mirror of https://github.com/python/cpython
e2b340ab41
Currently, asyncio.wait_for(fut), upon reaching the timeout deadline,
cancels the future and returns immediately. This is problematic for
when *fut* is a Task, because it will be left running for an arbitrary
amount of time. This behavior is iself surprising and may lead to
related bugs such as the one described in bpo-33638:
condition = asyncio.Condition()
async with condition:
await asyncio.wait_for(condition.wait(), timeout=0.5)
Currently, instead of raising a TimeoutError, the above code will fail
with `RuntimeError: cannot wait on un-acquired lock`, because
`__aexit__` is reached _before_ `condition.wait()` finishes its
cancellation and re-acquires the condition lock.
To resolve this, make `wait_for` await for the task cancellation.
The tradeoff here is that the `timeout` promise may be broken if the
task decides to handle its cancellation in a slow way. This represents
a behavior change and should probably not be back-patched to 3.6 and
earlier.
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|---|---|---|
| .. | ||
| __init__.py | ||
| __main__.py | ||
| echo.py | ||
| echo2.py | ||
| echo3.py | ||
| functional.py | ||
| keycert3.pem | ||
| pycacert.pem | ||
| ssl_cert.pem | ||
| ssl_key.pem | ||
| test_base_events.py | ||
| test_buffered_proto.py | ||
| test_context.py | ||
| test_events.py | ||
| test_futures.py | ||
| test_locks.py | ||
| test_pep492.py | ||
| test_proactor_events.py | ||
| test_queues.py | ||
| test_runners.py | ||
| test_selector_events.py | ||
| test_server.py | ||
| test_sslproto.py | ||
| test_streams.py | ||
| test_subprocess.py | ||
| test_tasks.py | ||
| test_transports.py | ||
| test_unix_events.py | ||
| test_windows_events.py | ||
| test_windows_utils.py | ||
| utils.py | ||