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inject/where/choose combination causes ClassCastException

See original GitHub issue

The following query causes a ClassCastException:

g.inject('test').
where(
  choose(
      __.V().hasLabel('DoesntMatter'),
      __.constant(true),
      __.constant(false)
  )
)

Note that while this gremlin is a little nonsensical, it represents a reduction of a much more complicated gremlin which also fails.

The exception trace is:

gremlin> g.inject('test').
......1> where(
......2>   choose(
......3>       __.V().hasLabel('DoesntMatter'),
......4>       __.constant(true),
......5>       __.constant(false)
......6>   )
......7> )
class java.lang.String cannot be cast to class org.umlg.sqlg.structure.SqlgElement (java.lang.String is in module java.base of loader 'bootstrap'; org.umlg.sqlg.structure.SqlgElement is in unnamed module of loader 'app')
Type ':help' or ':h' for help.
Display stack trace? [yN]y
java.lang.ClassCastException: class java.lang.String cannot be cast to class org.umlg.sqlg.structure.SqlgElement (java.lang.String is in module java.base of loader 'bootstrap'; org.umlg.sqlg.structure.SqlgElement is in unnamed module of loader 'app')
	at org.umlg.sqlg.step.barrier.SqlgBranchStepBarrier.processNextStart(SqlgBranchStepBarrier.java:80)
	at org.umlg.sqlg.step.SqlgAbstractStep.hasNext(SqlgAbstractStep.java:121)
	at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.hasNext(DefaultTraversal.java:196)
	at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalUtil.test(TraversalUtil.java:96)
	at org.apache.tinkerpop.gremlin.process.traversal.step.filter.TraversalFilterStep.filter(TraversalFilterStep.java:59)
	at org.apache.tinkerpop.gremlin.process.traversal.step.filter.FilterStep.processNextStart(FilterStep.java:38)
	at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:144)
	at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.hasNext(DefaultTraversal.java:196)
	at java_util_Iterator$hasNext.call(Unknown Source)
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:115)
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:119)
	at org.apache.tinkerpop.gremlin.console.Console$_closure3.doCall(Console.groovy:257)

FWIW, this seems to work around the problem:

g.V().limit(1).constant("test")
where(
  choose(
      __.V().hasLabel('DoesntMatter'),
      __.constant(true),
      __.constant(false)
  )
)

Issue Analytics

State:
Created 2 years ago
Comments:6 (3 by maintainers)

Top GitHub Comments

1reaction

pietermartincommented, Jun 30, 2021

@allenhadden can you please test your more complex query? I added a bunch of InjectStep optimizations.

1reaction

pietermartincommented, Jun 27, 2021

Some feedback, I have made progress, at least the trimmed down test you provided, thanks for that, passes. Your usecase bypasses Sqlg’s bypassing of inject. Sqlg does not optimize traversals that contain InjectStep. However your gremlin’s nested traversals did not quite realize the input came via an inject and attempted to optimize it…

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