remove dart:io import and use UniversalPlatform

[stefanschaller]

Fix #550

Please add the following to the pubspec.yaml to test it in other projects:

dependencies: 
  # vector map
  maplibre_gl:
    git:
      url: https://github.com/maplibre/flutter-maplibre-gl.git
      ref: 550-bug-unsupported-operation-platform_operatingsystem
      path: maplibre_gl

dependency_overrides:
  maplibre_gl_platform_interface:
    git:
      url: https://github.com/maplibre/flutter-maplibre-gl.git
      ref: 550-bug-unsupported-operation-platform_operatingsystem
      path: maplibre_gl_platform_interface

[albertmoravec]

I get that dart:io sucks, but please consider if it is necessary to import new package for a single if-statement where kIsWeb check would be enough. If it is planned to be used further then of course it's not an issue.

For end users though this would add an additional version constraint on universal_platform and prevent them from upgrading to newer major version in the future unless Flutter MapLibre GL upgrades as well.

[kuhnroyal]

@stefanschaller Thanks! Can you please use https://pub.dev/packages/platform instead.

[stefanschaller]

@kuhnroyal I changed the dependency to platform, but I'm unsure about the goal since https://pub.dev/packages/platform is still importing dart:io; It's not working again in web with the latest commit.

@albertmoravec What would you recommend to do? We could also copy past some code to avoid dependencies, but I'm not a huge fan.
We could also use a wide range of versions like: universal_platform: ">=1.0.0 <2.0.0"

[kuhnroyal]

Yea, sorry, I thought the platform package supports web...

Since the interface package already relies on Flutter, we can use kIsWeb (thanks @albertmoravec).
I added a test and CI test jobs.

[Live4win]

I could be wrong, but it seems that the 'Unsupported operation' error still persists even with the latest commits. Can anyone confirm?

[stefanschaller]

@kuhnroyal We are still using the io import, which is not working for web!

[kuhnroyal]

No, this is compiled out for web as the kIsWeb is a compiler-constant.
The test is running successfully on Chrome.

[kuhnroyal]

See https://github.com/maplibre/flutter-maplibre-gl/actions/runs/14168733155/job/39687603749?pr=551#step:5:19

[kuhnroyal]

Just the occurrence of the dart:io import does not prevent it from working on web, only if the dart:io code is called during runtime.

As you can see here, the example uses dart:io in its main.dart file:
https://github.com/maplibre/flutter-maplibre-gl/blob/main/maplibre_gl_example/lib/main.dart#L5