StateMachine 0.9.0

2022-12-21

Python compatibility 0.9.0

StateMachine 0.9 supports Python 2.7, 3.5, 3.6, 3.7, 3.8.

What’s new in 0.9

Args and kwargs now are passed to bounded transitions

Parameters sent with the event trigger will now be propagated to the transition handlers.

>>> from statemachine import StateMachine, State

>>> class CampaignMachine(StateMachine):
...     draft = State("Draft", initial=True)
...     producing = State("Being produced")
...
...     produce = draft.to(producing) | producing.to(producing)
...
...     def on_enter_producing(self, approver=None):
...         print(f"Approved by: {approver}")

>>> sm = CampaignMachine()

>>> sm.produce(approver="Aragorn")  # imperative
Approved by: Aragorn

State machine declarations now with final states

Now you can declare final states and the machine will make sure they have no transitions.

>>> from statemachine import StateMachine, State

>>> class ApprovalMachine(StateMachine):
...     """A workflow machine"""
...     requested = State("Requested", initial=True)
...     accepted = State("Accepted")
...     rejected = State("Rejected")
...     completed = State("Completed", final=True)
...
...     validate = requested.to(accepted, cond="is_ok") | requested.to(rejected)
...     release = accepted.to(completed)
...     reopen = completed.to(requested)
Traceback (most recent call last):
...
InvalidDefinition: Cannot declare transitions from final state. Invalid state(s): ['completed']

See Final state for more details.

Minor features and bug fixes

• Doctesting all documentation including README (with issues on examples fixed).

• Fix state value misjudged when state value is an “boolean False value” (tks @the5fire)

• Fix returning dict as result of transitions callback.