mongo/jstests/multiVersion/genericBinVersion/auto_bootstrap_upgrade_behavior.js

import "jstests/multiVersion/libs/multi_rs.js";

import {ReplSetTest} from "jstests/libs/replsettest.js";

function fetchShardIdentityDoc(conn) {
    return conn.getDB("admin").system.version.findOne({_id: "shardIdentity"});
}

(function () {
    jsTest.log("Test auto-bootstrap doesn't happen for standalone in old fcv");

    let oldStandalone = MongoRunner.runMongod({binVersion: "last-lts"});

    MongoRunner.stopMongod(oldStandalone, null, {noCleanData: true});

    let newStandalone = MongoRunner.runMongod({
        noCleanData: true,
        dbpath: oldStandalone.dbpath,
        port: oldStandalone.port,
        setParameter: {featureFlagAllMongodsAreSharded: true},
    });

    assert.soon(() => {
        return newStandalone.getDB("admin").hello().isWritablePrimary;
    });

    assert.eq(null, fetchShardIdentityDoc(newStandalone));

    MongoRunner.stopMongod(newStandalone, null);
})();

(function () {
    jsTest.log("Test auto-bootstrap doesn't happen for replSet in old fcv");

    let nodeOption = {binVersion: "last-lts"};
    // Need at least 2 nodes because upgradeSet method needs to be able call step down
    // with another primary eligible node available.
    let replSet = new ReplSetTest({nodes: [nodeOption, nodeOption]});
    replSet.startSet();
    replSet.initiate(null, null, {initiateWithDefaultElectionTimeout: true});

    replSet.upgradeSet({binVersion: "latest", setParameter: {featureFlagAllMongodsAreSharded: true}});

    let primary = replSet.getPrimary();
    assert.eq(null, fetchShardIdentityDoc(primary));

    assert.commandWorked(primary.adminCommand({transitionToShardedCluster: 1, writeConcern: {w: "majority"}}));

    assert.neq(null, fetchShardIdentityDoc(primary));
    assert.neq(null, primary.getDB("config").shards.findOne());

    replSet.stopSet();
})();