[issue21326] asyncio: request clearer error message when event loop closed
STINNER Victor added the comment: The initial issue is now fixed, thanks for the report Mark Dickinson. -- resolution: - fixed status: open - closed ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Roundup Robot added the comment: New changeset 7912179335cc by Victor Stinner in branch '3.4': Issue #21326: Add a new is_closed() method to asyncio.BaseEventLoop http://hg.python.org/cpython/rev/7912179335cc -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
STINNER Victor added the comment: This issue was discussed on the python-dev mailing list. The conclusion is that adding a new method to asyncio is safe because asyncio has a provisional API (whereas the selectors module doesn't). Ok, Python 3.4.2 will have the new method BaseEventLoop.is_closed(), that's all. -- versions: +Python 3.4 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Changes by Giampaolo Rodola' g.rod...@gmail.com: -- components: +Asyncio ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Guido van Rossum added the comment: I don't want the 3.4 and 3.5 versions of asyncio to be different. You should just copy the 3.5 code back into the 3.4 tree. A new method is fine. Really. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Roundup Robot added the comment: New changeset 690b6ddeee9c by Victor Stinner in branch 'default': Issue #21326: Add asyncio.BaseEventLoop.is_closed() method http://hg.python.org/cpython/rev/690b6ddeee9c -- nosy: +python-dev ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
STINNER Victor added the comment: I fixed the issue in Python 3.5 by adding a new BaseEventLoop.is_closed() method. Calling run_forever() or run_until_complete() now raises an error. I don't know yet if this issue should be fixed in Python 3.4. If it should be fixed, I don't know how it should be fixed. Guido was unhappy with subclasses of BaseEventLoop accessing the private attribute BaseEventLoop._closed in the review of my patch. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Changes by Yury Selivanov yselivanov...@gmail.com: -- nosy: +yselivanov ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
STINNER Victor added the comment: Attached asyncio_closed_py34.patch: minimum patch to fix this issue. run_forever() and run_until_complete() raises a RuntimeError if the event loop was closed. The patch only uses the private attribute BaseEventLoop._closed in the BaseEventLoop class, not outside. -- keywords: +patch Added file: http://bugs.python.org/file35474/asyncio_closed_py34.patch ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
STINNER Victor added the comment: I proposed a patch upstream (in Tulip) to solve this issue: http://code.google.com/p/tulip/issues/detail?id=169 -- nosy: +haypo ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
New submission from Mark Dickinson: In the new asyncio library, it's easy for newbies (like me) to accidentally try to run a coroutine on a closed event loop. Doing so leads to a rather inscrutable exception and traceback: loop.run_until_complete(compute()) Traceback (most recent call last): File stdin, line 1, in module File /opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py, line 203, in run_until_complete self.run_forever() File /opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py, line 184, in run_forever self._run_once() File /opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py, line 778, in _run_once event_list = self._selector.select(timeout) AttributeError: 'NoneType' object has no attribute 'select' Is it possible to replace this with something clearer? For example, something like: RuntimeError(Can't schedule coroutine on closed event loop.) Here's the full code snippet: Python 3.4.0 (default, Mar 25 2014, 11:07:05) [GCC 4.2.1 Compatible Apple LLVM 5.1 (clang-503.0.38)] on darwin Type help, copyright, credits or license for more information. import asyncio @asyncio.coroutine ... def compute(): ... print(Starting computation) ... yield from asyncio.sleep(2.0) ... print(Complete) ... loop = asyncio.get_event_loop() loop.run_until_complete(compute()) Starting computation Complete loop.close() # whoops # some time later ... loop = asyncio.get_event_loop() loop.run_until_complete(compute()) Traceback (most recent call last): File stdin, line 1, in module File /opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py, line 203, in run_until_complete self.run_forever() File /opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py, line 184, in run_forever self._run_once() File /opt/local/Library/Frameworks/Python.framework/Versions/3.4/lib/python3.4/asyncio/base_events.py, line 778, in _run_once event_list = self._selector.select(timeout) AttributeError: 'NoneType' object has no attribute 'select' -- components: Library (Lib) messages: 216994 nosy: gvanrossum, mark.dickinson priority: normal severity: normal stage: needs patch status: open title: asyncio: request clearer error message when event loop closed type: enhancement versions: Python 3.5 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Guido van Rossum added the comment: Hm, I've never hear from someone who did this before. It might be easy to fix, but it would be ugly too (every EventLoop method would have to check this), and not very useful (you'll only make this mistake once in your life). How much time did you waste debugging this? Maybe we can just change repr(loop) to make it clear that it's closed? -- priority: normal - low ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Mark Dickinson added the comment: Maybe we can just change repr(loop) to make it clear that it's closed? That sounds good to me. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue21326] asyncio: request clearer error message when event loop closed
Mark Dickinson added the comment: How much time did you waste debugging this? Not much: less than 5 minutes. While I *probably* won't make this mistake again (though I'm not going to make any promises on that front), it would be nice to prevent other people from doing so. More info: I got to the issue by randomly pasting examples from the asyncio docs, one of which had a `.close` call in, without taking the time to read and understand those docs properly first - I was keen to get to the coroutine part of it and didn't want to spend time on the event loop details. Without having thought about it, I wasn't expecting the result of `get_event_loop` to be a singleton; once I figured that bit out it was clear what was going on. So yes, stupidity on my part. I'd like to bet that I won't be the only person who runs into this, though. -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue21326 ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
