Hello,

I have a simple code which triggers a timeout if a task did not complete

import asyncio

async def task_timeout():
    condition = asyncio.Condition()
    with await condition:
        try:
            await asyncio.wait_for(condition.wait(), timeout=4)
        except asyncio.TimeoutError as e:
 
            print("timeout reached")
            # uncomment this line to make the code work
            # await asyncio.sleep(0)


f = asyncio.ensure_future(task_timeout())

loop= asyncio.get_event_loop()
loop.run_until_complete(f)

It throws an exception when leaving the scope for the condition because it expects the lock to be acquired:

RuntimeError: Lock is not acquired.

If you uncomment the line to sleep, it will work because it will continue in the coroutine Condition.wait and call:
 yield from self.acquire() => locks.py line 355

I think this is a bug and that this behaviour is not the expected one.

In my previous comment, what I want to implement is not a timeout for a task to complete but more precisely a timeout triggered if the coroutine was not wake up by a notify on the condition.

This is caused by wait_for not waiting for the cancelled task.  https://bugs.python.org/issue32751 tracks that bug.

New changeset e2b340ab4196e1beb902327f503574b5d7369185 by Yury Selivanov (Elvis Pranskevichus) in branch 'master':
bpo-32751: Wait for task cancellation in asyncio.wait_for() (GH-7216)
https://github.com/python/cpython/commit/e2b340ab4196e1beb902327f503574b5d7369185

New changeset d8948c5e09c4a2a818f6f6cfaf8064f2c2138fa5 by Miss Islington (bot) in branch '3.7':
bpo-32751: Wait for task cancellation in asyncio.wait_for() (GH-7216)
https://github.com/python/cpython/commit/d8948c5e09c4a2a818f6f6cfaf8064f2c2138fa5