Perfect rewriting isn't perfect

[ricroberts]

If you have a values clause in a query, and we pass in a values clause e.g. in this query ...then any live graphs passed in (which have changed) will be rewritten into the draft-graphs. All ok so far.

But if the metadata graph hasn't itself changed then there wont be a draft graph for it, with a pre-rewritten version of the ?ds_graph in the db for this clause to match:

?catalog_entry pmdcat:graph ?ds_graph .

So basically rewriting isn't actually 'perfect' when spanning across live and draft graphs, if you're trying to match graph identifiers.

[ricroberts]

In practice this means that to do some of the stuff we need in Muttnik admin (for showing / linking to changed datasets), we might need to use the raw stardog connection and do some 'manual' rewriting.

[ricroberts]

see also #618