rdflib.Graph.update might lie to us when using SPARQLUpdateStore with Fuseki

[jgonggrijp]

RDFLib/rdflib#1251 (comment)

Consequences:

• @GuillaumeLNB was unable to update the NLP ontology graph through our SPARQL update endpoint. The response came 200, yet had no effect. (As a stop-gap solution, I updated the ontology manually.)
• Potentially affects all places where we call .update on a Graph, including the present source ontology migrations (Source data model #444/Feature/source datamodel #500). Fortunately, we use different update mechanisms in most places, which seem to work.

We might need to work around this by passing update queries to the store directly (and qualify it ourselves), or possibly with ConjunctiveGraph/Dataset if this can be made to work at all. In either case, we'll have to take care of graph qualification by ourselves.

[jgonggrijp]

We might be able to close this due to the switch to Blazegraph. Would you agree with that, @JeltevanBoheemen?

[JeltevanBoheemen]

Yes, I agree.