No mechanism to abort created coroutine or suppress not-awaited warning

[ShengZhong]

BPO	34467
Nosy	@asvetlov, @1st1, @pppery

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2019-06-11.10:09:28.381>
created_at = <Date 2018-08-22.22:02:43.086>
labels = ['type-feature', '3.7', 'expert-asyncio']
title = 'No mechanism to abort created coroutine or suppress not-awaited warning'
updated_at = <Date 2019-06-11.10:09:28.381>
user = 'https://bugs.python.org/ShengZhong'

bugs.python.org fields:

activity = <Date 2019-06-11.10:09:28.381>
actor = 'asvetlov'
assignee = 'none'
closed = True
closed_date = <Date 2019-06-11.10:09:28.381>
closer = 'asvetlov'
components = ['asyncio']
creation = <Date 2018-08-22.22:02:43.086>
creator = 'Sheng Zhong'
dependencies = []
files = []
hgrepos = []
issue_num = 34467
keywords = []
message_count = 3.0
messages = ['323911', '323913', '344401']
nosy_count = 4.0
nosy_names = ['asvetlov', 'yselivanov', 'ppperry', 'Sheng Zhong']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue34467'
versions = ['Python 3.6', 'Python 3.7']

[ShengZhong]

As far as I know, there is no mechanism for aborting a created coroutine instance before it's executed with an await (directly or indirectly). I have a function which takes in coroutine instances and conditionally creates a task for them that I track so that they can be later gathered. When the condition is false, I'd like to not execute the passed in coroutine.

Simply ignoring the coroutine works but reports a RuntimeWarning about coroutine not being awaited on. Checking the conditional before calling the function works but damages maintainability and is putting the responsibility on the wrong party.

Creating the task then immediately cancelling it does not work since execution for it will start and leads to other cancellation issues.

Is there a way to abort a coroutine instance that I'm not aware of?

[pppery]

Does calling coro.close() not work?

[asvetlov]

Could you consider passing (async_func, args, kwargs) tuple instead async_func(*args, **kwargs) coroutine?

Looks like it solves your problem and doesn't require asyncio changes