[3.13] gh-133745: Fix asyncio task factory name/context kwarg breaks (#133948)

In 3.13.3 we accidentally broke the interface for custom task factory. Factory authors added workarounds.
This PR (for 3.13.4) unbreaks task factories that haven't made a workaround yet while also supporting those that have.

NOTE: The custom task factory API will change to what we accidentally released in 3.13.3.

Co-authored-by: Kumar Aditya <kumaraditya@python.org>
Co-authored-by: Guido van Rossum <gvanrossum@gmail.com>

diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
index 92b98e2b2c862c4bfb6783f2811e2815b55b7b51..20b1ccd105109ea5a0478a191131d56d4687c8f4 100644 (file)
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -355,7 +355,7 @@ Creating Futures and Tasks
 
    .. versionadded:: 3.5.2
 
-.. method:: loop.create_task(coro, *, name=None, context=None)
+.. method:: loop.create_task(coro, *, name=None, context=None, **kwargs)
 
    Schedule the execution of :ref:`coroutine <coroutine>` *coro*.
    Return a :class:`Task` object.
@@ -364,6 +364,11 @@ Creating Futures and Tasks
    for interoperability. In this case, the result type is a subclass
    of :class:`Task`.
 
+   The full function signature is largely the same as that of the
+   :class:`Task` constructor (or factory) - all of the keyword arguments to
+   this function are passed through to that interface, except *name*,
+   or *context* if it is ``None``.
+
    If the *name* argument is provided and not ``None``, it is set as
    the name of the task using :meth:`Task.set_name`.
 
@@ -377,6 +382,13 @@ Creating Futures and Tasks
    .. versionchanged:: 3.11
       Added the *context* parameter.
 
+   .. versionchanged:: 3.13.3
+      Added ``kwargs`` which passes on arbitrary extra parameters, including  ``name`` and ``context``.
+
+   .. versionchanged:: 3.13.4
+      Rolled back the change that passes on *name* and *context* (if it is None),
+      while still passing on other arbitrary keyword arguments (to avoid breaking backwards compatibility with 3.13.3).
+
 .. method:: loop.set_task_factory(factory)
 
    Set a task factory that will be used by
@@ -388,6 +400,13 @@ Creating Futures and Tasks
    event loop, and *coro* is a coroutine object.  The callable
    must pass on all *kwargs*, and return a :class:`asyncio.Task`-compatible object.
 
+   .. versionchanged:: 3.13.3
+      Required that all *kwargs* are passed on to :class:`asyncio.Task`.
+
+   .. versionchanged:: 3.13.4
+      *name* is no longer passed to task factories. *context* is no longer passed
+      to task factories if it is ``None``.
+
 .. method:: loop.get_task_factory()
 
    Return a task factory or ``None`` if the default one is in use.

diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py
index d2cedb689858533be29f082149724aa27e382f39..07ec6de6414ec26326be394207e6bb42da5b7300 100644 (file)
--- a/Lib/asyncio/base_events.py
+++ b/Lib/asyncio/base_events.py
@@ -458,18 +458,24 @@ class BaseEventLoop(events.AbstractEventLoop):
         """Create a Future object attached to the loop."""
         return futures.Future(loop=self)
 
-    def create_task(self, coro, **kwargs):
+    def create_task(self, coro, *, name=None, context=None, **kwargs):
         """Schedule a coroutine object.
 
         Return a task object.
         """
         self._check_closed()
         if self._task_factory is not None:
-            return self._task_factory(self, coro, **kwargs)
+            if context is not None:
+                kwargs["context"] = context
+
+            task = self._task_factory(self, coro, **kwargs)
+            task.set_name(name)
+
+        else:
+            task = tasks.Task(coro, loop=self, name=name, context=context, **kwargs)
+            if task._source_traceback:
+                del task._source_traceback[-1]
 
-        task = tasks.Task(coro, loop=self, **kwargs)
-        if task._source_traceback:
-            del task._source_traceback[-1]
         try:
             return task
         finally:

diff --git a/Lib/test/test_asyncio/test_taskgroups.py b/Lib/test/test_asyncio/test_taskgroups.py
index 9f2211e3232e54a99dd6f0e9a6824800ba3458f2..ad61cb46c7c07c38296b5f7b85ffa9f1056ded9d 100644 (file)
--- a/Lib/test/test_asyncio/test_taskgroups.py
+++ b/Lib/test/test_asyncio/test_taskgroups.py
@@ -1081,18 +1081,6 @@ class BaseTestTaskGroup:
         # cancellation happens here and error is more understandable
         await asyncio.sleep(0)
 
-    async def test_name(self):
-        name = None
-
-        async def asyncfn():
-            nonlocal name
-            name = asyncio.current_task().get_name()
-
-        async with asyncio.TaskGroup() as tg:
-            tg.create_task(asyncfn(), name="example name")
-
-        self.assertEqual(name, "example name")
-
 
 class TestTaskGroup(BaseTestTaskGroup, unittest.IsolatedAsyncioTestCase):
     loop_factory = asyncio.EventLoop

diff --git a/Misc/NEWS.d/next/Library/2025-05-14-08-13-08.gh-issue-133745.rjgJkH.rst b/Misc/NEWS.d/next/Library/2025-05-14-08-13-08.gh-issue-133745.rjgJkH.rst
new file mode 100644 (file)
index 0000000..78cc3d9
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-05-14-08-13-08.gh-issue-133745.rjgJkH.rst
@@ -0,0 +1 @@
+In 3.13.3 we accidentally changed the signature of the asyncio ``create_task()`` family of methods and how it calls a custom task factory in a backwards incompatible way. Since some 3rd party libraries have already made changes to work around the issue that might break if we simply reverted the changes, we're instead changing things to be backwards compatible with 3.13.2 while still supporting those workarounds for 3.13.3. In particular, the special-casing of ``name`` and ``context`` is back (until 3.14) and consequently eager tasks may still find that their name hasn't been set before they execute their first yielding await.