()
+
 
 class RunCoroutineThreadsafeTests(test_utils.TestCase):
     """Test case for asyncio.run_coroutine_threadsafe."""
diff --git a/Misc/NEWS.d/next/Library/2022-02-07-13-15-16.bpo-46672.4swIjx.rst b/Misc/NEWS.d/next/Library/2022-02-07-13-15-16.bpo-46672.4swIjx.rst
new file mode 100644
index 0000000000000..9a76c29a334d8
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-02-07-13-15-16.bpo-46672.4swIjx.rst
@@ -0,0 +1 @@
+Fix ``NameError`` in :func:`asyncio.gather` when initial type check fails.