Swift结构体初始化报错：Variable self.record used before being initialized

问题根源 #

报错Variable self.record used before being initialized的核心原因是初始化器的参数名与结构体存储属性名重名，导致Swift编译器在初始化流程中出现混淆，误判你在给self.record赋值前就已经访问了该属性。

解决方法 #

有两种简单的修复方式，任选其一即可：

方法1：修改初始化器参数名，避免重名

将第一个初始化器的参数名改为与属性名不同的名称（比如ckRecord），消除编译器的混淆：

struct MyAccount: Hashable ,Identifiable, CloudItem {
    
    var record: CKRecord
    var id = UUID()
    var network: NetworksDataModel.Networks
    var username: String
    
    init?(ckRecord: CKRecord) {
        guard let newNetworkString = ckRecord.object(forKey: "network") as? String else { return }
        guard let newNetwork = NetworksDataModel.Networks(rawValue: newNetworkString) else { return }
        guard let newUsername = ckRecord.object(forKey: "username") as? String else { return }
        self.network = newNetwork
        self.username = newUsername
        self.record = ckRecord
    }
    
    init?(network: NetworksDataModel.Networks, username: String) {
        let record = CKRecord(recordType: "account")
        record["network"] = network.rawValue
        record["username"] = username
        self.init(ckRecord: record)
    }
}

方法2：先给record属性赋值，再处理其他逻辑

调整赋值顺序，先完成self.record的赋值，再执行后续的guard校验：

struct MyAccount: Hashable ,Identifiable, CloudItem {
    
    var record: CKRecord
    var id = UUID()
    var network: NetworksDataModel.Networks
    var username: String
    
    init?(record: CKRecord) {
        self.record = record // 优先完成record属性的赋值
        guard let newNetworkString = record.object(forKey: "network") as? String else { return }
        guard let newNetwork = NetworksDataModel.Networks(rawValue: newNetworkString) else { return }
        guard let newUsername = record.object(forKey: "username") as? String else { return }
        self.network = newNetwork
        self.username = newUsername
    }
    
    init?(network: NetworksDataModel.Networks, username: String) {
        var record = CKRecord(recordType: "account")
        record["network"] = network.rawValue
        record["username"] = username
        self.init(record: record)
    }
}

补充说明 #

不需要将CKRecord设为可选类型——你的业务逻辑中record是实例必须的属性，保持非可选类型更符合设计逻辑，也能避免后续代码的可选解包成本。

内容的提问来源于stack exchange，提问作者Ben Kuryk