asyncio.iscoroutinefunction(<async_generator>.asend) returns False

[RaduMateiLcraru]

BPO	37190
Nosy	@asvetlov, @1st1

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

Show more details

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2019-06-07.08:57:50.425>
labels = ['type-bug', '3.7', 'expert-asyncio']
title = 'asyncio.iscoroutinefunction(<async_generator>.asend) returns False'
updated_at = <Date 2019-06-07.08:57:50.425>
user = 'https://bugs.python.org/RaduMateiLcraru'

bugs.python.org fields:

activity = <Date 2019-06-07.08:57:50.425>
actor = 'Radu Matei L\xc4\x83craru'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['asyncio']
creation = <Date 2019-06-07.08:57:50.425>
creator = 'Radu Matei L\xc4\x83craru'
dependencies = []
files = []
hgrepos = []
issue_num = 37190
keywords = []
message_count = 1.0
messages = ['344910']
nosy_count = 3.0
nosy_names = ['asvetlov', 'yselivanov', 'Radu Matei L\xc4\x83craru']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue37190'
versions = ['Python 3.6', 'Python 3.7']

Linked PRs

• gh-81371: implementing checking async generator methods #102129

[RaduMateiLcraru]

asyncio.iscoroutinefunction(<async_generator>.__anext__)
asyncio.iscoroutinefunction(<async_generator>.asend)
asyncio.iscoroutinefunction(<async_generator>.athrow)
asyncio.iscoroutinefunction(<async_generator>.aclose)

All of these return False, is this the intended behavior? Aren't all of these in fact coroutine functions?

[kumaraditya303]

These functions are not coroutine functions but rather functions which return an awaitable object. You can use inspect.isawaitable on the result of asend to check if it is awaitable.

[graingert]

@kumaraditya303 they are functions that return coroutines - otherwise they could not be used with asyncio.create_task(agen.asend())

>>> import asyncio
>>> async def async_generator(): yield
... 
>>> asyncio.iscoroutine(async_generator().asend(None))
True
>>> 

so I think this needs re-opening

[kumaraditya303]

It is not a coroutine object but rather async_generator_asend object which has methods and some attributes of coroutine so behaves like it. iscoroutinefunction only works correctly for async def functions not native methods which returns an awaitable object hence I suggested to use inspect.isawaitable.