asyncgen.athrow() checks args on asyncgen.athrow().send() but should check them on asyncgen.athrow()

Bug report

Bug description:

async def agen():
    return
    yield


try:
    athrow = agen().athrow()
    athrow.close()
except TypeError:
    print("good")
else:
    print("bad")

output:

bad

CPython versions tested on:

3.8, 3.9, 3.10, 3.11, 3.12, 3.13, CPython main branch

Operating systems tested on:

Linux

Linked PRs

gh-117852: eagerly check arguments to asyncgen.athrow() #134868

to get the error you have to actually await the coroutine:

async def agen():
    return
    yield


athrow = agen().athrow()
athrow.send(None)

output:

Traceback (most recent call last):
  File "/home/graingert/projects/cpython/demo.py", line 7, in <module>
    athrow.send(None)
    ~~~~~~~~~~~^^^^^^
TypeError: athrow expected at least 1 argument, got 0

Fixing this would be a change in behaviour, but it is hard to imagine it breaking any working code.

pythongh-117852: eagerly check arguments to asyncgen.athrow()

gh-117852: fix argument checking of `async_generator.athrow` (#134868)

pythongh-117852: fix argument checking of `async_generator.athrow` (p…

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asyncgen.athrow() checks args on asyncgen.athrow().send() but should check them on asyncgen.athrow() #117852

Bug report

Bug description:

CPython versions tested on:

Operating systems tested on:

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asyncgen.athrow() checks args on asyncgen.athrow().send() but should check them on asyncgen.athrow() #117852

Description

Bug report

Bug description:

CPython versions tested on:

Operating systems tested on:

Linked PRs

Activity

graingert commented on Apr 13, 2024

duaneg commented on May 28, 2025

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