Meta issue for platforms specific tooling

[leafpetersen]

This is the language meta issue tracking tooling support for platform specific compilation and analysis.

See #32960 for the background discussion.

Tracking issues:

• DDK entry in libraries.json: Add DDK entry to libraries.json #33198
• Codegen support: Discussion: Dart Codegen and Platforms build#1436
• Build support: Multi-platform support - with config specific imports build#1430
• Analyzer support: Analyzer: support platform specific analysis #33346

[natebosch]

Do we have an issue to specify the new format for config specific imports where only dart.library.* conditions are supported?

[jakemac53]

@leafpetersen can you add an action item as @natebosch mentioned for fully specifying exactly what the syntax is and exactly what identifiers are supported? Is it all libraries present in libraries.json? If so then we also need flutter to ship with a valid libraries.json file and in a consistent place with the regular dart sdk.

For reference package:build just has a hardcoded notion of what is supported right now, which is derived from libraries.json and we made a best guess for flutter. Something more explicit would be great though, and the more restricted the set the better probably (but I mostly just care that it is explicit and documented).

[natebosch]

In #34262 (comment) @lrhn indicates that the spec should not constrain it even if the tools do.

I think on another issue @matanlurey mentioned that if we're taking this approach we should consider adding a "tool spec" that indicates the subset of the language that the published SDK ships.

[matanlurey]

+1 on tool specification. If say, Fuischa, wants to ship their own compiler that supports arbitrary conditional imports, go for it - but we should be clear the tools we provide (including the analyzer) do not.

[leafpetersen]

Is a "tool spec" different from documentation?

What remains in question about the syntax?

[natebosch]

Is a "tool spec" different from documentation?

It would be centralized.

[Levi-Lesches]

Hi -- what about dartdoc support? I recently found myself having to flip between misleading documentation and the corresponding files on github. Should I open an issue there? Judging by dart-lang/dartdoc#1980, it didn't seem like they have any plans to implement it.