Thank you for patch but tests are needed.
You can take a look on tests from initial commit 8820c23 which had introduced generator based coroutines.
Copying generator tests but replacement generators with async defs would be easiest way I believe.

@asvetlov I think is more complicated as coroutines are not iterable objects. Take for example test_pdb_next_command_for_generator. Replacing def for async def in test_gen will raise TypeError on next(it).

I did mean not literal replacement but pointing on bdb tests style and required functionality.

@asvetlov My bad, I did not understood your comment correctly. I will try to generate the required tests. Thanks for the comments :)

No problem.

@asvetlov In 97a0652 you will find a proposal for test style and functionality. I am invoking the coroutines though an event loop to avoid having to manually control the state with the send attribute. Please, confirm that this is OK so I can continue adding other tests if needed.

This is the output without this patch for comparison:

> /home/pablogsal/github/cpython/cosa.py(10)test_f()
-> await test_gen()
(Pdb) s
--Call--
> /home/pablogsal/github/cpython/cosa.py(3)test_gen()
-> async def test_gen():
(Pdb) s
> /home/pablogsal/github/cpython/cosa.py(4)test_gen()
-> await asyncio.sleep(0)
(Pdb) n
--Return--
> /home/pablogsal/github/cpython/cosa.py(4)test_gen()->None
-> await asyncio.sleep(0)
(Pdb)
--Return--
> /home/pablogsal/github/cpython/cosa.py(10)test_f()->None
-> await test_gen()
(Pdb)
--Call--
> /usr/lib/python3.6/asyncio/base_events.py(564)call_soon()
-> def call_soon(self, callback, *args):
(Pdb) s
> /usr/lib/python3.6/asyncio/base_events.py(574)call_soon()
-> self._check_closed()
(Pdb) s
--Call--
> /usr/lib/python3.6/asyncio/base_events.py(355)_check_closed()
-> def _check_closed(self):
(Pdb) c

Looks perfect, please go ahead

@1st1 @njsmith you may be interesting in the PR

Andrew, I don't use pdb myself, so if you think the change is ok please feel free to merge it.

Keep in mind that it's better to be merged now in order for it to make it to beta1.

@asvetlov We can merge it now without closing the issue and implement more tests later if you are Ok with that.

@1st1 Do you think there is a better way to test this behaviour without invoking the coroutines though the event loop?

Sounds like a plan

You can just manually advance a coroutine a with coro.send() method.

@pablogsal I'm going to sleep.
Please make a next PR with missing tests

Thanks for contribution!

Thanks @pablogsal for the PR, and @asvetlov for merging it 🌮🎉.. I'm working now to backport this PR to: 3.6.
🐍🍒⛏🤖

GH-5402 is a backport of this pull request to the 3.6 branch.

Maybe you should also handle CO_ASYNC_GENERATOR flag.

@1st1 I am adding this in #5403