Fix explicit dataset (FROM and FROM NAMED clauses)

rdflib/plugins/sparql/evaluate.py

@@ -672,36 +672,14 @@ def evalQuery(
         :doc:`Security Considerations </security_considerations>`
         documentation.
     """
+    main = query.algebra
 
     initBindings = dict((Variable(k), v) for k, v in (initBindings or {}).items())
 
-    ctx = QueryContext(graph, initBindings=initBindings)
+    ctx = QueryContext(
+        graph, initBindings=initBindings, datasetClause=main.datasetClause
+    )
 
     ctx.prologue = query.prologue
-    main = query.algebra
-
-    if main.datasetClause:
-        if ctx.dataset is None:
-            raise Exception(
-                "Non-conjunctive-graph doesn't know about "
-                + "graphs! Try a query without FROM (NAMED)."
-            )
-
-        ctx = ctx.clone()  # or push/pop?
-
-        firstDefault = False
-        for d in main.datasetClause:
-            if d.default:
-                if firstDefault:
-                    # replace current default graph
-                    dg = ctx.dataset.get_context(BNode())
-                    ctx = ctx.pushGraph(dg)
-                    firstDefault = True
-
-                ctx.load(d.default, default=True)
-
-            elif d.named:
-                g = d.named
-                ctx.load(g, default=False)
 
     return evalPart(ctx, main)

rdflib/plugins/sparql/sparql.py

@@ -22,7 +22,7 @@
 import isodate
 
 import rdflib.plugins.sparql
-from rdflib.graph import ConjunctiveGraph, Graph
+from rdflib.graph import ConjunctiveGraph, Dataset, Graph
 from rdflib.namespace import NamespaceManager
 from rdflib.plugins.sparql.parserutils import CompValue
 from rdflib.term import BNode, Identifier, Literal, Node, URIRef, Variable
@@ -255,20 +255,39 @@ def __init__(
         graph: Optional[Graph] = None,
         bindings: Optional[Union[Bindings, FrozenBindings, List[Any]]] = None,
         initBindings: Optional[Mapping[str, Identifier]] = None,
+        datasetClause=None,
     ):
         self.initBindings = initBindings
         self.bindings = Bindings(d=bindings or [])
         if initBindings:
             self.bindings.update(initBindings)
 
         self.graph: Optional[Graph]
-        self._dataset: Optional[ConjunctiveGraph]
-        if isinstance(graph, ConjunctiveGraph):
-            self._dataset = graph
-            if rdflib.plugins.sparql.SPARQL_DEFAULT_GRAPH_UNION:
-                self.graph = self.dataset
+        self._dataset: Optional[Union[Dataset, ConjunctiveGraph]]
+        if isinstance(graph, (Dataset, ConjunctiveGraph)):
+            if datasetClause:
+                self._dataset = Dataset()
+                self.graph = Graph()
+                for d in datasetClause:
+                    if d.default:
+                        from_graph = graph.get_context(d.default)
+                        self.graph += from_graph
+                        if not from_graph:
+                            self.load(d.default, default=True)
+                    elif d.named:
+                        namedGraphs = Graph(
+                            store=self.dataset.store, identifier=d.named
+                        )
+                        from_named_graphs = graph.get_context(d.named)
+                        namedGraphs += from_named_graphs
+                        if not from_named_graphs:
+                            self.load(d.named, default=False)
             else:
-                self.graph = self.dataset.default_context
+                self._dataset = graph
+                if rdflib.plugins.sparql.SPARQL_DEFAULT_GRAPH_UNION:
+                    self.graph = self.dataset
+                else:
+                    self.graph = self.dataset.default_context
         else:
             self._dataset = None
             self.graph = graph

test/test_sparql/test_dataset_exclusive.py

@@ -0,0 +1,84 @@
+from rdflib.graph import Dataset, Graph
+from rdflib.term import URIRef
+
+dataset = Dataset(default_union=False)
+# Adding into default graph
+dataset.add((URIRef("urn:s0"), URIRef("urn:p0"), URIRef("urn:o0")))
+# Adding into named graphs
+dataset.add(
+    (
+        URIRef("urn:s1"),
+        URIRef("urn:p1"),
+        URIRef("urn:o1"),
+        Graph(identifier=URIRef("urn:g1")),
+    )
+)
+
+dataset.add(
+    (
+        URIRef("urn:s2"),
+        URIRef("urn:p2"),
+        URIRef("urn:o2"),
+        Graph(identifier=URIRef("urn:g2")),
+    )
+)
+
+dataset.add(
+    (
+        URIRef("urn:s3"),
+        URIRef("urn:p3"),
+        URIRef("urn:o3"),
+        Graph(identifier=URIRef("urn:g3")),
+    )
+)
+
+
+# Test implicit exlusive dataset
+def test_exclusive():
+    results = list(dataset.query("SELECT ?s ?p ?o WHERE {?s ?p ?o}"))
+    assert results == [(URIRef("urn:s0"), URIRef("urn:p0"), URIRef("urn:o0"))]
+
+
+# Test explicit default graph with exclusive dataset
+def test_from():
+    query = """
+        SELECT ?s ?p ?o
+        FROM <urn:g1>
+        WHERE {?s ?p ?o}
+    """
+    results = list(dataset.query(query))
+    assert results == [(URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1"))]
+
+
+# Test explicit named graphs with exclusive dataset
+def test_from_named():
+    query = """
+        SELECT
+        ?g ?s ?p ?o
+        FROM NAMED <urn:g1>
+        WHERE {
+            graph ?g {?s ?p ?o}
+        }
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (URIRef("urn:g1"), URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1"))
+    ]
+
+
+# Test that we can use from and from named in the same query
+def test_from_and_from_named():
+    query = """
+        SELECT ?g ?s ?p ?o
+        FROM <urn:g1>
+        FROM NAMED <urn:g2>
+        WHERE {
+            {?s ?p ?o}
+            UNION {graph ?g {?s ?p ?o}}
+        } ORDER BY ?s
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (None, URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1")),
+        (URIRef("urn:g2"), URIRef("urn:s2"), URIRef("urn:p2"), URIRef("urn:o2")),
+    ]

test/test_sparql/test_dataset_inclusive.py

@@ -0,0 +1,150 @@
+from rdflib.graph import Dataset, Graph
+from rdflib.term import URIRef
+
+dataset = Dataset(default_union=True)
+# Adding into default graph
+dataset.add((URIRef("urn:s0"), URIRef("urn:p0"), URIRef("urn:o0")))
+# Adding into named graphs
+dataset.add(
+    (
+        URIRef("urn:s1"),
+        URIRef("urn:p1"),
+        URIRef("urn:o1"),
+        Graph(identifier=URIRef("urn:g1")),
+    )
+)
+
+dataset.add(
+    (
+        URIRef("urn:s2"),
+        URIRef("urn:p2"),
+        URIRef("urn:o2"),
+        Graph(identifier=URIRef("urn:g2")),
+    )
+)
+
+dataset.add(
+    (
+        URIRef("urn:s3"),
+        URIRef("urn:p3"),
+        URIRef("urn:o3"),
+        Graph(identifier=URIRef("urn:g3")),
+    )
+)
+
+
+# Test implicit inclusive dataset
+# The query's default graph should contain a merge of all graphs:
+# The service's default graph + all the service's named graphs
+def test_inclusive():
+    query = """
+        SELECT ?s ?p ?o
+        WHERE {?s ?p ?o}
+        ORDER BY ?s
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (URIRef("urn:s0"), URIRef("urn:p0"), URIRef("urn:o0")),
+        (URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1")),
+        (URIRef("urn:s2"), URIRef("urn:p2"), URIRef("urn:o2")),
+        (URIRef("urn:s3"), URIRef("urn:p3"), URIRef("urn:o3")),
+    ]
+
+
+# Test explicit default graph with inclusive dataset
+def test_default_from_1():
+    query = """
+        SELECT ?s ?p ?o
+        FROM <urn:g1>
+        WHERE {?s ?p ?o}
+    """
+    results = list(dataset.query(query))
+    assert results == [(URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1"))]
+
+
+# test that we include more than one graph into the default graph
+def test_default_from_2():
+    query = """
+        SELECT ?s ?p ?o
+        FROM <urn:g1>
+        FROM <urn:g2>
+        WHERE {?s ?p ?o}
+        ORDER BY ?s
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1")),
+        (URIRef("urn:s2"), URIRef("urn:p2"), URIRef("urn:o2")),
+    ]
+
+
+# Since there is a FROM clause, we consider RDF dataset explicit
+# Thus if FROM NAMED is not defined, named graph is considered empty set
+def test_named_from():
+    query = """
+        SELECT ?s ?p ?o
+        FROM <urn:g1>
+        WHERE {
+            graph ?g {?s ?p ?o}
+        } ORDER BY ?s
+    """
+    results = list(dataset.query(query))
+    assert results == [], "no result expected"
+
+
+# Test explicit named graphs with inclusive dataset
+def test_named_from_named_1():
+    query = """
+        SELECT ?g ?s ?p ?o
+        FROM NAMED <urn:g1>
+        WHERE {
+            graph ?g {?s ?p ?o}
+        }
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (URIRef("urn:g1"), URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1"))
+    ]
+
+
+# test that we include more than one graph into the named graphs
+def test_named_from_named_2():
+    query = """
+    SELECT ?g ?s ?p ?o
+    FROM NAMED <urn:g1>
+    FROM NAMED <urn:g2>
+    WHERE {
+        graph ?g {?s ?p ?o}
+    } ORDER BY ?g
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (URIRef("urn:g1"), URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1")),
+        (URIRef("urn:g2"), URIRef("urn:s2"), URIRef("urn:p2"), URIRef("urn:o2")),
+    ]
+
+
+# Since there is a FROM NAMED clause, we consider RDF dataset explicit
+# Thus if FROM is not defined, default graph is considered empty
+def test_default_from_named():
+    results = list(
+        dataset.query("SELECT ?g ?s ?p ?o FROM NAMED <urn:g1> WHERE {?s ?p ?o}")
+    )
+    assert results == [], "no result expected"
+
+
+def test_from_and_from_named():
+    query = """
+        SELECT ?g ?s ?p ?o
+        FROM <urn:g1>
+        FROM NAMED <urn:g2>
+        WHERE {
+            {?s ?p ?o}
+            UNION {graph ?g {?s ?p ?o}}
+        } ORDER BY ?s
+    """
+    results = list(dataset.query(query))
+    assert results == [
+        (None, URIRef("urn:s1"), URIRef("urn:p1"), URIRef("urn:o1")),
+        (URIRef("urn:g2"), URIRef("urn:s2"), URIRef("urn:p2"), URIRef("urn:o2")),
+    ]