Commit Graph

1941 Commits (bd3668e2bf82b42799b49e6a0decd639dcd5e6c7)

Author SHA1 Message Date
Tyler Goodlet bd3668e2bf Add a `tests/test_root_infect_asyncio`
Might as well break apart the specific test set since there are some
(minor) subtleties and the orig test mod is already getting pretty big
XD

Includes both the new "independent"-event-loops test as well as the std
usage base case suite.
2025-01-10 18:02:06 -05:00
Tyler Goodlet d74dbab1be Impl a proto "unmasker" `@acm` alongside our test
Such that the suite verifies the wip `maybe_raise_from_masking_exc()`
will raise from a `trio.Cancelled.__context__` since I can't think of
any reason a `Cancelled` should ever be raised in-place of
a non-`Cancelled` XD

Not sure what should be raised instead (or maybe just a `log.warning()`
emitted?) but this starts a draft for refinement at the least. Use the
new `@pytest.mark.parametrize` explicit tuple-of-params form with an
`pytest.param + `.mark.xfail()` for the default behaviour case.
2025-01-10 17:29:11 -05:00
Tyler Goodlet 9be457fcf3 Add a "raise-from-`finally:`" example test
Since i wasted 2 days just to find an example of this inside an `@acm`,
figured I better reproduce for the purposes of maybe implementing
a warning sys (inside our wip proto `open_taskman()`) when a nursery
detects a single `Cancelled` in an eg where the `.__context__` is set to
some non-cancel error (which likely means a cancel-causing source
exception was suppressed by accident).

Left in a buncha commented code using `maybe_open_nursery()` which
i thought might be part of the issue but didn't end up being required;
will likely remove on a follow up refinement.
2025-01-10 15:46:00 -05:00
Tyler Goodlet e6f3f187b6 Yield a boxed-maybe-error from `open_crash_handler()`
Along the lines of something like `pytest.raises()` where the handled
exception can be inspected from the `pdbp` REPL using its `.value` field
B)

This is super handy in particular for understanding
`BaseException[Group]`s without manually adding surrounding handler code
to assign the `except[*] Exception as exc_var:` particularly when trying
to understand multi-cancelled eg trees.
2025-01-10 12:42:23 -05:00
Tyler Goodlet 924eff2985 Add an inter-leaved-task error test
Trying to replicate cases where errors are raised in both `trio` and
`asyncio` tasks independently (at least in `.to_asyncio` API terms) with
a new `test_trio_prestarted_task_bubbles` that generates 3 cases inside
a `@acm` calls stack composing a `trio.Nursery` with
a `to_asyncio.open_channel_from()` call where a set of `trio` tasks are
started in a loop using `.start()` with various exc raising sequences,
- the aio task raising *before* the last `trio` task spawns.
- the aio task raising just after the last trio task spawns, but before
  it starts.
- after the last trio task `.start()` call returns control to the
  parent - but (for now) did not error.

TODO, still more cases to discover as i'm still fighting a `modden` bug
of this sort atm..

Other,
- tweak some other tests to have timeouts since some recent hangs were
  found..
- started mucking with py3.13 and thus adjustments for strict egs in
  some tests; full patchset to test suite likely coming soon!
2025-01-09 08:59:30 -05:00
Tyler Goodlet 89fc072ca0 Hm, `asyncio.Task._fut_waiter.set_exception()`?
Since we can't use it to `Task.set_exception()` (since that task method never
seems to work.. XD) and setting the private/internal always seems to do
the desired raising in the task? I realize it's an internal `asyncio`
runtime field but i'd rather take the risk of it breaking then having to
rely on our own equivalent hack..

Also, it seems like the case where the task's associated (and internal)
future-waiter field is null, we won't run into the (same?) prior hanging
issues (maybe since there's nothing for `asyncio` internals to use to
wait XD ??) when `Task.cancel()` is used..??

Main deats,
- add and `Future.set_exception()` a new signal-exception
  `class TrioTaskExited(AsyncioCancelled):` whenever the trio-task exits
  gracefully and the asyncio-side task is still doing blocking work (of
  some sort) which *seem to* be predicated by a check that
  `._fut_waiter is not None`.
- always call `asyncio.Queue.shutdown()` for the same^ as well as
  whenever we decide to call `Task.cancel()`; in that case the shutdown
  relays correctly?

Some further refinements,
- only warn about `Task.cancel()` usage when actually used ;)
- more local scope vars setting in the exit phase of
  `translate_aio_errors()`.
- also in ^ use explicit caught-exc var names for each error-type.
2025-01-02 15:35:36 -05:00
Tyler Goodlet 7b8a8dcc7c Much more limited `asyncio.Task.cancel()` use
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..
2024-12-31 18:10:09 -05:00
Tyler Goodlet c63b94f61f Expose `debug_filter` from `open_root_actor()` also
Such that actor-runtime graceful cancel handling can be used throughout
any process tree.
2024-12-28 14:35:05 -05:00
Tyler Goodlet 0e39b3902f Drop extra nl from boxed error fmt 2024-12-28 14:34:24 -05:00
Tyler Goodlet bf9689e10a Raise explicitly on missing `greenback` portal
When `.pause_from_sync()` is called from an `asyncio.Task` which was
never bestowed a portal we want to be mega pedantic about it; indicate
that the task was NOT spawned from our `.to_asyncio` API and likely by
some out-of-our-control code (normally using
`asyncio.ensure_future()/.create_task()`). Though `greenback` already
errors on such usage, it's not always clear why no portal exists;
explaining the situation of a 3rd-party-bg-spawned-task should avoid
dev confusion for most cases.

Impl deats,
- distinguish between an actor in infected mode versus the actual caller
  of `.pause_from_sync()` being an `asyncio.Task` with more explicit
  `asyncio_task` and `is_infected_aio` vars.
- ONLY in the case of being both an infected-mode-actor AND detecting
  that the caller is an `asyncio.Task`, check `greenback.has_portal()`
  such that when not bestowed we presume the aforementioned
  3rd-party-bg-task case above and raise a new explicit RTE with
  a detailed explanatory message.
- add some masked draft code for handling the speical case of a root
  actor `asyncio.Task` caller which could (in theory) not actually
  require gb portal use since the `Lock` can be acquired directly
  without IPC.
 |_this will likely require factoring of various pause machinery funcs
   into a `_pause_from_root_task()` to mk the impl sane XD

Other,
- expose a new `debug_filter: Callable` which can be provided by the
  caller of `_maybe_enter_pm()` to predicate whether to enter the
  debugger REPL based on the caught `BaseException|BaseExceptionGroup`;
  this is handy for customizing the meaning of "graceful cancellations"
  so as to avoid crash handling on expected egs of more then
  `trioCancelled`.
|_ make the default as it was implemented: `not is_multi_cancelled(err)`
- pass-through a new `ignore: set[BaseException]` as
  `open_crash_handler(ignore_nested=ignore)` to allow for the same
  silent-cancellation-egs-swallowing as desired from outside the actor
  runtime.
2024-12-28 14:07:01 -05:00
Tyler Goodlet 350a94f39e Accept err-type override in `is_multi_cancelled()`
Such that equivalents of `trio.Cancelled` from other runtimes such as
`asyncio.CancelledError` and `subprocess.CalledProcessError` (with
a `.returncode == -2`) can be gracefully ignored as needed by the
caller.

For example this is handy if you want to avoid debug-mode REPL entry on
an exception-group full of only some subset of exception types since you
expect certain tasks to raise such errors after having been cancelled by
a request from some parent supervision sys (some "higher up"
`trio.CancelScope`, a remote triggered `ContextCancelled` or just from
and OS SIGINT).

Impl deats,
- offer a new `ignore_nested: set[BaseException]` param which by
  default we add `trio.Cancelled` to when no other types are provided.
- use `ExceptionGroup.subgroup(tuple(ignore_nested)` to filter to egs of
  the "ignored sub-errors set" and return any such match (instead of
  `True`).
- detail a comment on exclusion case.
2024-12-27 14:07:50 -05:00
Tyler Goodlet 0945631629 Support passing pre-conf-ed `Logger`
Such that we can hook into 3rd-party-libs more easily to monkey them and
use our (prettier/hipper) console logging with something like (an
example from the client project `modden`),

```python
    connection_mod = i3ipc.connection
    tractor_style_i3ipc_logger: logging.LoggingAdapter = tractor.log.get_console_log(
        _root_name=connection_mod.__name__,
        logger=i3ipc.connection_mod.logger,
        level='info',
    )
    # monkey the instance-ref in 3rd-party module
    connection_mod.logger = our_logger
```

Impl deats,
- expose as `get_console_log(logger: logging.Logger)` and add default
  failover logic.
- toss in more typing, also for mod-global instance.
2024-12-18 12:30:17 -05:00
Tyler Goodlet 0a0d30d108 Support and test infected-`asyncio`-mode for root
Such that you can use,

```python

    tractor.to_asyncio.run_as_asyncio_guest(
        trio_main=_trio_main,
    )
```

to boostrap the root actor (and thus main parent process) to embed
the actor-rumtime into an `asyncio` loop. Prove it all works with an
subactor-free version of the aio echo-server test suite B)
2024-12-11 22:23:17 -05:00
Tyler Goodlet dcb6706489 Support `ctx: UnionType` annots for `@tractor.context` eps 2024-12-11 22:22:26 -05:00
Tyler Goodlet 170e198683 Use shorthand nursery var-names per convention in codebase 2024-12-11 20:26:13 -05:00
Tyler Goodlet 840c328f19 Better separate service tasks vs. ctxs via methods
Namely splitting the handles for each in 2 separate tables and adding
a `.cancel_service_task()`.

Also,
- move `_open_and_supervise_service_ctx()` to mod level.
- rename `target` -> `ctx_fn` params througout.
- fill out method doc strings.
2024-12-11 14:24:49 -05:00
Tyler Goodlet 46dbe6d2fc Mv over `ServiceMngr` from `piker` with mods
Namely distinguishing service "IPC contexts" (opened in a
subactor via a `Portal`) from just local `trio.Task`s started
and managed under the `.service_n` (more or less wrapping in the
interface of a "task-manager" style nursery - aka a one-cancels-one
supervision start).

API changes from original (`piker`) impl,
- mk `.start_service_task()` do ONLY that, start a task with a wrapping
  cancel-scope and completion event.
  |_ ideally this gets factored-out/re-implemented using the
    task-manager/OCO-style-nursery from GH #363.
- change what was the impl of `.start_service_task()` to `.start_service_ctx()`
  since it more explicitly defines the functionality of entering
  `Portal.open_context()` with a wrapping cs and completion event inside
  a bg task (which syncs the ctx's lifetime with termination of the
  remote actor runtime).
- factor out what was a `.start_service_ctx()` closure to a new
  `_open_and_supervise_service_ctx()` mod-func holding the meat of
  the supervision logic.

`ServiceMngr` API brief,
- use `open_service_mngr()` and `get_service_mngr()` to acquire the
  actor-global singleton.
- `ServiceMngr.start_service()` and `.cancel_service()` which allow for
  straight forward mgmt of "service subactor daemons".
2024-12-11 12:38:35 -05:00
Tyler Goodlet f08e888138 Initial idea-notes dump and @singleton factory idea from `trio`-gitter 2024-12-10 14:44:09 -05:00
Tyler Goodlet 441cf0962d TOSQUASH: 9002f60 howtorelease.md file 2024-12-10 14:43:39 -05:00
Tyler Goodlet fb04f74605 Draft a (pretty)`Struct.fields_diff()`
For comparing a `msgspec.Struct` against an input `dict` presumably to
be used as input for struct instantiation. The main diff with
`.__sub__()` is that non-existing fields on either are reported
(loudly).
2024-12-10 14:12:37 -05:00
Tyler Goodlet aa1f6fa4b5 Spitballing how to expose custom `msgspec` type hooks
Such that maybe we can eventually offer a nicer higher-level API which
implements much of the boilerplate required by `msgspec` (like
type-matched branching to serialization logic) via a type-table
interface or something?

Not sure if the idea is that useful so leaving it all as TODOs for now
obviously.
2024-12-09 21:09:48 -05:00
Tyler Goodlet 9002f608ee Add `notes_to_self/howtorelease.md` reminder doc 2024-12-09 18:14:11 -05:00
Tyler Goodlet 8ebc022535 Add TODO for a runtime-vars passing mechanism 2024-12-09 18:12:22 -05:00
Tyler Goodlet e26fa8330f Change masked `.pause()` line 2024-12-09 18:04:32 -05:00
Tyler Goodlet a2659069c5 Type the inter-loop chans 2024-12-09 17:37:32 -05:00
Tyler Goodlet 54699d7a0b Denoise duplicate chan logging for now 2024-12-09 17:36:52 -05:00
Tyler Goodlet b91ab9e3a8 Add TODO for a tb frame "filterer" sys.. 2024-12-09 17:14:51 -05:00
Tyler Goodlet cd14c4fe72 Set `RemoteActorError.pformat(boxer_header=self.relay_uid)` by def 2024-12-09 16:57:57 -05:00
Tyler Goodlet ad40fcd2bc Support custom `boxer_header: str` provided by `pformat_boxed_tb()` caller 2024-12-09 16:57:22 -05:00
Tyler Goodlet 508ba510a5 Expose a `_ctlc_ignore_header: str` for use in `sigint_shield()` 2024-12-09 16:56:30 -05:00
Tyler Goodlet b875b35b98 Change `tractor.breakpoint()` to new `.pause()` in test suite 2024-12-09 16:08:55 -05:00
Tyler Goodlet 46ddc214cd Wrap `asyncio_bp.py` ex into test suite
Ensuring we can at least use `breakpoint()` from an infected actor's
`asyncio.Task` spawned via a `.to_asyncio` API.

Also includes a little `tests/devx/` reorging,
- start splitting out non-`tractor.pause()` tests into a new
  `test_pause_from_non_trio.py` for all the `.pause_from_sync()`
  use in bg-threaded or `asyncio` applications.
- factor harness commonalities to the `devx/conftest` (namely
  the `do_ctlc()` masher).
- mv `test_pause_from_sync` to the new non`-trio` mod.

NOTE, the `ctlc=True` is still failing for
`test_pause_from_asyncio_task` which is a user-happiness bug but not
anything fundamentally broken - just need to handle the `asyncio` case
in `.devx._debug.sigint_shield()`!
2024-12-09 15:38:28 -05:00
Tyler Goodlet b3ee20d3b9 Add `breakpoint()` hook restoration example + test 2024-12-05 20:56:39 -05:00
Tyler Goodlet cf3e6c1218 Rename `n: trio.Nursery` -> `tn` (task nursery) 2024-12-04 14:01:38 -05:00
Tyler Goodlet 8af9b0201d Messy-teardown `DebugStatus` related fixes
Mostly fixing edge cases with `asyncio` and/or bg threads where the
`.repl_release: trio.Event` needs to be used from the main `trio`
thread OW confusing-but-valid teardown tracebacks can show under various
races.

Also improve,
- log reporting for such internal bugs to make them more obvious on
  console via `log.exception()`.
- only restore the SIGINT handler when runtime is (still) active.
- reporting when `tractor.pause(shield=True)` should be used and
  unhiding the internal frames from the tb in that case.
- for `pause_from_sync()` some deep fixes..
 |_add a `allow_no_runtime: bool = False` flag to allow
   **not** requiring the actor runtime to be active.
 |_fix the `greenback` case-branch to only trigger on `not
   is_trio_thread`.
 |_add a scope-global `repl_owner: Task|Thread|None = None` to
   avoid ref errors..
2024-12-03 15:26:25 -05:00
Tyler Goodlet 5c2e972315 Report any external-rent-task-canceller during msg-drain
As in whenever `Context.cancel()` is not (runtime internally) called
(i.e. `._cancel_called` is not set), we can attempt to detect the parent
`trio` nursery/cancel-scope that is the source. Emit the report with
a `.cancel()` level and attempt to repr in "sclang" form as well as
unhide the stack frame for debug/traceback-in.
2024-08-26 14:29:09 -04:00
Tyler Goodlet 59f4024242 Add `indent: str` suport to `Context.pformat()` using `textwrap` 2024-08-22 20:19:55 -04:00
Tyler Goodlet 7859e743cc Add `tb_hide: bool` ctl flag to `_open_and_supervise_one_cancels_all_nursery()` 2024-08-22 17:22:53 -04:00
Tyler Goodlet f7f738638d More `.pause_from_sync()` in bg-threads "polish"
Various `try`/`except` blocks around external APIs that raise when not
running inside an `tractor` and/or some async framework (mostly to avoid
too-late/benign error tbs on certain classes of actor tree teardown):
- for the `log.pdb()` prompts emitted before REPL console entry.
- inside `DebugStatus.is_main_trio_thread()`'s call to `sniffio`.
- in `_post_mortem()` by catching `NoRuntime` when called from a thread
  still active after the `.open_root_actor()` has already exited.

Also,
- create a dedicated `DebugStateError` for raising instead of `assert`s
  when we have actual debug-request inconsistencies (as seem to be most
  likely with bg thread usage of `breakpoint()`).
- show the `open_crash_handler()` frame on `bdb.BdbQuit` (for now?)
2024-08-22 17:10:01 -04:00
Tyler Goodlet ae95e0c83e Hide `[maybe]_open_crash_handler()` frame by default 2024-07-31 21:34:57 -04:00
Tyler Goodlet 3b39cce741 Use our `._post_mortem` from `open_crash_handler()`
Since it seems that `pdbp.xpm()` can sometimes lose the up-stack
traceback info/frames? Not sure why but ours seems to work just fine
from a `asyncio`-handler in `modden`'s use of `i3ipc` B)

Also call `DebugStatus.shield_sigint()` from `pause_from_sync()` in the
infected-`asyncio` case to get the same shielding behaviour as in all
other usage!
2024-07-29 17:56:00 -04:00
Tyler Goodlet 110a023a03 Drop `asyncio_bp` loglevel setting by default 2024-07-29 17:53:52 -04:00
Tyler Goodlet 89127614d5 First draft, `asyncio`-task, sync-pausing Bo
Mostly due to magic from @oremanj where we slap in a little bit of
`.from_asyncio`-type stuff to run a `trio`-task from `asyncio.Task`
code!

I'm not gonna go into tooo too much detail but basically the primary
thing needed was a way to (blocking-ly) invoke a `trio.lowlevel.Task`
from an `asyncio` one (which we now have with a new
`run_trio_task_in_future()` thanks to draft code from the aforementioned
jefe) which we now invoke from a dedicated aio case-branch inside
`.devx._debug.pause_from_sync()`. Further include a case inside
`DebugStatus.release()` to handle using the same func to set the
`repl_release: trio.Event` from the aio side when releasing the REPL on
exit cmds.

Prolly more refinements to come ;{o
2024-07-15 13:42:08 -04:00
Tyler Goodlet 1f1a3f19d5 Fix multi-daemon debug test `break` signal..
It was expecting `AssertionError` as a proceed-in-test signal (by
breaking from a continue loop), but `in_prompt_msg(raise_on_err=True)`
was changed to raise `ValueError`; so instead just use as a predicate
for the `break`.

Also rework `in_prompt_msg()` to accept the `child: BaseSpawn` as input
instead of `before: str` remove the casting boilerplate, and adjust all
usage to match.
2024-07-12 15:57:41 -04:00
Tyler Goodlet f7469442e3 Use "sclang"-style syntax in `to_asyncio` task logging
Just like we've started doing throughout the rest of the actor runtime
for reporting (and where "sclang" = "structured conc (s)lang", our
little supervision-focused operations syntax i've been playing with in
log msg content).

Further tweaks:
- report the `trio_done_fute` alongside the `main_outcome` value.
- add a todo list for supporting `greenback` for pause points.
2024-07-11 19:22:40 -04:00
Tyler Goodlet 8363317e11 Pass `infect_asyncio` setting via runtime-vars
The reason for this "duplication" with the `--asyncio` CLI flag (passed
to the child during spawn) is 2-fold:
- allows verifying inside `Actor._from_parent()` that the `trio` runtime was
  started via `.start_guest_run()` as well as if the
  `Actor._infected_aio` spawn-entrypoint value has been set (by the
  `._entry.<spawn-backend>_main()` whenever `--asyncio` is passed)
  such that any mismatch can be signaled via an `InternalError`.
- enables checking the `._state._runtime_vars['_is_infected_aio']` value
  directly (say from a non-actor/`trio`-thread) instead of calling
  `._state.current_actor(err_on_no_runtime=False)` in certain edge
  cases.

Impl/testing deats:
- add `._state._runtime_vars['_is_infected_aio'] = False` default.
- raise `InternalError` on any `--asyncio`-flag-passed vs.
  `_runtime_vars`-value-relayed-from-parent inside
  `Actor._from_parent()` and include a `Runner.is_guest` assert for good
  measure B)
- set and relay `infect_asyncio: bool` via runtime-vars to child in
  `ActorNursery.start_actor()`.
- verify `actor.is_infected_aio()`, `actor._infected_aio` and
  `_state._runtime_vars['_is_infected_aio']` are all set in test suite's
  `asyncio_actor()` endpoint.
2024-07-11 13:22:53 -04:00
Tyler Goodlet a628eabb30 Officially test proto-ed `stackscope` integration
By re-purposing our `pexpect`-based console matching with a new
`debugging/shield_hang_in_sub.py` example, this tests a few "hanging
actor" conditions more formally:

- that despite a hanging actor's task we can dump
  a `stackscope.extract()` tree on relay of `SIGUSR1`.
- the actor tree will terminate despite a shielded forever-sleep by our
  "T-800" zombie reaper machinery activating and hard killing the
  underlying subprocess.

Some test deats:
- simulates the expect actions of a real user by manually using
  `os.kill()` to send both signals to the actor-tree program.
- `pexpect`-matches against `log.devx()` emissions under normal
  `debug_mode == True` usage.
- ensure we get the actual "T-800 deployed" `log.error()` msg and
  that the actor tree eventually terminates!

Surrounding (re-org/impl/test-suite) changes:
- allow disabling usage via a `maybe_enable_greenback: bool` to
  `open_root_actor()` but enable by def.
- pretty up the actual `.devx()` content from `.devx._stackscope`
  including be extra pedantic about the conc-primitives for each signal
  event.
- try to avoid double handles of `SIGUSR1` even though it seems the
  original (what i thought was a) problem was actually just double
  logging in the handler..
  |_ avoid double applying the handler func via `signal.signal()`,
  |_ use a global to avoid double handle func calls and,
  |_ a `threading.RLock` around handling.
- move common fixtures and helper routines from `test_debugger` to
  `tests/devx/conftest.py` and import them for use in both test mods.
2024-07-10 19:58:27 -04:00
Tyler Goodlet d216068713 Start a new `tests/devx/` tooling-subsuite-pkg 2024-07-10 15:52:38 -04:00
Tyler Goodlet 131e3e8157 Move `mk_cmd()` to `._testing`
Since we're going to need it more generally for `.devx` sub-sys tooling
tests.

Also, up the sync-pause ctl-c delay another 10ms..
2024-07-10 15:40:44 -04:00
Tyler Goodlet fc95c6719f Get multi-threaded sync-pausing fully workin!
The final issue was making sure we do the same thing on ctl-c/SIGINT
from the user. That is, if there's already a bg-thread in REPL, we
`log.pdb()` about SIGINT shielding and re-draw the prompt; the same UX
as normal actor-runtime-task behaviour.

Reasons this wasn't workin.. and the fix:
- `.pause_from_sync()` was overriding the local `repl` var with `None`
  delivered by (transitive) calls to `_pause(debug_func=None)`.. so
  remove all that and only assign it OAOO prior to thread-type case
  branching.
- always call `DebugStatus.shield_sigint()` as needed from all requesting
  threads/tasks:
  - in `_pause_from_bg_root_thread()` BEFORE calling `._pause()` AND BEFORE
    yielding back to the bg-thread via `.started(out)` to ensure we're
    definitely overriding the handler in the `trio`-main-thread task
    before unblocking the requesting bg-thread.
  - from any requesting bg-thread in the root actor such that both its
    main-`trio`-thread scheduled task (as per above bullet) AND it are
    SIGINT shielded.
  - always call `.shield_sigint()` BEFORE any `greenback._await()` case
    don't entirely grok why yet, but it works)?
  - for `greenback._await()` case always set `bg_task` to the current one..
- tweaks to the `SIGINT` handler, now renamed `sigint_shield()` so as
  not to name-collide with the methods when editor-searching:
  - always try to `repr()` the REPL thread/task "owner" as well as the
    active `PdbREPL` instance.
  - add `.devx()` notes around the prompt flushing deats and comments
    for any root-actor-bg-thread edge cases.

Related/supporting refinements:
- add `get_lock()`/`get_debug_req()` factory funcs since the plan is to
  eventually implement both as `@singleton` instances per actor.
- fix `acquire_debug_lock()`'s call-sig-bug for scheduling
  `request_root_stdio_lock()`..
- in `._pause()` only call `mk_pdb()` when `debug_func != None`.
- add some todo/warning notes around the `cls.repl = None` in
  `DebugStatus.release()`

`test_pause_from_sync()` tweaks:
- don't use a `attach_patts.copy()`, since we always `break` on match.
- do `pytest.fail()` on that ^ loop's fallthrough..
- pass `do_ctlc(child, patt=attach_key)` such that we always match the
  the current thread's name with the ctl-c triggered `.pdb()` emission.
- oh yeah, return the last `before: str` from `do_ctlc()`.
- in the script, flip `abandon_on_cancel=True` since when `False` it
  seems to cause `trio.run()` to hang on exit from the last bg-thread
  case?!?
2024-07-10 12:29:05 -04:00