fix: use BoundEvent.put() for error.communication in SCXML send actions

Replace machine.send() with BoundEvent.put() for error.communication
events in _send_to_invoke and create_send_action_callable. These are
always called within the processing loop, so put() is sufficient and
avoids unawaited coroutine warnings in AsyncEngine.

Author: fgmacedo

statemachine/io/scxml/actions.py

@@ -7,6 +7,7 @@
 from typing import Callable
 from uuid import uuid4
 
+from ...event import BoundEvent
 from ...event import Event
 from ...event import _event_data_kwargs
 from ...spec_parser import InState
@@ -426,7 +427,7 @@ def _send_to_invoke(action: SendAction, invokeid: str, **kwargs):
         params_values[param.name] = _eval(param.expr, **kwargs)
     if not machine._engine._invoke_manager.send_to_child(invokeid, event, **params_values):
         # Per SCXML spec: if target is not reachable → error.communication
-        machine.send("error.communication", internal=True)
+        BoundEvent("error.communication", internal=True, _sm=machine).put()
 
 
 def create_send_action_callable(action: SendAction) -> Callable:  # noqa: C901
@@ -452,7 +453,7 @@ def send_action(*args, **kwargs):  # noqa: C901
         if target not in _valid_targets:
             if target and target.startswith("#_scxml_"):
                 # Valid SCXML session reference but undispatchable → error.communication
-                machine.send("error.communication", internal=True)
+                BoundEvent("error.communication", internal=True, _sm=machine).put()
             elif target and target.startswith("#_"):
                 # #_<invokeid> → route to invoked child session
                 _send_to_invoke(action, target[2:], **kwargs)

tests/test_scxml_units.py

@@ -522,7 +522,9 @@ def test_sends_error_communication_when_child_not_found(self):
 
         _send_to_invoke(action, "unknown", machine=machine)
 
-        machine.send.assert_called_once_with("error.communication", internal=True)
+        machine._put_nonblocking.assert_called_once()
+        trigger_data = machine._put_nonblocking.call_args[0][0]
+        assert str(trigger_data.event) == "error.communication"
 
     def test_evaluates_eventexpr(self):
         """_send_to_invoke evaluates eventexpr when event is None."""
@@ -610,7 +612,9 @@ def test_send_action_callable_scxml_session_target(self):
 
         send_callable(machine=machine)
 
-        machine.send.assert_called_once_with("error.communication", internal=True)
+        machine._put_nonblocking.assert_called_once()
+        trigger_data = machine._put_nonblocking.call_args[0][0]
+        assert str(trigger_data.event) == "error.communication"
         machine._engine._invoke_manager.send_to_child.assert_not_called()