text: // test that a rollback of collMod altering TTL will cause the node to go into a FATAL state
  //
  // If all data-bearing nodes in a replica set are using an ephemeral storage engine, the set will
  // not be able to survive a scenario where all data-bearing nodes are down simultaneously. In such a
  // scenario, none of the members will have any data, and upon restart will each look for a member to
  // inital sync from, so no primary will be elected. This test induces such a scenario, so cannot be
  // run on ephemeral storage engines.
  // @tags: [requires_persistence]
  
  // set up a set and grab things for later
  var name = "rollback_collMod_fatal";
  var replTest = new ReplSetTest({name: name, nodes: 3});
  var nodes = replTest.nodeList();
  var conns = replTest.startSet();
  replTest.initiate({
      "_id": name,
      "members": [
          {"_id": 0, "host": nodes[0], priority: 3},
          {"_id": 1, "host": nodes[1]},
          {"_id": 2, "host": nodes[2], arbiterOnly: true}
      ]
  });
  var a_conn = conns[0];
  var b_conn = conns[1];
  var AID = replTest.getNodeId(a_conn);
  var BID = replTest.getNodeId(b_conn);
  
  replTest.waitForState(replTest.nodes[0], ReplSetTest.State.PRIMARY);
  
  // get master and do an initial write
  var master = replTest.getPrimary();
  assert(master === conns[0], "conns[0] assumed to be master");
  assert(a_conn.host === master.host, "a_conn assumed to be master");
  var options = {writeConcern: {w: 2, wtimeout: 60000}, upsert: true};
  a_conn.getDB(name).foo.ensureIndex({x: 1}, {expireAfterSeconds: 3600});
  assert.writeOK(a_conn.getDB(name).foo.insert({x: 1}, options));
  
  // shut down master
  replTest.stop(AID);
  
  // do a collMod altering TTL which should cause FATAL when rolled back
  master = replTest.getPrimary();
  assert(b_conn.host === master.host, "b_conn assumed to be master");
  assert.commandWorked(b_conn.getDB(name).runCommand(
      {collMod: "foo", index: {keyPattern: {x: 1}, expireAfterSeconds: 10}}));
  
  // shut down B and bring back the original master
  replTest.stop(BID);
  replTest.restart(AID);
  master = replTest.getPrimary();
  assert(a_conn.host === master.host, "a_conn assumed to be master");
  
  // do a write so that B will have to roll back
  options = {
      writeConcern: {w: 1, wtimeout: 60000},
      upsert: true
  };
  assert.writeOK(a_conn.getDB(name).foo.insert({x: 2}, options));
  
  // restart B, which should attempt rollback but then fassert
  clearRawMongoProgramOutput();
  replTest.restart(BID);
  assert.soon(function() {
      return rawMongoProgramOutput().match("cannot rollback a collMod command");
  }, "B failed to fassert");
  
  replTest.stop(BID, undefined, {allowedExitCode: MongoRunner.EXIT_ABRUPT});
  replTest.stopSet();