[Python] Asyncio future, running Future objects

I have a code:

import asyncio as aio


async def coro(future: aio.Future):
print('Coro start')
await aio.sleep(3)
print('Coro finish')
future.set_result('coro result')


async def main():
future = aio.Future()
aio.create_task(coro(future))
await future
coro_result = future.result()
print(coro_result)


aio.run(main())


In main() I create an empty aio.Future object, then I create a task with aio.create_task(coro(future)) using coroutine which takes aio.Future object. Then I 'run' the empty future with await future. Somehow this line runs the task instead of running the empty coroutine! I don't understand how it works and why it goes like this, because I expect the line await future to run the empty future, not task!

If I reorganize my main() like this:

import asyncio as aio


async def coro(future: aio.Future):
print('Coro start')
await aio.sleep(3)
print('Coro finish')
future.set_result('coro result')


async def main():
future = aio.Future()
await aio.create_task(coro(future))
# await future
coro_result = future.result()
print(coro_result)


aio.run(main())


I get the same result but the code behaviour becomes much more explicit for me.

Continue reading...