添加Notification Service Extension后iOS出现firebase_auth/notification-not-forwarded错误

问题原因 #

添加Notification Service Extension后，iOS远程通知会优先经过Extension处理，可能导致主App的AppDelegate无法接收到Firebase Phone Auth的验证码通知；若手动禁用了Firebase的方法swizzling，未将通知转发给FIRAuth也会触发该错误。

解决方案 #

情况1：默认开启Swizzling（Firebase默认配置） #

Notification Service Extension会拦截所有远程通知，需让它跳过Firebase Auth的验证码通知，交给主App处理：

• 在Extension的NotificationService.swift中，判断通知的userInfo是否包含Firebase相关字段，若是则直接调用contentHandler，不做自定义处理：

import UserNotifications

class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)
        
        // 识别Firebase Auth通知，直接转交主App
        if let userInfo = request.content.userInfo as? [String: Any], userInfo["firebase"] != nil {
            contentHandler(request.content)
            return
        }
        
        // 处理你的自定义通知逻辑（如添加附件、修改内容）
        if let bestAttemptContent = bestAttemptContent {
            contentHandler(bestAttemptContent)
        }
    }
    
    override func serviceExtensionTimeWillExpire() {
        if let contentHandler = contentHandler, let bestAttemptContent = bestAttemptContent {
            contentHandler(bestAttemptContent)
        }
    }
}

情况2：手动禁用了Swizzling #

若你在Info.plist中添加了FirebaseAppDelegateProxyEnabled并设为NO，需在主App的AppDelegate.swift中手动转发通知给Firebase Auth：

import Firebase
import FirebaseAuth

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        FirebaseApp.configure()
        return true
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        // 转发Auth通知给Firebase处理
        if Auth.auth().canHandleNotification(userInfo) {
            completionHandler(.noData)
            return
        }
        // 处理其他类型通知
        completionHandler(.noData)
    }
}

额外检查项 #

• 确保主App和Extension的Bundle ID配置正确（Extension需为主App Bundle ID加后缀，如com.yourapp.notification-service）
• 确认Apple开发者账号中已为Extension开启Push Notification权限，且APNs证书配置正确
• 更新Firebase SDK到最新版本，避免版本兼容问题

内容的提问来源于stack exchange，提问作者Thanon K