.select() in finds and firsts does not seem to exclude any fields

[pmmlo]

Hey @cbaker6 - Do you think this could be an encoding problem or a potential parse-server bug?

struct GameScore: ParseObject {
    var objectId: String?
    var createdAt: Date?
    var updatedAt: Date?
    var ACL: ParseACL?

    var score: Int?
}

var score = GameScore()
score.score = 200
try score.save()

let afterDate = Date().addingTimeInterval(-300)
var query = GameScore.query("createdAt" > afterDate).select(["score"]).limit(1)

query.find() { results in
    print(results) /// <<< I would expect only the GameScore objects with createdAt after afterDate to only return the "score" field. (Yes, this is lazy.)
}

/// Alternatively
query.first() { results in
    print(results)
}

Anybody have any thoughts? Will dig deeper into the source, if not. Thanks!

EDIT:
.select() does seem to work, as of late. Reference: https://stackoverflow.com/questions/61100282/parse-server-select-a-few-fields-from-included-object

[pmmlo]

I could be wrong, but I think this test may be incorrectly written:

func testSelectKeys() {
        let query = GameScore.query()
        XCTAssertNil(query.keys)
        var query2 = GameScore.query().select("yolo")
        XCTAssertEqual(query2.keys?.count, 1)
        XCTAssertEqual(query2.keys?.first, "yolo")
        query2 = query2.select("yolo", "wow")
        XCTAssertEqual(query2.keys?.count, 2)
        XCTAssertEqual(query2.keys, ["yolo", "wow"])
        query2 = query2.select(["yolo"])
        XCTAssertEqual(query2.keys?.count, 1)
        XCTAssertEqual(query2.keys, ["yolo"])
}

I would imagine it could be something like:

func testSelectKeys() {
///  Poorly assuming .select() is equally effective on .first() and .find()
        let query = GameScore.query()
        let results = try? query.first()
        XCTAssertNotEqual(results?.updatedAt, nil)

        let query2 = GameScore.query().select("score")
        let results2 = try? query2.first()
        XCTAssertEqual(results2?.createdAt, nil)
        XCTAssertEqual(results2?.updatedAt, nil)
        XCTAssertNotEqual(results2?.score, nil)

        let query3 = GameScore.query().select(["score", "createdAt"])
        let results3 = try? query3.first()
        XCTAssertNotEqual(results3?.createdAt, nil)
        XCTAssertEqual(results3?.updatedAt, nil)
        XCTAssertNotEqual(results3?.score, nil)
}

[cbaker6]

What error are you getting when trying select?

[cbaker6]

I could be wrong, but I think this test may be incorrectly written:

The test looks okay from what I see. An improvement could be to check that the selected keys are encoded because if keys is accidentally removed from CodingKeys then the current test would miss this while it should fail. The improved test would be similar to

Parse-Swift/Tests/ParseSwiftTests/ParseQueryTests.swift

Lines 595 to 619 in 65bfd41

	func testWhereKeyExists() {
	let expected: [String: AnyCodable] = [
	"yolo": ["$exists": true]
	]
	let constraint = exists(key: "yolo")
	let query = GameScore.query(constraint)
	let queryWhere = query.`where`
	do {
	let encoded = try ParseCoding.jsonEncoder().encode(queryWhere)
	let decodedDictionary = try JSONDecoder().decode([String: AnyCodable].self, from: encoded)
	XCTAssertEqual(expected.keys, decodedDictionary.keys)
	guard let expectedValues = expected.values.first?.value as? [String: Bool],
	let decodedValues = decodedDictionary.values.first?.value as? [String: Bool] else {
	XCTFail("Should have casted")
	return
	}
	XCTAssertEqual(expectedValues, decodedValues)
	} catch {
	XCTFail(error.localizedDescription)
	return
	}
	}

let results2 = try? query2.first()

There's no need to actually perform the query as 1) you will need to mock the network (like some of the other tests) 2) Testing to see if the keys array is populated/encoded properly is good enough for a client side test since the Parse Server does the rest.

[cbaker6]

If you add an example in Playgrounds to https://github.com/parse-community/Parse-Swift/blob/main/ParseSwift.playground/Pages/2%20-%20Finding%20Objects.xcplaygroundpage/Contents.swift

I can take a look

[cbaker6]

I've tested this by adding to the playgrounds file I mentioned above and it seems to work fine.

struct GameScore: ParseObject {
    var objectId: String?
    var createdAt: Date?
    var updatedAt: Date?
    var ACL: ParseACL?

    var score: Int?
    var oldScore: Int?
}

var score = GameScore()
score.score = 200
score.oldScore = 10
do {
    try score.save()
} catch {
    print(error)
}

let afterDate = Date().addingTimeInterval(-300)
var query = GameScore.query("score" > 100, "createdAt" > afterDate)

// Query first asynchronously (preferred way) - Performs work on background
// queue and returns to designated on designated callbackQueue.
// If no callbackQueue is specified it returns to main queue.
query.first { results in
    switch results {
    case .success(let score):

        guard score.objectId != nil,
            let createdAt = score.createdAt else { fatalError() }
        assert(createdAt.timeIntervalSince1970 > afterDate.timeIntervalSince1970, "date should be ok")
        print("Found score: \(score)")

    case .failure(let error):
        assertionFailure("Error querying: \(error)")
    }
}

//The above outputs:
// Found score: GameScore ({"objectId":"oBdHL84zSZ9qCWXFrB4RkhR5AOJd0a5U","updatedAt":{"__type":"Date","iso":"2021-03-02T18:30:07.596Z"},"score":200,"createdAt":{"__type":"Date","iso":"2021-03-02T18:30:07.482Z"}})

let querySelect = query.select("score")
querySelect.first { results in
    switch results {
    case .success(let score):

        guard score.objectId != nil,
            let createdAt = score.createdAt else { fatalError() }
        assert(createdAt.timeIntervalSince1970 > afterDate.timeIntervalSince1970, "date should be ok")
        print("Found score using select: \(score)")

    case .failure(let error):
        assertionFailure("Error querying: \(error)")
    }
}

//Outputs:
//Found score using select: GameScore ({"objectId":"oBdHL84zSZ9qCWXFrB4RkhR5AOJd0a5U","updatedAt":{"__type":"Date","iso":"2021-03-02T18:30:07.596Z"},"score":200,"createdAt":{"__type":"Date","iso":"2021-03-02T18:30:07.482Z"}})

In the last output, oldScore is missing because it wasn't selected.

[cbaker6]

Note that if you add a property to the your type that isn't optional (added highestScore):

struct GameScore: ParseObject {
    var objectId: String?
    var createdAt: Date?
    var updatedAt: Date?
    var ACL: ParseACL?

    var score: Int?
    var oldScore: Int?
    var highestScore: Int //New property
}

highestScore must be one of the keys selected or else the compiler can't decode GameScore. This would be considered a user error, because you are telling the compiler that GameScore requires a value for highestScore

[cbaker6]

There may be something up with this...

[pmmlo]

Thanks @cbaker6 Glad it's working! I can't seem to reproduce your results, so I'll play around and see if I'm bugging out.

What error are you getting when trying select?

No error, but I'm getting all the fields back.

An improvement could be to check that the selected keys are encoded because if keys is accidentally removed from CodingKeys then the current test would miss this while it should fail.

Agree.

EDIT: I'm using Parse-Swift 1.1.6 and Parse-Server 4.5.0.

[cbaker6]

Noting that this has been classified as a server-side bug as oppose to a Parse-Swift bug. Check the linked PR and issue for details.

[cbaker6]

The fix on the server side has been merged to the master. If you would like to use select and and exclude with the ParseSwift client, please use the latest master branch of the parse-server.