CODEWITHSUNDEEP
pythonasynchronousasync-awaittaskpython-asyncio
pegasus
pegasus

Reputation: 69

Any difference between await asyncio.Task and asyncio.Task.result()?

After the task already completed, is there any difference between await asyncio.Task and asyncio.Task.result()?

The only difference in the following code is how I read the value in task.

import asyncio
from asyncio import TaskGroup

async def func():
    await asyncio.sleep(2)
    return 0

async def main():
    async with TaskGroup() as tg:
        task = tg.create_task(func())
        print(await task)

asyncio.run(main())

vs

import asyncio
from asyncio import TaskGroup

async def func():
    await asyncio.sleep(2)
    return 0

async def main():
    async with TaskGroup() as tg:
        task = tg.create_task(func())
    # The await is implicit when the context manager exits.
    print(task.result())

asyncio.run(main())

Which code is the preferred one?

Upvotes: 0

Views: 40

Answers (1)

VPfB
VPfB

Reputation: 17342

The source code snippet below shows that await task ends up calling task.result() if the task is done. So the answer is: no difference in this case.

    def __await__(self):
        if not self.done():
            self._asyncio_future_blocking = True
            yield self  # This tells Task to wait for completion.
        if not self.done():
            raise RuntimeError("await wasn't used with future")
        return self.result()  # May raise too.

# location: asyncio/futures.py, in class _Future,
# the Task class is derived from it

Upvotes: 1

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