mongo/jstests/core/query/array/arrayfind5.js

// Test indexed elemmatch of missing field.
// @tags: [
//   requires_getmore
// ]

let t = db.jstests_arrayfind5;
t.drop();

function check(nullElemMatch) {
    assert.eq(1, t.find({"a.b": 1}).itcount());
    assert.eq(1, t.find({a: {$elemMatch: {b: 1}}}).itcount());
    assert.eq(nullElemMatch ? 1 : 0, t.find({"a.b": null}).itcount());
    assert.eq(nullElemMatch ? 1 : 0, t.find({a: {$elemMatch: {b: null}}}).itcount()); // see SERVER-3377
}

t.save({a: [{}, {b: 1}]});
check(true);
t.createIndex({"a.b": 1});
check(true);

t.drop();

t.save({a: [5, {b: 1}]});
check(false);
t.createIndex({"a.b": 1});
check(false);