import asyncio
import functools

def foo(x): raise Exception()

loop = asyncio.get_event_loop()
loop.call_soon(functools.partial(foo, x=1))
loop.run_forever()

Current error message:
    Exception in callback foo()() at ...:4

Expected error message:
    Exception in callback foo(x=1)() at ...:4

Oh, wow. I didn't even know we special-case partial() there. In general we tend to focus more on positional arguments (since asyncio intentionally doesn't take keyword args for callbacks) but I see no reason why we couldn't add this here. Maybe you're interested in writing a patch yourself? You could do it as a PR for the "upstream" git repo https://github.com/python/asyncio

Created a PR https://github.com/python/asyncio/pull/328. Please review. Thanks.

> Oh, wow. I didn't even know we special-case partial() there.

I wrote the code doing that. I did it to get more readable and shorter logs since asyncio produces a lot of logs.

Example:

    Exception in callback print("Hello", "World!")() at ...:4

without special case:

    Exception in functools.partial(<built-in function print>, 'Hello', 'World!') at ...:4

New changeset 4ab64ea31d75 by Yury Selivanov in branch '3.5':
Issue #26654: Inspect functools.partial in asyncio.Handle.__repr__.
https://hg.python.org/cpython/rev/4ab64ea31d75

New changeset 03257f04ee9f by Yury Selivanov in branch '3.6':
Merge 3.5 (issue #26654)
https://hg.python.org/cpython/rev/03257f04ee9f

New changeset 1dbe3addba28 by Yury Selivanov in branch 'default':
Merge 3.6 (issue #26654)
https://hg.python.org/cpython/rev/1dbe3addba28

Merged! Thank you!