/**
 * Test that $ne: [] queries are cached correctly. See SERVER-39764.
 */
(function() {
const coll = db.ne_array_indexability;
coll.drop();

coll.createIndex({"obj": 1});
coll.createIndex({"obj": 1, "abc": 1});

assert.commandWorked(coll.insert({obj: "hi there"}));

function runTest(queryToCache, queryToRunAfterCaching) {
    assert.eq(coll.find(queryToCache).itcount(), 1);
    assert.eq(coll.find(queryToCache).itcount(), 1);

    const cacheEntries =
        coll.aggregate([
                {$planCacheStats: {}},
                {
                    $match: {
                        isActive: true,
                        createdFromQuery: {query: queryToCache, sort: {}, projection: {}}
                    }
                }
            ])
            .toArray();
    assert.eq(cacheEntries.length, 1);

    assert.eq(coll.find(queryToRunAfterCaching).itcount(), 1);

    const explain = assert.commandWorked(coll.find(queryToRunAfterCaching).explain());
    // The query with the $ne: array should have the same queryHash, but a different
    // planCacheKey.
    assert.eq(explain.queryPlanner.queryHash, cacheEntries[0].queryHash);
    assert.neq(explain.queryPlanner.planCacheKey, cacheEntries[0].planCacheKey);
}

runTest({'obj': {$ne: 'def'}}, {'obj': {$ne: [[1]]}});

// Clear the cache.
assert.commandWorked(coll.runCommand('planCacheClear'));

runTest({'obj': {$nin: ['abc', 'def']}}, {'obj': {$nin: [[1], 'abc']}});
})();