Move `.is_multi_cancelled()` to `.trioniics._beg`

Since it's for beg filtering, the current impl should be renamed anyway;
it's not just for filtering cancelled excs.

Deats,
- added a real doc string, links to official eg docs and fixed the
  return typing.
- adjust all internal imports to match.

tests/test_context_stream_semantics.py

@@ -252,7 +252,7 @@ def test_simple_context(
             pass
         except BaseExceptionGroup as beg:
             # XXX: on windows it seems we may have to expect the group error
-            from tractor._exceptions import is_multi_cancelled
+            from tractor.trionics import is_multi_cancelled
             assert is_multi_cancelled(beg)
     else:
         trio.run(main)

tractor/_exceptions.py

@@ -1246,55 +1246,6 @@ def unpack_error(
     return exc
 
 
-def is_multi_cancelled(
-    exc: BaseException|BaseExceptionGroup,
-
-    ignore_nested: set[BaseException] = set(),
-
-) -> bool|BaseExceptionGroup:
-    '''
-    Predicate to determine if an `BaseExceptionGroup` only contains
-    some (maybe nested) set of sub-grouped exceptions (like only
-    `trio.Cancelled`s which get swallowed silently by default) and is
-    thus the result of "gracefully cancelling" a collection of
-    sub-tasks (or other conc primitives) and receiving a "cancelled
-    ACK" from each after termination.
-
-    Docs:
-    ----
-    - https://docs.python.org/3/library/exceptions.html#exception-groups
-    - https://docs.python.org/3/library/exceptions.html#BaseExceptionGroup.subgroup
-
-    '''
-
-    if (
-        not ignore_nested
-        or
-        trio.Cancelled in ignore_nested
-        # XXX always count-in `trio`'s native signal
-    ):
-        ignore_nested.update({trio.Cancelled})
-
-    if isinstance(exc, BaseExceptionGroup):
-        matched_exc: BaseExceptionGroup|None = exc.subgroup(
-            tuple(ignore_nested),
-
-            # TODO, complain about why not allowed XD
-            # condition=tuple(ignore_nested),
-        )
-        if matched_exc is not None:
-            return matched_exc
-
-    # NOTE, IFF no excs types match (throughout the error-tree)
-    # -> return `False`, OW return the matched sub-eg.
-    #
-    # IOW, for the inverse of ^ for the purpose of
-    # maybe-enter-REPL--logic: "only debug when the err-tree contains
-    # at least one exc-type NOT in `ignore_nested`" ; i.e. the case where
-    # we fallthrough and return `False` here.
-    return False
-
-
 def _raise_from_unexpected_msg(
     ctx: Context,
     msg: MsgType,

tractor/_root.py

@@ -61,9 +61,11 @@ from ._addr import (
     mk_uuid,
     wrap_address,
 )
+from .trionics import (
+    is_multi_cancelled,
+)
 from ._exceptions import (
     RuntimeFailure,
-    is_multi_cancelled,
 )
 
 

tractor/_supervise.py

@@ -40,8 +40,10 @@ from ._state import current_actor, is_main_process
 from .log import get_logger, get_loglevel
 from ._runtime import Actor
 from ._portal import Portal
-from ._exceptions import (
+from .trionics import (
     is_multi_cancelled,
+)
+from ._exceptions import (
     ContextCancelled,
 )
 from ._root import (

tractor/devx/debug/_post_mortem.py

@@ -59,7 +59,7 @@ from tractor._state import (
     debug_mode,
 )
 from tractor.log import get_logger
-from tractor._exceptions import (
+from tractor.trionics import (
     is_multi_cancelled,
 )
 from ._trace import (

tractor/to_asyncio.py

@@ -38,7 +38,6 @@ from typing import (
 import tractor
 from tractor._exceptions import (
     InternalError,
-    is_multi_cancelled,
     TrioTaskExited,
     TrioCancelled,
     AsyncioTaskExited,
@@ -59,6 +58,9 @@ from tractor.log import (
 # from tractor.msg import (
 #     pretty_struct,
 # )
+from tractor.trionics import (
+    is_multi_cancelled,
+)
 from tractor.trionics._broadcast import (
     broadcast_receiver,
     BroadcastReceiver,

tractor/trionics/__init__.py

@@ -32,4 +32,5 @@ from ._broadcast import (
 from ._beg import (
     collapse_eg as collapse_eg,
     maybe_collapse_eg as maybe_collapse_eg,
+    is_multi_cancelled as is_multi_cancelled,
 )

tractor/trionics/_beg.py

@@ -22,6 +22,11 @@ first-class-`trio` from a historical perspective B)
 from contextlib import (
     asynccontextmanager as acm,
 )
+from typing import (
+    Literal,
+)
+
+import trio
 
 
 def maybe_collapse_eg(
@@ -56,3 +61,62 @@ async def collapse_eg():
             raise exc
 
         raise beg
+
+
+def is_multi_cancelled(
+    beg: BaseException|BaseExceptionGroup,
+
+    ignore_nested: set[BaseException] = set(),
+
+) -> Literal[False]|BaseExceptionGroup:
+    '''
+    Predicate to determine if an `BaseExceptionGroup` only contains
+    some (maybe nested) set of sub-grouped exceptions (like only
+    `trio.Cancelled`s which get swallowed silently by default) and is
+    thus the result of "gracefully cancelling" a collection of
+    sub-tasks (or other conc primitives) and receiving a "cancelled
+    ACK" from each after termination.
+
+    Docs:
+    ----
+    - https://docs.python.org/3/library/exceptions.html#exception-groups
+    - https://docs.python.org/3/library/exceptions.html#BaseExceptionGroup.subgroup
+
+    '''
+
+    if (
+        not ignore_nested
+        or
+        trio.Cancelled not in ignore_nested
+        # XXX always count-in `trio`'s native signal
+    ):
+        ignore_nested.update({trio.Cancelled})
+
+    if isinstance(beg, BaseExceptionGroup):
+        # https://docs.python.org/3/library/exceptions.html#BaseExceptionGroup.subgroup
+        # |_ "The condition can be an exception type or tuple of
+        #   exception types, in which case each exception is checked
+        #   for a match using the same check that is used in an
+        #   except clause. The condition can also be a callable
+        #   (other than a type object) that accepts an exception as
+        #   its single argument and returns true for the exceptions
+        #   that should be in the subgroup."
+        matched_exc: BaseExceptionGroup|None = beg.subgroup(
+            tuple(ignore_nested),
+
+            # ??TODO, complain about why not allowed to use
+            # named arg style calling???
+            # XD .. wtf?
+            # condition=tuple(ignore_nested),
+        )
+        if matched_exc is not None:
+            return matched_exc
+
+    # NOTE, IFF no excs types match (throughout the error-tree)
+    # -> return `False`, OW return the matched sub-eg.
+    #
+    # IOW, for the inverse of ^ for the purpose of
+    # maybe-enter-REPL--logic: "only debug when the err-tree contains
+    # at least one exc-type NOT in `ignore_nested`" ; i.e. the case where
+    # we fallthrough and return `False` here.
+    return False

tractor/trionics/_mngrs.py

@@ -40,6 +40,8 @@ from typing import (
 import trio
 from tractor._state import current_actor
 from tractor.log import get_logger
+# from ._beg import collapse_eg
+
 
 if TYPE_CHECKING:
     from tractor import ActorNursery
@@ -111,17 +113,19 @@ async def gather_contexts(
     None,
 ]:
     '''
-    Concurrently enter a sequence of async context managers (acms),
-    each from a separate `trio` task and deliver the unwrapped
-    `yield`-ed values in the same order once all managers have entered.
+    Concurrently enter a sequence of async context managers (`acm`s),
+    each scheduled in a separate `trio.Task` and deliver their
+    unwrapped `yield`-ed values in the same order once all `@acm`s
+    in every task have entered.
 
-    On exit, all acms are subsequently and concurrently exited.
+    On exit, all `acm`s are subsequently and concurrently exited with
+    **no order guarantees**.
 
     This function is somewhat similar to a batch of non-blocking
     calls to `contextlib.AsyncExitStack.enter_async_context()`
     (inside a loop) *in combo with* a `asyncio.gather()` to get the
     `.__aenter__()`-ed values, except the managers are both
-    concurrently entered and exited and *cancellation just works*(R).
+    concurrently entered and exited and *cancellation-just-works™*.
 
     '''
     seed: int = id(mngrs)
@@ -141,16 +145,20 @@ async def gather_contexts(
     if not mngrs:
         raise ValueError(
             '`.trionics.gather_contexts()` input mngrs is empty?\n'
+            '\n'
             'Did try to use inline generator syntax?\n'
-            'Use a non-lazy iterator or sequence type intead!'
+            'Use a non-lazy iterator or sequence-type intead!\n'
         )
 
-    async with trio.open_nursery(
-        strict_exception_groups=False,
+    async with (
+        # collapse_eg(),
+        trio.open_nursery(
+            # strict_exception_groups=False,
             # ^XXX^ TODO? soo roll our own then ??
             # -> since we kinda want the "if only one `.exception` then
             # just raise that" interface?
-    ) as tn:
+        ) as tn,
+    ):
         for mngr in mngrs:
             tn.start_soon(
                 _enter_and_wait,
@@ -167,7 +175,7 @@ async def gather_contexts(
         try:
             yield tuple(unwrapped.values())
         finally:
-            # NOTE: this is ABSOLUTELY REQUIRED to avoid
+            # XXX NOTE: this is ABSOLUTELY REQUIRED to avoid
             # the following wacky bug:
             # <tractorbugurlhere>
             parent_exit.set()