Since it can not only cause the guest-mode run to abandon but also in
some edge cases prevent `trio`-errors from propagating (at least on
py3.12-13?) as discovered as part of supporting this mode officially
in the *root actor*.
As such try to avoid that method as much as possible instead opting to
pass the `trio`-side error via the iter-task channel ref.
Deats,
- add a `LinkedTaskChannel._trio_err: BaseException|None` which gets set
whenver the `trio.Task` error is caught; ONLY set `AsyncioCancelled`
when the `trio` task was for sure the cause, whether itself cancelled
or errored.
- always check for this error when exiting the `asyncio` side (even when
terminated via a call to `asyncio.Task.cancel()` or during any other
`CancelledError` handling such that the `asyncio`-task can expect to
handle `AsyncioCancelled` due to the above^^ cases.
- never `cs.cancel()` the `trio` side unless that cancel scope has not
yet been `.cancel_called` whatsoever; it's a noop anyway.
- only raise any exc from `asyncio.Task.result()` when `chan._aio_err`
does not already match it since the existence of the pre-existing
`task_err` means `asyncio` prolly intends (or has already) raised and
interrupted the task elsewhere.
Various supporting tweaks,
- don't bother maybe-init-ing `greenback` from the actor entrypoint
since we already need to (and do) bestow the portals to each `asyncio`
task spawned using the `run_task()`/`open_channel_from()` API; further
the init-ing should be done already by client code that enables
infected mode (even in the root actor).
|_we should prolly also codify it from any
`run_daemon(infected_aio=True, debug_mode=True)` usage we offer.
- pass all the `_<field>`s to `Linked TaskChannel` explicitly in named
kwarg style.
- better sclang-style log reports throughout, particularly on teardowns.
- generally more/better comments and docs around (not well understood)
edge cases.
- prep to just inline `maybe_raise_aio_side_err()` closure..
9167fbb0a8