Comment-tag pause points in `asycnio_bp.py`

Thought i already did this but, obvi needed these to make the expect
matches pass in our test.

examples/debugging/asyncio_bp.py

@@ -25,7 +25,7 @@ async def bp_then_error(
 
 ) -> None:
 
-    # sync with ``trio``-side (caller) task
+    # sync with `trio`-side (caller) task
     to_trio.send_nowait('start')
 
     # NOTE: what happens here inside the hook needs some refinement..
@@ -33,8 +33,7 @@ async def bp_then_error(
     #    we set `Lock.local_task_in_debug = 'sync'`, we probably want
     #    some further, at least, meta-data about the task/actor in debug
     #    in terms of making it clear it's `asyncio` mucking about.
-    breakpoint()
+    breakpoint()  # asyncio-side
-
 
     # short checkpoint / delay
     await asyncio.sleep(0.5)  # asyncio-side
@@ -58,7 +57,6 @@ async def trio_ctx(
     # this will block until the ``asyncio`` task sends a "first"
     # message, see first line in above func.
     async with (
-
         to_asyncio.open_channel_from(
             bp_then_error,
             # raise_after_bp=not bp_before_started,
@@ -69,7 +67,7 @@ async def trio_ctx(
         assert first == 'start'
 
         if bp_before_started:
-            await tractor.pause()
+            await tractor.pause()  # trio-side
 
         await ctx.started(first)  # trio-side
 
@@ -111,7 +109,7 @@ async def main(
 
             # pause in parent to ensure no cross-actor
             # locking problems exist!
-            await tractor.pause()
+            await tractor.pause()  # trio-root
 
             if cancel_from_root:
                 await ctx.cancel()

tractor/_exceptions.py

@@ -103,7 +103,16 @@ class AsyncioTaskExited(Exception):
 
     '''
 
-class TrioTaskExited(AsyncioCancelled):
+class TrioCancelled(Exception):
+    '''
+    Trio cancelled translation (non-base) error
+    for use with the `to_asyncio` module
+    to be raised in the `asyncio.Task` to indicate
+    that the `trio` side raised `Cancelled` or an error.
+
+    '''
+
+class TrioTaskExited(Exception):
     '''
     The `trio`-side task exited without explicitly cancelling the
     `asyncio.Task` peer.
@@ -406,6 +415,9 @@ class RemoteActorError(Exception):
         String-name of the (last hop's) boxed error type.
 
         '''
+        # TODO, maybe support also serializing the
+        # `ExceptionGroup.exeptions: list[BaseException]` set under
+        # certain conditions?
         bt: Type[BaseException] = self.boxed_type
         if bt:
             return str(bt.__name__)
@@ -821,8 +833,11 @@ class MsgTypeError(
         '''
         if (
             (_bad_msg := self.msgdata.get('_bad_msg'))
-            and
+            and (
-            isinstance(_bad_msg, PayloadMsg)
+                isinstance(_bad_msg, PayloadMsg)
+                or
+                isinstance(_bad_msg, msgtypes.Start)
+            )
         ):
             return _bad_msg
 
@@ -1015,18 +1030,6 @@ class MessagingError(Exception):
 
     '''
 
-class AsyncioCancelled(Exception):
-    '''
-    Asyncio cancelled translation (non-base) error
-    for use with the ``to_asyncio`` module
-    to be raised in the ``trio`` side task
-
-    NOTE: this should NOT inherit from `asyncio.CancelledError` or
-    tests should break!
-
-    '''
-
-
 def pack_error(
     exc: BaseException|RemoteActorError,
 
@@ -1206,7 +1209,7 @@ def is_multi_cancelled(
         trio.Cancelled in ignore_nested
         # XXX always count-in `trio`'s native signal
     ):
-        ignore_nested |= {trio.Cancelled}
+        ignore_nested.update({trio.Cancelled})
 
     if isinstance(exc, BaseExceptionGroup):
         matched_exc: BaseExceptionGroup|None = exc.subgroup(