每次我从模拟数据切换到Firebase的真实数据时，我的应用就会崩溃：

只要修改以下3行代码，应用就会崩溃：

主代码 #

import SwiftUI

struct InboxView: View {
    
    @State private var showNewMessageView = false
//    @StateObject var viewModel = InboxViewModel() // uncomment this
    @State private var user = User.MOCK_USER // comment out this
    
//    private var user: User? { //uncomment this
//        return viewModel.currentUser
//    }
    
    var body: some View {
        NavigationStack {
            ScrollView {
                ActiveNowView()
                
                List {
                    ForEach(0 ... 10, id: \.self) { message in
                        InboxRowView()
                    }
                }
                .listStyle(PlainListStyle())
                .frame(height: UIScreen.main.bounds.height - 120)
            }
            .navigationDestination(for: User.self, destination: { user in
                ProfileView(user: user)
            })
            .fullScreenCover(isPresented: $showNewMessageView, content: {
                NewMessageView()
            })
            .toolbar {
                ToolbarItem(placement: .topBarLeading) {
                    HStack {
                        NavigationLink(value: user) {
                            CircularProfileImageView(user: user, size: .xsmall)
                        }
                        
                        Text("Chats")
                            .font(.title)
                            .fontWeight(.semibold)
                    }
                }
                
                ToolbarItem(placement: .topBarTrailing) {
                    Button {
                        showNewMessageView.toggle()
                    } label: {
                        Image(systemName: "square.and.pencil.circle.fill")
                            .resizable()
                            .frame(width: 32, height: 32)
                            .foregroundStyle(.black, Color(.systemGray5))
                    }
                }
            }
        }
    }
}

InboxViewModel #

import Foundation
import Combine
import Firebase

class InboxViewModel: ObservableObject {
    
    @Published var currentUser: User?
    
    private var cancellabels = Set<AnyCancellable>()
    
    init() {
        setupSuscribers()
    }
    
    private func setupSuscribers() {
        UserService.shared.$currentUser.sink { [weak self] user in
            self?.currentUser = user
        }.store(in: &cancellabels)
    }
}

User 模型 #

import FirebaseFirestore
import SwiftUI
import Firebase

struct User: Codable, Identifiable, Hashable {
    @DocumentID var uid: String?

    let fullname: String
    let email: String
    let profileImageUrl: String?
    
    var id: String {
        return uid ?? NSUUID().uuidString
    }
}

extension User {
    static let MOCK_USER = User(fullname: "Bruce Wayne", email: "batman@gmail.com", profileImageUrl: "batman")
}

授权服务 #

import Foundation
import Firebase
import FirebaseAuth
import FirebaseFirestore

class AuthService {
    
    @Published var userSession: FirebaseAuth.User?
    
    static let shared = AuthService()
    
    init() {
        self.userSession = Auth.auth().currentUser
        loadCurrentUserData()
        print("User session id is \(userSession?.uid)")
    }
    
    @MainActor
    // Log in
    func login(withEmail email: String, password: String) async throws {
        do {
            let result = try await Auth.auth().signIn(withEmail: email, password: password)
            self.userSession = result.user
            loadCurrentUserData()
        } catch {
            print("DEBUG: Failed to sign in user with error: \(error.localizedDescription)")
        }
    }
    
    @MainActor
    // Sign in
    func createUser(withEmail email: String, password: String, fullname: String) async throws {
        do {
            let result = try await Auth.auth().createUser(withEmail: email, password: password)
            self.userSession = result.user
            try await self.uploadUserData(email: email, fullname: fullname, id: result.user.uid)
            loadCurrentUserData()
        } catch {
            print("DEBUG: Failed to create user with error: \(error.localizedDescription)")
        }
    }
    
    // Log out
    func signOut() {
        do {
            try Auth.auth().signOut() // signs out on backend
            self.userSession = nil // update routing logic
            UserService.shared.currentUser = nil
        }   catch {
            print("DEBUG: Failed to sign out with error: \(error.localizedDescription)")
        }
    }
    
    
    // Data upload
    private func uploadUserData(email: String, fullname: String, id: String) async throws {
        let user = User(fullname: fullname, email: email, profileImageUrl: nil)
        guard let encodeUser = try? Firestore.Encoder().encode(user) else { return }
        try await Firestore.firestore().collection("users").document(id).setData(encodeUser)
    }
    
    
    // bug fix (user details)
    private func loadCurrentUserData() {
        Task { try await UserService.shared.fetchCurrentUser() }
    }
}

运行代码后，终端抛出以下错误：

I0000 00:00:1732088994.725995 1362774 subchannel.cc:806] subchannel 0x101c70a80 {address=ipv6:%5B2404:6800:4002:81a::200a%5D:443, args={grpc.client_channel_factory=0x60000002b3e0, grpc.default_authority=firestore.googleapis.com, grpc.http2_scheme=https, grpc.internal.channel_credentials=0x60000263cb40, grpc.internal.client_channel_call_destination=0x103d64828, grpc.internal.event_engine=0x60000002b4e0, grpc.internal.security_connector=0x600002c2d900, grpc.internal.subchannel_pool=0x600002949500, grpc.keepalive_time_ms=30000, grpc.primary_user_agent=grpc-c++/1.65.1, grpc.resource_quota=0x600000c99680, grpc.server_uri=dns:///firestore.googleapis.com}}: connect failed (UNKNOWN:(domain:NSPOSIXErrorDomain, code:50, description:The operation couldn’t be completed. Network is down) {file:"/var/folders/hn/5bx1f4_d4ds5vhwhkxc7vdcr0000gn/T/ZipRelease/2024-07-25T04-01-28/project-ios/Pods/gRPC-Core/src/core/lib/transport/error_utils.cc", file_line:150, created_time:"2024-11-20T13:19:54.724606+05:30", grpc_status:2}), backing off for 874 ms

DEBUG: Current user is Optional(Messenger.User(_uid: FirebaseFirestore.DocumentID<Swift.String>(value: Optional("Tg2TbvUlWBdjtL1XKkFJD6MeGKn1")), fullname: "Bruce Wayne", email: "batman@gmail.com", profileImageUrl: nil))

备注：内容来源于stack exchange，提问作者Anubhav Tomar