aiocontextvars ContextVar value not kept independently for the different async functions that set it

[ocelotl]

• aiocontextvars version: 0.2.2
• Python version: 3.5.0
• Operating System: Ubuntu 18.04.3

Description

Mismatching results when running an asyncio script with Python 3.5.0 and aiocontextvars vs. Python 3.7.5rc1 and native contextvars package.

What I Did

I created a virtual environment with Python 3.5.0 and installed aiocontextvars via pip3. I activated the virtual environment and ran the script below. I ran the same script with Python 3.7.5rc1 and got different results. The results that I got from running with Python 3.7.5rc1 are the ones I expected. When I run the script with aiocontextvars it seems like the ContextVar value is not kept independently for the different async functions that set its value.

(3-5-0) ocelotl@harrison:~$ cat async_contextvar.py 
from asyncio import sleep, gather, get_event_loop
from contextvars import ContextVar

local_name = ContextVar("async_name")


async def waiting(async_name, first_sleep, second_sleep):

    await sleep(first_sleep)

    local_name.set(async_name)

    print("async_name:\t{}".format(async_name))
    print("local_name:\t{}".format(local_name.get()))
    print()

    await sleep(second_sleep)

    print("async_name:\t{}".format(async_name))
    print("local_name:\t{}".format(local_name.get()))
    print()


async def main():
    await gather(waiting("A", 0, 1), waiting("B", 0.1, 3), waiting("C", 2, 1))

loop = get_event_loop()
loop.run_until_complete(main())
loop.close()

(3-5-0) ocelotl@harrison:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.3 LTS
Release:        18.04
Codename:       bionic
(3-5-0) ocelotl@harrison:~$ python3 --version
Python 3.5.0
(3-5-0) ocelotl@harrison:~$ pip3 freeze
aiocontextvars==0.2.2
contextvars==2.4
immutables==0.11
You are using pip version 7.1.2, however version 19.3.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
(3-5-0) ocelotl@harrison:~$ python3 async_contextvar.py 
async_name:     A
local_name:     A

async_name:     B
local_name:     B

async_name:     A
local_name:     B

async_name:     C
local_name:     C

async_name:     C
local_name:     C

async_name:     B
local_name:     C

(3-5-0) ocelotl@harrison:~$ 

ocelotl@harrison:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.3 LTS
Release:        18.04
Codename:       bionic
ocelotl@harrison:~$ python3 --version
Python 3.7.5rc1
ocelotl@harrison:~$ python3 async_contextvar.py 
async_name:     A
local_name:     A

async_name:     B
local_name:     B

async_name:     A
local_name:     A

async_name:     C
local_name:     C

async_name:     C
local_name:     C

async_name:     B
local_name:     B

ocelotl@harrison:~$ 

[condorcet]

@ocelotl Hi! Seems that you forget to import aiocontextvars at the beginning, it makes all magic around contextvars :(

[ocelotl]

@ocelotl Hi! Seems that you forget to import aiocontextvars at the beginning, it makes all magic around contextvars :(

Yes! That does it, @condorcet, thanks. I'm closing this issue right now. 👍