Can't use functools.partial() to wrap coroutine in debug mode -- bug or not?

[gvanrossum]

In #222 I note that after fixing the original issue (__name__ raises an AttributeError) the example program still fails in debug mode, because of the way partial() is wrapping a CoroWrapper. Should we consider this a bug or a feature? I'm copying the sample program here:

import asyncio
import functools

@asyncio.coroutine
def func(x, y):
    print('func with x = {} and y = {}'.format(x, y))
    yield from asyncio.sleep(0.1)
    print('exit func')


partial_func = asyncio.coroutine(functools.partial(func, 1))

loop = asyncio.get_event_loop()
try:
    loop.run_until_complete(partial_func(2))
finally:
    loop.close()

In non-debug mode this prints

func with x = 1 and y = 2
exit func

but in debug mode I get a traceback:

PYTHONASYNCIODEBUG=1 python3 p.py
<CoroWrapper func() running at p.py:4, created at /Users/guido/src/asyncio/asyncio/coroutines.py:141> was never yielded from
Coroutine object created at (most recent call last):
  File "p.py", line 15, in <module>
    loop.run_until_complete(partial_func(2))

(etc.)

I think the example code is equivalent to

@asyncio.coroutine
def func(x, y):
    ...
@asyncio.coroutine
def partial_func(y):
    return func(1, y)

I think this exposes the bug in the original program -- the final line should really be

    return yield from func(1, y)

[1st1]

This one was merged, closing the issue.