Partial reading of CSV file results in RuntimeError

[and3rson]

Sample code:

import asyncio
import aiocsv
import aiofiles

async def main():
    async with aiofiles.open('/tmp/test.csv', mode='w', encoding='utf-8', newline='') as fobj:
        writer = aiocsv.AsyncDictWriter(fobj, fieldnames=['foo', 'bar'])
        await writer.writeheader()
        await writer.writerow({'foo': '1', 'bar': '1'})
        await writer.writerow({'foo': '2', 'bar': '2'})
        await writer.writerow({'foo': '3', 'bar': '3'})

    async with aiofiles.open('/tmp/test.csv', mode='r', encoding='utf-8', newline='') as fobj:
        row = aiocsv.AsyncReader(fobj)
        print(await anext(row))  # I want to read header only

asyncio.run(main(), debug=True)

Output:

['foo', 'bar']
unhandled exception during asyncio.run() shutdown
task: <Task finished name='Task-2' coro=<<async_generator_athrow without __name__>()> exception=RuntimeError("can't send non-None value to a just-started coroutine") created at /usr/lib/python3.10/asyncio/events.py:80>
RuntimeError: can't send non-None value to a just-started coroutine

[MKuranowski]

This is an issue with Cython 0.29.*. I have regenerated the parser code with 3.0.0b2, seems to be fixed in 1.2.4.