/**
 * Tests that wildcard indexes will correctly match for empty arrays.
 * @tags: [
 *   sbe_incompatible,
 * ]
 */
(function() {
"use strict";

load("jstests/aggregation/extras/utils.js");  // For arrayEq.

const coll = db.wildcard_empty_arrays;
coll.drop();

const assertArrayEq = (l, r) => assert(arrayEq(l, r), tojson(l) + " != " + tojson(r));

const indexWildcard = {
    "$**": 1
};
assert.commandWorked(coll.createIndex(indexWildcard));

assert.commandWorked(coll.insert({a: 1, b: 1, c: [], d: {e: [5, 6]}}));
assert.commandWorked(coll.insert({a: 2, b: 2, c: [1, 2], d: {e: []}}));
assert.commandWorked(coll.insert({a: 1, b: 2, c: [3, 4], d: {e: [7, 8]}, f: [{g: []}]}));
assert.commandWorked(coll.insert({a: 2, b: [[]], c: 1, d: 4}));

// $** index matches empty array.
assertArrayEq(coll.find({c: []}, {_id: 0}).hint(indexWildcard).toArray(),
              [{a: 1, b: 1, c: [], d: {e: [5, 6]}}]);

// $** index supports equality to array offset.
assertArrayEq(coll.find({"c.0": 1}, {_id: 0}).hint(indexWildcard).toArray(),
              [{a: 2, b: 2, c: [1, 2], d: {e: []}}]);

// $** index matches empty array nested in object.
assertArrayEq(coll.find({"d.e": []}, {_id: 0}).hint(indexWildcard).toArray(),
              [{a: 2, b: 2, c: [1, 2], d: {e: []}}]);

// $** index matches empty array nested within an array of objects.
assertArrayEq(coll.find({"f.0.g": []}, {_id: 0}).hint(indexWildcard).toArray(),
              [{a: 1, b: 2, c: [3, 4], d: {e: [7, 8]}, f: [{g: []}]}]);

// $** index matches empty array nested within an array.
assertArrayEq(coll.find({"b": []}, {_id: 0}).hint(indexWildcard).toArray(),
              [{a: 2, b: [[]], c: 1, d: 4}]);
})();