🐛 Bug Report: Crash with Query, AppwriteModels/Document.swift:94: Fatal error: Unexpectedly found nil

[Jaycyn]

👟 Reproduction steps

When I attempt to perform a simple query operation which includes a select, the Appwrite code crashes

The setup is very simple; there's a collection of Books as shown in the documentation. Each Book has two properties, title and author (again per the documentation).

The query is for document title matching Book A and I want to return only the title and author properties. (yes, I know that's the only two but for this report it demonstrates the bug)

If in the below code the queries section is removed OR the select statement is removed, the query works properly.

The code:

func outputSampleBooks() async throws {
    do {
        let documentList = try await databases.listDocuments(
            databaseId: databaseId,
            collectionId: collectionId,
            queries: [
                Query.equal("title", value: "Book A"),
                Query.select(["title", "author"])
            ]
        )
    } catch {
        print(error)
    }
}

The books collection is attached below

and then the crash:

AppwriteModels/Document.swift:94: Fatal error: Unexpectedly found nil while unwrapping an Optional value

The crash is located in AppwriteModels->DocumentList.swift->from(map:)

public static func from(map: [String: Any] ) -> DocumentList {
        return DocumentList(
            total: map["total"] as! Int,
            documents: (map["documents"] as! [[String: Any]]).map { Document.from(map: $0) } //crash
        )
    }

👍 Expected behavior

It should... not crash

👎 Actual Behavior

It actually crashes whenever the query includes a select statement

🎲 Appwrite version

Different version (specify in environment)

💻 Operating system

Linux

🧱 Your Environment

AppWrite sdk-for-apple 9.0.1
XCode 16
macOS Sequoia 15.5

I've duplicated this on several workstations with similar setups

👀 Have you spent some time to check if this issue has been raised before?

• I checked and didn't find similar issue

🏢 Have you read the Code of Conduct?

• I have read the Code of Conduct

[ChiragAgg5k]

@Jaycyn thanks for raising this issue 🙏
I have notified the team about it and will work on a solution soon

[ChiragAgg5k]

@Jaycyn I have a follow up from the team, this is due a change where we removed returning of internal attributes like $id when using select queries. this change is in plan to be reverted after some internal discussions.

so for now, a workaround would be to select these mandatory attributes along side with the one you want.

i know not the best solution... but its the best for now. thank you for your patience 🙏

[Jaycyn]

@ChiragAgg5k

That doesn't appear to be a solution, but perhaps my implementation is wrong.

a workaround would be to select these mandatory attributes along side with the one you want.

Upon reviewing the Document API - I see the mandatory attributes as follows

{
    "$id": "5e5ea5c16897e",
    "$collectionId": "5e5ea5c15117e",
    "$databaseId": "5e5ea5c15117e",
    "$createdAt": "2020-10-15T06:38:00.000+00:00",
    "$updatedAt": "2020-10-15T06:38:00.000+00:00",
    "$permissions": [
        "read(\"any\")"
    ]
}

So I update the Query.select to include those mandatory attributes along side the one I want, author

let documents = try await databases.listDocuments(
    databaseId: databaseId,
    collectionId: collectionId,
    queries: [
        Query.equal("author", value: "Jay"),
        Query.select(["$id", "$collectionId", "$databaseId", "$createdAt", "$updatedAt", "$permissions", "author"])
    ],
    nestedType: Book.self
)
print("found \(documents.total) books")

the result is

Invalid query: Attribute not found in schema: $collectionId

if I remove that attribute from the .select, we then get this error

Invalid query: Attribute not found in schema: $databaseId

if we then remove that attribute we get the same crash as in my original post.

So... which mandatory fields does the .select need to include?

[ChiragAgg5k]

@Jaycyn I see the issue now. Currently backend restricts selection of internal attributes, and we plan on changing this in future. Thanks for raising a light on this 🙏 We will update the sdk to not be strict in Document typing.

[ChiragAgg5k]

@Jaycyn the latest release should fix the errors caused by select queries - https://github.com/appwrite/sdk-for-apple/releases/tag/10.1.1

[Jaycyn]

@ChiragAgg5k

Hmmm. We removed the older sdk and added 10.1.1 through SPM and have different results but it still doesn't work as expected.

Here's the code

do {
    let documents = try await databases.listDocuments(
        databaseId: databaseId,
        collectionId: collectionId,
        queries: [
            Query.equal("author", value: "Jay"),
            Query.select(["author"])
        ],
        nestedType: Book.self
    )

which, like the above crashes in the package here

public static func from(map: [String: Any] ) -> Document {
        return Document(
            id: map["$id"] as? String ?? "",
            collectionId: map["$collectionId"] as? String ?? "",
            databaseId: map["$databaseId"] as? String ?? "",
            createdAt: map["$createdAt"] as? String ?? "",
            updatedAt: map["$updatedAt"] as? String ?? "",
            permissions: map["$permissions"] as? [String] ?? [],
            data: try! JSONDecoder().decode(T.self, from: JSONSerialization.data(withJSONObject: map, options: []))  /crash
        )
    }

Thread 3: Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.keyNotFound(CodingKeys(stringValue: "$id", intValue: nil), Swift.DecodingError.Context(codingPath: [], debugDescription: "No value associated with key CodingKeys(stringValue: "$id", intValue: nil) ("$id").", underlyingError: nil))

We tried adding $id

Query.select(["$id", "author"])

which crashes

Thread 6: Fatal error: 'try!' expression unexpectedly raised an error: Swift.DecodingError.keyNotFound(CodingKeys(stringValue: "title", intValue: nil)

so then we added title.... and the good news, it worked!

Query.select(["$id", "title", "author"])

However we believe the purpose of .select is to only return wanted fields, not all of them?

[ChiragAgg5k]

@Jaycyn i just did a quick test and it seems to be working for me, the issue might be due to the package conflicts like i suggested in the other issue thread.

can you please verify that for me and try again?

[Jaycyn]

@ChiragAgg5k

Thanks for checking on it. Looks like we are making some headway. So no, there is no package conflict as we are using only the sdk-for-apple on a clean, fresh project.

While the code in your response does now appear to work - addressing the initial bug report, simply adding nestedType: Book.self makes it crash per my above posts

let documents = try await databases.listDocuments(
    databaseId: databaseId,
    collectionId: collectionId,
    queries: [
        Query.equal("title", value: "Book A"),
        Query.select(["author"])
    ],
    nestedType: Book.self
)

I am not sure if the initial bug, fix and the bug with nestedType are related but it definitely does not work and crashes 100% of the time. Seems like the fix introduced a new bug with .nestedType.

Perhaps our Book model is causing the issue?

struct Book: Encodable, Decodable {
    var id: String
    let title: String
    let author: String

    enum CodingKeys: String, CodingKey {
        case id = "$id"
        case title = "title"
        case author = "author"
    }
}

[ChiragAgg5k]

hi there, looks like you are passing nestedType as a parameter for listDocuments method? The method itself doesnt support this attribute

for proper typing we recommend mapping your encodables like this:

[ChiragAgg5k]

@Jaycyn here is the encodable used in this example - https://gist.github.com/ChiragAgg5k/f888b2ab88db21abdf7556a7bb56d3ce

[Jaycyn]

@ChiragAgg5k

hi there, looks like you are passing nestedType as a parameter for listDocuments method? The method itself doesnt support this attribute

That's interesting as it was working previously and I took that code right from the sdk-for-apple 10.1.1 download.

[Jaycyn]

@ChiragAgg5k

This is an off-topic question but somewhat related per your above example. We are getting a little mixed messaging here so really need clarity. Your above post states

for proper typing we recommend mapping your encodables like this:

let user = User. from(map: document.data.mapValues { $0.value })

which seems to be a somewhat old and manual process when working with Codable & json.

The sdk-for-apple has built in functions to handle json->Object mapping in Codable+JSON.swift, coupled with the .nestedType function make using json data a snap

func listBooks() async throws {
    do {
        let documents = try await databases.listDocuments(
            databaseId: databaseId,
            collectionId: collectionId,
            nestedType: Book.self  //objects are typed as as book - Awesome!
        )
        print("found \(documents.total) books")
        
        let bookDocs = documents.documents //bookDocs typed <Book> array
        
        bookDocs.forEach { bookDoc in
            let book = bookDoc.data
            print(book.title, book.author)
        }
    }
}

Are you saying we should NOT use .nestedType function and NOT use the built in conversions supplied in the SDK, like fromJson and toJson as shown in the sdk-for-apple example code?

[ChiragAgg5k]

@Jaycyn You are right... it does seem nestedType are the preferred way to do this here. I had been doing my tests in sdk-for-swift and seems like the convention is not present there.

Currently our engineer @abnegate who specializes in swift is OOO and will by back by Monday.

I will try to recreate the issue by using sdk-for-apple next, and let you know if the bug is reproducable. Thanks for your patience 🙏