[Bug]: DeviceInfoPlugin.webBrowserInfo fails locally on Safari

[sergioprot]

Platform

Web

Plugin

device_info_plus

Version

11.1.1

Flutter SDK

3.24.5

Steps to reproduce

Write a Flutter app that uses device_info_plus plugin to get web browser info.

Run web server locally on a macOS device:

flutter run -d web-server --web-hostname 0.0.0.0 --web-port 8080

Open a Flutter app on a Safari browser locally. A TypeError is thrown. The error does not occur in a --release build though.

Code Sample

import 'package:device_info_plus/device_info_plus.dart';
import 'package:flutter/material.dart';

Future<void> main() async {
  try {
    DeviceInfoPlugin deviceInfo = DeviceInfoPlugin();
    WebBrowserInfo webBrowserInfo = await deviceInfo.webBrowserInfo;
    print('Running on ${webBrowserInfo.userAgent}');
  } on TypeError catch (e, stacktrace) {
    print(e);
    print(stacktrace);
  }
  runApp(const MaterialApp(
    home: Scaffold(),
  ));
}

Logs

[Log] TypeError: null: type 'Null' is not a subtype of type 'double' (dart_sdk.js, line 38043)
[Log] dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 247:26  DartError (dart_sdk.js, line 38043)
dart-sdk/lib/_internal/js_dev_runtime/private/ddc_runtime/errors.dart 296:28  throw_
dart-sdk/lib/_internal/js_shared/lib/rti.dart 1405:3                          _failedAsCheck
dart-sdk/lib/_internal/js_shared/lib/rti.dart 1383:3                          _generalAsCheckImplementation
packages/device_info_plus/src/device_info_plus_web.dart.js 50:399             deviceInfo
packages/device_info_plus/device_info_plus.dart.js 92:146                     webBrowserInfo
dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54            runBody
dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 127:12           _async
packages/flutter_input_test/main.dart.js 262:47                               main
dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 84:54            runBody
dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 127:12           _async
lib/ui_web/ui_web/initialization.dart 41:15                                   <fn>
dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 45:50            <fn>
dart-sdk/lib/async/future_impl.dart 861:44                                    handleValueCallback
dart-sdk/lib/async/future_impl.dart 890:32                                    _propagateToListeners
dart-sdk/lib/async/future_impl.dart 666:5                                     <fn>
dart-sdk/lib/async/future_impl.dart 736:7                                     <fn>
dart-sdk/lib/async/schedule_microtask.dart 40:11                              _microtaskLoop
dart-sdk/lib/async/schedule_microtask.dart 49:5                               _startMicrotaskLoop
dart-sdk/lib/_internal/js_dev_runtime/patch/async_patch.dart 181:15           <fn>

Flutter Doctor

[✓] Flutter (Channel stable, 3.24.5, on macOS 15.1 24B83 darwin-arm64, locale en-LV)
    • Flutter version 3.24.5 on channel stable at /Users/sergey/Developer/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision dec2ee5c1f (4 weeks ago), 2024-11-13 11:13:06 -0800
    • Engine revision a18df97ca5
    • Dart version 3.5.4
    • DevTools version 2.37.3

[✓] Android toolchain - develop for Android devices (Android SDK version 33.0.1)
    • Android SDK at /Users/sergey/Library/Android/sdk
    • Platform android-34, build-tools 33.0.1
    • ANDROID_HOME = /Users/sergey/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jbr/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 17.0.11+0-17.0.11b1207.24-11852314)
    • All Android licenses accepted.

Checklist before submitting a bug

• I searched issues in this repository and couldn't find such bug/problem
• I Google'd a solution and I couldn't find it
• I searched on StackOverflow for a solution and I couldn't find it
• I read the README.md file of the plugin
• I'm using the latest version of the plugin
• All dependencies are up to date with flutter pub upgrade
• I did a flutter clean
• I tried running the example project

[miquelbeltran]

type 'Null' is not a subtype of type 'double'

It's a strange issue, the only property that is a double? is the deviceMemory which is already nullable: https://github.com/fluttercommunity/plus_plugins/blob/main/packages/device_info_plus/device_info_plus/lib/src/model/web_browser_info.dart

[davidequadrelli-b]

@miquelbeltran We are having the same issue also with Chrome sometimes. I don't know why sometimes the deviceMemory property is missing from navigator, but the problem seems to be in the web package:

https://github.com/dart-lang/web/blob/3619fd8391b32ddde18a1ca441b288ff3c39f524/web/lib/src/dom/html.dart#L12018

Here deviceMemory is defined as a double and not a double?, so when the value is missing, accessing the property throws an error. Even if the device_info_plus plugin has a nullable interface, the fact that the underlying web library is not nullable is the real problem.

We tested the following code and this could be a temporary fix for the library. With the following extension

extension SafeNavigationGetterExtensions on html.Navigator {
  double? safeDeviceMemory() {
    try {
      return deviceMemory;
    } catch (e) {
      return 0.0;
    }
  }
}

we can change the DeviceInfoPlusWebPlugin class in the device_info_plus_web.dart file to use the new safe getter:

@override
  Future<BaseDeviceInfo> deviceInfo() {
    return Future<WebBrowserInfo>.value(
      WebBrowserInfo.fromMap(
        {
          'appCodeName': _navigator.appCodeName,
          'appName': _navigator.appName,
          'appVersion': _navigator.appVersion,
          'deviceMemory': _navigator.safeDeviceMemory(),
          'language': _navigator.language,
          'languages': _navigator.languages,
          'platform': _navigator.platform,
          'product': _navigator.product,
          'productSub': _navigator.productSub,
          'userAgent': _navigator.userAgent,
          'vendor': _navigator.vendor,
          'vendorSub': _navigator.vendorSub,
          'hardwareConcurrency': _navigator.hardwareConcurrency,
          'maxTouchPoints': _navigator.maxTouchPoints,
        },
      ),
    );

This solution can be used also for fixing other fields with the same problem.

Do you think this fix can be integrated in the package?

[miquelbeltran]

Yes, thanks for researching this, feel free to submit a PR with the change