Be extra sure to re-raise EoCs from translator

That is whenever `trio.EndOfChannel` is raised (presumably from the
`._to_trio.receive()` call inside `LinkedTaskChannel.receive()`) we need
to be extra certain that we let it bubble upward transparently DESPITE
special exc-as-signal handling that is normally suppressed from the aio
side; REPEAT we want to ALWAYS bubble any `trio_err ==
trio.EndOfChannel` in the `finally:` handler of `translate_aio_errors()`
despite `chan._trio_to_raise == AsyncioTaskExited` such that the
caller's iterable machinery will operate as normal when the inter-task
stream is stopped (again, presumably by the aio side task terminating
the inter-task stream).

Main impl deats for this,
- in the EoC handler block ensure we assign both `chan._trio_err` and
  the local `trio_err` as well as continue to re-raise.
- add a case to the match block in the `finally:` handler which FOR SURE
  re-raises any `type(trio_err) is EndOfChannel`!

Additionally fix a bad bug,
- a ref bug where we were NOT using the
  `except BaseException as _trio_err` to assign to `chan._trio_err` (by
  accident was missing the leading `_`..)

Unrelated impl tweak,
- move all `maybe_raise_aio_side_err()` content back to inline with its
  parent func - makes it easier to use `tractor.pause()` mostly Bp
- go back to trying to use `aio_task.set_exception(aio_taskc)` for now
  even though i'm pretty sure we're going to move to a try-fute-first
  style helper for this in the future.

Adjust some tests to match/mk-them-green,
- break from `aio_echo_server()` recv loop on
  `to_asyncio.TrioTaskExited` much like how you'd expect to (implicitly
  with a `for`) with a `trio.EndOfChannel`.
- toss in a masked `value is None` pause point i needed for debugging
  inf looping caused by not re-raising EoCs per the main patch
  description.
- add a debug-mode sized delay to root-infected test.

tests/test_infected_asyncio.py

@@ -491,7 +491,13 @@ async def stream_from_aio(
                 ],
             ):
                 async for value in chan:
-                    print(f'trio received {value}')
+                    print(f'trio received: {value!r}')
+
+                    # XXX, debugging EoC not being handled correctly
+                    # in `transate_aio_errors()`..
+                    # if value is None:
+                    #     await tractor.pause(shield=True)
+
                     pulled.append(value)
 
                     if value == 50:
@@ -733,7 +739,13 @@ async def aio_echo_server(
     to_trio.send_nowait('start')
 
     while True:
+        try:
             msg = await from_trio.get()
+        except to_asyncio.TrioTaskExited:
+            print(
+                'breaking aio echo loop due to `trio` exit!'
+            )
+            break
 
         # echo the msg back
         to_trio.send_nowait(msg)

tests/test_root_infect_asyncio.py

@@ -39,7 +39,7 @@ def test_infected_root_actor(
 
     '''
     async def _trio_main():
-        with trio.fail_after(2):
+        with trio.fail_after(2 if not debug_mode else 999):
             first: str
             chan: to_asyncio.LinkedTaskChannel
             async with (
@@ -59,7 +59,11 @@ def test_infected_root_actor(
                     assert out == i
                     print(f'asyncio echoing {i}')
 
-                    if raise_error_mid_stream and i == 500:
+                    if (
+                        raise_error_mid_stream
+                        and
+                        i == 500
+                    ):
                         raise raise_error_mid_stream
 
                     if out is None:

tests/test_trioisms.py

@@ -64,7 +64,9 @@ def test_stashed_child_nursery(use_start_soon):
     async def main():
 
         async with (
-            trio.open_nursery() as pn,
+            trio.open_nursery(
+                strict_exception_groups=False,
+            ) as pn,
         ):
             cn = await pn.start(mk_child_nursery)
             assert cn

tractor/devx/_debug.py

@@ -2287,6 +2287,13 @@ def _set_trace(
     repl.set_trace(frame=caller_frame)
 
 
+# XXX TODO! XXX, ensure `pytest -s` doesn't just
+# hang on this being called in a test.. XD
+# -[ ] maybe something in our test suite or is there
+#     some way we can detect output capture is enabled
+#     from the process itself?
+# |_ronny: ?
+#
 async def pause(
     *,
     hide_tb: bool = True,
@@ -3194,6 +3201,15 @@ async def maybe_wait_for_debugger(
     return False
 
 
+class BoxedMaybeException(Struct):
+    '''
+    Box a maybe-exception for post-crash introspection usage
+    from the body of a `open_crash_handler()` scope.
+
+    '''
+    value: BaseException|None = None
+
+
 # TODO: better naming and what additionals?
 # - [ ] optional runtime plugging?
 # - [ ] detection for sync vs. async code?
@@ -3224,9 +3240,6 @@ def open_crash_handler(
     '''
     __tracebackhide__: bool = tb_hide
 
-    class BoxedMaybeException(Struct):
-        value: BaseException|None = None
-
     # TODO, yield a `outcome.Error`-like boxed type?
     # -[~] use `outcome.Value/Error` X-> frozen!
     # -[x] write our own..?
@@ -3268,6 +3281,8 @@ def open_crash_handler(
 def maybe_open_crash_handler(
     pdb: bool = False,
     tb_hide: bool = True,
+
+    **kwargs,
 ):
     '''
     Same as `open_crash_handler()` but with bool input flag
@@ -3278,9 +3293,11 @@ def maybe_open_crash_handler(
     '''
     __tracebackhide__: bool = tb_hide
 
-    rtctx = nullcontext
+    rtctx = nullcontext(
+        enter_result=BoxedMaybeException()
+    )
     if pdb:
-        rtctx = open_crash_handler
+        rtctx = open_crash_handler(**kwargs)
 
-    with rtctx():
-        yield
+    with rtctx as boxed_maybe_exc:
+        yield boxed_maybe_exc

tractor/to_asyncio.py

@@ -348,7 +348,6 @@ def _run_asyncio_task(
     trio_task: trio.Task = trio.lowlevel.current_task()
     trio_cs = trio.CancelScope()
     aio_task_complete = trio.Event()
-    aio_err: BaseException|None = None
 
     chan = LinkedTaskChannel(
         _to_aio=aio_q,  # asyncio.Queue
@@ -392,7 +391,7 @@ def _run_asyncio_task(
             if (
                 result != orig
                 and
-                aio_err is None
+                chan._aio_err is None
                 and
 
                 # in the `open_channel_from()` case we don't
@@ -429,8 +428,7 @@ def _run_asyncio_task(
                     not chan._aio_err
                 ):
                     chan._trio_to_raise = AsyncioTaskExited(
-                        f'Task existed with final result\n'
-                        f'{result!r}\n'
+                        f'Task exited with final result: {result!r}\n'
                     )
 
                 # only close the sender side which will relay
@@ -742,7 +740,6 @@ async def translate_aio_errors(
     aio_done_before_trio: bool = aio_task.done()
     assert aio_task
     trio_err: BaseException|None = None
-    to_raise_trio: BaseException|None = None
     try:
         yield  # back to one of the cross-loop apis
     except trio.Cancelled as taskc:
@@ -778,8 +775,9 @@ async def translate_aio_errors(
     # called from `LinkedTaskChannel.receive()` which we want
     # passthrough and further we have no special meaning for it in
     # terms of relaying errors or signals from the aio side!
-    except trio.EndOfChannel:
-        raise
+    except trio.EndOfChannel as eoc:
+        trio_err = chan._trio_err = eoc
+        raise eoc
 
     # NOTE ALSO SEE the matching note in the `cancel_trio()` asyncio
     # task-done-callback.
@@ -825,7 +823,7 @@ async def translate_aio_errors(
             raise cre
 
     except BaseException as _trio_err:
-        trio_err = chan._trio_err = trio_err
+        trio_err = chan._trio_err = _trio_err
         # await tractor.pause(shield=True)  # workx!
         entered: bool = await _debug._maybe_enter_pm(
             trio_err,
@@ -866,25 +864,27 @@ async def translate_aio_errors(
                 f'The `trio`-side task crashed!\n'
                 f'{trio_err}'
             )
-            aio_task.set_exception(aio_taskc)
-            wait_on_aio_task = False
-            # try:
+            # ??TODO? move this into the func that tries to use
+            # `Task._fut_waiter: Future` instead??
+            #
             # aio_task.set_exception(aio_taskc)
-            # except (
-            #     asyncio.InvalidStateError,
-            #     RuntimeError,
-            #     # ^XXX, uhh bc apparently we can't use `.set_exception()`
-            #     # any more XD .. ??
-            # ):
             # wait_on_aio_task = False
+            try:
+                aio_task.set_exception(aio_taskc)
+            except (
+                asyncio.InvalidStateError,
+                RuntimeError,
+                # ^XXX, uhh bc apparently we can't use `.set_exception()`
+                # any more XD .. ??
+            ):
+                wait_on_aio_task = False
 
     finally:
         # record wtv `trio`-side error transpired
         if trio_err:
-            if chan._trio_err is not trio_err:
-                await tractor.pause(shield=True)
-
-            # assert chan._trio_err is trio_err
+            assert chan._trio_err is trio_err
+            # if chan._trio_err is not trio_err:
+            #     await tractor.pause(shield=True)
 
         ya_trio_exited: bool = chan._trio_exited
         graceful_trio_exit: bool = (
@@ -1032,15 +1032,8 @@ async def translate_aio_errors(
                 'asyncio-task is done and unblocked trio-side!\n'
             )
 
-        # TODO?
-        # -[ ] make this a channel method, OR
-        # -[ ] just put back inline below?
-        #
-        # await tractor.pause(shield=True)
-        # TODO, go back to inlining this..
-        def maybe_raise_aio_side_err(
-            trio_err: Exception,
-        ) -> None:
+        # NOTE, was a `maybe_raise_aio_side_err()` closure that
+        # i moved inline BP
         '''
         Raise any `trio`-side-caused cancellation or legit task
         error normally propagated from the caller of either,
@@ -1059,20 +1052,26 @@ async def translate_aio_errors(
             raise trio_to_raise from (aio_err or trio_err)
 
         if trio_to_raise:
-                # import pdbp; pdbp.set_trace()
             match (
                 trio_to_raise,
                 trio_err,
             ):
                 case (
                     AsyncioTaskExited(),
-                        trio.Cancelled()|None,
+                    trio.Cancelled()|
+                    None,
                 ):
                     log.info(
                         'Ignoring aio exit signal since trio also exited!'
                     )
                     return
 
+                case (
+                    AsyncioTaskExited(),
+                    trio.EndOfChannel(),
+                ):
+                    raise trio_err
+
                 case (
                     AsyncioCancelled(),
                     trio.Cancelled(),
@@ -1091,24 +1090,6 @@ async def translate_aio_errors(
             aio_err is not None
             and
             type(aio_err) is not AsyncioCancelled
-                # and (
-                #     type(aio_err) is not AsyncioTaskExited
-                #     and
-                #     not ya_trio_exited
-                #     and
-                #     not trio_err
-                # )
-
-                    # TODO, case where trio_err is not None and
-                    # aio_err is AsyncioTaskExited => raise eg!
-                    # -[ ] maybe use a match bc this get's real
-                    # complex fast XD
-                    #
-                    # or
-                    # type(aio_err) is not AsyncioTaskExited
-                    # and
-                    # trio_err
-                # )
         ):
             # always raise from any captured asyncio error
             if trio_err:
@@ -1123,13 +1104,11 @@ async def translate_aio_errors(
         if trio_err:
             raise trio_err
 
-        # await tractor.pause()
-        # NOTE: if any ``asyncio`` error was caught, raise it here inline
-        # here in the ``trio`` task
-        # if trio_err:
-        maybe_raise_aio_side_err(
-            trio_err=to_raise_trio or trio_err
-        )
+        # ^^TODO?? case where trio_err is not None and
+        # aio_err is AsyncioTaskExited => raise eg!
+        # -[x] maybe use a match bc this get's real
+        #     complex fast XD
+        #  => i did this above for silent exit cases ya?
 
 
 async def run_task(