Problem of Customized child classes due to AAS Constraint 108 in SEList about basyx-python-sdk

[jkhsjdhjs]

Hmmm, possible solutions would be checking using issubclass instead of is when checking whether elements in the list are compatible with typeValueListElement or using issubclass when checking the class assigned to typeValueListElement.

However, since custom class names wouldn't be compliant with the serialization, allowing other classes than those specified in KEY_TYPES_CLASSES won't be possible. Thus, we'll probably go with the first solution.

[jkhsjdhjs]

@s-heppner Can you re-open this issue? It isn't resolved yet. We can discuss the possible solutions it in the next meeting.

[jkhsjdhjs]

I just had a look at the implementation again, and I think it's impossible to allow custom subclasses of SubmodelElements where a specific SubmodelElement is expected. I used an explicit is check, because isinstance or issubclass would also allow e.g. AnnotatedRelationshipElement, where a RelationshipElement is expected:

basyx-python-sdk/basyx/aas/model/submodel.py

Lines 749 to 752 in ab298a7

	# We can't use isinstance(new, self.type_value_list_element) here, because each subclass of
	# self.type_value_list_element wouldn't raise a ConstraintViolation, when it should.
	# Example: AnnotatedRelationshipElement is a subclass of RelationshipElement
	if type(new) is not self.type_value_list_element:

[jorgegomezjumh]

I have this classes for it (e.g. QosFlowStatus) which inherit from e.g. SubmodelElementCollection class:

class QosFlowStatus(SubmodelElementCollection):                      
    def __init__(
        self, 
        qfi, 
        qos_profile, 
        alternative_qos_profiles, 
        rrm_parameters, 
        id_short: NameType | None, 
        value: Iterable[SubmodelElement] = ..., 
        display_name: MultiLanguageNameType | None = None, 
        category: NameType | None = None, 
        description: MultiLanguageTextType | None = None, 
        parent: UniqueIdShortNamespace | None = None, 
        semantic_id: Reference | None = None, qualifier: Iterable[Qualifier] = ..., 
        extension: Iterable[Extension] = ..., 
        supplemental_semantic_id: Iterable[Reference] = ..., 
        embedded_data_specifications: Iterable[EmbeddedDataSpecification] = ...
    ):

When I try to add this collection to QosFlowStatusList:

class QosFlowStatusList(SubmodelElementList):
    def __init__(
        self,  
        id_short: NameType | None, 
        type_value_list_element: type, 
        value: Iterable = ..., 
        semantic_id_list_element: Reference | None = None, 
        value_type_list_element: DataTypeDefXsd | None = None, 
        order_relevant: bool = True, 
        display_name: MultiLanguageNameType | None = None, 
        category: NameType | None = None, 
        description: MultiLanguageTextType | None = None, 
        parent: UniqueIdShortNamespace | None = None, 
        semantic_id: Reference | None = None, 
        qualifier: Iterable[Qualifier] = ..., 
        extension: Iterable[Extension] = ..., 
        supplemental_semantic_id: Iterable[Reference] = ..., 
        embedded_data_specifications: Iterable[EmbeddedDataSpecification] = ...
    ):

And I obtain this error (which I don´t understand):

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[4], [line 275](vscode-notebook-cell:?execution_count=4&line=275)
    [273](vscode-notebook-cell:?execution_count=4&line=273)                 print(elemento_ref_2._type_value_list_element)
    [274](vscode-notebook-cell:?execution_count=4&line=274)                 qos_flow_list=QosFlowStatusList(elemento_ref_2.id_short, elemento_ref_2._type_value_list_element, elemento_ref_2._value, elemento_ref_2._semantic_id_list_element, elemento_ref_2._value_type_list_element, elemento_ref_2._order_relevant, elemento_ref_2.display_name, elemento_ref_2.category, elemento_ref_2.description, elemento_ref_2.parent, elemento_ref_2.semantic_id, elemento_ref_2.qualifier, elemento_ref_2.extension, elemento_ref_2.supplemental_semantic_id, elemento_ref_2.embedded_data_specifications)
--> [275](vscode-notebook-cell:?execution_count=4&line=275)                 qos_flow_list.value.add(qos_flow)
    [277](vscode-notebook-cell:?execution_count=4&line=277)     pdu_session=PDUSessionStatus(ip_address,qos_flow_list, elemento_ref.id_short, elemento_ref.value, elemento_ref.display_name, elemento_ref.category, elemento_ref.description, elemento_ref.parent, elemento_ref.semantic_id, elemento_ref.qualifier, elemento_ref.extension, elemento_ref.supplemental_semantic_id, elemento_ref.embedded_data_specifications)
    [279](vscode-notebook-cell:?execution_count=4&line=279) pdu_session_list=PDUSessionStatusList(elemento_contenido.id_short, elemento_contenido._type_value_list_element, elemento_contenido._value, elemento_contenido._semantic_id_list_element, elemento_contenido._value_type_list_element, elemento_contenido._order_relevant, elemento_contenido.display_name, elemento_contenido.category, elemento_contenido.description, elemento_contenido.parent, elemento_contenido.semantic_id, elemento_contenido.qualifier, elemento_contenido.extension, elemento_contenido.supplemental_semantic_id, elemento_contenido.embedded_data_specifications)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082), in OrderedNamespaceSet.add(self, element)
   [2081](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2081) def add(self, element: _NSO):
-> [2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082)     super().add(element)
   [2083](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2083)     self._order.append(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1884](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1884), in NamespaceSet.add(self, element)
   [1881](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1881)     raise ValueError("Object has already a parent; it cannot belong to two namespaces.")
   [1882](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1882)     # TODO remove from current parent instead (allow moving)?
-> [1884](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1884) self._execute_item_id_set_hook(element)
   [1885](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1885) self._validate_namespace_constraints(element)
   [1886](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1886) self._execute_item_add_hook(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1921](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1921), in NamespaceSet._execute_item_id_set_hook(self, element)
   [1919](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1919) def _execute_item_id_set_hook(self, element: _NSO):
   [1920](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1920)     if self._item_id_set_hook is not None:
-> [1921](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1921)         self._item_id_set_hook(element)
...
    [624](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:624)     else:

File <frozen _collections_abc>:1030, in index(self, value, start, stop)

Then I have tried to add this qos_flow to a very simple list like that:

my_list = SubmodelElementList(
    id_short="lista_1",
    type_value_list_element=SubmodelElementCollection,
    value_type_list_element=None  # Set to None for SubmodelElementCollection
)
# Creating new SubmodelElement instances (replace SubmodelElement with the actual class)
new_element1 = SubmodelElementCollection(id_short=None)
new_element2 = SubmodelElementCollection(id_short=None)

# Adding elements to the SubmodelElementList
my_list.value.add(new_element1)
my_list.value.add(new_element2)

So now I check attributes of qos_flow and try to add to this simple list:

qos_flow.id_short

generated_submodel_list_hack_4ecbd1f2c73f11ee8000f057a6e54ba0

Now I try to add this qos_flow:

my_list.value.add(qos_flow)

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[8], [line 1](vscode-notebook-cell:?execution_count=8&line=1)
----> [1](vscode-notebook-cell:?execution_count=8&line=1) my_list.value.add(qos_flow)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082), in OrderedNamespaceSet.add(self, element)
   [2081](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2081) def add(self, element: _NSO):
-> [2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082)     super().add(element)
   [2083](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2083)     self._order.append(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1881](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1881), in NamespaceSet.add(self, element)
   [1879](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1879) def add(self, element: _NSO):
   [1880](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1880)     if element.parent is not None and element.parent is not self.parent:
-> [1881](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1881)         raise ValueError("Object has already a parent; it cannot belong to two namespaces.")
   [1882](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1882)         # TODO remove from current parent instead (allow moving)?
   [1884](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1884)     self._execute_item_id_set_hook(element)

ValueError: Object has already a parent; it cannot belong to two namespaces.

So, I try this:

qos_flow.parent=None
my_list.value.add(qos_flow)

---------------------------------------------------------------------------
AASConstraintViolation                    Traceback (most recent call last)
Cell In[9], [line 2](vscode-notebook-cell:?execution_count=9&line=2)
      [1](vscode-notebook-cell:?execution_count=9&line=1) qos_flow.parent=None
----> [2](vscode-notebook-cell:?execution_count=9&line=2) my_list.value.add(qos_flow)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082), in OrderedNamespaceSet.add(self, element)
   [2081](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2081) def add(self, element: _NSO):
-> [2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082)     super().add(element)
   [2083](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2083)     self._order.append(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1884](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1884), in NamespaceSet.add(self, element)
   [1881](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1881)     raise ValueError("Object has already a parent; it cannot belong to two namespaces.")
   [1882](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1882)     # TODO remove from current parent instead (allow moving)?
-> [1884](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1884) self._execute_item_id_set_hook(element)
   [1885](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1885) self._validate_namespace_constraints(element)
   [1886](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1886) self._execute_item_add_hook(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1921](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1921), in NamespaceSet._execute_item_id_set_hook(self, element)
   [1919](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1919) def _execute_item_id_set_hook(self, element: _NSO):
   [1920](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1920)     if self._item_id_set_hook is not None:
-> [1921](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1921)         self._item_id_set_hook(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\submodel.py:739](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:739), in SubmodelElementList._generate_id_short(self, new)
    [737](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:737) def _generate_id_short(self, new: _SE) -> None:
...
    [742](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:742)     # have an id_short. The alternative would be making SubmodelElementList a special kind of base.Namespace without
    [743](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:743)     # a unique attribute for child-elements (which contradicts the definition of a Namespace).
    [744](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:744)     new.id_short = "generated_submodel_list_hack_" + uuid.uuid1(clock_seq=self._uuid_seq).hex

AASConstraintViolation: Objects with an id_short may not be added to a SubmodelElementList, got QosFlowStatus[generated_submodel_list_hack_4ecbd1f2c73f11ee8000f057a6e54ba0] with id_short=generated_submodel_list_hack_4ecbd1f2c73f11ee8000f057a6e54ba0 (Constraint AASd-120)

So now I try with id_short=None:

qos_flow.id_short=None
my_list.value.add(qos_flow)

And I have found this error:

---------------------------------------------------------------------------
AASConstraintViolation                    Traceback (most recent call last)
Cell In[10], [line 2](vscode-notebook-cell:?execution_count=10&line=2)
      [1](vscode-notebook-cell:?execution_count=10&line=1) qos_flow.id_short=None
----> [2](vscode-notebook-cell:?execution_count=10&line=2) my_list.value.add(qos_flow)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082), in OrderedNamespaceSet.add(self, element)
   [2081](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2081) def add(self, element: _NSO):
-> [2082](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2082)     super().add(element)
   [2083](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:2083)     self._order.append(element)

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1886](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1886), in NamespaceSet.add(self, element)
   [1884](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1884) self._execute_item_id_set_hook(element)
   [1885](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1885) self._validate_namespace_constraints(element)
-> [1886](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1886) self._execute_item_add_hook(element)
   [1888](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1888) element.parent = self.parent
   [1889](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1889) for key_attr_name, (backend, case_sensitive) in self._backend.items():

File [c:\Users\uwicore\anaconda3\Lib\site-packages\basyx\aas\model\base.py:1926](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1926), in NamespaceSet._execute_item_add_hook(self, element)
   [1924](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1924) if self._item_add_hook is not None:
   [1925](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1925)     try:
-> [1926](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1926)         self._item_add_hook(element, self.__iter__())
   [1927](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1927)     except Exception as e:
   [1928](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/base.py:1928)         self._execute_item_del_hook(element)
...
    [770](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:770)     raise base.AASConstraintViolation(107, f"If semantic_id_list_element={self.semantic_id_list_element!r} "
    [771](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:771)                                            "is specified all first level children must have the same "
    [772](file:///C:/Users/uwicore/anaconda3/Lib/site-packages/basyx/aas/model/submodel.py:772)                                            f"semantic_id, got {new!r} with semantic_id={new.semantic_id!r}")

AASConstraintViolation: All first level elements must be of the type specified in type_value_list_element=SubmodelElementCollection, got QosFlowStatus (Constraint AASd-108)

So, the last thing that I have tried is to ask if this qos_flow is a submodelElementCollection:

if isinstance(qos_flow,SubmodelElementCollection): print("Yes, it is")
Yes, it is

So now I don´t know what can I do with this list. If you need more information to try to find the solution to this problem, let me know.

Thank you in advance.

EDIT (by @s-heppner): I took the liberty to fix the syntax in your issue. Feel free to check the text, for example by pressing "edit" yourself, so that you can learn how to write more readable issues