Finish the examples-typing sweep with the last non-docs-visible
scripts: `-> None` on the two `trio/` behavior-demo mains (plus a
`trio.TaskStatus` on `hold_lock_forever`) and nursery/portal typing
on `integration/mpi4py/inherit_parent_main.py`.
Leaves `concurrent_futures_primes` (a verbatim stdlib baseline) and
`integration/open_context_and_sleep` (its tractor nursery is
commented out) as-is, and the paren-group `trio.open_nursery()`
bindings unannotated (no clean spot for a preceding annotation).
Completes the examples-typing bullet in #472.
(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code
Remove all the `tractor` usage (with IPC ctxs) and just get us
a min-reproducing-example with a multi-task-single `trio.Lock`.
The wrapping test suite runs the exact same with an ignore case and
an `.xfail()` for when we let the `trio.WouldBlock` be unmasked.
Demonstrating the guilty `trio.Lock.acquire()` impl which puts
a checkpoint inside its `trio.WouldBlock` handler and which will always
appear to mask the "sync path" case on (graceful) cancellation.
This first script draft demos the issue from within a `tractor.context`
ep bc that's where it was orig discovered, however i'm going to factor
out the `tractor` code and instead just use
a `.trionics.maybe_raise_from_masking_exc()` to demo its low-level
ignore-case feature.
Further, this script exposed a previously unhandled remote graceful
cancellation case which hangs:
- parent actor spawns child and opens a >1 ctxs with it,
- the parent then OoB (out-of-band) cancels the child actor (with
`Portal.cancel_actor()`),
- since the open ctxs raise a ctxc with a `.canceller == parent.uid` the
`Context._is_self_cancelled()` will eval `True`,
- the `Context._scope` will NOT be cancelled in
`._maybe_cancel_and_set_remote_error()` resulting in any bg-task which
is waiting on a `Portal.open_context()` to not be cancelled/unblocked.
So my plan is to factor this ^^ scenario into a standalone unit test
as well as another test which consumes from al low-level `trio`-only
version of **this** script-scenario to sanity check the interaction
of the unmasker-with-ignore-cases usage implicitly around a ctx ep.
Gud Boi
Tyler Goodlet