2022-06-13 23:18:00 [gremlin-server-exec-2] [WARN] o.a.t.g.s.h.HttpHandlerUtil - Invalid request - responding with 500 Internal Server Error and Error encountered evaluating script: g.V(3).repeat(inE('child').outV().simplePath()).until(or(inE().count().is(0),loops().is(eq(2)))).path()
java.lang.NullPointerException: null
	at com.baidu.hugegraph.traversal.optimize.HugeVertexStepStrategy.apply(HugeVertexStepStrategy.java:73) ~[classes/:?]
	at com.baidu.hugegraph.auth.HugeGraphAuthProxy$TraversalStrategyProxy.apply(HugeGraphAuthProxy.java:1722) ~[classes/:?]
	at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper.applyTraversalRecursively(TraversalHelper.java:467) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper.applyTraversalRecursively(TraversalHelper.java:475) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper.applyTraversalRecursively(TraversalHelper.java:475) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper.applyTraversalRecursively(TraversalHelper.java:475) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.applyStrategies(DefaultTraversal.java:151) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.hasNext(DefaultTraversal.java:221) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils.fill(IteratorUtils.java:62) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils.list(IteratorUtils.java:85) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils.asList(IteratorUtils.java:382) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.server.handler.HttpGremlinEndpointHandler.lambda$channelRead$1(HttpGremlinEndpointHandler.java:221) ~[gremlin-server-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.util.function.FunctionUtils.lambda$wrapFunction$0(FunctionUtils.java:36) ~[gremlin-core-3.5.1.jar:3.5.1]
	at org.apache.tinkerpop.gremlin.groovy.engine.GremlinExecutor.lambda$eval$0(GremlinExecutor.java:278) ~[gremlin-groovy-3.5.1.jar:3.5.1]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_111]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_111]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_111]
	at com.baidu.hugegraph.auth.HugeGraphAuthProxy$ContextTask.run(HugeGraphAuthProxy.java:1838) [classes/:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_111]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_111]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_111]