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fgmacedo committed Jan 12, 2023
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2 changes: 1 addition & 1 deletion docs/auto_examples/all_actions_machine.ipynb
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},
"outputs": [],
"source": [
"%matplotlib inline"
"# import piplite\n# await piplite.install('python-statemachine[diagrams]')"
]
},
{
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2 changes: 1 addition & 1 deletion docs/auto_examples/guess_the_number_machine.ipynb
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},
"outputs": [],
"source": [
"%matplotlib inline"
"# import piplite\n# await piplite.install('python-statemachine[diagrams]')"
]
},
{
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2 changes: 1 addition & 1 deletion docs/auto_examples/order_control_machine.ipynb
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},
"outputs": [],
"source": [
"%matplotlib inline"
"# import piplite\n# await piplite.install('python-statemachine[diagrams]')"
]
},
{
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2 changes: 1 addition & 1 deletion docs/auto_examples/order_control_rich_model_machine.ipynb
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},
"outputs": [],
"source": [
"%matplotlib inline"
"# import piplite\n# await piplite.install('python-statemachine[diagrams]')"
]
},
{
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2 changes: 1 addition & 1 deletion docs/auto_examples/traffic_light_machine.ipynb
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},
"outputs": [],
"source": [
"%matplotlib inline"
"# import piplite\n# await piplite.install('python-statemachine[diagrams]')"
]
},
{
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5 changes: 4 additions & 1 deletion docs/conf.py
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"min_reported_time": 9999,
"thumbnail_size": (400, 280),
"image_scrapers": ("matplotlib", MachineScraper()),
# "first_notebook_cell": "",
"first_notebook_cell": (
"# import piplite\n"
"# await piplite.install('python-statemachine[diagrams]')\n"
),
}
228 changes: 2 additions & 226 deletions docs/releases/1.0.0.md
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*January 11, 2022*

Welcome to StateMachine 1.0!

This version is a huge refactoring adding a lot of new and exiting features. We hope that
you enjoy.

These release notes cover the [](#whats-new-in-10), as well as
some [backwards incompatible changes](#backwards-incompatible-changes-in-10) you'll
want to be aware of when upgrading from StateMachine 0.9.0 or earlier. We've
[begun the deprecation process for some features](#deprecated-features-in-10).


## Python compatibility in 1.0

StateMachine 1.0 supports Python 2.7, 3.5, 3.6, 3.7, 3.8, 3.9, 3.10, and 3.11.

This is the last release to support Python 2.7, 3.5 and 3.6.

## What's new in 1.0


### Validators and Guards

Transitions now support `cond` and `unless` parameters, to restrict
the execution.

```python
class ApprovalMachine(StateMachine):
"A workflow machine"
requested = State("Requested", initial=True)
accepted = State("Accepted")
rejected = State("Rejected")
completed = State("Completed")

validate = requested.to(accepted, cond="is_ok") | requested.to(rejected)
```

```{seealso}
See {ref}`validators-and-guards` for more details.
```

### Support for diagrams

You can generate diagrams from your statemachine.

Example:

![OrderControl](../images/order_control_machine_initial.png)


```{seealso}
See {ref}`diagrams` for more details.
```

### Unified dispatch mecanism for callbacks (actions and guards)

Every single callback, being {ref}`actions` or {ref}`guards`, is now handled equally by the library.

Also, we've improved the internals in a way that you can implement your callbacks with any
number of arbritrary positional or keyword arguments (`*args, **kwargs`), and the dispatch will
match the available arguments with your method signature.

This means that if on your `on_enter_<state>()` or `on_execute_<event>()` method, you also
need to know the `source` ({ref}`state`), or the `event` ({ref}`event`), or access a keyword
argument passed with the trigger, you're covered. Just add this parameter to the method and It
will be passed by the dispatch mechanics.

Example of what's available:

```py
def action_or_guard_method_name(self, *args, event_data, event, source, state, model, **kwargs):
pass
```

```{seealso}
See {ref}`dynamic-dispatch` for more details.
```

### Add observers to a running StateMachine

Observers are a way do generically add behaviour to a StateMachine without
changing it's internal implementation.

The `StateMachine` itself is registered as an observer, so by using `StateMachine.add_observer()`
an external object can have the same level of functionalities provided to the built-in class.

```{seealso}
See {ref}`observers` for more details.
```

## Minor features in 1.0

- Fixed mypy complaining about incorrect type for ``StateMachine`` class.
- The initial {ref}`state` is now entered when the machine starts. The {ref}`actions`, if defined,
`on_enter_state` and `on_enter_<state>` are now called.



## Backwards incompatible changes in 1.0


### Multiple targets from the same origin state

Prior to this release, as we didn't have {ref}`validators-and-guards`, there wasn't an elegant way
to declare multiples target states starting from the same pair (event, state). But the library
allowed a near-hackish way, by declaring a target state as the result of the `on_<event>` callback.

So, the previous code (not valid anymore):

```py
class ApprovalMachine(StateMachine):
"A workflow machine"
requested = State('Requested', initial=True)
accepted = State('Accepted')
rejected = State('Rejected')

validate = requested.to(accepted, rejected)

def on_validate(self, current_time):
if self.model.is_ok():
self.model.accepted_at = current_time
return self.accepted
else:
return self.rejected
```

Should be rewriten to use {ref}`guards`, like this:

``` py
class ApprovalMachine(StateMachine):
"A workflow machine"
requested = State("Requested", initial=True)
accepted = State("Accepted")
rejected = State("Rejected")

validate = requested.to(accepted, conditions="is_ok") | requested.to(rejected)

def on_validate(self, current_time):
self.model.accepted_at = current_time
```

```{seealso}
See {ref}`validators-and-guards` of more details.
```

### StateMachine now enters the initial state

This issue was reported at [#265](https://github.com/fgmacedo/python-statemachine/issues/265).

Now StateMachine will execute the actions associated with the `on_enter_state` and
`on_enter_<state>` when initialized, if they exists.

```{seealso}
See {ref}`State actions` for more details.
```

### Integrity is checked at class definition

Statemachine integrity checks are now performed at class declaration (import time) instead of on
instance creation. This allows early feedback of invalid definitions.

This was the previous behaviour, you only got an error when trying to instantiate a StateMachine:

```py
class CampaignMachine(StateMachine):
"A workflow machine"
draft = State('Draft', initial=True)
producing = State('Being produced')
closed = State('Closed', initial=True) # Should raise an Exception when instantiated

add_job = draft.to(draft) | producing.to(producing)
produce = draft.to(producing)
deliver = producing.to(closed)

with pytest.raises(exceptions.InvalidDefinition):
CampaignMachine()
```

Not this is performed as the class definition is performed:

```py
with pytest.raises(exceptions.InvalidDefinition):

class CampaignMachine(StateMachine):
"A workflow machine"
draft = State("Draft", initial=True)
producing = State("Being produced")
closed = State(
"Closed", initial=True
) # Should raise an Exception right after the class is defined

add_job = draft.to(draft) | producing.to(producing)
produce = draft.to(producing)
deliver = producing.to(closed)
```

### Other backwards incompatible changes in 1.0

- Due to the check validations and setup performed at the machine initialization, it's now harder
to perform monkey-patching to add callbacks at runtime (not a bad thing after all).
- `TransitionNotAllowed` changed internal attr from `transition` to `event`.
- `CombinedTransition` does not exist anymore. {ref}`State` now holds a flat {ref}`Transition` list
called `TransitionList` that implements de `OR` operator. This turns a valid StateMachine
traversal much easier: `[transition for state in machine.states for transition in state.transitions]`.
- `StateMachine.get_transition` is removed. See {ref}`event`.
- The previous excetions `MultipleStatesFound` and `MultipleTransitionCallbacksFound` are removed.
Since now you can have more than one callback defined to the same transition.
- `on_enter_state` and `on_exit_state` now accepts any combination of parameters following the
{ref}`dynamic-dispatch` rules. Previously it only accepted the `state` param.
- `Transition.__init__` param `on_execute` renamed to simply `on`, and now follows the
{ref}`dynamic-dispatch`.
- `Transition.destinations` removed in favor of `Transition.target` (following SCXML convention).
Now each transition only points to a unique target. Each `source->target` pair is holded by a
single `Transition`.

## Deprecated features in 1.0

### Statemachine class

- `StateMachine.run` is deprecated in favor of `StateMachine.send`.
- `StateMachine.allowed_transitions` is deprecated in favor of `StateMachine.allowed_events`.
- `Statemachine.is_<state>` is deprecated in favor of `StateMachine.<state>.is_active`.


### State class

- `State.identification` is deprecated in favor of `State.id`.
This release tag was replaced by [](1.0.1.md) due to an error on the metadata when uploading to
pypi.
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