mongo/jstests/core/update_arraymatch3.js

// @tags: [requires_multi_updates, requires_non_retryable_writes]

t = db.update_arraymatch3;
t.drop();

o = {
    _id: 1,
    title: "ABC",
    comments: [{"by": "joe", "votes": 3}, {"by": "jane", "votes": 7}]
};

t.save(o);
assert.eq(o, t.findOne(), "A1");

t.update({'comments.by': 'joe'}, {$inc: {'comments.$.votes': 1}}, false, true);
o.comments[0].votes++;
assert.eq(o, t.findOne(), "A2");