Reset graph on exit from context

2 files changed, 36 insertions, 1 deletions

diff --git a/rdflib/plugins/sparql/evaluate.py b/rdflib/plugins/sparql/evaluate.py
index 496bc872..f5fd86ed 100644
--- a/rdflib/plugins/sparql/evaluate.py
+++ b/rdflib/plugins/sparql/evaluate.py
@@ -187,6 +187,7 @@ def evalGraph(ctx, part):
 
     ctx = ctx.clone()
     graph = ctx[part.term]
+    prev_graph = ctx.graph
     if graph is None:
 
         for graph in ctx.dataset.contexts():
@@ -199,11 +200,13 @@ def evalGraph(ctx, part):
             c = c.push()
             graphSolution = [{part.term: graph.identifier}]
             for x in _join(evalPart(c, part.p), graphSolution):
+                x.ctx.graph = prev_graph
                 yield x
 
     else:
         c = ctx.pushGraph(ctx.dataset.get_context(graph))
         for x in evalPart(c, part.p):
+            x.ctx.graph = prev_graph
             yield x
 
 
diff --git a/test/test_sparql.py b/test/test_sparql.py
index fdf29c3c..c6af2056 100644
--- a/test/test_sparql.py
+++ b/test/test_sparql.py
@@ -1,4 +1,5 @@
-from rdflib import Graph, URIRef, Literal, BNode
+from rdflib import Graph, URIRef, Literal, BNode, ConjunctiveGraph
+from rdflib.namespace import Namespace, RDF, RDFS
 from rdflib.plugins.sparql import prepareQuery
 from rdflib.compare import isomorphic
 
@@ -112,6 +113,37 @@ def test_sparql_update_with_bnode_serialize_parse():
     assert not raised
 
 
+def test_named_filter_graph_query():
+    g = ConjunctiveGraph()
+    g.namespace_manager.bind('rdf', RDF)
+    g.namespace_manager.bind('rdfs', RDFS)
+    ex = Namespace('https://ex.com/')
+    g.namespace_manager.bind('ex', ex)
+    g.get_context(ex.g1).parse(format="turtle", data=f"""
+    prefix ex: <https://ex.com/>
+    prefix rdfs: <{str(RDFS)}>
+    ex:Boris rdfs:label "Boris" .
+    ex:Susan rdfs:label "Susan" .
+    """)
+    g.get_context(ex.g2).parse(format="turtle", data="""
+    prefix ex: <https://ex.com/>
+    ex:Boris a ex:Person .
+    """)
+
+    assert list(g.query("select ?l where { graph ex:g1 { ?a rdfs:label ?l } ?a a ?type }",
+                        initNs={'ex': ex})) == [(Literal('Boris'),)]
+    assert list(g.query("select ?l where { graph ex:g1 { ?a rdfs:label ?l } filter exists { ?a a ?type }}",
+                        initNs={'ex': ex})) == [(Literal('Boris'),)]
+    assert list(g.query("select ?l where { graph ex:g1 { ?a rdfs:label ?l } filter not exists { ?a a ?type }}",
+                        initNs={'ex': ex})) == [(Literal('Susan'),)]
+    assert list(g.query("select ?l where { graph ?g { ?a rdfs:label ?l } ?a a ?type }",
+                        initNs={'ex': ex})) == [(Literal('Boris'),)]
+    assert list(g.query("select ?l where { graph ?g { ?a rdfs:label ?l } filter exists { ?a a ?type }}",
+                        initNs={'ex': ex})) == [(Literal('Boris'),)]
+    assert list(g.query("select ?l where { graph ?g { ?a rdfs:label ?l } filter not exists { ?a a ?type }}",
+                        initNs={'ex': ex})) == [(Literal('Susan'),)]
+
+
 if __name__ == "__main__":
     import nose