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from_enum in Compound States #606
Description
Just wanted to first say thanks so much for making such an awesome library! 😄
I have been using version 3.0.0 a bunch, and I was wondering if it is possible to use from_enum() in a compound state?
Using an Enum in the compound state:
from enum import Enum, auto
from statemachine import State, StateChart
from statemachine.states import States
class outer_sts(Enum):
FOO = auto()
BAR = auto()
class inner_sts(Enum):
FIZZ = auto()
BUZZ = auto()
class SC(StateChart):
baz = States.from_enum(outer_sts, initial = outer_sts.FOO, final = outer_sts.BAR)
class inner(State.Compound):
qux = States.from_enum(inner_sts, initial = inner_sts.FIZZ, final = inner_sts.BUZZ)
fizz_to_buzz = qux.FIZZ.to(qux.BUZZ)
baz_foo_to_inner = baz.FOO.to(inner)
inner_to_baz_bar = inner.to(baz.BAR)
sm = SC()
print(sm.configuration)
sm.send("baz_foo_to_inner")
print(sm.configuration)
sm.send("fizz_to_buzz")
print(sm.configuration)
sm.send("inner_to_baz_bar")
print(sm.configuration)
Output:
{Foo}
{Inner}
{Inner}
{Bar}
Using Declarative states in the compound state
from enum import Enum, auto
from statemachine import State, StateChart
from statemachine.states import States
class outer_sts(Enum):
FOO = auto()
BAR = auto()
class inner_sts(Enum):
FIZZ = auto()
BUZZ = auto()
class SC(StateChart):
baz = States.from_enum(outer_sts, initial = outer_sts.FOO, final = outer_sts.BAR)
class inner(State.Compound):
fizz = State("fizz", initial=True)
buzz = State("buzz", final=True)
fizz_to_buzz = fizz.to(buzz)
baz_foo_to_inner = baz.FOO.to(inner)
inner_to_baz_bar = inner.to(baz.BAR)
sm = SC()
print(sm.configuration)
sm.send("baz_foo_to_inner")
print(sm.configuration)
sm.send("fizz_to_buzz")
print(sm.configuration)
sm.send("inner_to_baz_bar")
print(sm.configuration)
Output:
{Foo}
{Inner, fizz}
{Inner, buzz}
{Bar}
This is the output I think I would expect from using an Enum with the child in the configuration. Is this something that is just not supported, or am I using it incorrectly?
Activity
fix: support `States.from_enum()` inside compound and parallel states (…
fgmacedo commentedon Apr 2, 2026
Hey @vincedbowen, thanks so much for the kind words and for taking the time to report this with such a clear reproduction! Really appreciate the sponsorship too 🙏
The root cause was that
NestedStateFactory(the metaclass behindState.CompoundandState.Parallel) only looked for individualStateinstances when processing class bodies, soStates.from_enum()containers were silently ignored. The fix is up at #607.This will be available in the 3.1 release.
fix: support `States.from_enum()` inside compound and parallel states (…