web: PlatformException(error, type 'Null' is not a 'bool' ...

[MarcVanDaele90]

When running ClientInformation.fetch() in flutter web (on Linux) I get

Error: PlatformException(error, type 'Null' is not a 'bool' in boolean expression, null, null)
    at Object.throw_ [as throw] (http://localhost:41583/dart_sdk.js:5067:11)
    at StandardMethodCodec.decodeEnvelope (http://localhost:41583/packages/flutter/src/services/restoration.dart.lib.js:2359:19)
    at MethodChannel._invokeMethod (http://localhost:41583/packages/flutter/src/services/restoration.dart.lib.js:1562:47)
    at _invokeMethod.next (<anonymous>)

Please let me know if I can help in debugging somehow.

[Kent1011]

Can you provide your flutter environment information by running flutter doctor -v.

And if possible, you can paste your code snippet to help me figure out the problem. :)

[MarcVanDaele90]

Thank for looking into this!

output of flutter doctor -v

[✓] Flutter (Channel stable, 2.10.3, on Linux Mint 20.2 5.11.0-43-generic, locale en_US.UTF-8)
    • Flutter version 2.10.3 at /home/marc/snap/flutter/common/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 7e9793dee1 (3 weeks ago), 2022-03-02 11:23:12 -0600
    • Engine revision bd539267b4
    • Dart version 2.16.1
    • DevTools version 2.9.2

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
    • Android SDK at /home/marc/Android/Sdk
    • Platform android-31, build-tools 31.0.0
    • Java binary at: /home/marc/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7249189)
    • All Android licenses accepted.

[✓] Chrome - develop for the web
    • Chrome at google-chrome

[✓] Linux toolchain - develop for Linux desktop
    • clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
    • cmake version 3.10.2
    • ninja version 1.8.2
    • pkg-config version 0.29.1

[✓] Android Studio (version 2020.3)
    • Android Studio at /home/marc/android-studio
    • Flutter plugin version 59.0.2
    • Dart plugin version 203.8292
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7249189)

[✓] VS Code (version 1.65.1)
    • VS Code at /usr/share/code
    • Flutter extension can be installed from:
      🔨 https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[✓] Connected device (2 available)
    • Linux (desktop) • linux  • linux-x64      • Linux Mint 20.2 5.11.0-43-generic
    • Chrome (web)    • chrome • web-javascript • Google Chrome 99.0.4844.51

[✓] HTTP Host Availability
    • All required HTTP hosts are available

• No issues found!

I just use a default/initial Flutter application where I add a call to test() inside _MyHomePageState.build() where test() is

  void test() async {
    // Get client information
    print(">>>test");
    ClientInformation info = await ClientInformation.fetch();

    print(info.deviceId); // EA625164-4XXX-XXXX-XXXXXXXXXXXX
    print(info.osName); // iOS
    print("<<<test");

  }

The stacktrace is

Error: PlatformException(error, type 'Null' is not a 'bool' in boolean expression, null, null)
    at Object.throw_ [as throw] (http://localhost:37601/dart_sdk.js:5067:11)
    at StandardMethodCodec.decodeEnvelope (http://localhost:37601/packages/flutter/src/services/restoration.dart.lib.js:2359:19)
    at MethodChannel._invokeMethod (http://localhost:37601/packages/flutter/src/services/restoration.dart.lib.js:1562:47)
    at _invokeMethod.next (<anonymous>)
    at http://localhost:37601/dart_sdk.js:40571:33
    at _RootZone.runUnary (http://localhost:37601/dart_sdk.js:40441:59)
    at _FutureListener.thenAwait.handleValue (http://localhost:37601/dart_sdk.js:35363:29)
    at handleValueCallback (http://localhost:37601/dart_sdk.js:35931:49)
    at Function._propagateToListeners (http://localhost:37601/dart_sdk.js:35969:17)
    at _Future.new.[_completeWithValue] (http://localhost:37601/dart_sdk.js:35817:23)
    at async._AsyncCallbackEntry.new.callback (http://localhost:37601/dart_sdk.js:35838:35)
    at Object._microtaskLoop (http://localhost:37601/dart_sdk.js:40708:13)
    at _startMicrotaskLoop (http://localhost:37601/dart_sdk.js:40714:13)
    at http://localhost:37601/dart_sdk.js:36191:9

[Kent1011]

I can't reproduce it. ;(

Could you try to run the package's example project? And tell me the result?

[MarcVanDaele90]

It's a pity that you can't reproduce the issue.

The example project prints (I've added a catch to the on PlatformException to print the actual exception) "Failed to get client information PlatformException(error, Failed assertion: boolean expression must not be null, null, null)"

So apparently, it is somehow related to my environment

[MarcVanDaele90]

I was able to fix it: in _Software _getOS you use '!osName' construct. I've replaced it with 'osName==null' and now it seems to work fine. When I code something like this (negation operator on an object), I get an error in my Dart Analysis tab of Android Studio.

see also https://dart.dev/tools/diagnostic-messages#non_bool_negation_expression

[NavidHosseini]

same issue

[fsvaren]

I am really just a newbie when it comes to Dart, but I fixed the problem locally with this change, seems to work in Linux and Flutter-Web. https://github.com/Kent1011/client_information/pull/8

(I have only tested it on Linux, that's all I have access to this week)