Index issue when a value is removed and added to a list property

[To-om]

Hello,

I found a bug on the indexation of list property. When the same value is removed and added again to the list in the same transaction, the value is duplicated in the index. I reproduced the problem with Cassandra/ES and Berkeley/Lucene.

The database schema creation

graph = JanusGraphFactory.open('conf/janusgraph-berkeletje-lucene.properties')

// Create schema
mgmt = graph.openManagement()
tags = mgmt.makePropertyKey('tags').dataType(String.class).cardinality(Cardinality.LIST).make()
data = mgmt.makeVertexLabel('data').make()
mgmt.commit()

// Add indexes
mgmt = graph.openManagement()
tags = mgmt.getPropertyKey('tags')
mgmt.buildIndex('global', Vertex.class).addKey(tags, Mapping.STRING.asParameter()).buildMixedIndex('search')
mgmt.commit()

// Wait the indexes
ManagementSystem.awaitGraphIndexStatus(graph, 'global').call()

// Reindex data
mgmt = graph.openManagement()
mgmt.updateIndex(mgmt.getGraphIndex('global'), SchemaAction.REINDEX).get()
mgmt.commit()

// Wait the indexes
ManagementSystem.awaitGraphIndexStatus(graph, 'global').status(SchemaStatus.ENABLED).call()

The code below describes how to reproduce:

g = graph.traversal()

v = g.addV('data').property(list, 'tags', 't1').id().next()
g.tx().commit()   // index contains tags:[t1]
g.V(c).valueMap() // ==>[tags:[t1]]

g.V(v).properties('tags').drop().iterate()
g.V(v).property(list, 'tags', 't1').iterate()
g.tx().commit()   // index contains tags:[t1, t1]
g.V(c).valueMap() // ==>[tags:[t1]]

g.V(v).properties('tags').drop().iterate()
g.V(v).property(list, 'tags', 't2').iterate()
g.tx().commit()   // index contains tags:[t1, t2]
g.V(c).valueMap() // ==>[tags:[t2]]

g.V().has('tags', 't1') // should return empty traversal but returns the vertex v

I used to drop all values of the list and add new values because I want to set the entire list values in only one traversal (using sideEffect). I don't know if there is another way to do that. The problem doesn't occur with the "set" properties. Is it possible to convert a list property into set property without copying all values?