About the design of Predicate in EdgeExpand

[zhanglei1949]

In EdgeExpand, a predicate can possibly be given to filter unexpected results.

{
    "opr": {
        "edge": {
            "direction": "OUT",
            "params": {
                "tables": [
                    {
                        "id": 10
                    }
                ],
                "columns": [
                    {
                        "name": "workFrom"
                    }
                ],
                "isAllColumns": false,
                "predicate": {
                    "operators": [
                        {
                            "var": {
                                "property": {
                                    "key": {
                                        "name": "workFrom"
                                    }
                                },
                                "nodeType": {
                                    "dataType": "INT32"
                                }
                            },
                            "nodeType": {
                                "dataType": "INT32"
                            }
                        },
                        {
                            "nodeType": {
                                "dataType": "BOOLEAN"
                            },
                            "logical": "LT"
                        },
                        {
                            "param": {
                                "name": "workFromYear",
                                "index": 2,
                                "dataType": {
                                    "dataType": "INT32"
                                }
                            },
                            "nodeType": {
                                "dataType": "INT32"
                            }
                        }
                    ]
                },
                "sampleRatio": 1,
                "extra": {}
            },
            "expandOpt": "EDGE",
            "isOptional": false,
            "vTag": 1,
            "alias": 2
        }
    }
}

The may be confusing point about this predicate:

The tag of the Variable is not given, so should I use the current visiting edge or the previous visited HEAD?

[github-actions]

/cc @zhanglei1949 @BingqingLyu, this issus/pr has had no activity for for a long time, could you folks help to review the status ?
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