Unexpected Behaviour on passing empty list as paramters

[ansh-kaushik]

Can we access your project?

• I give permission for members of the FlutterFlow team to access and test my project for the sole purpose of investigating this issue.

Current Behavior

See, i have 2 pages , dashboard page , and a statement page ,
on dashboard i click on icon button -> do action(with output from supabase) if it returns an empty array
and then i pass that array as paramter to the next page it crashes ,

Expected Behavior

I dug deep into code and found out , the serialization of paramters is the problem ,

FF serialize parameters before navigating to next page but if a paramter is empty it returns null like serializeParam([]) = NULL which idk is expected or what but here it breaks two things 1) initilization of the next page state variables 2)If there is any loop on that parameter on that next page it breaks (error: unepxected null value ) cause it expects an empty to some size array which should be there but not its null so the loop actions break, whiout any problem

Steps to Reproduce

0))connect to supabase and a simple table (like todo/messages)
1)Create two pages
2) on first add a button -> add action (on tap) -> query rows(query as such there is empty array, like willingly make it empty )
3) on 2nd page add the paramter of that type suapbase table (as LIST) and let's say iterate a for loop on that page (loop actions (all default) ) for anything(render/assign/etc)
4) notice it will give error if list is empty

Note: U can verify in Debugger in local run , before naivagating and having a watch on variables(parameter one)

Reproducible from Blank

• The steps to reproduce above start from a blank project.

Bug Report Code (Required)

IT40iMjfsI52ocMA+KrpbfpR/SQ5JkAjR5IZjsBraCwqGJToPLUMPsneVFRuZr2lYXx9MWCKkTo0xvfqjvOWG/FcPUmbbKI9/7lUdg7jVkSmMISnCpGNfW1RL8JXfky5yraOnhNSGNVvLy0W7GC1fu+UfB7bK7rxIW0vLfK1KdeK2SrDX1iXc2URm05KZDPz

Visual documentation

Environment

- FlutterFlow version: Latest
- Platform:Android
- Browser name and version:Chrome Latest
- Operating system and version affected:Windows 11

Additional Information

No response

[ansh-kaushik]

To Help you out ( LOL i dig deep into more not to show but i have to)
it serializes the empty array correctly to "[ ]" as in our code

String? serializeParam(
  dynamic param,
  ParamType paramType, {
  bool isList = false,
}) {
  try {
    if (param == null) {
      return null;
    }
    if (isList) {
      final serializedValues = (param as Iterable)
          .map((p) => serializeParam(p, paramType, isList: false))
          .where((p) => p != null)
          .map((p) => p!)
          .toList();
      return json.encode(serializedValues);
    }
    String? data;
    switch (paramType) {
      case ParamType.int:
        data = param.toString();
      case ParamType.double:
        data = param.toString();
      case ParamType.String:
        data = param;
      case ParamType.bool:
        data = param ? 'true' : 'false';
      case ParamType.DateTime:
        data = (param as DateTime).millisecondsSinceEpoch.toString();
      case ParamType.DateTimeRange:
        data = dateTimeRangeToString(param as DateTimeRange);
      case ParamType.LatLng:
        data = (param as LatLng).serialize();
      case ParamType.Color:
        data = (param as Color).toCssString();
      case ParamType.FFPlace:
        data = placeToString(param as FFPlace);
      case ParamType.FFUploadedFile:
        data = uploadedFileToString(param as FFUploadedFile);
      case ParamType.JSON:
        data = json.encode(param);

      case ParamType.DataStruct:
        data = param is BaseStruct ? param.serialize() : null;

      case ParamType.SupabaseRow:
        return json.encode((param as SupabaseDataRow).data);

      default:
        data = null;
    }
    return data;
  } catch (e) {
    print('Error serializing parameter: $e');
    return null;
  }
}

But on Next page(2nd page )when we deserailzie it
via ur code (the deserialize function on serailiaztion.utl.dart) ( iwll not show whole code cuz it has types for my data)
it deserealize it to null
hint : 👍

[Alezanello]

Hello! 👋

While we’re checking on this, you can add a condition before opening the statement page. Based on the number of entries returned from the Supabase query:

• If the number of items is 0, send null.
• Otherwise, send the list.

This way, when the page opens, it can decide whether to trigger certain actions based on that parameter. This approach not only helps resolve the serialization issue but also prevents potential crashes by improving null safety throughout the app.

Additionally, there are other ways to prevent crashes — for example, by adding extra validation checks or safety conditions throughout your logic.