Add test and fix RDFLib#1808

rdflib/graph.py

@@ -18,7 +18,7 @@
 from rdflib.namespace import Namespace, RDF
 from rdflib import plugin, exceptions, query, namespace
 import rdflib.term
-from rdflib.term import BNode, IdentifiedNode, Node, URIRef, Literal, Genid
+from rdflib.term import BNode, IdentifiedNode, Node, RDFLibGenid, URIRef, Literal, Genid
 from rdflib.paths import Path
 from rdflib.store import Store
 from rdflib.serializer import Serializer
@@ -1512,10 +1512,17 @@ def do_de_skolemize(uriref, t):
 
         def do_de_skolemize2(t):
             (s, p, o) = t
-            if isinstance(s, Genid):
-                s = s.de_skolemize()
-            if isinstance(o, Genid):
-                o = o.de_skolemize()
+
+            if RDFLibGenid._is_external_skolem(s):
+                s = Genid(s).de_skolemize()
+            elif RDFLibGenid._is_rdflib_skolem(s):
+                s = RDFLibGenid(s).de_skolemize()
+
+            if RDFLibGenid._is_external_skolem(o):
+                o = Genid(o).de_skolemize()
+            elif RDFLibGenid._is_rdflib_skolem(o):
+                o = RDFLibGenid(o).de_skolemize()
+
             return s, p, o
 
         retval = Graph() if new_graph is None else new_graph

test/test_issues/test_issue1808.py

@@ -0,0 +1,44 @@
+from rdflib import Graph
+from rdflib.term import BNode, URIRef, rdflib_skolem_genid
+
+
+def test():
+    """Test skolemised URI query retrieves expected results.
+
+    Issue: https://github.com/RDFLib/rdflib/issues/1808
+    """
+
+    g = Graph()
+    g.parse(data='[] <urn:prop> "val" .', format="turtle")
+    for s, p, o in g:
+        assert isinstance(s, BNode)
+
+    gs = g.skolemize()
+    for s, p, o in gs:
+        assert isinstance(s, URIRef) and s.__contains__(rdflib_skolem_genid)
+
+    query_with_iri = 'select ?p ?o {{ <{}> ?p ?o }}'.format(s)
+    query_for_all = 'select ?s ?p ?o { ?s ?p ?o }'
+
+    count = 0
+    for row in gs.query(query_with_iri):
+        count += 1
+    assert count == 1
+
+    count = 0
+    for row in gs.query(query_for_all):
+        count += 1
+    assert count == 1
+
+    gp = Graph()
+    gp.parse(data=gs.serialize(format='turtle'), format='turtle')
+
+    count = 0
+    for row in gp.query(query_with_iri):
+        count += 1
+    assert count == 1
+
+    count = 0
+    for row in gp.query(query_for_all):
+        count += 1
+    assert count == 1