Adjust `test_trio_prestarted_task_bubbles()` suite to expect non-eg raises

Was failing due to the `.fail_after()` timeout being *too short* and
somehow the new interplay of that with strict-exception groups resulting
in the `TooSlowError` never raising but instead an eg with the embedded
`AssertionError`?? I still don't really get it honestly..

I've written up lengthy notes around the different `delay` settings that
can be used to see the diff outcomes, the failing case being the one
i still don't really grok and think is justification for `trio` to
bubble inner `Cancelled`s differently possibly?

For now i've included the original failing case as an `xfail`
parametrization for now which will hopefully drive a follow lowlevel
`trio` test in `test_trioisms`!

examples/advanced_faults/ipc_failure_during_stream.py

@@ -16,7 +16,6 @@ from tractor import (
     ContextCancelled,
     MsgStream,
     _testing,
-    trionics,
 )
 import trio
 import pytest
@@ -63,8 +62,9 @@ async def recv_and_spawn_net_killers(
     await ctx.started()
     async with (
         ctx.open_stream() as stream,
-        trionics.collapse_eg(),
-        trio.open_nursery() as tn,
+        trio.open_nursery(
+            strict_exception_groups=False,
+        ) as tn,
     ):
         async for i in stream:
             print(f'child echoing {i}')

examples/quick_cluster.py

@@ -23,8 +23,9 @@ async def main():
             modules=[__name__]
         ) as portal_map,
 
-        tractor.trionics.collapse_eg(),
-        trio.open_nursery() as tn,
+        trio.open_nursery(
+            strict_exception_groups=False,
+        ) as tn,
     ):
 
         for (name, portal) in portal_map.items():

examples/trio/send_chan_aclose_masks_beg.py

@@ -0,0 +1,145 @@
+from contextlib import (
+    contextmanager as cm,
+    # TODO, any diff in async case(s)??
+    # asynccontextmanager as acm,
+)
+from functools import partial
+
+import tractor
+import trio
+
+
+log = tractor.log.get_logger(__name__)
+tractor.log.get_console_log('info')
+
+@cm
+def teardown_on_exc(
+    raise_from_handler: bool = False,
+):
+    '''
+    You could also have a teardown handler which catches any exc and
+    does some required teardown. In this case the problem is
+    compounded UNLESS you ensure the handler's scope is OUTSIDE the
+    `ux.aclose()`.. that is in the caller's enclosing scope.
+
+    '''
+    try:
+        yield
+    except BaseException as _berr:
+        berr = _berr
+        log.exception(
+            f'Handling termination teardown in child due to,\n'
+            f'{berr!r}\n'
+        )
+        if raise_from_handler:
+            # XXX teardown ops XXX
+            # on termination these steps say need to be run to
+            # ensure wider system consistency (like the state of
+            # remote connections/services).
+            #
+            # HOWEVER, any bug in this teardown code is also
+            # masked by the `tx.aclose()`!
+            # this is also true if `_tn.cancel_scope` is
+            # `.cancel_called` by the parent in a graceful
+            # request case..
+
+            # simulate a bug in teardown handler.
+            raise RuntimeError(
+                'woopsie teardown bug!'
+            )
+
+        raise  # no teardown bug.
+
+
+async def finite_stream_to_rent(
+    tx: trio.abc.SendChannel,
+    child_errors_mid_stream: bool,
+
+    task_status: trio.TaskStatus[
+        trio.CancelScope,
+    ] = trio.TASK_STATUS_IGNORED,
+):
+    async with (
+        # XXX without this unmasker the mid-streaming RTE is never
+        # reported since it is masked by the `tx.aclose()`
+        # call which in turn raises `Cancelled`!
+        #
+        # NOTE, this is WITHOUT doing any exception handling
+        # inside the child  task!
+        #
+        # TODO, uncomment next LoC to see the supprsessed beg[RTE]!
+        # tractor.trionics.maybe_raise_from_masking_exc(),
+
+        tx as tx,  # .aclose() is the guilty masker chkpt!
+        trio.open_nursery() as _tn,
+    ):
+        # pass our scope back to parent for supervision\
+        # control.
+        task_status.started(_tn.cancel_scope)
+
+        with teardown_on_exc(
+            raise_from_handler=not child_errors_mid_stream,
+        ):
+            for i in range(100):
+                log.info(
+                    f'Child tx {i!r}\n'
+                )
+                if (
+                    child_errors_mid_stream
+                    and
+                    i == 66
+                ):
+                    # oh wait but WOOPS there's a bug
+                    # in that teardown code!?
+                    raise RuntimeError(
+                        'woopsie, a mid-streaming bug!?'
+                    )
+
+                await tx.send(i)
+
+
+async def main(
+    # TODO! toggle this for the 2 cases!
+    # 1. child errors mid-stream while parent is also requesting
+    #   (graceful) cancel of that child streamer.
+    #
+    # 2. child contains a teardown handler which contains a
+    #   bug and raises.
+    #
+    child_errors_mid_stream: bool,
+):
+    tx, rx = trio.open_memory_channel(1)
+
+    async with (
+        trio.open_nursery() as tn,
+        rx as rx,
+    ):
+
+        _child_cs = await tn.start(
+            partial(
+                finite_stream_to_rent,
+                child_errors_mid_stream=child_errors_mid_stream,
+                tx=tx,
+            )
+        )
+        async for msg in rx:
+            log.info(
+                f'Rent rx {msg!r}\n'
+            )
+
+            # simulate some external cancellation
+            # request **JUST BEFORE** the child errors.
+            if msg == 65:
+                log.cancel(
+                    f'Cancelling parent on,\n'
+                    f'msg={msg}\n'
+                    f'\n'
+                    f'Simulates OOB cancel request!\n'
+                )
+                tn.cancel_scope.cancel()
+
+
+if __name__ == '__main__':
+
+    for case in [True, False]:
+        trio.run(main, case)

tests/test_advanced_streaming.py

@@ -313,8 +313,9 @@ async def inf_streamer(
         # `trio.EndOfChannel` doesn't propagate directly to the above
         # .open_stream() parent, resulting in it also raising instead
         # of gracefully absorbing as normal.. so how to handle?
-        tractor.trionics.collapse_eg(),
-        trio.open_nursery() as tn,
+        trio.open_nursery(
+            strict_exception_groups=False,
+        ) as tn,
     ):
         async def close_stream_on_sentinel():
             async for msg in stream:

tests/test_cancellation.py

@@ -532,15 +532,10 @@ def test_cancel_via_SIGINT_other_task(
     async def main():
         # should never timeout since SIGINT should cancel the current program
         with trio.fail_after(timeout):
-            async with (
-
-                # XXX ?TODO? why no work!?
-                # tractor.trionics.collapse_eg(),
-                trio.open_nursery(
-                    strict_exception_groups=False,
-                ) as tn,
-            ):
-                await tn.start(spawn_and_sleep_forever)
+            async with trio.open_nursery(
+                strict_exception_groups=False,
+            ) as n:
+                await n.start(spawn_and_sleep_forever)
                 if 'mp' in spawn_backend:
                     time.sleep(0.1)
                 os.kill(pid, signal.SIGINT)

tests/test_child_manages_service_nursery.py

@@ -117,10 +117,9 @@ async def open_actor_local_nursery(
     ctx: tractor.Context,
 ):
     global _nursery
-    async with (
-        tractor.trionics.collapse_eg(),
-        trio.open_nursery() as tn
-    ):
+    async with trio.open_nursery(
+        strict_exception_groups=False,
+    ) as tn:
         _nursery = tn
         await ctx.started()
         await trio.sleep(10)

tests/test_discovery.py

@@ -11,7 +11,6 @@ import psutil
 import pytest
 import subprocess
 import tractor
-from tractor.trionics import collapse_eg
 from tractor._testing import tractor_test
 import trio
 
@@ -194,10 +193,10 @@ async def spawn_and_check_registry(
 
             try:
                 async with tractor.open_nursery() as an:
-                    async with (
-                        collapse_eg(),
-                        trio.open_nursery() as trion,
-                    ):
+                    async with trio.open_nursery(
+                        strict_exception_groups=False,
+                    ) as trion:
+
                         portals = {}
                         for i in range(3):
                             name = f'a{i}'
@@ -339,12 +338,11 @@ async def close_chans_before_nursery(
                         async with portal2.open_stream_from(
                             stream_forever
                         ) as agen2:
-                            async with (
-                                collapse_eg(),
-                                trio.open_nursery() as tn,
-                            ):
-                                tn.start_soon(streamer, agen1)
-                                tn.start_soon(cancel, use_signal, .5)
+                            async with trio.open_nursery(
+                                strict_exception_groups=False,
+                            ) as n:
+                                n.start_soon(streamer, agen1)
+                                n.start_soon(cancel, use_signal, .5)
                                 try:
                                     await streamer(agen2)
                                 finally:

tests/test_infected_asyncio.py

@@ -234,8 +234,10 @@ async def trio_ctx(
     with trio.fail_after(1 + delay):
         try:
             async with (
-                tractor.trionics.collapse_eg(),
-                trio.open_nursery() as tn,
+                trio.open_nursery(
+                    # TODO, for new `trio` / py3.13
+                    # strict_exception_groups=False,
+                ) as tn,
                 tractor.to_asyncio.open_channel_from(
                     sleep_and_err,
                 ) as (first, chan),

tests/test_trioisms.py

@@ -8,7 +8,6 @@ from contextlib import (
 )
 
 import pytest
-from tractor.trionics import collapse_eg
 import trio
 from trio import TaskStatus
 
@@ -65,8 +64,9 @@ def test_stashed_child_nursery(use_start_soon):
     async def main():
 
         async with (
-            collapse_eg(),
-            trio.open_nursery() as pn,
+            trio.open_nursery(
+                strict_exception_groups=False,
+            ) as pn,
         ):
             cn = await pn.start(mk_child_nursery)
             assert cn
@@ -197,8 +197,10 @@ def test_gatherctxs_with_memchan_breaks_multicancelled(
         async with (
             # XXX should ensure ONLY the KBI
             # is relayed upward
-            collapse_eg(),
-            trio.open_nursery(), # as tn,
+            trionics.collapse_eg(),
+            trio.open_nursery(
+                # strict_exception_groups=False,
+            ), # as tn,
 
             trionics.gather_contexts([
                 open_memchan(),

tractor/_runtime.py

@@ -1760,7 +1760,9 @@ async def async_main(
                 f'   {pformat(ipc_server._peers)}'
             )
             log.runtime(teardown_report)
-            await ipc_server.wait_for_no_more_peers()
+            await ipc_server.wait_for_no_more_peers(
+                shield=True,
+            )
 
         teardown_report += (
             '-]> all peer channels are complete.\n'

tractor/ipc/_server.py

@@ -814,14 +814,10 @@ class Server(Struct):
 
     async def wait_for_no_more_peers(
         self,
-        # XXX, should this even be allowed?
-        # -> i've seen it cause hangs on teardown
-        #    in `test_resource_cache.py`
-        # _shield: bool = False,
+        shield: bool = False,
     ) -> None:
-        await self._no_more_peers.wait()
-        # with trio.CancelScope(shield=_shield):
-        #     await self._no_more_peers.wait()
+        with trio.CancelScope(shield=shield):
+            await self._no_more_peers.wait()
 
     async def wait_for_peer(
         self,