While trying to port the example at <https://docs.python.org/3.5/library/asyncio-task.html#example-future-with-run-until-complete> to use “async def”, I discovered the ensure_future() function does not like the coroutine field name changes introduced in Issue 24400:

>>> asyncio.ensure_future(slow_operation(future))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/proj/python/cpython/Lib/asyncio/futures.py", line 196, in __repr__
    info = self._repr_info()
  File "/home/proj/python/cpython/Lib/asyncio/tasks.py", line 105, in _repr_info
    coro = coroutines._format_coroutine(self._coro)
  File "/home/proj/python/cpython/Lib/asyncio/coroutines.py", line 242, in _format_coroutine
    filename = coro.gi_code.co_filename
AttributeError: 'coroutine' object has no attribute 'gi_code'

I understand the gi_ names all changed to cr_, so I guess this code has to adjust as well.

It's not the first time that a bug in found in _format_coroutine(). We need more unit tests!

Previous bug: https://github.com/python/asyncio/issues/222

New changeset 8f4e738cb07f by Yury Selivanov in branch '3.5':
Issue #24495, #24400: Test asyncio.Task.repr in debug mode
https://hg.python.org/cpython/rev/8f4e738cb07f

Should be fixed now. Thanks for discovering this, Martin!

Victor, I'll make a PR on github/asyncio with some refactoring or CoroWrapper etc.  The code became too cumbersome, and has to be properly refactored.  At least we should have one wrapper class for generator based coroutines, and another one for 'async def' ones.