mongo/jstests/core/update_arraymatch6.js

// Cannot implicitly shard accessed collections because of following errmsg: A single
// update/delete on a sharded collection must contain an exact match on _id or contain the shard
// key.
// @tags: [assumes_unsharded_collection]

var res;
t = db.jstests_update_arraymatch6;
t.drop();

function doTest() {
    t.save({a: [{id: 1, x: [5, 6, 7]}, {id: 2, x: [8, 9, 10]}]});
    res = t.update({'a.id': 1}, {$set: {'a.$.x': [1, 1, 1]}});
    assert.commandWorked(res);
    assert.eq.automsg("1", "t.findOne().a[ 0 ].x[ 0 ]");
}

doTest();
t.drop();
t.ensureIndex({'a.id': 1});
doTest();