Hi, The following query no longer works on 3.2.4
@Test public void testOptionalWithOrderBy() { final TinkerGraph g = TinkerGraph.open(); Vertex a1 = g.addVertex(T.label, "A", "name", "a1"); Vertex b1 = g.addVertex(T.label, "B", "name", "b1"); Vertex b2 = g.addVertex(T.label, "B", "name", "b2"); Vertex b3 = g.addVertex(T.label, "B", "name", "b3"); Vertex c1 = g.addVertex(T.label, "C", "name", "c1"); Vertex c2 = g.addVertex(T.label, "C", "name", "c2"); Vertex c3 = g.addVertex(T.label, "C", "name", "c3"); a1.addEdge("ab", b1, "order", 3); a1.addEdge("ab", b2, "order", 2); a1.addEdge("ab", b3, "order", 1); b1.addEdge("bc", c1, "order", 3); b1.addEdge("bc", c2, "order", 2); b1.addEdge("bc", c3, "order", 1); GraphTraversal<Vertex, Vertex> traversal = g.traversal().V(a1.id()) .optional( __.outE("ab").as("ab").otherV().as("vb") .optional( __.outE("bc").as("bc").otherV().as("vc") ) ) .order().by(__.select("ab").by("order"), Order.incr).by(__.select("bc").by("order"), Order.incr); while (traversal.hasNext()) { System.out.println(traversal.next().<String>value("name")); } } On 3.2.3 it returns b3 b2 c3 c2 c1 On 3.2.4 it throws the following exception, java.lang.IllegalArgumentException: The provided traverser does not map to a value: v[6]->[SelectOneStep(bc,value(order))] at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil.apply(TraversalUtil.java:45) at org.apache.tinkerpop.gremlin.process.traversal.step.map.OrderGlobalStep.createProjectedTraverser(OrderGlobalStep.java:155) at org.apache.tinkerpop.gremlin.process.traversal.step.map.OrderGlobalStep.processAllStarts(OrderGlobalStep.java:74) at org.apache.tinkerpop.gremlin.process.traversal.step.util.CollectingBarrierStep.processNextStart(CollectingBarrierStep.java:108) at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143) at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.hasNext(DefaultTraversal.java:184) Has the semantics changed or is it a bug? Thanks Pieter