StateMachine parts removed out (almost)

src/plumpy/base/state_machine.py

@@ -74,8 +74,8 @@ def event(
     if from_states != '*':
         if inspect.isclass(from_states):
             from_states = (from_states,)
-        if not all(issubclass(state, State) for state in from_states):  # type: ignore
-            raise TypeError(f'from_states: {from_states}')
+        # if not all(issubclass(state, State) for state in from_states):  # type: ignore
+        #     raise TypeError(f'from_states: {from_states}')
     if to_states != '*':
         if inspect.isclass(to_states):
             to_states = (to_states,)
@@ -138,7 +138,6 @@ def label(self) -> LABEL_TYPE:
         """Convenience property to get the state label"""
         return self.LABEL
 
-    @super_check
     def enter(self) -> None:
         """Entering the state"""
 
@@ -158,7 +157,7 @@ def create_state(self, state_label: Hashable, *args: Any, **kwargs: Any) -> 'Sta
         return self.state_machine.create_state(state_label, *args, **kwargs)
 
     def do_enter(self) -> None:
-        call_with_super_check(self.enter)
+        self.enter()
         self.in_state = True
 
     def do_exit(self) -> None:
@@ -240,7 +239,7 @@ def __ensure_built(cls) -> None:
         # Build the states map
         cls._STATES_MAP = {}
         for state_cls in cls.STATES:
-            assert issubclass(state_cls, State)
+            # assert issubclass(state_cls, State)
             label = state_cls.LABEL
             assert label not in cls._STATES_MAP, f"Duplicate label '{label}'"
             cls._STATES_MAP[label] = state_cls

src/plumpy/process_states.py

@@ -4,11 +4,13 @@
 import traceback
 from enum import Enum
 from types import TracebackType
-from typing import TYPE_CHECKING, Any, Callable, Optional, Tuple, Type, Union, cast
+from typing import TYPE_CHECKING, Any, Callable, Hashable, Optional, Tuple, Type, Union, cast
 
 import yaml
 from yaml.loader import Loader
 
+from plumpy.base.utils import call_with_super_check
+
 try:
     import tblib
 
@@ -265,8 +267,10 @@ def _action_command(self, command: Union[Kill, Stop, Wait, Continue]) -> State:
         return cast(State, state)  # casting from base.State to process.State
 
 
-class Waiting(state_machine.State, persistence.Savable):
 # class Waiting(state_machine.State):
+class Waiting(state_machine.State, persistence.Savable):
+    """The basic waiting state."""
+
     LABEL = ProcessState.WAITING
     ALLOWED = {
         ProcessState.RUNNING,
@@ -280,6 +284,7 @@ class Waiting(state_machine.State, persistence.Savable):
 
     _interruption = None
     _auto_persist = {'msg', 'data', 'in_state'}
+    is_terminal_state = False
 
     def __str__(self) -> str:
         state_info = super().__str__()
@@ -295,7 +300,8 @@ def __init__(
         data: Any | None = None,
         saver: Savable | None = None,
     ) -> None:
-        super().__init__(process)
+        self._process = process
+        self.in_state: bool = False
         self.done_callback = done_callback
         self.msg = msg
         self.data = data
@@ -306,7 +312,10 @@ def process(self) -> state_machine.StateMachine:
         """
         :return: The process
         """
-        return self.state_machine
+        return self._process
+
+    def create_state(self, state_label: Hashable, *args: Any, **kwargs: Any) -> 'state_machine.State':
+        return self._process.create_state(state_label, *args, **kwargs)
 
     def save_instance_state(self, out_state: SAVED_STATE_TYPE, save_context: persistence.LoadSaveContext) -> None:
         super().save_instance_state(out_state, save_context)
@@ -316,7 +325,8 @@ def save_instance_state(self, out_state: SAVED_STATE_TYPE, save_context: persist
     def load_instance_state(self, saved_state: SAVED_STATE_TYPE, load_context: persistence.LoadSaveContext) -> None:
         super().load_instance_state(saved_state, load_context)
 
-        self.state_machine = load_context.process
+        # FIXME: the save/load instance state methods should be generic from Saver
+        self._process = load_context.process
         callback_name = saved_state.get(self.DONE_CALLBACK, None)
         if callback_name is not None:
             self.done_callback = getattr(self.process, callback_name)
@@ -353,6 +363,20 @@ def resume(self, value: Any = NULL) -> None:
 
         self._waiting_future.set_result(value)
 
+    def do_enter(self) -> None:
+        self.in_state = True
+
+    def do_exit(self) -> None:
+        if self.is_terminal():
+            raise exceptions.InvalidStateError(f'Cannot exit a terminal state {self.LABEL}')
+
+        self.in_state = False
+
+    @classmethod
+    def is_terminal(cls) -> bool:
+        # deprecated using class attribute `is_terminal_state` directly.
+        return cls.is_terminal_state
+
 
 class Excepted(State):
     LABEL = ProcessState.EXCEPTED

src/plumpy/workchains.py

@@ -70,7 +70,7 @@ def get_outline(self) -> Union['_Instruction', '_FunctionCall']:
 
 @persistence.auto_persist('_awaiting')
 class Waiting(process_states.Waiting):
-    """Overwrite the waiting state"""
+    """WorkChain waiting state that can wait on its awaiting list."""
 
     def __init__(
         self,
@@ -90,6 +90,13 @@ def enter(self) -> None:
         for awaitable in self._awaiting:
             awaitable.add_done_callback(self._awaitable_done)
 
+    def do_enter(self) -> None:
+        for awaitable in self._awaiting:
+            awaitable.add_done_callback(self._awaitable_done)
+
+        # FIXME:
+        self.in_state = True
+
     def exit(self) -> None:
         super().exit()
         for awaitable in self._awaiting:
@@ -105,6 +112,13 @@ def _awaitable_done(self, awaitable: asyncio.Future) -> None:
             if not self._awaiting:
                 self._waiting_future.set_result(lang.NULL)
 
+    def do_exit(self) -> None:
+        if self.is_terminal():
+            raise exceptions.InvalidStateError(f'Cannot exit a terminal state {self.LABEL}')
+
+        # FIXME:
+        self.in_state = False
+
 
 class WorkChain(mixins.ContextMixin, processes.Process):
     """