Example Code Has a Static Compilation Error

[zkjxx1548]

Background:

Flutter 2.10.5 braze_plugin 2.6.1 example code: https://github.com/braze-inc/braze-flutter-sdk/commit/5276be6c1ce7ec53219e04b4eede0f71ebed1e4f#diff-72fd825ad17ce7800a2078e06f0dff1e12836ee59760465e78d9a5d222cebd15:~:text=inAppMessage%2C%20prefix%3A%20%22STREAM%22)%3B-,return,-%3B

_braze?.subscribeToInAppMessages((BrazeInAppMessage inAppMessage) {
      return;
});

# It will throw **The return value is missing after 'return'.**

[OlegLozovyi]

contentCardsStreamSubscription = _brazePlugin.subscribeToContentCards((cards) => (){});

//for any reason =>(){} empty funcrtion or not empty works same. on event function its not called anyway by the braze.

then add a listener on subscription itself

contentCardsStreamSubscription.onData((data) {
  if(data is List<BrazeContentCard>){
    _onNewData(data);
  }
});

something like this helped me. But on IoS the subscription is not starting for some reason.

[zkjxx1548]

@OlegLozovyi Thanks for you code. @hokstuff Still hope braze flutter team will update the example code soon.

[hokstuff]

Hi @zkjxx1548,

We are unable to reproduce this issue in the sample app using both Flutter 2.10.5 and the latest Flutter version 3.3.8. Can you try to restart the analysis server and/or clear any cache for your IDE and try again? And is it accurate to say that this is just a warning and that our sample app still compiles and runs on your computer?

[zkjxx1548]

@hokstuff Thanks for reply. I download the example code and open it in my local. It really has no error.

But you can reproduce the error by this way:

1. create a new flutter repo.

2. add dependency in yaml

   dependencies:
   flutter:
   sdk: flutter
   
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^1.0.2
   braze_plugin: ^2.6.1

3. use example code in any dart file

   class _MyHomePageState extends State<MyHomePage> {
   int _counter = 0;
   
   @override
   void initState() {
   super.initState();
   
   BrazePlugin().subscribeToInAppMessages((BrazeInAppMessage inAppMessage) {
     return; // dart will return error: The return value is missing after 'return'.(dart return_without_value)
   });
   }
   }

you will see the dart error. The return value is missing after 'return'

[hokstuff]

Thanks for verifying the sample app in the codebase. It is odd that you are seeing an error in your app but not in the sample app in our Flutter codebase. The API's parameter passes in a Function type, so it's interesting that the compiler says it expects a value.

If you aren't able to find a workaround and this is blocking your development, please send an email to support@braze.com with more details on your integration to figure out what is happening in your application. Since there are no direct action items and the code in the sample application is working as expected without errors, I will close out this issue.

Thank you!

[zkjxx1548]

I am very curious whether you have seen the error report through the reproduction steps I provided.

And the listen function's parameter type is void Function(BrazeInAppMessage)?. But the type of parameter passed in by subscribeToInAppMessages is Function Function(BrazeInAppMessage)

Looking forward your reply.

[hokstuff]

Hi @zkjxx1548,

Thanks for getting back on this. We have been able to reproduce based on your steps above. If we updated the braze_plugin APIs to be the following, does that fix your issue (it follows the syntax described here from this comment):

StreamSubscription subscribeToInAppMessages(void Function(BrazeInAppMessage) onEvent) {
    // implementation code
}

StreamSubscription subscribeToContentCards(void Function(List<BrazeContentCard>) onEvent) {
    // implementation code
}

[hokstuff]

Hi @zkjxx1548,

We have released version 3.0.0 which updates the syntax for these two APIs to the proposed method signatures above.

Thanks!