[TINKERPOP-2920] SubgraphStrategy failure when property key not present on vertex in by()

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.5.5
• Fix Version/s: 3.7.0, 3.5.7, 3.6.5
• Component/s: process
• Assignee: Stephen Mallette
• Reporter: Stephen Mallette
• Created: 01/Apr/23 15:33
• Updated: 07/Jul/23 17:40
• Resolved: 07/Jul/23 17:40

Description

The following triggers the failure assuming "example" isn't present on a vertex:

g.withStrategies(new SubgraphStrategy(vertexProperties: constant(true))).
  V().project("example").by("example")

Note that values('example") will work on 3.6.2, but not 3.5.5 which probably has something to do with differences in by() handling and ProductiveByStrategy.

gremlin> g.withStrategies(new SubgraphStrategy(vertexProperties: constant(true))).
......1>   withoutStrategies(ProductiveByStrategy).
......2>   V().project("example").by(values("example"))
The provided traverser does not map to a value: v[1][TinkerVertex]->[PropertiesStep([example],property), OrStep([[ClassFilterStep(VertexProperty)], [TraversalFilterStep([ConstantStep(true)])]]), PropertyValueStep][DefaultGraphTraversal] parent[[TinkerGraphStep(vertex,[]), ProjectStep([example],[[PropertiesStep([example],property), OrStep([[ClassFilterStep(VertexProperty)], [TraversalFilterStep([ConstantStep(true)])]]), PropertyValueStep]])]]
Type ':help' or ':h' for help.
Display stack trace? [yN]
......1>   V().project("example").by("example")
The provided traverser does not map to a value: v[1][TinkerVertex]->[PropertiesStep([example],property), TraversalFilterStep([ConstantStep(true)]), OrStep([[ClassFilterStep(VertexProperty)], [TraversalFilterStep([ConstantStep(true)])]]), PropertyValueStep][DefaultTraversal] parent[[CoalesceStep([value([PropertiesStep([example],property), TraversalFilterStep([ConstantStep(true)]), OrStep([[ClassFilterStep(VertexProperty)], [TraversalFilterStep([ConstantStep(true)])]]), PropertyValueStep]), (null)])]]
Type ':help' or ':h' for help.
Display stack trace? [yN]