SPARQL Update: DatasetGraphOne: NPE when COPY or MOVE to named graph

When executing SPARQL Update requests against a dataset that does not automatically create new graphs, COPY or MOVE operations with a non-existing graph as the target will result in a NullPointerException. The same happens when adding SILENT.

I would expect these requests to result in UpdateExceptions, with a message pointing out the non-existing graph. Or nothing in the case of SILENT.

The attached JUnit 4 test demonstrates this by running queries against a DatasetGraphOne:

COPY DEFAULT TO <http://example.org/no-such-graph>
COPY SILENT DEFAULT TO <http://example.org/no-such-graph>
MOVE DEFAULT TO <http://example.org/no-such-graph>
MOVE SILENT DEFAULT TO <http://example.org/no-such-graph>

Each request produces an NPE.