collection.update with options.upsert set to true is returning an object rather than a number

[wkeithchau]

There is a bug with using collection.update with upsert:true. collection.update should always be return the number of matched documents. When redis-oplog is in use, using collection.update with options.upsert set tot true returns an object with numberAffected and insertedId (this is an output similar to when using collection.upsert).

I did some digging and it looks like when upsert is true for an update, it will call Mutator._handleUpsert, this explains why it returns like an upsert. A possible fix is to attach _returnObject: false to the config that is passed into _handleUpsert and switch around how the config fields are merged together for the Originals.update.call in _handleUpsert.

Here are some basic assertions that can be used to verify the fix:

const fooCollection = new Mongo.Collection('foo')

const updateRes = fooCollection.update(
    { name: 'Test 0' },
    { $set: { colour: 'white' } },
)
expect(updateRes).to.be.a('number')

const updateUpsertRes = fooCollection.update(
    { name: 'Test 1' },
    { $set: { colour: 'red' } },
    { upsert: true },
)
expect(updateUpsertRes).to.be.a('number')

const upsertRes = fooCollection.upsert(
    { name: 'Test 2' },
    { $set: { colour: 'blue' } },
)
expect(upsertRes).to.be.an('object')
expect(upsertRes).to.have.property('numberAffected')
expect(upsertRes).to.have.property('insertedId')