/**
 * Unlimited index key length is supported in 4.2.
 * However, we should still disallow this feature under FCV4.0.
 * TODO SERVER-36385: remove this test in 4.4.
 */
(function() {
    'use strict';

    load("jstests/libs/feature_compatibility_version.js");

    TestData.replSetFeatureCompatibilityVersion = "4.0";
    const rst = new ReplSetTest({
        nodes: [
            {binVersion: 'latest'},
            {rsConfig: {priority: 0, votes: 0}},
        ]
    });
    rst.startSet();
    rst.initiate();
    rst.restart(1, {binVersion: '4.0'});

    const dbName = "test";
    const collName = "index_bigkeys";

    const largeKey = 's'.repeat(12345);
    const documentWithLargeKey = {x: largeKey};

    const primary = rst.getPrimary();
    const testDB = primary.getDB(dbName);
    const testColl = testDB[collName];

    testColl.drop();
    assert.commandWorked(
        testDB.runCommand({createIndexes: collName, indexes: [{key: {x: 1}, name: "x_1"}]}));

    assert.commandFailedWithCode(
        testDB.runCommand({insert: collName, documents: [documentWithLargeKey]}),
        ErrorCodes.KeyTooLong);
    assert.eq(0, testColl.count());

    rst.stopSet();
}());