potentialGraphFromPatterns where patterns don't have graph property

[simonvbrae]

In the function potentialGraphFromPatterns, when elements in the patterns array don't have a graph property. What should the function return?

Such an occurrence causes the bug described in this issue: Issue: https://github.com/comunica/comunica/issues/1223

[joachimvh]

When there is no Graph the function returns the BGP itself: https://github.com/joachimvh/SPARQLAlgebra.js/blob/b14f2351d3fe95a2ccce1d02e163ed5d268ea496/lib/sparql.ts#L984-L986

If you mean that the graph value can be undefined, that same if-statement would have to be triggered. But that seems like something might have gone wrong earlier as the typings of a Pattern define that the graph value should always be defined.

[simonvbrae]

Good to know! I'll look for why a pattern without a graph is defined. The graph value is indeed undefined, leading an error when .value is called in the if statement.

[simonvbrae]

The query that results in an error is the following:

SELECT ?s
WHERE {
     graph <http://graph.ucdavis.edu/> {
       ?s ?p ?o.
       filter(uri(?s))
     }
     GRAPH <http://other.ucdavis.edu/> {
       ?s ?p  ?o.
      }
}