Firestore日期对象行为变更警告：未用Date能否安全忽略？

先直接给你结论：你完全可以安全忽略这个警告，原因如下：

警告的核心影响范围 #

这个Firestore的警告是针对读取数据环节的类型变更通知：未来版本中，Firestore存储的时间戳会以Firebase原生的Timestamp对象返回，而不再是系统的Date对象。它主要影响那些从Firestore读取时间戳字段、并将其转换为Date类型处理的代码。

结合你的代码分析 #

看你提供的创建用户记录的代码：

void createCloudStoreRecord(FirebaseUser user) { 
  // Create/Update user record with uid 
  final DocumentReference docRefUsers = Firestore.instance.collection("users").document(user.uid); 
  docRefUsers.get().then((datasnapshot) { 
    if (datasnapshot.exists) { 
      // Exists, so do nothing 
    } else { 
      // Does not exist, let's create 
      Map<String, String> data = <String, String> { 
        "email": user.email, 
        "photoURL": user.photoUrl, 
      }; 
      // Save data 
      docRefUsers.setData(data).whenComplete(() { 
      }).catchError((e) => print(e)); 
    } 
  });

你的代码只做了两件事：

• 检查用户记录是否存在
• 不存在时写入email和photoURL两个字符串类型的字段

既没有写入任何日期/时间戳类型的数据，也没有读取数据后处理日期相关的逻辑，完全碰不到警告里提到的「Date对象转Timestamp对象」的场景。

补充提醒 #

如果之后你的业务需要在Firestore中存储或读取日期/时间戳数据，那时候就必须按照警告里的提示配置相关设置（Flutter/Dart里的配置逻辑和警告里的iOS代码一致，仅语法不同），并更新代码适配Timestamp类型，避免未来版本更新时出现兼容性问题。

附上你收到的警告原文：

5.0.0 - [Firebase/Firestore][I-FST000001] The behavior for system Date objects stored in Firestore is going to change AND YOUR APP MAY BREAK. To hide this warning and ensure your app does not break, you need to add the following code to your app before calling any other Cloud Firestore methods:
let db = Firestore.firestore()
let settings = db.settings
settings.areTimestampsInSnapshotsEnabled = true
db.settings = settings
With this change, timestamps stored in Cloud Firestore will be read back as Firebase Timestamp objects instead of as system Date objects. So you will also need to update code expecting a Date to instead expect a Timestamp. or example:
// old: let date: Date = documentSnapshot.get("created_at") as! Date
// new: let timestamp: Timestamp = documentSnapshot.get("created_at") as! Timestamp
let date: Date = timestamp.dateValue()
Please audit all existing usages of Date when you enable the new behavior. In a future release, the behavior will be changed to the new behavior, so if you do not follow these steps, YOUR APP MAY BREAK.

内容的提问来源于stack exchange，提问作者LiveRock