feat: Internal transitions

Author: fgmacedo

statemachine/engines/async_.py

@@ -72,7 +72,9 @@ async def _trigger(self, trigger_data: TriggerData):
             await self._activate(trigger_data, transition)
             return self._sentinel
 
-        state = self.sm.current_state
+        # TODO: Fix async engine
+        state = next(iter(self.sm.configuration))
+
         for transition in state.transitions:
             if not transition.match(trigger_data.event):
                 continue
@@ -83,7 +85,7 @@ async def _trigger(self, trigger_data: TriggerData):
             break
         else:
             if not self.sm.allow_event_without_transition:
-                raise TransitionNotAllowed(trigger_data.event, state)
+                raise TransitionNotAllowed(trigger_data.event, self.sm.configuration)
 
         return result if executed else None
 

statemachine/engines/base.py

@@ -1,11 +1,15 @@
+import logging
 from dataclasses import dataclass
 from itertools import chain
 from queue import PriorityQueue
 from queue import Queue
 from threading import Lock
 from typing import TYPE_CHECKING
+from typing import Any
 from typing import Callable
+from typing import Dict
 from typing import List
+from typing import cast
 from weakref import proxy
 
 from ..event import BoundEvent
@@ -20,6 +24,8 @@
 if TYPE_CHECKING:
     from ..statemachine import StateMachine
 
+logger = logging.getLogger(__name__)
+
 
 @dataclass(frozen=True, unsafe_hash=True)
 class StateTransition:
@@ -76,7 +82,7 @@ def empty(self):
     def put(self, trigger_data: TriggerData, internal: bool = False):
         """Put the trigger on the queue without blocking the caller."""
         if not self.running and not self.sm.allow_event_without_transition:
-            raise TransitionNotAllowed(trigger_data.event, self.sm.current_state)
+            raise TransitionNotAllowed(trigger_data.event, self.sm.configuration)
 
         if internal:
             self.internal_queue.put(trigger_data)
@@ -117,7 +123,9 @@ def _conditions_match(self, transition: Transition, trigger_data: TriggerData):
         self.sm._callbacks.call(transition.validators.key, *args, **kwargs)
         return self.sm._callbacks.all(transition.cond.key, *args, **kwargs)
 
-    def _filter_conflicting_transitions(self, transitions: OrderedSet[Transition]):
+    def _filter_conflicting_transitions(
+        self, transitions: OrderedSet[Transition]
+    ) -> OrderedSet[Transition]:
         """
         Remove transições conflitantes, priorizando aquelas com estados de origem descendentes
         ou que aparecem antes na ordem do documento.
@@ -128,18 +136,18 @@ def _filter_conflicting_transitions(self, transitions: OrderedSet[Transition]):
         Returns:
             OrderedSet[Transition]: Conjunto de transições sem conflitos.
         """
-        filtered_transitions = OrderedSet()
+        filtered_transitions = OrderedSet[Transition]()
 
         # Ordena as transições na ordem dos estados que as selecionaram
         for t1 in transitions:
             t1_preempted = False
-            transitions_to_remove = OrderedSet()
+            transitions_to_remove = OrderedSet[Transition]()
 
             # Verifica conflitos com as transições já filtradas
             for t2 in filtered_transitions:
                 # Calcula os conjuntos de saída (exit sets)
-                t1_exit_set = self._compute_exit_set(t1)
-                t2_exit_set = self._compute_exit_set(t2)
+                t1_exit_set = self._compute_exit_set([t1])
+                t2_exit_set = self._compute_exit_set([t2])
 
                 # Verifica interseção dos conjuntos de saída
                 if t1_exit_set & t2_exit_set:  # Há interseção
@@ -162,7 +170,7 @@ def _filter_conflicting_transitions(self, transitions: OrderedSet[Transition]):
     def _compute_exit_set(self, transitions: List[Transition]) -> OrderedSet[StateTransition]:
         """Compute the exit set for a transition."""
 
-        states_to_exit = OrderedSet()
+        states_to_exit = OrderedSet[StateTransition]()
 
         for transition in transitions:
             if transition.target is None:
@@ -193,6 +201,8 @@ def get_transition_domain(self, transition: Transition) -> "State | None":
             and all(state.is_descendant(transition.source) for state in states)
         ):
             return transition.source
+        elif transition.internal and transition.is_self and transition.target.is_atomic:
+            return transition.source
         else:
             return self.find_lcca([transition.source] + list(states))
 
@@ -213,6 +223,7 @@ def find_lcca(states: List[State]) -> "State | None":
         ancestors = [anc for anc in head.ancestors() if anc.is_compound]
 
         # Find the first ancestor that is also an ancestor of all other states in the list
+        ancestor: State
         for ancestor in ancestors:
             if all(state.is_descendant(ancestor) for state in tail):
                 return ancestor
@@ -233,13 +244,16 @@ def _select_transitions(
         self, trigger_data: TriggerData, predicate: Callable
     ) -> OrderedSet[Transition]:
         """Select the transitions that match the trigger data."""
-        enabled_transitions = OrderedSet()
+        enabled_transitions = OrderedSet[Transition]()
 
         # Get atomic states, TODO: sorted by document order
         atomic_states = (state for state in self.sm.configuration if state.is_atomic)
 
-        def first_transition_that_matches(state: State, event: Event) -> "Transition | None":
+        def first_transition_that_matches(
+            state: State, event: "Event | None"
+        ) -> "Transition | None":
             for s in chain([state], state.ancestors()):
+                transition: Transition
                 for transition in s.transitions:
                     if (
                         not transition.initial
@@ -248,6 +262,8 @@ def first_transition_that_matches(state: State, event: Event) -> "Transition | N
                     ):
                         return transition
 
+            return None
+
         for state in atomic_states:
             transition = first_transition_that_matches(state, trigger_data.event)
             if transition is not None:
@@ -264,6 +280,7 @@ def microstep(self, transitions: List[Transition], trigger_data: TriggerData):
         )
 
         states_to_exit = self._exit_states(transitions, trigger_data)
+        logger.debug("States to exit: %s", states_to_exit)
         result += self._execute_transition_content(transitions, trigger_data, lambda t: t.on.key)
         self._enter_states(transitions, trigger_data, states_to_exit)
         self._execute_transition_content(
@@ -304,7 +321,7 @@ def _exit_states(self, enabled_transitions: List[Transition], trigger_data: Trig
             #     self.history_values[history.id] = history_value
 
             # Execute `onexit` handlers
-            if info.source is not None and not info.transition.internal:
+            if info.source is not None:  # TODO: and not info.transition.internal:
                 self.sm._callbacks.call(info.source.exit.key, *args, **kwargs)
 
             # TODO: Cancel invocations
@@ -343,22 +360,29 @@ def _enter_states(
         """Enter the states as determined by the given transitions."""
         states_to_enter = OrderedSet[StateTransition]()
         states_for_default_entry = OrderedSet[StateTransition]()
-        default_history_content = {}
+        default_history_content: Dict[str, Any] = {}
 
         # Compute the set of states to enter
         self.compute_entry_set(
             enabled_transitions, states_to_enter, states_for_default_entry, default_history_content
         )
 
         # We update the configuration atomically
-        states_targets_to_enter = OrderedSet(info.target for info in states_to_enter)
+        states_targets_to_enter = OrderedSet(
+            info.target for info in states_to_enter if info.target
+        )
+        logger.debug("States to enter: %s", states_targets_to_enter)
+
         configuration = self.sm.configuration
-        self.sm.configuration = (configuration - states_to_exit) | states_targets_to_enter
+        self.sm.configuration = cast(
+            OrderedSet[State], (configuration - states_to_exit) | states_targets_to_enter
+        )
 
         # Sort states to enter in entry order
         # for state in sorted(states_to_enter, key=self.entry_order):   # TODO: ordegin of states_to_enter # noqa: E501
         for info in states_to_enter:
             target = info.target
+            assert target
             transition = info.transition
             event_data = EventData(trigger_data=trigger_data, transition=transition)
             event_data.state = target
@@ -376,8 +400,8 @@ def _enter_states(
             #     state.is_first_entry = False
 
             # Execute `onentry` handlers
-            if not transition.internal:
-                self.sm._callbacks.call(target.enter.key, *args, **kwargs)
+            # TODO: if not transition.internal:
+            self.sm._callbacks.call(target.enter.key, *args, **kwargs)
 
             # Handle default initial states
             # TODO: Handle default initial states
@@ -396,11 +420,17 @@ def _enter_states(
                     parent = target.parent
                     grandparent = parent.parent
 
-                    self.internal_queue.put(BoundEvent(f"done.state.{parent.id}", _sm=self.sm))
+                    self.internal_queue.put(
+                        BoundEvent(f"done.state.{parent.id}", _sm=self.sm).build_trigger(
+                            machine=self.sm
+                        )
+                    )
                     if grandparent.parallel:
                         if all(child.final for child in grandparent.states):
                             self.internal_queue.put(
-                                BoundEvent(f"done.state.{parent.id}", _sm=self.sm)
+                                BoundEvent(f"done.state.{parent.id}", _sm=self.sm).build_trigger(
+                                    machine=self.sm
+                                )
                             )
 
     def compute_entry_set(
@@ -476,8 +506,19 @@ def add_descendant_states_to_enter(
         #     return
 
         # Add the state to the entry set
-        states_to_enter.add(info)
+        if (
+            not self.sm.enable_self_transition_entries
+            and info.transition.internal
+            and (
+                info.transition.is_self
+                or info.transition.target.is_descendant(info.transition.source)
+            )
+        ):
+            pass
+        else:
+            states_to_enter.add(info)
         state = info.target
+        assert state
 
         if state.is_compound:
             # Handle compound states
@@ -541,6 +582,7 @@ def add_ancestor_states_to_enter(
             default_history_content: A dictionary to hold temporary content for history states.
         """
         state = info.target
+        assert state
         for anc in state.ancestors(parent=ancestor):
             # Add the ancestor to the entry set
             info_to_add = StateTransition(

statemachine/engines/sync.py

@@ -1,3 +1,4 @@
+import logging
 from time import sleep
 from time import time
 from typing import TYPE_CHECKING
@@ -12,6 +13,8 @@
 if TYPE_CHECKING:
     from ..transition import Transition
 
+logger = logging.getLogger(__name__)
+
 
 class SyncEngine(BaseEngine):
     def start(self):
@@ -58,6 +61,7 @@ def processing_loop(self):  # noqa: C901
         # We will collect the first result as the processing result to keep backwards compatibility
         # so we need to use a sentinel object instead of `None` because the first result may
         # be also `None`, and on this case the `first_result` may be overridden by another result.
+        logger.debug("Processing loop started: %s", self.sm.current_state_value)
         first_result = self._sentinel
         try:
             took_events = True
@@ -82,6 +86,7 @@ def processing_loop(self):  # noqa: C901
 
                             enabled_transitions = self.select_transitions(internal_event)
                     if enabled_transitions:
+                        logger.debug("Eventless/internal queue: %s", enabled_transitions)
                         took_events = True
                         self.microstep(list(enabled_transitions), internal_event)
 
@@ -102,6 +107,7 @@ def processing_loop(self):  # noqa: C901
                 while not self.external_queue.is_empty():
                     took_events = True
                     external_event = self.external_queue.pop()
+                    logger.debug("External event: %s", external_event)
                     current_time = time()
                     if external_event.execution_time > current_time:
                         self.put(external_event)
@@ -122,6 +128,7 @@ def processing_loop(self):  # noqa: C901
                     #             self.send(inv.id, external_event)
 
                     enabled_transitions = self.select_transitions(external_event)
+                    logger.debug("Enabled transitions: %s", enabled_transitions)
                     if enabled_transitions:
                         try:
                             result = self.microstep(list(enabled_transitions), external_event)
@@ -136,7 +143,7 @@ def processing_loop(self):  # noqa: C901
 
                     else:
                         if not self.sm.allow_event_without_transition:
-                            raise TransitionNotAllowed(external_event.event, self.sm.current_state)
+                            raise TransitionNotAllowed(external_event.event, self.sm.configuration)
 
         finally:
             self._processing.release()

statemachine/exceptions.py

@@ -1,4 +1,5 @@
 from typing import TYPE_CHECKING
+from typing import MutableSet
 
 from .i18n import _
 
@@ -30,12 +31,13 @@ class AttrNotFound(InvalidDefinition):
 
 
 class TransitionNotAllowed(StateMachineError):
-    "Raised when there's no transition that can run from the current :ref:`state`."
+    "Raised when there's no transition that can run from the current :ref:`configuration`."
 
-    def __init__(self, event: "Event | None", state: "State"):
+    def __init__(self, event: "Event | None", configuration: MutableSet["State"]):
         self.event = event
-        self.state = state
+        self.configuration = configuration
+        name = ", ".join([s.name for s in configuration])
         msg = _("Can't {} when in {}.").format(
-            self.event and self.event.name or "transition", self.state.name
+            self.event and self.event.name or "transition", name
         )
         super().__init__(msg)

statemachine/factory.py

@@ -52,7 +52,7 @@ def __init__(
         if not cls.states:
             return
 
-        cls._initials_by_document_order(cls.states, parent=None)
+        cls._initials_by_document_order(list(cls.states), parent=None)
 
         initials = [s for s in cls.states if s.initial]
         parallels = [s.id for s in cls.states if s.parallel]
@@ -81,7 +81,7 @@ def __init__(
 
         def __getattr__(self, attribute: str) -> Any: ...
 
-    def _initials_by_document_order(cls, states, parent: "State | None" = None):
+    def _initials_by_document_order(cls, states: List[State], parent: "State | None" = None):
         """Set initial state by document order if no explicit initial state is set"""
         initial: "State | None" = None
         for s in states:

statemachine/io/__init__.py

@@ -118,6 +118,7 @@ def create_machine_class_from_definition(
                 transition = source.to(
                     target,
                     event=event_name,
+                    internal=transition_data.get("internal"),
                     initial=transition_data.get("initial"),
                     cond=transition_data.get("cond"),
                     unless=transition_data.get("unless"),

statemachine/io/scxml/actions.py

@@ -166,7 +166,10 @@ def __call__(self, *args, **kwargs):
             kwargs["_ioprocessors"] = self.processor.wrap(**kwargs)
 
         try:
-            return _eval(self.action, **kwargs)
+            result = _eval(self.action, **kwargs)
+            logger.debug("Cond %s -> %s", self.action, result)
+            return result
+
         except Exception as e:
             machine.send("error.execution", error=e, internal=True)
             return False
@@ -238,6 +241,7 @@ def __call__(self, *args, **kwargs):
                 f"got: {self.action.location}"
             )
         setattr(obj, attr, value)
+        logger.debug(f"Assign: {self.action.location} = {value!r}")
 
 
 class Log(CallableAction):