bpo-31709: Drop support for asynchronous __aiter__. (#3903)
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index 31a7671..153b58b 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -2520,9 +2520,8 @@
Asynchronous Iterators
----------------------
-An *asynchronous iterable* is able to call asynchronous code in its
-``__aiter__`` implementation, and an *asynchronous iterator* can call
-asynchronous code in its ``__anext__`` method.
+An *asynchronous iterator* can call asynchronous code in
+its ``__anext__`` method.
Asynchronous iterators can be used in an :keyword:`async for` statement.
@@ -2552,48 +2551,14 @@
.. versionadded:: 3.5
-.. note::
+.. versionchanged:: 3.7
+ Prior to Python 3.7, ``__aiter__`` could return an *awaitable*
+ that would resolve to an
+ :term:`asynchronous iterator <asynchronous iterator>`.
- .. versionchanged:: 3.5.2
- Starting with CPython 3.5.2, ``__aiter__`` can directly return
- :term:`asynchronous iterators <asynchronous iterator>`. Returning
- an :term:`awaitable` object will result in a
- :exc:`PendingDeprecationWarning`.
-
- The recommended way of writing backwards compatible code in
- CPython 3.5.x is to continue returning awaitables from
- ``__aiter__``. If you want to avoid the PendingDeprecationWarning
- and keep the code backwards compatible, the following decorator
- can be used::
-
- import functools
- import sys
-
- if sys.version_info < (3, 5, 2):
- def aiter_compat(func):
- @functools.wraps(func)
- async def wrapper(self):
- return func(self)
- return wrapper
- else:
- def aiter_compat(func):
- return func
-
- Example::
-
- class AsyncIterator:
-
- @aiter_compat
- def __aiter__(self):
- return self
-
- async def __anext__(self):
- ...
-
- Starting with CPython 3.6, the :exc:`PendingDeprecationWarning`
- will be replaced with the :exc:`DeprecationWarning`.
- In CPython 3.7, returning an awaitable from ``__aiter__`` will
- result in a :exc:`RuntimeError`.
+ Starting with Python 3.7, ``__aiter__`` must return an
+ asynchronous iterator object. Returning anything else
+ will result in a :exc:`TypeError` error.
.. _async-context-managers: