mongo/jstests/core/ref3.js

// to run:
//   ./mongo jstests/ref3.js

db.otherthings3.drop();
db.things3.drop();

var other = {s: "other thing", n: 1};
db.otherthings3.save(other);

db.things3.save({name: "abc"});
x = db.things3.findOne();
x.o = new DBRef("otherthings3", other._id);
db.things3.save(x);

assert(db.things3.findOne().o.fetch().n == 1, "dbref broken 2");

other.n++;
db.otherthings3.save(other);
assert(db.things3.findOne().o.fetch().n == 2, "dbrefs broken");