(function() { // Start a 1-node replica set with a 3.6 node. let rst = ReplSetTest({nodes: [{binVersion: "latest" }]}); rst.startSet(); // Change catchUpTimeoutMillis to a value 3.4 will understand. let replSetConfig = rst.getReplSetConfig(); replSetConfig.settings = {catchUpTimeoutMillis: 2000}; rst.initiate(replSetConfig); // Set FCV to 3.4 so that a 3.4 node can join the set. let primary = rst.getPrimary() assert .commandWorked(primary.adminCommand({setFeatureCompatibilityVersion: "3.4" })); // Add a 3.4 node to the set. let secondary = rst.add({binVersion: "3.4" }); rst.reInitiate(); // Ensure the 3.4 node succeeded its initial sync. assert .writeOK(primary.getDB( "test" ).coll.insert({awaitRepl: true }, {writeConcern: {w: 2}})); // Run {setFCV: "3.4" }. This should be idempotent. assert .adminCommandWorkedAllowingNetworkError(primary, {setFeatureCompatibilityVersion: "3.4" }); // The 3.4 node crashes due to replicating the targetVersion. assert .soon(function() { try { secondary.adminCommand({ping: 1}); } catch (e) { return true ; } return false ; }); rst.stop(secondary, undefined, {allowedExitCode: MongoRunner.EXIT_ABRUPT}); rst.stopSet(); })();