Make pub aware of used platforms

[wujek-srujek]

I'm writing a mobile app with Flutter and I'm using packages (wakelock and package_info_plus) that in their most recent versions have a conflict in their win32 dependency. For this reason, my project fails to resolve dependencies, even though I don't care about Windows at all (this is a fact and won't change, the app makes no sense on the desktop).

Pub could know about the platforms my project supports (I specify them when I create a new project with flutter create --platforms ...) and then it could decide to not report error conditions for irrelevant ones.

[sigurdm]

There was a push once to base resolution on "features" that could be enabled/disabled, but we have left that behind.
The main reasons:

• Added complexity
  While there might be a few times like this where a platform-specific dependency would save the day,
  it comes at the cost of a cognitive overhead of enabling/disabling features, and also the implementation
  cost in the pub client.
• Doesn't work well with the language
  Currently Dart has only very limited support for compile-time conditional inclusion. There are conditional imports, but they only condition on library-availability (web vs. non-web).
• Usually it helps everybody more if there is a bigger push to keep packages compatible and up-to-date.

Hopefully the packages in question will soon be updated to be compatible, or you can try to use a dependency_overrides to force a version.

[sigurdm]

Will close this for now, as I don't think we currently have any plans to support this.