mirror of https://github.com/python/cpython
354 lines
11 KiB
Python
354 lines
11 KiB
Python
import asyncio
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import unittest
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import time
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from test import support
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def tearDownModule():
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asyncio.set_event_loop_policy(None)
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# The following value can be used as a very small timeout:
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# it passes check "timeout > 0", but has almost
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# no effect on the test performance
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_EPSILON = 0.0001
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class SlowTask:
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""" Task will run for this defined time, ignoring cancel requests """
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TASK_TIMEOUT = 0.2
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def __init__(self):
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self.exited = False
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async def run(self):
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exitat = time.monotonic() + self.TASK_TIMEOUT
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while True:
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tosleep = exitat - time.monotonic()
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if tosleep <= 0:
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break
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try:
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await asyncio.sleep(tosleep)
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except asyncio.CancelledError:
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pass
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self.exited = True
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class AsyncioWaitForTest(unittest.IsolatedAsyncioTestCase):
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async def test_asyncio_wait_for_cancelled(self):
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t = SlowTask()
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waitfortask = asyncio.create_task(
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asyncio.wait_for(t.run(), t.TASK_TIMEOUT * 2))
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await asyncio.sleep(0)
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waitfortask.cancel()
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await asyncio.wait({waitfortask})
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self.assertTrue(t.exited)
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async def test_asyncio_wait_for_timeout(self):
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t = SlowTask()
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try:
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await asyncio.wait_for(t.run(), t.TASK_TIMEOUT / 2)
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except asyncio.TimeoutError:
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pass
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self.assertTrue(t.exited)
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async def test_wait_for_timeout_less_then_0_or_0_future_done(self):
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loop = asyncio.get_running_loop()
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fut = loop.create_future()
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fut.set_result('done')
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ret = await asyncio.wait_for(fut, 0)
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self.assertEqual(ret, 'done')
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self.assertTrue(fut.done())
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async def test_wait_for_timeout_less_then_0_or_0_coroutine_do_not_started(self):
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foo_started = False
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async def foo():
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nonlocal foo_started
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foo_started = True
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with self.assertRaises(asyncio.TimeoutError):
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await asyncio.wait_for(foo(), 0)
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self.assertEqual(foo_started, False)
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async def test_wait_for_timeout_less_then_0_or_0(self):
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loop = asyncio.get_running_loop()
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for timeout in [0, -1]:
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with self.subTest(timeout=timeout):
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foo_running = None
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started = loop.create_future()
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async def foo():
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nonlocal foo_running
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foo_running = True
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started.set_result(None)
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try:
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await asyncio.sleep(10)
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finally:
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foo_running = False
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return 'done'
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fut = asyncio.create_task(foo())
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await started
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with self.assertRaises(asyncio.TimeoutError):
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await asyncio.wait_for(fut, timeout)
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self.assertTrue(fut.done())
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# it should have been cancelled due to the timeout
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self.assertTrue(fut.cancelled())
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self.assertEqual(foo_running, False)
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async def test_wait_for(self):
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foo_running = None
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async def foo():
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nonlocal foo_running
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foo_running = True
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try:
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await asyncio.sleep(support.LONG_TIMEOUT)
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finally:
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foo_running = False
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return 'done'
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fut = asyncio.create_task(foo())
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with self.assertRaises(asyncio.TimeoutError):
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await asyncio.wait_for(fut, 0.1)
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self.assertTrue(fut.done())
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# it should have been cancelled due to the timeout
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self.assertTrue(fut.cancelled())
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self.assertEqual(foo_running, False)
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async def test_wait_for_blocking(self):
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async def coro():
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return 'done'
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res = await asyncio.wait_for(coro(), timeout=None)
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self.assertEqual(res, 'done')
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async def test_wait_for_race_condition(self):
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loop = asyncio.get_running_loop()
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fut = loop.create_future()
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task = asyncio.wait_for(fut, timeout=0.2)
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loop.call_soon(fut.set_result, "ok")
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res = await task
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self.assertEqual(res, "ok")
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async def test_wait_for_cancellation_race_condition(self):
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async def inner():
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with self.assertRaises(asyncio.CancelledError):
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await asyncio.sleep(1)
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return 1
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result = await asyncio.wait_for(inner(), timeout=.01)
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self.assertEqual(result, 1)
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async def test_wait_for_waits_for_task_cancellation(self):
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task_done = False
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async def inner():
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nonlocal task_done
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try:
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await asyncio.sleep(10)
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except asyncio.CancelledError:
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await asyncio.sleep(_EPSILON)
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raise
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finally:
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task_done = True
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inner_task = asyncio.create_task(inner())
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with self.assertRaises(asyncio.TimeoutError) as cm:
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await asyncio.wait_for(inner_task, timeout=_EPSILON)
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self.assertTrue(task_done)
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chained = cm.exception.__context__
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self.assertEqual(type(chained), asyncio.CancelledError)
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async def test_wait_for_waits_for_task_cancellation_w_timeout_0(self):
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task_done = False
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async def foo():
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async def inner():
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nonlocal task_done
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try:
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await asyncio.sleep(10)
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except asyncio.CancelledError:
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await asyncio.sleep(_EPSILON)
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raise
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finally:
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task_done = True
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inner_task = asyncio.create_task(inner())
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await asyncio.sleep(_EPSILON)
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await asyncio.wait_for(inner_task, timeout=0)
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with self.assertRaises(asyncio.TimeoutError) as cm:
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await foo()
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self.assertTrue(task_done)
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chained = cm.exception.__context__
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self.assertEqual(type(chained), asyncio.CancelledError)
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async def test_wait_for_reraises_exception_during_cancellation(self):
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class FooException(Exception):
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pass
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async def foo():
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async def inner():
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try:
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await asyncio.sleep(0.2)
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finally:
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raise FooException
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inner_task = asyncio.create_task(inner())
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await asyncio.wait_for(inner_task, timeout=_EPSILON)
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with self.assertRaises(FooException):
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await foo()
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async def _test_cancel_wait_for(self, timeout):
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loop = asyncio.get_running_loop()
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async def blocking_coroutine():
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fut = loop.create_future()
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# Block: fut result is never set
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await fut
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task = asyncio.create_task(blocking_coroutine())
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wait = asyncio.create_task(asyncio.wait_for(task, timeout))
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loop.call_soon(wait.cancel)
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with self.assertRaises(asyncio.CancelledError):
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await wait
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# Python issue #23219: cancelling the wait must also cancel the task
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self.assertTrue(task.cancelled())
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async def test_cancel_blocking_wait_for(self):
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await self._test_cancel_wait_for(None)
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async def test_cancel_wait_for(self):
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await self._test_cancel_wait_for(60.0)
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async def test_wait_for_cancel_suppressed(self):
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# GH-86296: Suppressing CancelledError is discouraged
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# but if a task suppresses CancelledError and returns a value,
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# `wait_for` should return the value instead of raising CancelledError.
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# This is the same behavior as `asyncio.timeout`.
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async def return_42():
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try:
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await asyncio.sleep(10)
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except asyncio.CancelledError:
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return 42
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res = await asyncio.wait_for(return_42(), timeout=0.1)
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self.assertEqual(res, 42)
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async def test_wait_for_issue86296(self):
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# GH-86296: The task should get cancelled and not run to completion.
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# inner completes in one cycle of the event loop so it
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# completes before the task is cancelled.
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async def inner():
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return 'done'
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inner_task = asyncio.create_task(inner())
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reached_end = False
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async def wait_for_coro():
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await asyncio.wait_for(inner_task, timeout=100)
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await asyncio.sleep(1)
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nonlocal reached_end
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reached_end = True
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task = asyncio.create_task(wait_for_coro())
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self.assertFalse(task.done())
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# Run the task
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await asyncio.sleep(0)
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task.cancel()
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with self.assertRaises(asyncio.CancelledError):
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await task
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self.assertTrue(inner_task.done())
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self.assertEqual(await inner_task, 'done')
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self.assertFalse(reached_end)
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class WaitForShieldTests(unittest.IsolatedAsyncioTestCase):
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async def test_zero_timeout(self):
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# `asyncio.shield` creates a new task which wraps the passed in
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# awaitable and shields it from cancellation so with timeout=0
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# the task returned by `asyncio.shield` aka shielded_task gets
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# cancelled immediately and the task wrapped by it is scheduled
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# to run.
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async def coro():
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await asyncio.sleep(0.01)
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return 'done'
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task = asyncio.create_task(coro())
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with self.assertRaises(asyncio.TimeoutError):
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shielded_task = asyncio.shield(task)
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await asyncio.wait_for(shielded_task, timeout=0)
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# Task is running in background
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self.assertFalse(task.done())
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self.assertFalse(task.cancelled())
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self.assertTrue(shielded_task.cancelled())
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# Wait for the task to complete
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await asyncio.sleep(0.1)
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self.assertTrue(task.done())
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async def test_none_timeout(self):
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# With timeout=None the timeout is disabled so it
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# runs till completion.
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async def coro():
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await asyncio.sleep(0.1)
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return 'done'
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task = asyncio.create_task(coro())
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await asyncio.wait_for(asyncio.shield(task), timeout=None)
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self.assertTrue(task.done())
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self.assertEqual(await task, "done")
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async def test_shielded_timeout(self):
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# shield prevents the task from being cancelled.
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async def coro():
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await asyncio.sleep(0.1)
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return 'done'
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task = asyncio.create_task(coro())
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with self.assertRaises(asyncio.TimeoutError):
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await asyncio.wait_for(asyncio.shield(task), timeout=0.01)
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self.assertFalse(task.done())
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self.assertFalse(task.cancelled())
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self.assertEqual(await task, "done")
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if __name__ == '__main__':
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unittest.main()
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