This fixes an previously undetected bug where if an
`.open_channel_from()` spawned task errored the error would not be
propagated to the `trio` side and instead would fail silently with
a console log error. What was most odd is that it only seems easy to
trigger when you put a slight task sleep before the error is raised
(:eyeroll:). This patch adds a few things to address this and just in
general improve iter-task lifetime syncing:
- add `LinkedTaskChannel._trio_exited: bool` a flag set from the `trio`
side when the channel block exits.
- add a `wait_on_aio_task: bool` flag to `translate_aio_errors` which
toggles whether to wait the `asyncio` task termination event on exit.
- cancel the `asyncio` task if the trio side has ended, when
`._trio_exited == True`.
- always close the `trio` mem channel when the task exits such that
the `asyncio` side can error on any next `.send()` call.
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.
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
This actually catches a lot of bugs to do with stream termination and
``MsgStream.subscribe()`` usage where the underlying stream closes from
the producer side. When this passes the broadcaster logic will have to
ensure non-lossy fan out semantics and closure tracking.
If we make it too fast a nursery with debug mode children can cancel
too fast and causes some test failures. It's likely not a huge deal
anyway since the purpose of this poll/check is for human interaction
and the current delay isn't really that noticeable.
Decrease log levels in the debug module to avoid console noise when in
use. Toss in some more detailed comments around the new debugger lock
points.
Tyler Goodlet