https://docs.python.org/3.7/library/asyncio-task.html#running-tasks-concurrently

For asyncio.gather, the docs should probably say

The loop argument is deprecated and scheduled for removal in Python 3.10.

as they do for all the other loop arguments of other functions.

Hi,

Reading the asyncio.gather code not seem to be deprecrated.
loop is used on a lot of line of code. 

Maybe, the deprecate idea is on other place where I don't know.

Just to be clear, I don't know if loop is deprecated on this function like on all the others, I just suspect it to be. But it currently is completely undocumented, which either way is a bug. :)

@dtrauma jus for clarify. You say that if loop is not deprecated document it else document it.


Right?

Yes, exactly, document deprecation status XOR what it does :)

*Passing* loop to gather should be deprecated.

*Using* loop by *internal logic* is pretty fine, we do it in asyncio everywhere.

Yuri, I think we should deprecate explicit loop everywhere in non-deprecated asyncio API by Python 3.8.

We can do it even in Python beta I think.

> Yuri, I think we should deprecate explicit loop everywhere in non-deprecated asyncio API by Python 3.8.

+1

A champion is welcome :)

hello, I will work on it, if there are no objection. :-)

Thank you.

The change is pretty straightforward.

There is no need to jumbo PR, you can split the work into PR-per-module if it is more comfortable to you.

I'm ok with reviewing any approach.

Hi
> There is no need to jumbo PR, you can split the work into PR-per-module if it is more comfortable to you.
Yes, I think that is better split I will try it.
> I'm ok with reviewing any approach.
Thanks!

New changeset 6d64a8f49eb321116f585c4b036c81bb976d2d5c by Miss Islington (bot) (Emmanuel Arias) in branch 'master':
bpo-36373:  Deprecate explicit loop parameter in all public asyncio APIs [streams] (GH-13671)
https://github.com/python/cpython/commit/6d64a8f49eb321116f585c4b036c81bb976d2d5c

New changeset 8899b11b95f08e2e03478f2acad336ad5933a2d1 by Miss Islington (bot) in branch '3.8':
bpo-36373:  Deprecate explicit loop parameter in all public asyncio APIs [streams] (GH-13671)
https://github.com/python/cpython/commit/8899b11b95f08e2e03478f2acad336ad5933a2d1

New changeset 537877d85d1c27d2c2f5189e39da64a7a0c413d3 by Miss Islington (bot) (Emmanuel Arias) in branch 'master':
 bpo-36373: Deprecate explicit loop parameter in all public asyncio APIs [locks] (GH-13920)
https://github.com/python/cpython/commit/537877d85d1c27d2c2f5189e39da64a7a0c413d3

New changeset bb8fc8bd309419c159b632068dff73c3c76d478c by Miss Islington (bot) in branch '3.8':
bpo-36373: Deprecate explicit loop parameter in all public asyncio APIs [locks] (GH-13920)
https://github.com/python/cpython/commit/bb8fc8bd309419c159b632068dff73c3c76d478c

New changeset 9008be303a89bfab8c3314c6a42330b5523adc8b by Miss Islington (bot) (Emmanuel Arias) in branch 'master':
bpo-36373: Deprecate explicit loop parameter in all public asyncio APIs [queue] (GH-13950)
https://github.com/python/cpython/commit/9008be303a89bfab8c3314c6a42330b5523adc8b

New changeset 55daf1a56163e0673654712bb92ce47a9b6f7be3 by Miss Islington (bot) in branch '3.8':
bpo-36373: Deprecate explicit loop parameter in all public asyncio APIs [queue] (GH-13950)
https://github.com/python/cpython/commit/55daf1a56163e0673654712bb92ce47a9b6f7be3

async_case passes loop parameter to the queue used to collect tests and this causes below DeprecationWarning with last change over deprecation in queues and locks API.

./python.exe -m unittest Lib.unittest.test.test_async_case
/Users/karthikeyansingaravelan/stuff/python/cpython/Lib/unittest/async_case.py:116: DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.
  self._asyncioCallsQueue = asyncio.Queue(loop=loop)
/Users/karthikeyansingaravelan/stuff/python/cpython/Lib/asyncio/queues.py:48: DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.
  self._finished = locks.Event(loop=self._loop)
.......
----------------------------------------------------------------------
Ran 7 tests in 0.083s

OK

Few more tests and call sites

./python.exe -Wall -m test test_asyncio
Run tests sequentially
0:00:00 load avg: 2.41 [1/1] test_asyncio
/Users/karthikeyansingaravelan/stuff/python/cpython/Lib/asyncio/locks.py:335: DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.
  lock = Lock(loop=self._loop)
test_asyncio passed in 1 min 38 sec

== Tests result: SUCCESS ==

1 test OK.

Total duration: 1 min 38 sec
Tests result: SUCCESS

call sites 

>>> list(asyncio.tasks.as_completed([asyncio.ensure_future(asyncio.sleep(1))]))
/Users/karthikeyansingaravelan/stuff/python/cpython/Lib/asyncio/tasks.py:579: DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.
  done = Queue(loop=loop)
/Users/karthikeyansingaravelan/stuff/python/cpython/Lib/asyncio/queues.py:48: DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.
  self._finished = locks.Event(loop=self._loop)

Thanks for the report xtreak, I'll make a fix.

Is it okay to have _asyncio_internal keyword with default value as False and the places where it's used internally in stdlib like AsyncMock (Condition), async_case (Queue) and other tests we can pass in True? I have a patch if that would be a good approach :)

Better to avoid _asyncio_internal if not strictly necessary.
Currently, _asyncio_internal is used for protection of asyncio class direct instantiation.

E.g. stream = asyncio.Stream() is forbidden, people should use factories like stream = await asyncio.connect(...) for it.

Ah okay. There were places like Condition's constructor that has a deprecation warning and we construct a Lock with loop passed in the constructor and I passed along _asyncio_internal. I would be happy to look into your PR since mine is just passing along _asyncio_internal=True for all the stdlib calls.

I think it would be good if tests ran with warnings (at least DeprecationWarning and some class of warnings) as error but not sure why :(

(copying my GitHub message on this topic from https://github.com/python/cpython/pull/15889#issuecomment-530030002)


I thought we were going to be more subtle about this.

We have two scenarios:

1. Somebody creates an instance of asyncio.Lock outside of a coroutine, also manually creating the loop, etc. In this case the user has to pass the lock argument.

2. Somebody creates an instance of asyncio.Lock in a coroutine (that is, wheh asyncio.get_running_loop() returns a loop). In this case passing the loop argument is an error.

The (1) approach is how people were used to writing asyncio programs before asyncio.run() (that was the only way actually).

The (2) approach is how we want people to write asyncio programs.

There's a subtle difference between things like asyncio.gather() and asyncio.Lock. Passing loop to the former is just nonsensical. Passing loop to the latter can be a valid thing, it's the (1).

If we remove the loop parameter entirely from classes like asyncio.Lock we're making (1) impossible. I'm not sure that is what we are ready to do now.

@asvetlov thoughts?

Answered in https://github.com/python/cpython/pull/15889

New changeset 7264e92b718d307cc499b2f10eab7644b00f0499 by Miss Islington (bot) (Andrew Svetlov) in branch 'master':
bpo-36373: Fix deprecation warnings (GH-15889)
https://github.com/python/cpython/commit/7264e92b718d307cc499b2f10eab7644b00f0499

New changeset 4601f7a49fe8ed00c4b6b70b0eda2b3922568e9b by Andrew Svetlov in branch '3.8':
[3.8] bpo-36373: Fix deprecation warnings (GH-15889) (GH-15901)
https://github.com/python/cpython/commit/4601f7a49fe8ed00c4b6b70b0eda2b3922568e9b

New changeset a488879cbaf4b8b52699cadccf73bb4c271bcb29 by Andrew Svetlov in branch 'master':
bpo-36373: Deprecate explicit loop in task and subprocess API (GH-16033)
https://github.com/python/cpython/commit/a488879cbaf4b8b52699cadccf73bb4c271bcb29

New changeset 345bfc990f5f3e873774051d43136b06bfed82cb by Miss Islington (bot) in branch '3.8':
bpo-36373: Deprecate explicit loop in task and subprocess API (GH-16033)
https://github.com/python/cpython/commit/345bfc990f5f3e873774051d43136b06bfed82cb