From 3fae04b10e2655a20a3aadb5e0d63e87206d0c67 Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Tue, 6 Dec 2022 17:15:44 +0200 Subject: [3.11] gh-93453: Only emit deprecation warning in asyncio.get_event_loop when a new event loop is created (#99949) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It no longer emits a deprecation warning if the current event loop was set. Co-authored-by: Łukasz Langa --- Doc/library/asyncio-eventloop.rst | 22 +++++---- Doc/library/asyncio-llapi-index.rst | 2 +- Doc/library/asyncio-policy.rst | 5 ++ Lib/asyncio/events.py | 22 +++++++-- Lib/test/test_asyncio/test_base_events.py | 2 +- Lib/test/test_asyncio/test_events.py | 54 +++++++++------------ Lib/test/test_asyncio/test_futures.py | 24 ++++------ Lib/test/test_asyncio/test_streams.py | 24 ++++------ Lib/test/test_asyncio/test_tasks.py | 56 ++++++++-------------- Lib/test/test_asyncio/test_unix_events.py | 3 +- Lib/test/test_coroutines.py | 3 +- .../2022-12-02-13-05-00.gh-issue-93453.EFj1NN.rst | 3 ++ Modules/_asynciomodule.c | 12 ++--- 13 files changed, 109 insertions(+), 123 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2022-12-02-13-05-00.gh-issue-93453.EFj1NN.rst diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst index a10658d..28b7a90 100644 --- a/Doc/library/asyncio-eventloop.rst +++ b/Doc/library/asyncio-eventloop.rst @@ -43,10 +43,12 @@ an event loop: Get the current event loop. - If there is no current event loop set in the current OS thread, - the OS thread is main, and :func:`set_event_loop` has not yet - been called, asyncio will create a new event loop and set it as the - current one. + When called from a coroutine or a callback (e.g. scheduled with + call_soon or similar API), this function will always return the + running event loop. + + If there is no running event loop set, the function will return + the result of ``get_event_loop_policy().get_event_loop()`` call. Because this function has rather complex behavior (especially when custom event loop policies are in use), using the @@ -58,10 +60,14 @@ an event loop: event loop. .. deprecated:: 3.10 - Emits a deprecation warning if there is no running event loop. - In future Python releases, this function may become an alias of - :func:`get_running_loop` and will accordingly raise a - :exc:`RuntimeError` if there is no running event loop. + Deprecation warning is emitted if there is no current event loop. + In Python 3.12 it will be an error. + + .. note:: + In Python versions 3.10.0--3.10.8 and 3.11.0 this function + (and other functions which used it implicitly) emitted a + :exc:`DeprecationWarning` if there was no running event loop, even if + the current loop was set. .. function:: set_event_loop(loop) diff --git a/Doc/library/asyncio-llapi-index.rst b/Doc/library/asyncio-llapi-index.rst index b7ad888..9ce48a2 100644 --- a/Doc/library/asyncio-llapi-index.rst +++ b/Doc/library/asyncio-llapi-index.rst @@ -19,7 +19,7 @@ Obtaining the Event Loop - The **preferred** function to get the running event loop. * - :func:`asyncio.get_event_loop` - - Get an event loop instance (current or via the policy). + - Get an event loop instance (running or current via the current policy). * - :func:`asyncio.set_event_loop` - Set the event loop as current via the current policy. diff --git a/Doc/library/asyncio-policy.rst b/Doc/library/asyncio-policy.rst index bfc3e30..d0af45f 100644 --- a/Doc/library/asyncio-policy.rst +++ b/Doc/library/asyncio-policy.rst @@ -112,6 +112,11 @@ asyncio ships with the following built-in policies: On Windows, :class:`ProactorEventLoop` is now used by default. + .. deprecated:: 3.11.1 + :meth:`get_event_loop` now emits a :exc:`DeprecationWarning` if there + is no current event loop set and a new event loop has been implicitly + created. In Python 3.12 it will be an error. + .. class:: WindowsSelectorEventLoopPolicy diff --git a/Lib/asyncio/events.py b/Lib/asyncio/events.py index 0d26ea5..af3f9e9 100644 --- a/Lib/asyncio/events.py +++ b/Lib/asyncio/events.py @@ -671,6 +671,21 @@ class BaseDefaultEventLoopPolicy(AbstractEventLoopPolicy): if (self._local._loop is None and not self._local._set_called and threading.current_thread() is threading.main_thread()): + stacklevel = 2 + try: + f = sys._getframe(1) + except AttributeError: + pass + else: + while f: + module = f.f_globals.get('__name__') + if not (module == 'asyncio' or module.startswith('asyncio.')): + break + f = f.f_back + stacklevel += 1 + import warnings + warnings.warn('There is no current event loop', + DeprecationWarning, stacklevel=stacklevel) self.set_event_loop(self.new_event_loop()) if self._local._loop is None: @@ -786,12 +801,13 @@ def get_event_loop(): def _get_event_loop(stacklevel=3): + # This internal method is going away in Python 3.12, left here only for + # backwards compatibility with 3.10.0 - 3.10.8 and 3.11.0. + # Similarly, this method's C equivalent in _asyncio is going away as well. + # See GH-99949 for more details. current_loop = _get_running_loop() if current_loop is not None: return current_loop - import warnings - warnings.warn('There is no current event loop', - DeprecationWarning, stacklevel=stacklevel) return get_event_loop_policy().get_event_loop() diff --git a/Lib/test/test_asyncio/test_base_events.py b/Lib/test/test_asyncio/test_base_events.py index 063174a..6ba602d 100644 --- a/Lib/test/test_asyncio/test_base_events.py +++ b/Lib/test/test_asyncio/test_base_events.py @@ -746,7 +746,7 @@ class BaseEventLoopTests(test_utils.TestCase): def test_env_var_debug(self): code = '\n'.join(( 'import asyncio', - 'loop = asyncio.get_event_loop()', + 'loop = asyncio.new_event_loop()', 'print(loop.get_debug())')) # Test with -E to not fail if the unit test was run with diff --git a/Lib/test/test_asyncio/test_events.py b/Lib/test/test_asyncio/test_events.py index 05d9107..c431fea 100644 --- a/Lib/test/test_asyncio/test_events.py +++ b/Lib/test/test_asyncio/test_events.py @@ -2547,8 +2547,9 @@ class PolicyTests(unittest.TestCase): def test_get_event_loop(self): policy = asyncio.DefaultEventLoopPolicy() self.assertIsNone(policy._local._loop) - - loop = policy.get_event_loop() + with self.assertWarns(DeprecationWarning) as cm: + loop = policy.get_event_loop() + self.assertEqual(cm.filename, __file__) self.assertIsInstance(loop, asyncio.AbstractEventLoop) self.assertIs(policy._local._loop, loop) @@ -2562,7 +2563,10 @@ class PolicyTests(unittest.TestCase): policy, "set_event_loop", wraps=policy.set_event_loop) as m_set_event_loop: - loop = policy.get_event_loop() + with self.assertWarns(DeprecationWarning) as cm: + loop = policy.get_event_loop() + self.addCleanup(loop.close) + self.assertEqual(cm.filename, __file__) # policy._local._loop must be set through .set_event_loop() # (the unix DefaultEventLoopPolicy needs this call to attach @@ -2596,7 +2600,8 @@ class PolicyTests(unittest.TestCase): def test_set_event_loop(self): policy = asyncio.DefaultEventLoopPolicy() - old_loop = policy.get_event_loop() + old_loop = policy.new_event_loop() + policy.set_event_loop(old_loop) self.assertRaises(TypeError, policy.set_event_loop, object()) @@ -2709,15 +2714,11 @@ class GetEventLoopTestsMixin: asyncio.set_event_loop_policy(Policy()) loop = asyncio.new_event_loop() - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaises(TestError): - asyncio.get_event_loop() - self.assertEqual(cm.filename, __file__) + with self.assertRaises(TestError): + asyncio.get_event_loop() asyncio.set_event_loop(None) - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaises(TestError): - asyncio.get_event_loop() - self.assertEqual(cm.filename, __file__) + with self.assertRaises(TestError): + asyncio.get_event_loop() with self.assertRaisesRegex(RuntimeError, 'no running'): asyncio.get_running_loop() @@ -2731,16 +2732,11 @@ class GetEventLoopTestsMixin: loop.run_until_complete(func()) asyncio.set_event_loop(loop) - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaises(TestError): - asyncio.get_event_loop() - self.assertEqual(cm.filename, __file__) - + with self.assertRaises(TestError): + asyncio.get_event_loop() asyncio.set_event_loop(None) - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaises(TestError): - asyncio.get_event_loop() - self.assertEqual(cm.filename, __file__) + with self.assertRaises(TestError): + asyncio.get_event_loop() finally: asyncio.set_event_loop_policy(old_policy) @@ -2764,10 +2760,8 @@ class GetEventLoopTestsMixin: self.addCleanup(loop2.close) self.assertEqual(cm.filename, __file__) asyncio.set_event_loop(None) - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaisesRegex(RuntimeError, 'no current'): - asyncio.get_event_loop() - self.assertEqual(cm.filename, __file__) + with self.assertRaisesRegex(RuntimeError, 'no current'): + asyncio.get_event_loop() with self.assertRaisesRegex(RuntimeError, 'no running'): asyncio.get_running_loop() @@ -2781,15 +2775,11 @@ class GetEventLoopTestsMixin: loop.run_until_complete(func()) asyncio.set_event_loop(loop) - with self.assertWarns(DeprecationWarning) as cm: - self.assertIs(asyncio.get_event_loop(), loop) - self.assertEqual(cm.filename, __file__) + self.assertIs(asyncio.get_event_loop(), loop) asyncio.set_event_loop(None) - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaisesRegex(RuntimeError, 'no current'): - asyncio.get_event_loop() - self.assertEqual(cm.filename, __file__) + with self.assertRaisesRegex(RuntimeError, 'no current'): + asyncio.get_event_loop() finally: asyncio.set_event_loop_policy(old_policy) diff --git a/Lib/test/test_asyncio/test_futures.py b/Lib/test/test_asyncio/test_futures.py index f8fe2e7..987772e 100644 --- a/Lib/test/test_asyncio/test_futures.py +++ b/Lib/test/test_asyncio/test_futures.py @@ -145,10 +145,8 @@ class BaseFutureTests: self.assertTrue(f.cancelled()) def test_constructor_without_loop(self): - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaisesRegex(RuntimeError, 'There is no current event loop'): - self._new_future() - self.assertEqual(cm.filename, __file__) + with self.assertRaisesRegex(RuntimeError, 'no current event loop'): + self._new_future() def test_constructor_use_running_loop(self): async def test(): @@ -158,12 +156,10 @@ class BaseFutureTests: self.assertIs(f.get_loop(), self.loop) def test_constructor_use_global_loop(self): - # Deprecated in 3.10 + # Deprecated in 3.10, undeprecated in 3.11.1 asyncio.set_event_loop(self.loop) self.addCleanup(asyncio.set_event_loop, None) - with self.assertWarns(DeprecationWarning) as cm: - f = self._new_future() - self.assertEqual(cm.filename, __file__) + f = self._new_future() self.assertIs(f._loop, self.loop) self.assertIs(f.get_loop(), self.loop) @@ -499,10 +495,8 @@ class BaseFutureTests: return (arg, threading.get_ident()) ex = concurrent.futures.ThreadPoolExecutor(1) f1 = ex.submit(run, 'oi') - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaises(RuntimeError): - asyncio.wrap_future(f1) - self.assertEqual(cm.filename, __file__) + with self.assertRaisesRegex(RuntimeError, 'no current event loop'): + asyncio.wrap_future(f1) ex.shutdown(wait=True) def test_wrap_future_use_running_loop(self): @@ -517,16 +511,14 @@ class BaseFutureTests: ex.shutdown(wait=True) def test_wrap_future_use_global_loop(self): - # Deprecated in 3.10 + # Deprecated in 3.10, undeprecated in 3.11.1 asyncio.set_event_loop(self.loop) self.addCleanup(asyncio.set_event_loop, None) def run(arg): return (arg, threading.get_ident()) ex = concurrent.futures.ThreadPoolExecutor(1) f1 = ex.submit(run, 'oi') - with self.assertWarns(DeprecationWarning) as cm: - f2 = asyncio.wrap_future(f1) - self.assertEqual(cm.filename, __file__) + f2 = asyncio.wrap_future(f1) self.assertIs(self.loop, f2._loop) ex.shutdown(wait=True) diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py index 0c49099..95fc7a1 100644 --- a/Lib/test/test_asyncio/test_streams.py +++ b/Lib/test/test_asyncio/test_streams.py @@ -810,10 +810,8 @@ os.close(fd) self.assertEqual(data, b'data') def test_streamreader_constructor_without_loop(self): - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaisesRegex(RuntimeError, 'There is no current event loop'): - asyncio.StreamReader() - self.assertEqual(cm.filename, __file__) + with self.assertRaisesRegex(RuntimeError, 'no current event loop'): + asyncio.StreamReader() def test_streamreader_constructor_use_running_loop(self): # asyncio issue #184: Ensure that StreamReaderProtocol constructor @@ -827,21 +825,17 @@ os.close(fd) def test_streamreader_constructor_use_global_loop(self): # asyncio issue #184: Ensure that StreamReaderProtocol constructor # retrieves the current loop if the loop parameter is not set - # Deprecated in 3.10 + # Deprecated in 3.10, undeprecated in 3.11.1 self.addCleanup(asyncio.set_event_loop, None) asyncio.set_event_loop(self.loop) - with self.assertWarns(DeprecationWarning) as cm: - reader = asyncio.StreamReader() - self.assertEqual(cm.filename, __file__) + reader = asyncio.StreamReader() self.assertIs(reader._loop, self.loop) def test_streamreaderprotocol_constructor_without_loop(self): reader = mock.Mock() - with self.assertWarns(DeprecationWarning) as cm: - with self.assertRaisesRegex(RuntimeError, 'There is no current event loop'): - asyncio.StreamReaderProtocol(reader) - self.assertEqual(cm.filename, __file__) + with self.assertRaisesRegex(RuntimeError, 'no current event loop'): + asyncio.StreamReaderProtocol(reader) def test_streamreaderprotocol_constructor_use_running_loop(self): # asyncio issue #184: Ensure that StreamReaderProtocol constructor @@ -855,13 +849,11 @@ os.close(fd) def test_streamreaderprotocol_constructor_use_global_loop(self): # asyncio issue #184: Ensure that StreamReaderProtocol constructor # retrieves the current loop if the loop parameter is not set - # Deprecated in 3.10 + # Deprecated in 3.10, undeprecated in 3.11.1 self.addCleanup(asyncio.set_event_loop, None) asyncio.set_event_loop(self.loop) reader = mock.Mock() - with self.assertWarns(DeprecationWarning) as cm: - protocol = asyncio.StreamReaderProtocol(reader) - self.assertEqual(cm.filename, __file__) + protocol = asyncio.StreamReaderProtocol(reader) self.assertIs(protocol._loop, self.loop) def test_multiple_drain(self): diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py index 6b875cf..9900e30 100644 --- a/Lib/test/test_asyncio/test_tasks.py +++ b/Lib/test/test_asyncio/test_tasks.py @@ -200,10 +200,8 @@ 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()) @@ -213,12 +211,10 @@ class BaseTaskTests: self.assertTrue(t.done()) self.assertEqual(t.result(), 'ok') - # Deprecated in 3.10 + # Deprecated in 3.10, undeprecated in 3.11.1 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()) @@ -1536,10 +1532,8 @@ 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() @@ -1969,10 +1963,8 @@ 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(): @@ -1986,15 +1978,13 @@ class BaseTaskTests: self.assertEqual(res, 42) def test_shield_coroutine_use_global_loop(self): - # Deprecated in 3.10 + # Deprecated in 3.10, undeprecated in 3.11.1 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) @@ -2820,7 +2810,7 @@ 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): @@ -2984,10 +2974,8 @@ 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(): @@ -3000,12 +2988,10 @@ 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 3.11.1 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) @@ -3093,10 +3079,8 @@ 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(): @@ -3110,16 +3094,14 @@ 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 3.11.1 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) diff --git a/Lib/test/test_asyncio/test_unix_events.py b/Lib/test/test_asyncio/test_unix_events.py index 1d92278..01c1214 100644 --- a/Lib/test/test_asyncio/test_unix_events.py +++ b/Lib/test/test_asyncio/test_unix_events.py @@ -1740,7 +1740,8 @@ class PolicyTests(unittest.TestCase): def test_child_watcher_replace_mainloop_existing(self): policy = self.create_policy() - loop = policy.get_event_loop() + loop = policy.new_event_loop() + policy.set_event_loop(loop) # Explicitly setup SafeChildWatcher, # default ThreadedChildWatcher has no _loop property diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py index a15736e..10f1a9e 100644 --- a/Lib/test/test_coroutines.py +++ b/Lib/test/test_coroutines.py @@ -2411,7 +2411,8 @@ class UnawaitedWarningDuringShutdownTest(unittest.TestCase): def test_unawaited_warning_during_shutdown(self): code = ("import asyncio\n" "async def f(): pass\n" - "asyncio.gather(f())\n") + "async def t(): asyncio.gather(f())\n" + "asyncio.run(t())\n") assert_python_ok("-c", code) code = ("import sys\n" diff --git a/Misc/NEWS.d/next/Library/2022-12-02-13-05-00.gh-issue-93453.EFj1NN.rst b/Misc/NEWS.d/next/Library/2022-12-02-13-05-00.gh-issue-93453.EFj1NN.rst new file mode 100644 index 0000000..dd4f433 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2022-12-02-13-05-00.gh-issue-93453.EFj1NN.rst @@ -0,0 +1,3 @@ +:func:`asyncio.get_event_loop` now only emits a deprecation warning when a +new event loop was created implicitly. It no longer emits a deprecation +warning if the current event loop was set. diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c index d503018..40f1f80 100644 --- a/Modules/_asynciomodule.c +++ b/Modules/_asynciomodule.c @@ -339,13 +339,6 @@ get_event_loop(int stacklevel) return loop; } - if (PyErr_WarnEx(PyExc_DeprecationWarning, - "There is no current event loop", - stacklevel)) - { - return NULL; - } - policy = PyObject_CallNoArgs(asyncio_get_event_loop_policy); if (policy == NULL) { return NULL; @@ -3129,6 +3122,11 @@ _asyncio_get_event_loop_impl(PyObject *module) return get_event_loop(1); } +// This internal method is going away in Python 3.12, left here only for +// backwards compatibility with 3.10.0 - 3.10.8 and 3.11.0. +// Similarly, this method's Python equivalent in asyncio.events is going +// away as well. +// See GH-99949 for more details. /*[clinic input] _asyncio._get_event_loop stacklevel: int = 3 -- cgit v0.12