Add documentation.

python · serhiy-storchaka · Apr 25, 2021 · Nov 28, 2020 · Nov 30, 2020 · Dec 6, 2020
commit b717f71a4a9c2d6cd99656ca708f24b7c1b094c0
diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
@@ -53,6 +53,11 @@ an event loop:
    Consider also using the :func:`asyncio.run` function instead of using
    lower level functions to manually create and close an event loop.
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if there is no running event loop.
+      If future Python releases this function will be an alias of
+      :func:`get_running_loop`.
+
 .. function:: set_event_loop(loop)
 
    Set *loop* as a current event loop for the current OS thread.

diff --git a/Doc/library/asyncio-future.rst b/Doc/library/asyncio-future.rst
@@ -57,12 +57,20 @@ Future Functions
    .. versionchanged:: 3.5.1
       The function accepts any :term:`awaitable` object.
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if *obj* is not a Future-like object
+      and *loop* is not specified and there is no running event loop.
+
 
 .. function:: wrap_future(future, \*, loop=None)
 
    Wrap a :class:`concurrent.futures.Future` object in a
    :class:`asyncio.Future` object.
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if *future* is not a Future-like object
+      and *loop* is not specified and there is no running event loop.
+
 
 Future Object
 =============
@@ -90,6 +98,10 @@ Future Object
    .. versionchanged:: 3.7
       Added support for the :mod:`contextvars` module.
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if *loop* is not specified
+      and there is no running event loop.
+
    .. method:: result()
 
       Return the result of the Future.

diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
@@ -393,6 +393,11 @@ Running Tasks Concurrently
       If the *gather* itself is cancelled, the cancellation is
       propagated regardless of *return_exceptions*.
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if no positional arguments are provided
+      or not all positional arguments are Future-like objects
+      and there is no running event loop.
+
 
 Shielding From Cancellation
 ===========================
@@ -430,6 +435,10 @@ Shielding From Cancellation
        except CancelledError:
            res = None
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if *aw* is not Future-like object
+      and there is no running event loop.
+
 
 Timeouts
 ========
@@ -589,6 +598,10 @@ Waiting Primitives
            earliest_result = await coro
            # ...
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if not all awaitable objects in the *aws*
+      iterable are Future-like objects and there is no running event loop.
+
 
 Running in Threads
 ==================
@@ -771,6 +784,10 @@ Task Object
    .. deprecated-removed:: 3.8 3.10
       The *loop* parameter.
 
+   .. deprecated:: 3.10
+      Deprecation warning is emitted if *loop* is not specified
+      and there is no running event loop.
+
    .. method:: cancel(msg=None)
 
       Request the Task to be cancelled.

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
@@ -442,6 +442,19 @@ Deprecated
   scheduled for removal in Python 3.12.
   (Contributed by Erlend E. Aasland in :issue:`42264`.)
 
+* :func:`asyncio.get_event_loop` emits now a deprecation warning if there is
+  no running event loop. In future it will be an alias of
+  :func:`~asyncio.get_running_loop`.
+  :mod:`asyncio` functions which implicitly create a :class:`~asyncio.Future`
+  or :class:`~asyncio.Task` objects emit now
+  a deprecation warning if there is no running event loop and no explicit
+  *loop* argument is passed: :func:`~asyncio.ensure_future`,
+  :func:`~asyncio.wrap_future`, :func:`~asyncio.gather`,
+  :func:`~asyncio.shield`, :func:`~asyncio.as_completed` and constructors of
+  :class:`~asyncio.Future`, :class:`~asyncio.Task`,
+  :class:`~asyncio.StreamReader`, :class:`~asyncio.StreamReaderProtocol`.
+  (Contributed by Serhiy Storchaka in :issue:`39529`.)
+
 
 Removed
 =======

diff --git a/Misc/NEWS.d/next/Library/2020-12-06-20-21-16.bpo-39529.9Zrg43.rst b/Misc/NEWS.d/next/Library/2020-12-06-20-21-16.bpo-39529.9Zrg43.rst
@@ -0,0 +1,9 @@
+Deprecated use of :func:`asyncio.get_event_loop` without running event loop.
+Emit deprecation warning for :mod:`asyncio` functions which implicitly
+create a :class:`~asyncio.Future` or :class:`~asyncio.Task` objects if there
+is no running event loop and no explicit *loop* argument is passed:
+:func:`~asyncio.ensure_future`, :func:`~asyncio.wrap_future`,
+:func:`~asyncio.gather`, :func:`~asyncio.shield`,
+:func:`~asyncio.as_completed` and constructors of :class:`~asyncio.Future`,
+:class:`~asyncio.Task`, :class:`~asyncio.StreamReader`,
+:class:`~asyncio.StreamReaderProtocol`.