From 0c6f898005099be189ee65bcfda659f5fc13b802 Mon Sep 17 00:00:00 2001
From: Thomas Grainger <tagrain@gmail.com>
Date: Sun, 24 Jul 2022 21:18:05 +0100
Subject: [PATCH] gh-95051: ensure that timeouts scheduled with
`asyncio.Timeout` that have already expired are deliverered promptly (#95109)
Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
---
Doc/library/asyncio-task.rst | 3 +++
Lib/asyncio/timeouts.py | 8 +++----
Lib/test/test_asyncio/test_timeouts.py | 24 +++++++++++++++++++
...2-07-21-22-59-22.gh-issue-95109.usxA9r.rst | 1 +
4 files changed, 32 insertions(+), 4 deletions(-)
create mode 100644 Misc/NEWS.d/next/Library/2022-07-21-22-59-22.gh-issue-95109.usxA9r.rst
diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
index a307d22e456..a6b638c1124 100644
--- a/Doc/library/asyncio-task.rst
+++ b/Doc/library/asyncio-task.rst
@@ -625,6 +625,9 @@ Timeouts
If *when* is a float, it is set as the new deadline.
+ if *when* is in the past, the timeout will trigger on the next
+ iteration of the event loop.
+
.. method:: expired() -> bool
Return whether the context manager has exceeded its deadline
diff --git a/Lib/asyncio/timeouts.py b/Lib/asyncio/timeouts.py
index a89205348ff..94d25535fbc 100644
--- a/Lib/asyncio/timeouts.py
+++ b/Lib/asyncio/timeouts.py
@@ -52,10 +52,10 @@ def reschedule(self, when: Optional[float]) -> None:
self._timeout_handler = None
else:
loop = events.get_running_loop()
- self._timeout_handler = loop.call_at(
- when,
- self._on_timeout,
- )
+ if when <= loop.time():
+ self._timeout_handler = loop.call_soon(self._on_timeout)
+ else:
+ self._timeout_handler = loop.call_at(when, self._on_timeout)
def expired(self) -> bool:
"""Is timeout expired during execution?"""
diff --git a/Lib/test/test_asyncio/test_timeouts.py b/Lib/test/test_asyncio/test_timeouts.py
index 9801541e55b..b9bac6f7837 100644
--- a/Lib/test/test_asyncio/test_timeouts.py
+++ b/Lib/test/test_asyncio/test_timeouts.py
@@ -105,6 +105,30 @@ async def test_timeout_zero(self):
self.assertLess(t1-t0, 2)
self.assertTrue(t0 <= cm.when() <= t1)
+ async def test_timeout_zero_sleep_zero(self):
+ loop = asyncio.get_running_loop()
+ t0 = loop.time()
+ with self.assertRaises(TimeoutError):
+ async with asyncio.timeout(0) as cm:
+ await asyncio.sleep(0)
+ t1 = loop.time()
+ self.assertTrue(cm.expired())
+ # 2 sec for slow CI boxes
+ self.assertLess(t1-t0, 2)
+ self.assertTrue(t0 <= cm.when() <= t1)
+
+ async def test_timeout_in_the_past_sleep_zero(self):
+ loop = asyncio.get_running_loop()
+ t0 = loop.time()
+ with self.assertRaises(TimeoutError):
+ async with asyncio.timeout(-11) as cm:
+ await asyncio.sleep(0)
+ t1 = loop.time()
+ self.assertTrue(cm.expired())
+ # 2 sec for slow CI boxes
+ self.assertLess(t1-t0, 2)
+ self.assertTrue(t0 >= cm.when() <= t1)
+
async def test_foreign_exception_passed(self):
with self.assertRaises(KeyError):
async with asyncio.timeout(0.01) as cm:
diff --git a/Misc/NEWS.d/next/Library/2022-07-21-22-59-22.gh-issue-95109.usxA9r.rst b/Misc/NEWS.d/next/Library/2022-07-21-22-59-22.gh-issue-95109.usxA9r.rst
new file mode 100644
index 00000000000..40196dd214a
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-07-21-22-59-22.gh-issue-95109.usxA9r.rst
@@ -0,0 +1 @@
+Ensure that timeouts scheduled with :class:`asyncio.Timeout` that have already expired are delivered promptly.
--
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