[infra] Convert this mono_repo to use pub workspaces

[dcharkes]

From Dart 3.5 on, pub supports single resolution for related packages.

• https://flutter.dev/go/pub-workspace

This would be very useful for:

• native_assets_cli
• native_assets_builder
• native_toolchain_c

We can get rid of all the path dependencies / overrides.

Also, having a single resolution ensures that package:jni for example doesn't have any dependency conflicts with package:native_assets_cli.

It might be a slight over-specification to have all packages in this repo as a single resolution, and it would mean bumping major versions needs to be done in PRs that touch all packages. But that might be a small price to pay.

We have to wait until Dart 3.5 reaches stable, the SDK constraint for the packages must be at least 3.5, and we don't want to push the packages to only work on beta/dev.

Thanks for the great work @sigurdm! ❤️

FYI @HosseinYousefi @liamappelbe @mosuem

[dcharkes]

We might also need the resolution: local feature (dart-lang/pub#4317), we have some example/test projects with a pubspec.yaml that are intentionally a different resolution:

• Flutter and non-Flutter test projects.
• Some example projects that explicitly target published older version of packages in this repo to ensure that version skew doesn't crash things.

@sigurdm What about projects that have sdk: flutter how does that relate to the requirement to have sdk: 3.5.0?

[sigurdm]

What about projects that have sdk: flutter how does that relate to the requirement to have sdk: 3.5.0?

If you have sdk:flutter you need to have a flutter sdk with a dart that includes that specific version.
(You might get away with pointing FLUTTER_ROOT to a flutter repo if you just want to resolve)

[sigurdm]

flutter commands (flutter_tools) still don't support workspaces. We'll have to wait for flutter/flutter#150196