bpo-32650: Add native coroutine support to bdb when stepping over line

[pablogsal]

https://bugs.python.org/issue32650

CC: @asvetlov

[asvetlov]

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.

[pablogsal]

@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).

[asvetlov]

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

[pablogsal]

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

[asvetlov]

No problem.

[pablogsal]

@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.

[pablogsal]

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

[asvetlov]

Looks perfect, please go ahead

[asvetlov]

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

[1st1]

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

[1st1]

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

[pablogsal]

@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?

[asvetlov]

Sounds like a plan

[1st1]

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

[asvetlov]

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

[asvetlov]

Thanks for contribution!

[miss-islington]

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

[bedevere-bot]

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

[1st1]

Maybe you should also handle CO_ASYNC_GENERATOR flag.

[pablogsal]

@1st1 I am adding this in #5403