Update shells with PATCH operation

[sebastiankb]

What?

It seems, for /shells only supports PUT for updating the content of an existing shell. However, this is not consistent to other API operations such as for /submodels that allows to use PATCH for updating submodel's content

How?

Support PATCH operation for /shells for updating shells content

[sebastiankb]

It seems there is the same situation for the thumbnail API.

[sebbader-sap]

If I remember correctly, we didn't add the operation as no requirement or use case was reported from the community. Can you elaborate for what it's needed?
"Only" for symmetry with the Submodel endpoints? Or is there a scenario that could not be covered otherwise?

Shell objects are rather small and restricted in size compared to Submodels (that could contain arbitrarily many attributes). It therefore seemed feasible to send the whole object every time a change is needed.

[sebastiankb]

I think, it is a question of symmetry and consistency since PATCH is allowed, e.g., on submodel and submodel-element level. The argument of the object size would not match to the submodel-element level. There I would also expect relative small objects, but PATCH is supported there.

[mjacoby]

I agree with @sebastiankb that for symmetry reasons this call should be present.
However, as currently the payload & behavior of PATCH in general is not well defined in the AAS API, it is probably not the right time to introduce this now. Once PATCH is properly defined this call should be added.