https://github.com/python/cpython/commit/43b4a9c4bb2a7dd45c56aaff059b7ae7a7a93efd
commit: 43b4a9c4bb2a7dd45c56aaff059b7ae7a7a93efd
branch: main
author: Timofei Ivankov <[email protected]>
committer: kumaraditya303 <[email protected]>
date: 2026-09-11T13:54:27Z
summary:
gh-157058: Fix missing awaited-by edge in asyncio.wait_for(fut, 0) (#157059)
files:
A Misc/NEWS.d/next/Library/2026-09-07-12-24-11.gh-issue-157058.2SoQU7.rst
M Lib/asyncio/tasks.py
M Lib/test/test_asyncio/test_graph.py
diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py
index 3ef3a578d93ab4..29c5d9af9b4029 100644
--- a/Lib/asyncio/tasks.py
+++ b/Lib/asyncio/tasks.py
@@ -543,6 +543,10 @@ async def _cancel_and_wait(fut):
cb = functools.partial(_release_waiter, waiter)
fut.add_done_callback(cb)
+ # gh-157058: awaiting the waiter leaves no edge on fut, add it here
+ cur_task = current_task()
+ futures.future_add_to_awaited_by(fut, cur_task)
+
try:
fut.cancel()
# We cannot wait on *fut* directly to make
@@ -550,6 +554,7 @@ async def _cancel_and_wait(fut):
await waiter
finally:
fut.remove_done_callback(cb)
+ futures.future_discard_from_awaited_by(fut, cur_task)
class _AsCompletedIterator:
diff --git a/Lib/test/test_asyncio/test_graph.py
b/Lib/test/test_asyncio/test_graph.py
index f0fda848927dd4..a442a346ff06d9 100644
--- a/Lib/test/test_asyncio/test_graph.py
+++ b/Lib/test/test_asyncio/test_graph.py
@@ -173,6 +173,33 @@ class FakeCoro:
self.assertEqual(len(result.call_stack), 2)
+ async def test_stack_wait_for_non_positive_timeout(self):
+ # gh-157058: wait_for(fut, 0) must still record the waiter
+ cleanup = asyncio.Future()
+
+ async def worker():
+ try:
+ await asyncio.Future()
+ finally:
+ await cleanup
+
+ async def probe(t):
+ await asyncio.wait_for(t, 0)
+
+ t = asyncio.ensure_future(worker())
+ p = asyncio.create_task(probe(t), name='probe')
+ for _ in range(5):
+ await asyncio.sleep(0)
+
+ stack = capture_test_stack(fut=t)
+
+ cleanup.set_result(None)
+ await asyncio.gather(p, t, return_exceptions=True)
+
+ self.assertEqual(stack[0][2], [
+ ['T<probe>', ['a _cancel_and_wait', 'a wait_for', 'a probe'], []],
+ ])
+
async def test_stack_gather(self):
stack_for_deep = None
diff --git
a/Misc/NEWS.d/next/Library/2026-09-07-12-24-11.gh-issue-157058.2SoQU7.rst
b/Misc/NEWS.d/next/Library/2026-09-07-12-24-11.gh-issue-157058.2SoQU7.rst
new file mode 100644
index 00000000000000..9122ae0919dcb1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-09-07-12-24-11.gh-issue-157058.2SoQU7.rst
@@ -0,0 +1,2 @@
+:func:`asyncio.wait_for` with a non-positive timeout now records the waiter
+in the call graph.
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