Christopher Smith created TINKERPOP-2510:
--------------------------------------------
Summary: by-modulator throws when token is used after elementMap()
Key: TINKERPOP-2510
URL: https://issues.apache.org/jira/browse/TINKERPOP-2510
Project: TinkerPop
Issue Type: Bug
Affects Versions: 3.4.9
Reporter: Christopher Smith
I'm attempting to write a "join" traversal to return the values of several
related vertices (of different types), starting from an entry vertex. In order
to extract the relevant properties, I am currently using {{elementMap}}, then
trying to stash the vertex properties to continue with my query:
{code:groovy}
gts.V(entryPoint).as('p')
.sideEffect(__.elementMap().group('pp').by(T.id))
.out...
...
.select('pp', ...)
{code}
As {{elementMap}} produces a map that includes the tokens as map keys, I
expected {{by(T.id)}} to extract a map keyed on the vertex ID with the
properties as the value (right now folded, but I'm crunching on that later).
Using strings like {{'firstName'}} works as expected, but of course using the
string {{'id'}} does not because the map key is the token, not the string.
However, passing {{T.id}} to the by-modulator when the value is a map (instead
of an element) produces a {{ClassCastException}}. As far as I can tell, the
processor is assuming somewhere that {{by(T.id)}} indicates that the incoming
value is an element, which (at least after the addition of {{elementMap}}) is
not true.
{code}
java.lang.ClassCastException: class java.util.LinkedHashMap cannot be cast to
class org.apache.tinkerpop.gremlin.structure.Element (java.util.LinkedHashMap
is in module java.base of loader 'bootstrap';
org.apache.tinkerpop.gremlin.structure.Element is in unnamed module of loader
'app')
at
org.apache.tinkerpop.gremlin.process.traversal.lambda.TokenTraversal.addStart(TokenTraversal.java:46)
at
org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil.apply(TraversalUtil.java:42)
at
org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil.applyNullable(TraversalUtil.java:87)
at
org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.GroupSideEffectStep.sideEffect(GroupSideEffectStep.java:114)
at
org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.SideEffectStep.processNextStart(SideEffectStep.java:39)
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:197)
at
org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.TraversalSideEffectStep.sideEffect(TraversalSideEffectStep.java:48)
at
org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.SideEffectStep.processNextStart(SideEffectStep.java:39)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.filter.FilterStep.processNextStart(FilterStep.java:37)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.filter.FilterStep.processNextStart(FilterStep.java:37)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.map.FlatMapStep.processNextStart(FlatMapStep.java:48)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:143)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.ExpandableStepIterator.next(ExpandableStepIterator.java:50)
at
org.apache.tinkerpop.gremlin.process.traversal.step.map.MapStep.processNextStart(MapStep.java:36)
at
org.apache.tinkerpop.gremlin.process.traversal.step.map.SelectOneStep.processNextStart(SelectOneStep.java:131)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.next(AbstractStep.java:128)
at
org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.next(AbstractStep.java:38)
at
org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.next(DefaultTraversal.java:205)
at com.example.Queries.query(Queries.groovy:39)
{code}
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