Flutter应用Firebase创建用户时Firestore未写入的类型转换问题

问题现象 #

使用Firebase创建用户时，Firebase认证已成功生成用户，但用户数据未写入Firestore，同时控制台抛出类型转换错误。

错误日志 #

W/System ( 9991): Ignoring header X-Firebase-Locale because its value was null.
W/System ( 9991): Ignoring header X-Firebase-Locale because its value was null.
I/tergooglesigni( 9991): Background concurrent copying GC freed 63914(2787KB) AllocSpace objects, 9(308KB) LOS objects, 49% free, 3305KB/6611KB, paused 965us total 100.504ms
D/FirebaseAuth( 9991): Notifying id token listeners about user ( WsAb4Bc7dEgbw3FQdmsRQZbWMQZ2 ).
D/FirebaseAuth( 9991): Notifying auth state listeners about user ( WsAb4Bc7dEgbw3FQdmsRQZbWMQZ2 ).
I/flutter ( 9991): Error occurred: Error: type 'List<Object?>' is not a subtype of type 'PigeonUserDetails?' in type cast
I/flutter ( 9991): <<<-----------------------------------------------: Error: type 'List<Object?>' is not a subtype of type 'PigeonUserDetails?' in type cast--------------------------------------------->>>
F/crash_dump32(13059): crash_dump.cpp:474] failed to attach to thread 180: Permission denied
I/tergooglesigni( 9991): Thread[6,tid=10003,WaitingInMainSignalCatcherLoop,Thread*=0x9b400e10,peer=0xa06401e8,"Signal Catcher"]: reacting to signal 3
I/tergooglesigni( 9991):
I/libc ( 9991): Requested dump for tid 9991 (tergooglesignin)
I/tergooglesigni( 9991): Wrote stack traces to tombstoned

相关代码（authentication.dart） #

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';

class AuthServices {
  final FirebaseFirestore _firestore = FirebaseFirestore.instance;
  final FirebaseAuth _firebaseAuth = FirebaseAuth.instance;

  Future<String> signupUser({
    required String name,
    required String email,
    required String password,
  }) async {
    if (name.isEmpty || email.isEmpty || password.isEmpty) {
      return "Error: Invalid input parameters";
    }

    String res = "An error occurred"; // Default error message

    try {
      // Create a new user with email and password
      UserCredential userCredential = await _firebaseAuth
          .createUserWithEmailAndPassword(email: email, password: password);

      if (userCredential.user != null) {
        String uid = userCredential.user!.uid;
        print("User ID: $uid");

        // Add user details to Firestore under 'users' collection
        await _firestore.collection("users").doc(uid).set({
          'name': name,
          'email': email,
          'uid': uid,
        });

        print("Successfully added to Firestore");
        res = "Successfully executed";
      } else {
        res = "User creation failed: user is null";
        print("Error: User creation failed");
      }
    } catch (e) {
      // Log detailed error message
      res = "Error: ${e.toString()}";
      print("Error occurred: $res");
    }

    print("<<<-----------------------------------------------: $res--------------------------------------------->>>");
    return res;
  }
}

解决方案 #

• 核心原因：错误'List<Object?>' is not a subtype of type 'PigeonUserDetails?'由Firebase依赖版本不兼容导致，Pigeon是Firebase内部跨平台通信工具，版本冲突会引发类型转换异常。

1. 更新Firebase依赖到兼容版本
   在pubspec.yaml中，将所有Firebase相关依赖更新至最新稳定版，示例如下：

   firebase_core: ^2.24.2
   firebase_auth: ^4.16.0
   cloud_firestore: ^4.15.0
   

2. 清理缓存并重新获取依赖
   执行以下命令清除旧缓存，重新下载依赖：

   flutter clean
   flutter pub get
   

3. 验证Firestore安全规则
   确保Firestore允许认证用户创建自己的文档，测试阶段可临时使用以下规则：

   rules_version = '2';
   service cloud.firestore {
     match /databases/{database}/documents {
       match /users/{userId} {
         allow create: if request.auth != null && request.auth.uid == userId;
       }
     }
   }
   

4. 添加Firestore写入单独异常捕获
   修改代码中写入Firestore的部分，单独捕获异常，明确是否在写入环节出现问题：

   if (userCredential.user != null) {
     String uid = userCredential.user!.uid;
     print("User ID: $uid");
   
     // Add user details to Firestore under 'users' collection
     try {
       await _firestore.collection("users").doc(uid).set({
         'name': name,
         'email': email,
         'uid': uid,
       });
       print("Successfully added to Firestore");
       res = "Successfully executed";
     } catch (firestoreError) {
       print("Firestore写入错误: ${firestoreError.toString()}");
       res = "Firestore写入失败: ${firestoreError.toString()}";
     }
   }
   

内容的提问来源于stack exchange，提问作者Vamsi Krishna Peruri