[issue36607] asyncio.all_tasks() crashes if asyncio is used in multiple threads

[Nick Davies]

Nick Davies <python at nicolasdavies.com.au> added the comment:

My preference would actually be number 3 because:

 1: I agree that this isn't really a safe option because it could slow things down (possibly a lot)
 2: I haven't found this to be rare in my situation but I am not sure how common my setup is. We have a threaded server with a mix of sync and asyncio so we use run in a bunch of places inside threads. Any time the server gets busy any task creation that occurs during the return of run crashes. My two main reservations about this approach are:
    - There is a potentially unbounded number of times that this could need to retry.
    - Also this is covering up a thread unsafe operation and we are pretty lucky based on the current implementation that it explodes in a consistent and sane way that we can catch and retry.
 3: Loop is already expected to be hashable in 3.7 as far as I can tell (https://github.com/python/cpython/blob/3.7/Lib/asyncio/tasks.py#L822) so other than the slightly higher complexity this feels like the cleanest solution.


> The fix can be applied to 3.7 and 3.8 only, sorry. Python 3.6 is in security mode now.

Thats fine, you can work around the issue using asyncio.set_task_factory to something that tracks the tasks per loop with some care.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue36607>
_______________________________________