将 @DocumentID 与自定义 `Codable` 实现一起使用不会填充 @DocumentID 变量

如何解决将 @DocumentID 与自定义 `Codable` 实现一起使用不会填充 @DocumentID 变量

我已经创建了这样的结构：

struct TestObject: Codable {
    public enum CodingKeys: String,CodingKey {
        case ref = "r"
        case string = "s"
    }

    @DocumentID
    public var ref: DocumentReference?
    public var string: String

    public init(string: String) {
        ref = nil
        self.string = string
    }

    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        ref = try container.decodeIfPresent(DocumentReference.self,forKey: .ref)
        string = try container.decode(String.self,forKey: .string)
    }

    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try container.encodeIfPresent(ref,forKey: .ref)
        try container.encode(string,forKey: .string)
    }

}

如果我随后将对象保存到 Firestore 并在快照侦听器中接收它，则 .ref 为 nil：

self.firestore.collection("test").addSnapshotListener { (snapshot,error) in
    if let snapshot = snapshot,let document = snapshot.documents.first
    {
        let testObject = try! document.data(as: TestObject.self)!
        XCTAssertNotNil(testObject.ref) // <-- this is `nil`,but `document.documentID` is populated
    }
}

是的 - 我已经验证 document.documentID 实际上已设置为快照。