# # Originally vendored from https://github.com/erdewit/nest_asyncio # # BSD 2-Clause License # Copyright (c) 2025 Ritchie Vink # Copyright (c) 2018-2020, Ewald de Wit # All rights reserved. # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are met: # * Redistributions of source code must retain the above copyright notice, this # list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above copyright notice, # this list of conditions and the following disclaimer in the documentation # and/or other materials provided with the distribution. # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. # Ignore all lints, file is currently copied. # ruff: noqa # type: ignore """Patch asyncio to allow nested event loops.""" import asyncio import asyncio.events as events import os import sys import threading from contextlib import contextmanager, suppress from heapq import heappop def apply(loop=None): """Patch asyncio to make its event loop reentrant.""" _patch_asyncio() _patch_policy() _patch_tornado() loop = loop or asyncio.get_event_loop() _patch_loop(loop) def _patch_asyncio(): """Patch asyncio module to use pure Python tasks and futures.""" def run(main, *, debug=False): loop = asyncio.get_event_loop() loop.set_debug(debug) task = asyncio.ensure_future(main) try: return loop.run_until_complete(task) finally: if not task.done(): task.cancel() with suppress(asyncio.CancelledError): loop.run_until_complete(task) def _get_event_loop(stacklevel=3): loop = events._get_running_loop() if loop is None: loop = events.get_event_loop_policy().get_event_loop() return loop # Use module level _current_tasks, all_tasks and patch run method. if hasattr(asyncio, "_nest_patched"): return if sys.version_info >= (3, 6, 0): asyncio.Task = asyncio.tasks._CTask = asyncio.tasks.Task = asyncio.tasks._PyTask asyncio.Future = asyncio.futures._CFuture = asyncio.futures.Future = ( asyncio.futures._PyFuture ) if sys.version_info < (3, 7, 0): asyncio.tasks._current_tasks = asyncio.tasks.Task._current_tasks asyncio.all_tasks = asyncio.tasks.Task.all_tasks if sys.version_info >= (3, 9, 0): events._get_event_loop = events.get_event_loop = asyncio.get_event_loop = ( _get_event_loop ) asyncio.run = run asyncio._nest_patched = True def _patch_policy(): """Patch the policy to always return a patched loop.""" def get_event_loop(self): if self._local._loop is None: loop = self.new_event_loop() _patch_loop(loop) self.set_event_loop(loop) return self._local._loop policy = events.get_event_loop_policy() policy.__class__.get_event_loop = get_event_loop def _patch_loop(loop): """Patch loop to make it reentrant.""" def run_forever(self): with manage_run(self), manage_asyncgens(self): while True: self._run_once() if self._stopping: break self._stopping = False def run_until_complete(self, future): with manage_run(self): f = asyncio.ensure_future(future, loop=self) if f is not future: f._log_destroy_pending = False while not f.done(): self._run_once() if self._stopping: break if not f.done(): raise RuntimeError("Event loop stopped before Future completed.") return f.result() def _run_once(self): """ Simplified re-implementation of asyncio's _run_once that runs handles as they become ready. """ ready = self._ready scheduled = self._scheduled while scheduled and scheduled[0]._cancelled: heappop(scheduled) timeout = ( 0 if ready or self._stopping else min(max(scheduled[0]._when - self.time(), 0), 86400) if scheduled else None ) event_list = self._selector.select(timeout) self._process_events(event_list) end_time = self.time() + self._clock_resolution while scheduled and scheduled[0]._when < end_time: handle = heappop(scheduled) ready.append(handle) for _ in range(len(ready)): if not ready: break handle = ready.popleft() if not handle._cancelled: # preempt the current task so that that checks in # Task.__step do not raise curr_task = curr_tasks.pop(self, None) try: handle._run() finally: # restore the current task if curr_task is not None: curr_tasks[self] = curr_task handle = None @contextmanager def manage_run(self): """Set up the loop for running.""" self._check_closed() old_thread_id = self._thread_id old_running_loop = events._get_running_loop() try: self._thread_id = threading.get_ident() events._set_running_loop(self) self._num_runs_pending += 1 if self._is_proactorloop: if self._self_reading_future is None: self.call_soon(self._loop_self_reading) yield finally: self._thread_id = old_thread_id events._set_running_loop(old_running_loop) self._num_runs_pending -= 1 if self._is_proactorloop: if ( self._num_runs_pending == 0 and self._self_reading_future is not None ): ov = self._self_reading_future._ov self._self_reading_future.cancel() if ov is not None: self._proactor._unregister(ov) self._self_reading_future = None @contextmanager def manage_asyncgens(self): if not hasattr(sys, "get_asyncgen_hooks"): # Python version is too old. return old_agen_hooks = sys.get_asyncgen_hooks() try: self._set_coroutine_origin_tracking(self._debug) if self._asyncgens is not None: sys.set_asyncgen_hooks( firstiter=self._asyncgen_firstiter_hook, finalizer=self._asyncgen_finalizer_hook, ) yield finally: self._set_coroutine_origin_tracking(False) if self._asyncgens is not None: sys.set_asyncgen_hooks(*old_agen_hooks) def _check_running(self): """Do not throw exception if loop is already running.""" pass if hasattr(loop, "_nest_patched"): return if not isinstance(loop, asyncio.BaseEventLoop): raise ValueError("Can't patch loop of type %s" % type(loop)) cls = loop.__class__ cls.run_forever = run_forever cls.run_until_complete = run_until_complete cls._run_once = _run_once cls._check_running = _check_running cls._check_runnung = _check_running # typo in Python 3.7 source cls._num_runs_pending = 1 if loop.is_running() else 0 cls._is_proactorloop = os.name == "nt" and issubclass( cls, asyncio.ProactorEventLoop ) if sys.version_info < (3, 7, 0): cls._set_coroutine_origin_tracking = cls._set_coroutine_wrapper curr_tasks = ( asyncio.tasks._current_tasks if sys.version_info >= (3, 7, 0) else asyncio.Task._current_tasks ) cls._nest_patched = True def _patch_tornado(): """ If tornado is imported before nest_asyncio, make tornado aware of the pure-Python asyncio Future. """ if "tornado" in sys.modules: import tornado.concurrent as tc # type: ignore tc.Future = asyncio.Future if asyncio.Future not in tc.FUTURES: tc.FUTURES += (asyncio.Future,)