/*
 * This test performs a read using linearizable read concern that will run in the end phase of step
 * up where the new primary is set to primary but is not yet accepting writes.
 * The linearizable read should not crash the server, but should hang, after the read, before the
 * write -- linearizable does a read then no-op write
 */

load('jstests/replsets/rslib.js');
load('jstests/libs/parallelTester.js');
load('jstests/libs/write_concern_util.js');

(function() {
'use strict';

var sendLinearizableReadOnFailpoint = function() {
    // Linearizable read concern is not allowed on secondaries. But set this flag so we can start
    // the operation during the transition from secondary to primary. The read sent at this state
    // should be handled gracefully with appropriate response from the server and not crash.
    db.getMongo().setSecondaryOk();

    var coll = db.getSiblingDB("test").foo;

    try {
        jsTestLog(
            'Waiting for new primary to reach drain complete state where the node is primary but is not yet accepting writes');
        assert.commandWorked(db.getMongo().adminCommand({
            waitForFailPoint: "hangAfterReconfigOnDrainComplete",
            timesEntered: 1,
            maxTimeMS: 5 * 60 * 1000
        }));

        jsTestLog('Sending in linearizable read in secondary thread');

        // In lock free reads this will timeout as we cannot perform the necessary write after the
        // read. Without lock free reads we timeout because we can't acquire the RSTL.
        assert.commandFailedWithCode(
            coll.runCommand(
                {'find': 'foo', readConcern: {level: "linearizable"}, maxTimeMS: 10000}),
            ErrorCodes.MaxTimeMSExpired);
    } finally {
        // Turn off fail point so we can cleanup.
        assert.commandWorked(db.getMongo().adminCommand(
            {configureFailPoint: "hangAfterReconfigOnDrainComplete", mode: "off"}));
    }
};

var num_nodes = 3;
var name = 'stepup_with_linearizable_read';
var replTest = new ReplSetTest({name: name, nodes: num_nodes});
var config = replTest.getReplSetConfig();

// Increased election timeout to avoid having unrelated primary step down while we are
// testing linearizable functionality on a specific node.
config.settings = {
    electionTimeoutMillis: 60000
};

replTest.startSet();
replTest.initiate(config);
replTest.awaitReplication();

var primary = replTest.getPrimary();
var secondaries = replTest.getSecondaries();

// Do a write to have something to read, make sure it is replicated to all nodes so the step up will
// succeed.
assert.commandWorked(primary.getDB("test").foo.insert(
    {"number": 7}, {"writeConcern": {"w": num_nodes, "wtimeout": ReplSetTest.kDefaultTimeoutMS}}));

var newPrimary = secondaries[0];

jsTestLog(
    "Set failpoint so we hang during stepup when drain mode is complete but before we are writable.");

assert.commandWorked(newPrimary.adminCommand(
    {configureFailPoint: "hangAfterReconfigOnDrainComplete", mode: "alwaysOn"}));

jsTestLog("Starting parallel reader");

var parallelShell = startParallelShell(sendLinearizableReadOnFailpoint, newPrimary.port);

jsTestLog(
    "Stepping up secondary, which will hang before step-up completion so that the parallel linearizable read can run, and then it will finish.");

// Stepping up to be new primary. This will not finish until the fail point is turned off in the
// parallel shell.
assert.commandWorked(newPrimary.adminCommand({"replSetStepUp": 1}));

// Wait for the parallel shell to finish.
parallelShell();

replTest.stopSet();
}());