// Test that missing values are not returned when the connectFrom value in a $graphLookup is null.
import {arrayEq} from "jstests/aggregation/extras/utils.js";

let local = db[jsTestName()];

local.drop();

assert.commandWorked(
    local.insert([
        {"_id": 0, "x": 1, "y": 1},
        {"_id": 1, "x": 1, "y": null},
        {"_id": 2, "x": 1, "y": 1},
        {"_id": 3, "x": 1},
    ]),
);

let result = local
    .aggregate([
        {
            $graphLookup: {
                from: local.getName(),
                startWith: "$y",
                connectFromField: "x",
                connectToField: "y",
                as: "arr",
                maxDepth: 0,
            },
        },
    ])
    .toArray();
let expected = [
    {
        "_id": 0,
        "x": 1,
        "y": 1,
        "arr": [
            {"_id": 2, "x": 1, "y": 1},
            {"_id": 0, "x": 1, "y": 1},
        ],
    },
    {"_id": 1, "x": 1, "y": null, "arr": [{"_id": 1, "x": 1, "y": null}]},
    {
        "_id": 2,
        "x": 1,
        "y": 1,
        "arr": [
            {"_id": 2, "x": 1, "y": 1},
            {"_id": 0, "x": 1, "y": 1},
        ],
    },
    {"_id": 3, "x": 1, "arr": []},
];
assert(arrayEq(expected, result), "Expected:\n" + tojson(expected) + "\nGot:\n" + tojson(result));
assert.commandWorked(local.insert({"_id": 4, "x": 1, "y": undefined}));

result = local
    .aggregate([
        {
            $graphLookup: {
                from: local.getName(),
                startWith: null,
                connectFromField: "x",
                connectToField: "y",
                as: "arr",
                maxDepth: 0,
            },
        },
    ])
    .toArray();

expected = [
    {"_id": 0, "x": 1, "y": 1, "arr": [{"_id": 1, "x": 1, "y": null}]},
    {"_id": 1, "x": 1, "y": null, "arr": [{"_id": 1, "x": 1, "y": null}]},
    {"_id": 2, "x": 1, "y": 1, "arr": [{"_id": 1, "x": 1, "y": null}]},
    {"_id": 3, "x": 1, "arr": [{"_id": 1, "x": 1, "y": null}]},
    {"_id": 4, "x": 1, "y": undefined, "arr": [{"_id": 1, "x": 1, "y": null}]},
];
assert(arrayEq(expected, result), "Expected:\n" + tojson(expected) + "\nGot:\n" + tojson(result));

local.drop();

// Test missing doesn't match missing.
assert.commandWorked(
    local.insert([
        {"_id": 0, "x": 1, "y": 1},
        {"_id": 1, "x": 2},
        {"_id": 3, "x": 1},
    ]),
);
result = local
    .aggregate([
        {
            $graphLookup: {
                from: local.getName(),
                startWith: "$y",
                connectFromField: "x",
                connectToField: "y",
                as: "arr",
                maxDepth: 0,
            },
        },
    ])
    .toArray();
expected = [
    {"_id": 0, "x": 1, "y": 1, "arr": [{"_id": 0, "x": 1, "y": 1}]},
    {"_id": 1, "x": 2, "arr": []},
    {"_id": 3, "x": 1, "arr": []},
];
assert(arrayEq(expected, result));
local.drop();
assert.commandWorked(
    local.insert([
        {"_id": 0, "x": 1},
        {"_id": 1, "x": 2},
        {"_id": 3, "x": 1},
    ]),
);
result = local
    .aggregate([
        {
            $graphLookup: {
                from: local.getName(),
                startWith: "$y",
                connectFromField: "x",
                connectToField: "y",
                as: "arr",
                maxDepth: 0,
            },
        },
    ])
    .toArray();
expected = [
    {"_id": 0, "x": 1, "arr": []},
    {"_id": 1, "x": 2, "arr": []},
    {"_id": 3, "x": 1, "arr": []},
];
assert(arrayEq(expected, result), "Expected:\n" + tojson(expected) + "\nGot:\n" + tojson(result));