[QUESTION] In GenerateSerializationByIds, does `includeConceptDescriptions` include transitively referenced ConceptDescriptions?

[empwilli]

Context

The GenerateSerializationByIds operation defines the boolean parameter includeConceptDescriptions with the description:

Include all concept descriptions that are referenced in the Submodels contained in the serialization and that are known to the server

However, there are some elements of concept descriptions, that, hold references to other concept descriptions. This raises the question whether these transitively reachable concept descriptions should be serialized, as well.

Example

A concrete case occurs with IEC61360 value lists.
In Part 3a (Data Specification Templates), value lists are defined such that each coded value represents an individual concept that may have its own ConceptDescription. A ConceptDescription can therefore reference other ConceptDescriptions indirectly through its dataSpecifications, specifically through:

• DataSpecificationIec61360.valueList
• where each ValueReferencePair.valueId may point to a ConceptDescription

Because of this, an AAS structure may contain the following chain:
SubmodelElement → ConceptDescription A → valueList entry → ConceptDescription B

Request for clarification

Please clarify the intended interpretation of includeConceptDescriptions in such cases?

Specifically:

1. Should servers include only ConceptDescriptions that are directly referenced by the serialized SubmodelElements?
2. Or should servers include all ConceptDescriptions that are reachable through transitive references (e.g., those occurring inside DataSpecificationIec61360.valueList)?
3. If both interpretations are valid today, is one of them intended to be normative for interoperability?

This distinction is important for interoperability and for clients that rely on predictable serialization behavior.

[sebbader-sap]

Hi @empwilli, thanks for raising this point. Please kindly review #512

[sebbader-sap]

Closing the issue as the proposed change has been merged.