[TINKERPOP-2449] Get edges in a graph by label

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Affects Version/s: 3.4.8
• Component/s: structure, tinkergraph
• Environment: java with tinkergraph and tp3Version=3.4.8
• Assignee: Unassigned
• Reporter: Fredrick Eisele
• Created: 19/Oct/20 16:39
• Updated: 19/Oct/20 16:55
• Resolved: 19/Oct/20 16:55

Description

Given the presence of a node with a self-referential edge with label 'root' I expect the following to get that node.

List<Vertex> roots = g.E("root").outV().toList();

The roots list is empty.

The following work-around gives me what I expect.

List<Vertex> roots = g.V().inE("root").outV().toList();

Here is a graphml fragment that illustrates the problem.

<?xml version="1.0" encoding="UTF-8"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
      xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns http://graphml.graphdrawing.org/xmlns/1.1/graphml.xsd">
    <graph id="G" edgedefault="directed">
        <node id="0">
            <data key="labelV">BLANK</data>
        </node>
        <node id="1">
            <data key="labelV">component</data>
        </node>
 
        <edge id="2" source="1" target="1">
            <data key="labelE">root</data>
        </edge>
    </graph>
</graphml>

I believe this has been a problem for a while...
https://groups.google.com/g/gremlin-users/c/wVOnJAvHSSU