Add feature model metamodel extension

[mgv99]

No description provided.

[ivan-alfonso]

Please add this line

from .feature_model import *

[ivan-alfonso]

Some comments:

1. Default Mutable Arguments in Constructors

There are empty lists assigned by default in some variables in the constructor methods. This can cause issues because lists are mutable objects shared between instances.

For example, in line 113:

features: list[Feature] = []

If you define the following:

f1 = FeatureGroup(kind="MANDATORY")
f1.features.append(1)
f2 = FeatureGroup(kind="MANDATORY")

Then f1.features will be the same as f2.features, which creates unintended shared states.

A simple fix for this issue is to use None as the default value and initialize the list inside the constructor:

def __init__(self, kind: str, features: List[Feature] = None):
    if features is None:
        features = []
    self.features: List[Feature] = features

2. Type Annotation

I think the standard way to define the code in line 139 is:

from typing import Union
self.value: Union[int, float, str] = None

3 value Attribute in FeatureConfiguration Constructor

The value attribute of the FeatureConfiguration class is not included in the __init__ method parameters. This means the value cannot be specified during the creation of an object. Is this omission intentional?

4 Missing relationship

It seems that the has_children relationship between FeatureGroup and Feature is either not directly implemented or not clearly defined.

[ivan-alfonso]

To maintain consistency with the rest of the BESSER metamodels, here are some suggestions for the metamodel figure:

• The names of the associations or end names should not contain spaces. For example, update the names to use underscores (_) instead: Replace has features with has_features or simply features

• The small arrow in the association names is unnecessary. Instead, position the label closer to the appropriate end of the association to indicate the direction. For example, move the has_features label closer to the Feature end to indicate that the list of Features can be accessed from FeatureGroup using this label.