From 3a5de511596f17575de082dcb8d43d63b2bd2da9 Mon Sep 17 00:00:00 2001 From: Andrew Svetlov Date: Sat, 4 Jan 2020 11:10:14 +0200 Subject: Fix #39191: Don't spawn a task before failing (#17796) --- Lib/asyncio/base_events.py | 10 +++++++--- .../next/Library/2020-01-02-17-28-03.bpo-39191.ur_scy.rst | 3 +++ 2 files changed, 10 insertions(+), 3 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2020-01-02-17-28-03.bpo-39191.ur_scy.rst diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py index adcdec1..e53ca73 100644 --- a/Lib/asyncio/base_events.py +++ b/Lib/asyncio/base_events.py @@ -573,14 +573,17 @@ class BaseEventLoop(events.AbstractEventLoop): except Exception as ex: self.call_soon_threadsafe(future.set_exception, ex) - def run_forever(self): - """Run until stop() is called.""" - self._check_closed() + def _check_runnung(self): if self.is_running(): raise RuntimeError('This event loop is already running') if events._get_running_loop() is not None: raise RuntimeError( 'Cannot run the event loop while another loop is running') + + def run_forever(self): + """Run until stop() is called.""" + self._check_closed() + self._check_runnung() self._set_coroutine_origin_tracking(self._debug) self._thread_id = threading.get_ident() @@ -612,6 +615,7 @@ class BaseEventLoop(events.AbstractEventLoop): Return the Future's result, or raise its exception. """ self._check_closed() + self._check_runnung() new_task = not futures.isfuture(future) future = tasks.ensure_future(future, loop=self) diff --git a/Misc/NEWS.d/next/Library/2020-01-02-17-28-03.bpo-39191.ur_scy.rst b/Misc/NEWS.d/next/Library/2020-01-02-17-28-03.bpo-39191.ur_scy.rst new file mode 100644 index 0000000..138c93c --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-01-02-17-28-03.bpo-39191.ur_scy.rst @@ -0,0 +1,3 @@ +Perform a check for running loop before starting a new task in +``loop.run_until_complete()`` to fail fast; it prevents the side effect of +new task spawning before exception raising. -- cgit v0.12