Pull the common `asyncio` -> `trio` error translation logic into
a common context manager and don't expect a final result to be captured
when using `open_channel_from()` since it's a manager interface and it
would be clunky to try and deliver some "final result" after exit.
Verify that if the `asyncio` side task cancels (itself) that we raise
that `asyncio.CancelledError` on the `trio` side. In the case where
`trio` initiated the cancel whether or not the `asyncio` side ended up
raising `CancelledError` doesn't really matter to us as long as the far
task did indeed terminate.
Close the mem chan before cancelling the `trio` task in order to ensure
we retrieve whatever error is shuttled from `asyncio` before the channel
read is potentially cancelled (previously a race?).
Handle `asyncio.CancelledError` specially such that we raise it directly
(instead of `raise aio_cancelled from other_err`) since it *is* the
source error in the case where the cancellation is `asyncio` internal.
Clearly this wasn't developed against a task that spawned just an async
func in `asyncio`.. Fix all that and remove a bunch of unnecessary func
layers. Add provisional support for the target receiving the `to_trio`
and `from_trio` channels and for the @tractor.stream marker.
This should mostly maintain top level SC principles for any task spawned
using `tractor.to_asyncio.run()`. When the `asyncio` task completes make
sure to cancel the pertaining `trio` cancel scope and raise any error
that may have resulted. This interface uses `trio`'s "guest-mode" to run
`asyncio` loop using a special entrypoint which is handed to Python
during process spawn.
If the one side of an inter-actor context cancels the other then that
side should always expect back a `ContextCancelled` message. However we
should not set this error in this case (where the cancel request was
sent and a `ContextCancelled` msg was received back) since it may
override some other error that caused the cancellation request to be
sent out in the first place. As an example when a context opens another
context to a peer and some error happens which causes the second peer
context to be cancelled but we want to propagate the original error.
Fixes the issue found in https://github.com/pikers/piker/issues/244
The underlying issue is actually that a nested `Context` which was
cancelled was overriding the local error that triggered that secondary's
context's cancellation in the first place XD. This test catches that
case.
Relates to https://github.com/pikers/piker/issues/244
Tyler Goodlet
goodboy