Leave all the proto native struct-msg stuff in `.types` since i'm
thinking it's the right name for the mod that will hold all the built-in
SCIPP msgspecs longer run. Obvi the naive codec stack stuff needs to be
cleaned out/up and anything useful moved into `._codec` ;)
The greasy details are strewn throughout a `msgspec` issue:
https://github.com/jcrist/msgspec/issues/140
and specifically this code was mostly written as part of POC example in
this comment:
https://github.com/jcrist/msgspec/issues/140#issuecomment-1177850792
This work obviously pertains to our desire and prep for typed messaging
and capabilities aware msg-oriented-protocols in #196. I added a "wants
to have" method to `Context` showing how I think we could offer a pretty
neat msg-type-set-as-capability-for-protocol system.
XXX NOTE XXX: this commit was rewritten during a rebase from a very old
version as per the prior commit.
XXX NOTE XXX: this is a heavily modified commit from the original
(ec226463) which was super out of date when rebased onto the current
branch. I went through a manual conflict rework and removed all the
legacy segments as well as rename-moved this original mod
`tractor.msg.py` -> `tractor.msg/_old_msg.py`. Further the
`NamespacePath` type def was discarded from this mod since it was from
a super old version which was already moved to a `.msg.ptr` submod.
As per original questions and discussion with `msgspec` author:
- https://github.com/jcrist/msgspec/issues/25
- https://github.com/jcrist/msgspec/issues/140
this prototypes a new (but very naive) `msgspec.Struct` codec
implementation which will be more filled out in the next commit.
Fitting in line with the issues outstanding:
- #36: (msg)spec-ing out our SCIPP (structured-con-inter-proc-prot).
(https://github.com/goodboy/tractor/issues/36)
- #196: adding strictly typed IPC msg dialog schemas, more or less
better described as "dialog/transaction scoped message specs"
using `msgspec`'s tagged unions and custom codecs.
(https://github.com/goodboy/tractor/issues/196)
- #365: using modern static type-annots to drive capability based
messaging and RPC.
(statically https://github.com/goodboy/tractor/issues/365)
This is a first draft of a new API for dynamically overriding IPC msg
codecs for a given interchange lib from any task in the runtime. Right
now we obviously only support `msgspec` but ideally this API holds
general enough to be used for other backends eventually (like
`capnproto`, and apache arrow).
Impl is in a new `tractor.msg._codec` with:
- a new `MsgCodec` type for encapsing `msgspec.msgpack.Encoder/Decoder`
pairs and configuring any custom enc/dec_hooks or typed decoding.
- factory `mk_codec()` for creating new codecs ad-hoc from a task.
- `contextvars` support for a new `trio.Task` scoped
`_ctxvar_MsgCodec: ContextVar[MsgCodec]` named 'msgspec_codec'.
- `apply_codec()` for temporarily modifying the above per task
as needed around `.open_context()` / `.open_stream()` operation.
A new test (suite) in `test_caps_msging.py`:
- verify a parent and its child can enable the same custom codec (in
this case to transmit `NamespacePath`s) with tons of pedantic ctx-vars
checks.
- ToDo: still need to implement #36 msg types in order to be able to get
decodes working (as in `MsgStream.receive()` will deliver an already
created `NamespacePath` obj) since currently all msgs come packed in `dict`-msg
wrapper packets..
-> use the proto from PR #35 to get nested `msgspec.Raw` processing up
and running Bo
By simply allowing an input `codec: tuple` of funcs for now to the
`MsgpackTCPStream` transport but, ideally wrapping this in a `Codec`
type with an API for dynamic extension of the interchange lib's msg
processing settings. Right now we're tied to `msgspec.msgpack` for this
transport but with the right design this can likely extend to other libs
in the future.
Relates to starting feature work toward #36, #196, #365.
It's **almost** there, we're just missing the final translation code to
get from an `asyncio` side task to be able to call
`.devx._debug..wait_for_parent_stdin_hijack()` to do root actor TTY
locking. Then we just need to ensure internals also do the right thing
with `greenback()` for equivalent sync `breakpoint()` style pause
points.
Since i'm deferring this until later, tossing in some xfail tests to
`test_infected_asyncio` with TODOs for the needed implementation as well
as eventual test org.
By "provision" it means we add:
- `greenback` init block to `_run_asyncio_task()` when debug mode is
enabled (but which will currently rte when `asyncio` is detected)
using `.bestow_portal()` around the `asyncio.Task`.
- a call to `_debug.maybe_init_greenback()` in the `run_as_asyncio_guest()`
guest-mode entry point.
- as part of `._debug.Lock.is_main_trio_thread()` whenever the async-lib
is not 'trio' error lock the backend name (which is obvi `'asyncio'`
in this use case).
In the particular case of the `Portal.open_context().__aexit__()` frame,
due to usage of `contextlib.asynccontextmanager`, we can't easily hook
into monkeypatching a `__tracebackhide__` set nor catch-n-reraise around
the block exit without defining our own `.__aexit__()` impl. Thus, it's
prolly most sane to do something with an override of
`contextlib._AsyncGeneratorContextManager` or the public exposed
`AsyncContextDecorator` (which uses the former internally right?).
Also fixup some old `._invoke` mod paths in comments and just show
`str(eoc)` in `.open_stream().__aexit__()` terminated-by-EoC log msg
since the `repr()` form won't pprint the IPC msg nicely..
Change the name to `Lock.is_main_trio_thread()` indicating that when
`True` the thread is both the main one **and** the one that called
`trio.run()`. Add a todo for just copying the
`trio._util.is_main_thread()` impl (since it's private / may change) and
some brief notes about potential usage of
`trio.from_thread.check_cancelled()` to detect non-`.to_thread` thread
spawns.
Now supports use from any `trio` task, any sync thread started with
`trio.to_thread.run_sync()` AND also via `breakpoint()` builtin API!
The only bit missing now is support for `asyncio` tasks when in infected
mode.. Bo
`greenback` setup/API adjustments:
- move `._rpc.maybe_import_gb()` to -> `devx._debug` and factor out the cached
import checking into a sync func whilst placing the async `.ensure_portal()`
bootstrapping into a new async `maybe_init_greenback()`.
- use the new init-er func inside `open_root_actor()` with the output
predicating whether we override the `breakpoint()` hook.
core `devx._debug` implementation deatz:
- make `mk_mpdb()` only return the `pdp.Pdb` subtype instance since
the sigint unshielding func is now accessible from the `Lock`
singleton from anywhere.
- add non-main thread support (at least for `trio.to_thread` use cases)
to our `Lock` with a new `.is_trio_thread()` predicate that delegates
directly to `trio`'s internal version.
- do `Lock.is_trio_thread()` checks inside any methods which require
special provisions when invoked from a non-main `trio` thread:
- `.[un]shield_sigint()` methods since `signal.signal` usage is only
allowed from cpython's main thread.
- `.release()` since `trio.StrictFIFOLock` can only be called from
a `trio` task.
- rework `.pause_from_sync()` itself to directly call `._set_trace()`
and don't bother with `greenback._await()` when we're already calling
it from a `.to_thread.run_sync()` thread, oh and try to use the
thread/task name when setting `Lock.local_task_in_debug`.
- make it an RTE for now if you try to use `.pause_from_sync()` from any
infected-`asyncio` task, but support is (hopefully) coming soon!
For testing we add a new `test_debugger.py::test_pause_from_sync()`
which includes a ctrl-c parametrization around the
`examples/debugging/sync_bp.py` script which includes all currently
supported/working usages:
- `tractor.pause_from_sync()`.
- via `breakpoint()` overload.
- from a `trio.to_thread.run_sync()` spawn.
This is what was breaking the nested debugger test (where it was failing
on the traceback content matching) and it makes sense.. XD
=> We always want to use the locally boxed `RemoteActorError`'s
traceback content NOT overwrite it with that from the src actor..
Also gets rid of setting the `'relay_uid'` since it's pulled from the
final element in the `'relay_path'` anyway.
Use new `RemoteActorError` fields in various assertions particularly
ensuring that an RTE relayed through the spawner from the little_bro
shows up at the client with the right number of entries in the
`.relay_path` and that the error is raised in the client as desired in
the original use case from `modden`'s remote spawn spawn request API
(which was kinda the whole original motivation to finally get all this
multi-actor error relay stuff workin).
Case extensions:
- RTE relayed from little_bro through spawner to client when
`raise_sub_spawn_error_after` is set; in this case test should raise
the relayed and RAE boxed RTE right up to the `trio.run()`.
-> ensure the `rae.src_uid`, `.relay_uid` are set correctly.
-> ensure ctx cancels are no acked.
- use `expect_ctxc()` around root's `tell_little_bro()` usage.
- do `debug_mode` assertions when enabled by test harness in each actor
layer.
- obvi use new `.src_type`/`.boxed_type` for final error propagation
assertions.
More or less just simplifies to not seeing the stream closure errors and
instead expecting KBIs from the simulated user who 'ctl-cs after hang'.
Toss in a little `stuff_hangin_ctlc()` to the script to wrap all that
and always check stream closure before sending the final KBI.
I swear long ago it used to operate this way but, I guess this finalizes
the design decision. It makes a lot more sense to *not* propagate any
`trio.EndOfChannel` raised from a `Context.open_stream() as stream:`
block when that EoC is due to graceful-explicit stream termination.
We use the EoC much like a `StopAsyncIteration` where the error
indicates termination of the stream due to either:
- reception of a stop IPC msg indicating the far end ended the stream
(gracecfully),
- closure of the underlying `Context._recv_chan` either by the runtime
or due to user code having called `MsgStream.aclose()`.
User code shouldn't expect to handle EoC outside the block since the
`@acm` having closed should indicate the exactly same lifetime state
(of said stream) ;)
Deats:
- add special EoC handler in `.open_stream()` which silently "absorbs"
the error only when the stream is already marked as closed (meaning
the EoC indeed corresponds to IPC closure) with an assert for now
ensuring the error is the same as set to `MsgStream._eoc`.
- in `MsgStream.receive()` break up the handlers for EoC and
`trio.ClosedResourceError` since the error instances are saved to
different variables and we **don't** want to rewrite the exception in
the eoc case (normally to mask `trio` internals in tbs) bc we need the
instance to be the exact one for doing checks inside
`.open_stream().__aexit__()` to absorb it.
Other surrounding "improvements":
- start using the new `Context.maybe_raise()` helper where it can easily
replace existing equivalent block-sections.
- use new `RemoteActorError.src_uid` as required.
The misname of `._boxed_type` as `._src_type` was only manifesting as
a reallly strange boxing error with a packed exception-group, not sure
how or why only that but it's fixed now XD
Start refining/cleaning out stuff for sure we don't need (based on
multiple local test runs):
- discard `.src_actor_uid` fully since test set has been moved over to
`.src_uid`; this means also removing the `.msgdata` insertion from
`pack_error()`; a patch to all internals is coming next obvi!
- don't pass `boxed_type` to `RemoteActorError.__init__()` from
`unpack_error()` since it's now set directly via the
`.msgdata["boxed_type_str"]`/`error_msg: dict` input , but in the case
where **it is passed as an arg** (only for ctxc in `._rpc._invoke()`
rn) make sure we only do the `.__init__()` insert when `boxed_type is
not None`.
Since adding more complex inter-peer (actor) testing scenarios, we
definitely have an immediate need for `trio`'s style of "inceptions" but
for nesting `RemoteActorError`s as they're relayed through multiple
actor-IPC hops. So for example, a remote error relayed "through" some
proxy actor to another ends up packing a `RemoteActorError` into another
one such that there are 2 layers of RAEs with the first
containing/boxing an original src actor error (type).
In support of this extension to `RemoteActorError` we add:
- `get_err_type()` error type resolver helper (factored fromthe
body of `unpack_error()`) to be used whenever rendering
`.src_type`/`.boxed_type`.
- `.src_type_str: str` which is pulled from `.msgdata` and holds the
above (eventually when unpacked) type as `str`.
- `._src_type: BaseException|None` for the original
"source" actor's error as unpacked in any remote (actor's) env and
exposed as a readonly property `.src_type`.
- `.boxed_type_str: str` the same as above but for the "last" boxed
error's type; when the RAE is unpacked at its first hop this will
be **the same as** `.src_type_str`.
- `._boxed_type: BaseException` which now similarly should be "rendered"
from the below type-`str` field instead of passed in as a error-type
via `boxed_type` (though we still do for the ctxc case atm, see
notes).
|_ new sanity checks in `.__init__()` mostly as a reminder to handle
that ^ ctxc case ^ more elegantly at some point..
|_ obvi we discard the previous `suberror_type` input arg.
- fully remove the `.type`/`.type_str` properties instead expecting
usage of `.boxed_/.src_` equivalents.
- start deprecation of `.src_actor_uid` and make it delegate to new
`.src_uid`
- add `.relay_uid` propery for the last relay/hop's actor uid.
- add `.relay_path: list[str]` which holds the per-hop updated sequence
of relay actor uid's which consecutively did boxing of an RAE.
- only include `.src_uid` and `.relay_path` in reprol() output.
- factor field-to-str rendering into a new `_mk_fields_str()`
and use it in `.__repr__()`/`.reprol()`.
- add an `.unwrap()` to (attempt to) render the src error.
- rework `pack_error()` to handle inceptions including,
- packing the correct field-values for the new `boxed_type_str`, `relay_uid`,
`src_uid`, `src_type_str`.
- always updating the `relay_path` sequence with the uid of the
current actor.
- adjust `unpack_error()` to match all these changes,
- pulling `boxed_type_str` and passing any resolved `boxed_type` to
`RemoteActorError.__init__()`.
- use the new `Context.maybe_raise()` convenience method.
Adjust `._rpc` packing to `ContextCancelled(boxed_type=trio.Cancelled)`
and tweak some more log msg formats.
- `trio_typing` is nearly obsolete since `trio >= 0.23`
- `exceptiongroup` is built-in to python 3.11
- `async_generator` primitives have lived in `contextlib` for quite
a while!
Since `._runtime` was getting pretty long (> 2k LOC) and much of the RPC
low-level machinery is fairly isolated to a handful of task-funcs, it
makes sense to re-org the RPC task scheduling and driving msg loop to
its own code space.
The move includes:
- `process_messages()` which is the main IPC business logic.
- `try_ship_error_to_remote()` helper, to box local errors for the wire.
- `_invoke()`, the core task scheduler entrypoing used in the msg loop.
- `_invoke_non_context()`, holds impls for non-`@context` task starts.
- `_errors_relayed_via_ipc()` which does all error catch-n-boxing for
wire-msg shipment using `try_ship_error_to_remote()` internally.
Also inside `._runtime` improve some `Actor` methods docs.
Finally, since normally you need the content from `._context.Context`
and surroundings in order to effectively grok `Portal.open_context()`
anyways, might as well move the impl to the ctx module as
`open_context_from_portal()` and just bind it on the `Portal` class def.
Associated/required tweaks:
- avoid circ import on `.devx` by only import
`.maybe_wait_for_debugger()` when debug mode is set.
- drop `async_generator` usage, not sure why this hadn't already been
changed to `contextlib`?
- use `@acm` alias throughout `._portal`
Previously i was trying to approach this using lots of
`__tracebackhide__`'s in various internal funcs but since it's not
exactly straight forward to do this inside core deps like `trio` and the
stdlib, it makes a bit more sense to optionally catch and re-raise
certain classes of errors from their originals using `raise from` syntax
as per:
https://docs.python.org/3/library/exceptions.html#exception-context
Deats:
- litter `._context` methods with `__tracebackhide__`/`hide_tb` which
were previously being shown but that don't need to be to application
code now that cancel semantics testing is finished up.
- i originally did the same but later commented it all out in `._ipc`
since error catch and re-raise instead in higher level layers
(above the transport) seems to be a much saner approach.
- add catch-n-reraise-from in `MsgStream.send()`/.`receive()` to avoid
seeing the depths of `trio` and/or our `._ipc` layers on comms errors.
Further this patch adds some refactoring to use the
same remote-error shipper routine from both the actor-core in the RPC
invoker:
- rename it as `try_ship_error_to_remote()` and call it from
`._invoke()` as well as it's prior usage.
- make it optionally accept `cid: str` a `remote_descr: str` and of
course a `hide_tb: bool`.
Other misc tweaks:
- add some todo notes around `Actor.load_modules()` debug hooking.
- tweak the zombie reaper log msg and timeout value ;)
Since importing from our top level `conftest.py` is not scaleable
or as "future forward thinking" in terms of:
- LoC-wise (it's only one file),
- prevents "external" (aka non-test) example scripts from importing
content easily,
- seemingly(?) can't be used via abs-import if using
a `[tool.pytest.ini_options]` in a `pyproject.toml` vs.
a `pytest.ini`, see:
https://docs.pytest.org/en/8.0.x/reference/customize.html#pyproject-toml)
=> Go back to having an internal "testing" pkg like `trio` (kinda) does.
Deats:
- move generic top level helpers into pkg-mod including the new
`expect_ctxc()` (which i needed in the advanced faults testing script.
- move `@tractor_test` into `._testing.pytest` sub-mod.
- adjust all the helper imports to be a `from tractor._testing import <..>`
Rework `test_ipc_channel_break_during_stream()` and backing script:
- make test(s) pull `debug_mode` from new fixture (which is now
controlled manually from `--tpdb` flag) and drop the previous
parametrized input.
- update logic in ^ test for "which-side-fails" cases to better match
recently updated/stricter cancel/failure semantics in terms of
`ClosedResouruceError` vs. `EndOfChannel` expectations.
- handle `ExceptionGroup`s with expected embedded errors in test.
- better pendantics around whether to expect a user simulated KBI.
- for `examples/advanced_faults/ipc_failure_during_stream.py` script:
- generalize ipc breakage in new `break_ipc()` with support for diff
internal `trio` methods and a #TODO for future disti frameworks
- only make one sub-actor task break and the other just stream.
- use new `._testing.expect_ctxc()` around ctx block.
- add a bit of exception handling with `print()`s around ctxc (unused
except if 'msg' break method is set) and eoc cases.
- don't break parent side ipc in loop any more then once
after first break, checked via flag var.
- add a `pre_close: bool` flag to control whether
`MsgStreama.aclose()` is called *before* any ipc breakage method.
Still TODO:
- drop `pytest.ini` and add the alt section to `pyproject.py`.
-> currently can't get `--rootdir=` opt to work.. not showing in
console header.
-> ^ also breaks on 'tests' `enable_modules` imports in subactors
during discovery tests?
With the seeming cause that some cases occasionally raise
`ExceptionGroup` instead of a (collapsed out) single error which, in
those cases at least try to check that `.exceptions` has the original
error.
Found exactly why trying this won't work when playing around with
opening workspaces in `modden` using a `Portal.open_context()` back to
the 'bigd' root actor: the RPC machinery only registers one entry in
`Actor._contexts` which will get overwritten by each task's side and
then experience race-based IPC msging errors (eg. rxing `{'started': _}`
on the callee side..). Instead make opening a ctx back to the self-actor
a runtime error describing it as an invalid op.
To match:
- add a new test `test_ctx_with_self_actor()` to the context semantics
suite.
- tried out adding a new `side: str` to the `Actor.get_context()` (and
callers) but ran into not being able to determine the value from in
`._push_result()` where it's needed to figure out which side to push
to.. So, just leaving the commented arg (passing) in the runtime core
for now in case we can come back to trying to make it work, tho i'm
thinking it's not the right hack anyway XD
Call it `allow_msg_keys: list[str] = ['yield']` and set it to accept
`['yield', 'return']` from the drain loop in `.aclose()`. Only pass the
last key error to `_raise_from_no_key_in_msg()` in the fall-through
case.
Somehow this seems to prevent all the intermittent test failures i was
seeing in local runs including when running the entire suite all in
sequence; i ain't complaining B)
Much like similar recent changes throughout the core, build out `msg:
str` depending on error cases and emit with `.cancel()` level as
appropes. Also mute (via level) some duplication in the cancel case
inside `_run_asyncio_task()` for console noise reduction.
Since apparently `str(KeyboardInterrupt()) == ''`? So instead add little
`<str> or repr(merr)` expressions throughout to avoid blank strings
rendering if various `repr()`/`.__str__()` outputs..
Such that it's set to whatever `Actor.reg_addrs: list[tuple]` is during
the actor's init-after-spawn guaranteeing each actor has at least the
registry infos from its parent. Ensure we read this if defined over
`_root._default_lo_addrs` in `._discovery` routines, namely
`.find_actor()` since it's the one API normally used without expecting
the runtime's `current_actor()` to be up.
Update the latest inter-peer cancellation test to use the `reg_addr`
fixture (and thus test this new runtime-vars value via `find_actor()`
usage) since it was failing if run *after* the infected `asyncio` suite
due to registry contact failure.
Not sure if it's really that useful other then for reporting errors from
`current_actor()` but at least it alerts `tractor` devs and/or users
when the runtime has already terminated vs. hasn't been started
yet/correctly.
Set the `._last_actor_terminated: tuple` in the root's final block which
allows testing for an already terminated tree which is the case where
`._state._current_actor == None` and the last is set.
Including mostly tweaking asserts on relayed `ContextCancelled`s and
the new pub ctx properties: `.outcome`, `.maybe_error`, etc. as it
pertains to graceful (absorbed) remote cancellation vs. loud ctxc cases
expected to be raised by any `Portal.cancel_actor()` style teardown.
Start checking a variety internals like `._remote/local_error`,
`._is_self_cancelled()`, `._is_final_result_set()`, `._cancel_msg`
where applicable.
Also factor out the new `expect_ctxc()` checker to our `conftest.py` for
use in other suites.
We're passing a `extra_frames_up_when_async=2` now (from prior attempt
to hide `CancelScope.__exit__()` when `shield=True`) and thus both
`debug_func`s must accept it 🤦
On the brighter side found out that the `TypeError` from the call-sig
mismatch was actually being swallowed entirely so add some
`.exception()` msgs for such cases to at least alert the dev they broke
stuff XD
Changes the condition logic to be more strict and moves it to a private
`._is_self_cancelled() -> bool` predicate which can be used elsewhere
(instead of having almost similar duplicate checks all over the
place..) and allows taking in a specific `remote_error` just for
verification purposes (like for tests).
Main strictness distinctions are now:
- obvi that `.cancel_called` is set (this filters any
`Portal.cancel_actor()` or other out-of-band RPC),
- the received `ContextCancelled` **must** have its `.canceller` set to
this side's `Actor.uid` (indicating we are the requester).
- `.src_actor_uid` **must** be the same as the `.chan.uid` (so the error
must have originated from the opposite side's task.
- `ContextCancelled.canceller` should be already set to the `.chan.uid`
indicating we received the msg via the runtime calling
`._deliver_msg()` -> `_maybe_cancel_and_set_remote_error()` which
ensures the error is specifically destined for this ctx-task exactly
the same as how `Actor._cancel_task()` sets it from an input
`requesting_uid` arg.
In support of the above adjust some impl deats:
- add `Context._actor: Actor` which is set once in `mk_context()` to
avoid issues (particularly in testing) where `current_actor()` raises
after the root actor / runtime is already exited. Use `._actor.uid` in
both `.cancel_acked` (obvi) and '_maybe_cancel_and_set_remote_error()`
when deciding whether to call `._scope.cancel()`.
- always cast `.canceller` to `tuple` if not null.
- delegate `.cancel_acked` directly to new private predicate (obvi).
- always set `._canceller` from any `RemoteActorError.src_actor_uid` or
failing over to the `.chan.uid` when a non-remote error (tho that
shouldn't ever happen right?).
- more extensive doc-string for `.cancel()` detailing the new strictness
rules about whether an eventual `.cancel_acked` might be set.
Also tossed in even more logging format tweaks by adding a
`type_only: bool` to `.repr_outcome()` as desired for simpler output in
the `state: <outcome-repr-here>` and `.repr_rpc()` sections of the
`.__str__()`.
Like how we set `Context._cancel_msg` in `._deliver_msg()` (in
which case normally it's an `{'error': ..}` msg), do the same when any
RPC task is remotely cancelled via `Actor._cancel_task` where that task
doesn't yet have a cancel msg set yet.
This makes is much easier to distinguish between ctx cancellations due
to some remote error vs. Explicit remote requests via any of
`Actor.cancel()`, `Portal.cancel_actor()` or `Context.cancel()`.
We don't expect `._scope.cancelled_caught` to be set really ever on
inter-peer cancellation since no ctx is ever cancelling itself, a peer
cancels some other and then bubbles back to all other peers.
Also add `ids: lambda` for `error_during_ctxerr_handling` param to
`test_peer_canceller()`
It's been on the todo for a while and I've given up trying to properly
hide the `trio.CancelScope.__exit__()` frame for now instead opting to
just `log.pdb()` a big apology XD
Users can obvi still just not use the flag and wrap `tractor.pause()` in
their own cs block if they want to avoid having to hit `'up'` in the pdb
REPL if needed in a cancelled task-scope.
Impl deatz:
- factor orig `.pause()` impl into new `._pause()` so that we can more tersely
wrap the original content depending on `shield: bool` input; only open
the cancel-scope when shield is set to avoid aforemented extra strack
frame annoyance.
- pass through `shield` to underlying `_pause` and `debug_func()` so we
can actually know when so log our apology.
- add a buncha notes to new `.pause()` wrapper regarding the inability
to hide the cancel-scope `.__exit__()`, inluding that overriding the
code in `trio._core._run.CancelScope` doesn't seem to solve the issue
either..
Unrelated `maybe_wait_for_debugger()` tweaks:
- don't read `Lock.global_actor_in_debug` more then needed, rename local
read var to `in_debug` (since it can also hold the root actor uid, not
just sub-actors).
- shield the `await debug_complete.wait()` since ideally we avoid the
root cancellation child-actors in debug even when the root calls this
func in a cancelled scope.
Buncha subtle details changed mostly to do with when `Context.cancel()`
gets called on "real" remote errors vs. (peer requested) cancellation
and then local side handling of `ContextCancelled`.
Specific changes to make tests pass:
- due to raciness with `sleeper_ctx.result()` raising the ctxc locally
vs. the child-peers receiving similar ctxcs themselves (and then
erroring and propagating back to the root parent), we might not see
`._remote_error` set during the sub-ctx loops (except for the sleeper
itself obvi).
- do not expect `.cancel_called`/`.cancel_caught` to be set on any
sub-ctx since currently `Context.cancel()` is only called non-shielded
and thus is not in invoked when `._scope.cancel()` is called as part
of each root-side ctx ref/block handling the inter-peer ctxc.
- do not expect `Context._scope.cancelled_caught` to be set in most cases
(even the sleeper)
TODO Outstanding adjustments not fixed yet:
-[ ] `_scope.cancelled_caught` checks outside the `.open_context()`
blocks.
Tyler Goodlet