/**
 * $lookup with a $rankFusion pipeline from a view V1 whose definition $lookup's another view V2:
 * V2's stages run twice.
 *
 * @tags: [requires_fcv_90]
 */
const conn = MongoRunner.runMongod({setParameter: {internalQueryDisablePlanCache: true}});
const db = conn.getDB(jsTestName());

assert.commandWorked(db.b.insert({_id: 1, n: 0}));
assert.commandWorked(db.o.insert({_id: 1}));
// V2 adds 1 to n, so every read through V2 must see n: 1.
assert.commandWorked(db.createView("V2", "b", [{$set: {n: {$add: ["$n", 1]}}}]));
assert.commandWorked(db.createView("V1", "b", [{$lookup: {from: "V2", as: "j", pipeline: [{$project: {n: 1}}]}}]));

const rf2 = {$rankFusion: {input: {pipelines: {a: [{$sort: {_id: 1}}], c: [{$sort: {_id: -1}}]}}}};
const rf1 = {$rankFusion: {input: {pipelines: {a: [{$sort: {_id: 1}}]}}}};
function run(label, fn) {
    const got = fn();
    jsTest.log.info("D run", {label, n: got});
    return got;
}
const viaLookup = (pipeline) =>
    db.o.aggregate([{$lookup: {from: "V1", as: "r", pipeline: pipeline.concat([{$project: {j: 1}}])}}]).toArray()[0]
        .r[0].j[0].n;

const direct = run("aggregate on V1", () => db.V1.aggregate([]).toArray()[0].j[0].n);
const directRf = run("aggregate on V1 with 2-input $rankFusion", () => db.V1.aggregate([rf2]).toArray()[0].j[0].n);
const plain = run("$lookup from V1, pipeline [$sort]", () => viaLookup([{$sort: {_id: 1}}]));
const union = run("$unionWith V1 with 2-input $rankFusion", () =>
    db.o.aggregate([{$match: {_id: -1}}, {$unionWith: {coll: "V1", pipeline: [rf2]}}]).toArray()[0].j[0].n);
const lk1 = run("$lookup from V1, 1-input $rankFusion", () => viaLookup([rf1]));
const lk2 = run("$lookup from V1, 2-input $rankFusion", () => viaLookup([rf2]));

// Controls: V2 is applied once on every other path.
assert.eq(direct, 1, "aggregate on V1");
assert.eq(directRf, 1, "aggregate on V1 with $rankFusion");
assert.eq(plain, 1, "$lookup without $rankFusion");
assert.eq(union, 1, "$unionWith with $rankFusion");
// Fails at ba06f31d06c: n is 2; V2's $set ran twice.
assert.eq(lk2, 1, "$lookup with 2-input $rankFusion");
jsTest.log.info("D lk1 (1-input) for reference", {lk1});

MongoRunner.stopMongod(conn);