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Code Issues Projects Releases Packages Wiki Activity Actions 9

gh-93453: No longer create an event loop in get_event_loop() (#98440)

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asyncio.get_event_loop() now always return either running event loop or
the result of get_event_loop_policy().get_event_loop() call. The latter
should now raise an RuntimeError if no current event loop was set
instead of creating and setting a new event loop.

It affects also a number of asyncio functions and constructors which
call get_event_loop() implicitly: ensure_future(), shield(), gather(),
etc.

DeprecationWarning is no longer emitted if there is no running event loop but
the current event loop was set.

Co-authored-by: Łukasz Langa <lukasz@langa.pl>
This commit is contained in:
Serhiy Storchaka 2022-12-06 19:42:12 +02:00 • committed by GitHub
parent b72014c783
commit fd38a2f0ec
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GPG key ID: 4AEE18F83AFDEB23
18 changed files with 114 additions and 251 deletions
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56
Lib/test/test_asyncio/test_tasks.py
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@ -196,10 +196,8 @@ class BaseTaskTests:
a = notmuch()
self.addCleanup(a.close)
with self.assertWarns(DeprecationWarning) as cm:
with self.assertRaisesRegex(RuntimeError, 'There is no current event loop'):
asyncio.ensure_future(a)
self.assertEqual(cm.filename, __file__)
with self.assertRaisesRegex(RuntimeError, 'no current event loop'):
asyncio.ensure_future(a)
async def test():
return asyncio.ensure_future(notmuch())
@ -209,12 +207,10 @@ class BaseTaskTests:
self.assertTrue(t.done())
self.assertEqual(t.result(), 'ok')
# Deprecated in 3.10
# Deprecated in 3.10, undeprecated in 3.12
asyncio.set_event_loop(self.loop)
self.addCleanup(asyncio.set_event_loop, None)
with self.assertWarns(DeprecationWarning) as cm:
t = asyncio.ensure_future(notmuch())
self.assertEqual(cm.filename, __file__)
t = asyncio.ensure_future(notmuch())
self.assertIs(t._loop, self.loop)
self.loop.run_until_complete(t)
self.assertTrue(t.done())
@ -1532,10 +1528,8 @@ class BaseTaskTests:
self.addCleanup(a.close)
futs = asyncio.as_completed([a])
with self.assertWarns(DeprecationWarning) as cm:
with self.assertRaisesRegex(RuntimeError, 'There is no current event loop'):
list(futs)
self.assertEqual(cm.filename, __file__)
with self.assertRaisesRegex(RuntimeError, 'no current event loop'):
list(futs)
def test_as_completed_coroutine_use_running_loop(self):
loop = self.new_test_loop()
@ -1965,10 +1959,8 @@ class BaseTaskTests:
inner = coro()
self.addCleanup(inner.close)
with self.assertWarns(DeprecationWarning) as cm:
with self.assertRaisesRegex(RuntimeError, 'There is no current event loop'):
asyncio.shield(inner)
self.assertEqual(cm.filename, __file__)
with self.assertRaisesRegex(RuntimeError, 'no current event loop'):
asyncio.shield(inner)
def test_shield_coroutine_use_running_loop(self):
async def coro():
@ -1982,15 +1974,13 @@ class BaseTaskTests:
self.assertEqual(res, 42)
def test_shield_coroutine_use_global_loop(self):
# Deprecated in 3.10
# Deprecated in 3.10, undeprecated in 3.12
async def coro():
return 42
asyncio.set_event_loop(self.loop)
self.addCleanup(asyncio.set_event_loop, None)
with self.assertWarns(DeprecationWarning) as cm:
outer = asyncio.shield(coro())
self.assertEqual(cm.filename, __file__)
outer = asyncio.shield(coro())
self.assertEqual(outer._loop, self.loop)
res = self.loop.run_until_complete(outer)
self.assertEqual(res, 42)
@ -2827,7 +2817,7 @@ class BaseCurrentLoopTests:
self.assertIsNone(asyncio.current_task(loop=self.loop))
def test_current_task_no_running_loop_implicit(self):
with self.assertRaises(RuntimeError):
with self.assertRaisesRegex(RuntimeError, 'no running event loop'):
asyncio.current_task()
def test_current_task_with_implicit_loop(self):
@ -2991,10 +2981,8 @@ class FutureGatherTests(GatherTestsBase, test_utils.TestCase):
return asyncio.gather(*args, **kwargs)
def test_constructor_empty_sequence_without_loop(self):
with self.assertWarns(DeprecationWarning) as cm:
with self.assertRaises(RuntimeError):
asyncio.gather()
self.assertEqual(cm.filename, __file__)
with self.assertRaisesRegex(RuntimeError, 'no current event loop'):
asyncio.gather()
def test_constructor_empty_sequence_use_running_loop(self):
async def gather():
@ -3007,12 +2995,10 @@ class FutureGatherTests(GatherTestsBase, test_utils.TestCase):
self.assertEqual(fut.result(), [])
def test_constructor_empty_sequence_use_global_loop(self):
# Deprecated in 3.10
# Deprecated in 3.10, undeprecated in 3.12
asyncio.set_event_loop(self.one_loop)
self.addCleanup(asyncio.set_event_loop, None)
with self.assertWarns(DeprecationWarning) as cm:
fut = asyncio.gather()
self.assertEqual(cm.filename, __file__)
fut = asyncio.gather()
self.assertIsInstance(fut, asyncio.Future)
self.assertIs(fut._loop, self.one_loop)
self._run_loop(self.one_loop)
@ -3100,10 +3086,8 @@ class CoroutineGatherTests(GatherTestsBase, test_utils.TestCase):
self.addCleanup(gen1.close)
gen2 = coro()
self.addCleanup(gen2.close)
with self.assertWarns(DeprecationWarning) as cm:
with self.assertRaises(RuntimeError):
asyncio.gather(gen1, gen2)
self.assertEqual(cm.filename, __file__)
with self.assertRaisesRegex(RuntimeError, 'no current event loop'):
asyncio.gather(gen1, gen2)
def test_constructor_use_running_loop(self):
async def coro():
@ -3117,16 +3101,14 @@ class CoroutineGatherTests(GatherTestsBase, test_utils.TestCase):
self.one_loop.run_until_complete(fut)
def test_constructor_use_global_loop(self):
# Deprecated in 3.10
# Deprecated in 3.10, undeprecated in 3.12
async def coro():
return 'abc'
asyncio.set_event_loop(self.other_loop)
self.addCleanup(asyncio.set_event_loop, None)
gen1 = coro()
gen2 = coro()
with self.assertWarns(DeprecationWarning) as cm:
fut = asyncio.gather(gen1, gen2)
self.assertEqual(cm.filename, __file__)
fut = asyncio.gather(gen1, gen2)
self.assertIs(fut._loop, self.other_loop)
self.other_loop.run_until_complete(fut)