Include `TransportClosed` in tpt-layer err handling

Add `TransportClosed` to except clauses where `trio`'s own
resource-closed errors are already caught, ensuring our
higher-level tpt exc is also tolerated in those same spots.
Likely i will follow up with a removal of the `trio` variants since most
*should be* caught and re-raised as tpt-closed out of the `.ipc` stack
now?

Add `TransportClosed` to various handler blocks,
- `._streaming.MsgStream.aclose()/.send()` except blocks.
- the broken-channel except in `._context.open_context_from_portal()`.
- obvi import it where necessary in those ^ mods.

Adjust `test_advanced_faults` suite + exs-script to match,
- update `ipc_failure_during_stream.py` example to catch
  `TransportClosed` alongside `trio.ClosedResourceError`
  in both the break and send-check paths.
- shield the `trio.sleep(0.01)` after tpt close in example to avoid
  taskc-raise/masking on that checkpoint since we want to simulate
  waiting for a user to send a KBI.
- loosen `ExceptionGroup` assertion to `len(excs) <= 2` and ensure all
  excs are `TransportClosed`.
- improve multi-line formatting, minor style/formatting fixes in
  condition expressions.

(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

examples/advanced_faults/ipc_failure_during_stream.py

@@ -17,6 +17,7 @@ from tractor import (
     MsgStream,
     _testing,
     trionics,
+    TransportClosed,
 )
 import trio
 import pytest
@@ -208,12 +209,16 @@ async def main(
                         # TODO: is this needed or no?
                         raise
 
-                    except trio.ClosedResourceError:
+                    except (
+                        trio.ClosedResourceError,
+                        TransportClosed,
+                    ) as _tpt_err:
                         # NOTE: don't send if we already broke the
                         # connection to avoid raising a closed-error
                         # such that we drop through to the ctl-c
                         # mashing by user.
-                        await trio.sleep(0.01)
+                        with trio.CancelScope(shield=True):
+                            await trio.sleep(0.01)
 
                     # timeout: int = 1
                     # with trio.move_on_after(timeout) as cs:
@@ -247,6 +252,7 @@ async def main(
                     await stream.send(i)
                     pytest.fail('stream not closed?')
                 except (
+                    TransportClosed,
                     trio.ClosedResourceError,
                     trio.EndOfChannel,
                 ) as send_err:

tests/test_advanced_faults.py

@@ -98,7 +98,8 @@ def test_ipc_channel_break_during_stream(
         expect_final_exc = TransportClosed
 
     mod: ModuleType = import_path(
-        examples_dir() / 'advanced_faults'
+        examples_dir()
+        / 'advanced_faults'
         / 'ipc_failure_during_stream.py',
         root=examples_dir(),
         consider_namespace_packages=False,
@@ -113,8 +114,9 @@ def test_ipc_channel_break_during_stream(
     if (
         # only expect EoC if trans is broken on the child side,
         ipc_break['break_child_ipc_after'] is not False
+        and
         # AND we tell the child to call `MsgStream.aclose()`.
-        and pre_aclose_msgstream
+        pre_aclose_msgstream
     ):
         # expect_final_exc = trio.EndOfChannel
         # ^XXX NOPE! XXX^ since now `.open_stream()` absorbs this
@@ -160,7 +162,8 @@ def test_ipc_channel_break_during_stream(
         ipc_break['break_child_ipc_after'] is not False
         and (
             ipc_break['break_parent_ipc_after']
-            > ipc_break['break_child_ipc_after']
+            >
+            ipc_break['break_child_ipc_after']
         )
     ):
         if pre_aclose_msgstream:
@@ -248,8 +251,13 @@ def test_ipc_channel_break_during_stream(
     # get raw instance from pytest wrapper
     value = excinfo.value
     if isinstance(value, ExceptionGroup):
-        excs = value.exceptions
+        excs: tuple[Exception] = value.exceptions
-        assert len(excs) == 1
+        assert (
+            len(excs) <= 2
+            and
+            (isinstance(exc, TransportClosed)
+             for exc in excs)
+        )
         final_exc = excs[0]
         assert isinstance(final_exc, expect_final_exc)
 

tractor/_context.py

@@ -70,6 +70,7 @@ from ._exceptions import (
     MsgTypeError,
     RemoteActorError,
     StreamOverrun,
+    TransportClosed,
     pack_from_raise,
     unpack_error,
 )
@@ -2431,6 +2432,7 @@ async def open_context_from_portal(
             except (
                 trio.BrokenResourceError,
                 trio.ClosedResourceError,
+                TransportClosed,
             ):
                 log.warning(
                     'IPC connection for context is broken?\n'

tractor/_streaming.py

@@ -38,6 +38,7 @@ import trio
 from ._exceptions import (
     ContextCancelled,
     RemoteActorError,
+    TransportClosed,
 )
 from .log import get_logger
 from .trionics import (
@@ -412,7 +413,8 @@ class MsgStream(trio.abc.Channel):
 
         except (
             trio.BrokenResourceError,
-            trio.ClosedResourceError
+            trio.ClosedResourceError,
+            TransportClosed,
         ) as re:
             # the underlying channel may already have been pulled
             # in which case our stop message is meaningless since
@@ -596,6 +598,7 @@ class MsgStream(trio.abc.Channel):
             trio.ClosedResourceError,
             trio.BrokenResourceError,
             BrokenPipeError,
+            TransportClosed,
         ) as _trans_err:
             trans_err = _trans_err
             if (