[Python] task.result() throws InvalidStateError instead of CancelledError on cancelled task

I build the following construct which is supposed to call a bunch of asynchronous operations and return as soon as any one of them completes or the timeout expires.

import asyncio

async def async_operation():
while True:
await asyncio.sleep(1)

async def main():
task1 = None
task2 = None
try:
task1 = asyncio.create_task(async_operation())
task2 = asyncio.create_task(async_operation())

await asyncio.wait([task1, task2], timeout=2, return_when=asyncio.FIRST_COMPLETED)
finally:
if task1 and not task1.done():
print("Cancelling task1!") # this is printed!
task1.cancel()
if task2 and not task2.done():
task2.cancel()
try:
# This throws:
# asyncio.exceptions.InvalidStateError: Result is not set.
res = task1.result()
# I would expect one of the following two cases to be true:
#
# 1. the task completes and thus the result is set or
# 2. it is cancelled in the finally block and thus calling .result()
# should raise CancelledError and not InvalidStateError
print(f"Got result: ${res}")
except asyncio.CancelledError:
print(f"Caught CancelledError!")

asyncio.run(main())


As pointed out in the code, it is not clear to me why trying to read the result of a cancelled task raises a InvalidStateError and not a CancelledError.

Looking at the documentation I'm getting a suspicion that it's because the cancellation is only scheduled and the coroutine is no longer actually being executed (in the IO loop) and thus it will never actually be cancelled.

I would welcome an explanation of the behavior as well as a suggestions for a more idiomatic implementation.

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