Bug report

asyncio.Protocol.data_received prototype not respected: when using create_connection to create a tcp transport data_received is being called with a bytearray object instead of bytes.
If this is expected behaviour libraries like httpx and such should be warned or the prototype modified, although I doubt it's intended because it would suppose the generator doesn't hold reference to it otherwise data could change while stored in buffered stuff.

import sys print(f'Python: {sys.version}\n') import asyncio class MyProto(asyncio.Protocol): def data_received(self, data: bytes) -> None: print('@@@@@@@@@@ ', data) def eof_received(self): print('##########') async def main(): t, proto = await asyncio.get_running_loop().create_connection(MyProto, 'example.com', 80) t.write(b'SITE BE MAD\n\n') await asyncio.sleep(1) t.close() asyncio.run(main())

Correct output: @@@@@@@@@@ b'HTTP/1.0 ...WHATEVER THE SERVER ANSWERS...'
Faulty output: @@@@@@@@@@ bytearray(b'HTTP/1.0 ...WHATEVER THE SERVER ANSWERS...')

Your environment

On Windows 11 x64

Tested on:

• 3.11.0 (main, Oct 24 2022, 18:26:48) [MSC v.1933 64 bit (AMD64)]
• 3.10.1 (tags/v3.10.1:2cd268a, Dec 6 2021, 19:10:37) [MSC v.1929 64 bit (AMD64)]

Working as expected in:

• 3.9.9 (tags/v3.9.9:ccb0e6a, Nov 15 2021, 18:08:50) [MSC v.1929 64 bit (AMD64)]

Related problems

Link to the thread where I found a conflicting thing (it's being solved there as a workaround)
encode/httpx#2305 (comment)

EDIT: simplified the minimal example

Linked PRs

• gh-99941: asyncio.Protocol.data_received now received immutable bytes #100053